Bot-S: The Complete Works of Aristotle

If that which it is true to affirm
is nothing other than that which it is false to deny, it is impossible that all statements should be false; for one
side of the contradiction must be true. Again, if it is necessary with regard to everything either to assert or to
deny it, it is impossible that both should be false; for it is one side of the contradiction that is false.-Therefore
all such views are also exposed to the often expressed objection, that they destroy themselves. For he who
says that everything is true makes even the statement contrary to his own true, and therefore his own not true
(for the contrary statement denies that it is true), while he who says everything is false makes himself also
false.-And if the former person excepts the contrary statement, saying it alone is not true, while the latter
excepts his own as being not false, none the less they are driven to postulate the truth or falsity of an infinite
number of statements; for that which says the true statement is true is true, and this process will go on to
infinity.

Evidently, again, those who say all things are at rest are not right, nor are those who say all things are in
movement. For if all things are at rest, the same statements will always be true and the same always

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false,-but this obviously changes; for he who makes a statement, himself at one time was not and again will
not be. And if all things are in motion, nothing will be true; everything therefore will be false. But it has been
shown that this is impossible. Again, it must be that which is that changes; for change is from something to
something. But again it is not the case that all things are at rest or in motion sometimes, and nothing for ever;
for there is something which always moves the things that are in motion, and the first mover is itself
unmoved.

BookV

'BEGINNING' means (1) that part of a thing from which one would start first, e.g a line or a road has a
beginning in either of the contrary directions. (2) That from which each thing would best be originated, e.g.
even in learning we must sometimes begin not from the first point and the beginning of the subject, but from
the point from which we should learn most easily. (4) That from which, as an immanent part, a thing first
comes to be, e,g, as the keel of a ship and the foundation of a house, while in animals some suppose the heart,
others the brain, others some other part, to be of this nature. (4) That from which, not as an immanent part, a
thing first comes to be, and from which the movement or the change naturally first begins, as a child comes
from its father and its mother, and a fight from abusive language. (5) That at whose will that which is moved
is moved and that which changes changes, e.g. the magistracies in cities, and oligarchies and monarchies and
tyrannies, are called arhchai, and so are the arts, and of these especially the architectonic arts. (6) That from
which a thing can first be known,-this also is called the beginning of the thing, e.g. the hypotheses are the
beginnings of demonstrations. (Causes are spoken of in an equal number of senses; for all causes are
beginnings.) It is common, then, to all beginnings to be the first point from which a thing either is or comes to
be or is known; but of these some are immanent in the thing and others are outside. Hence the nature of a
thing is a beginning, and so is the element of a thing, and thought and will, and essence, and the final
cause-for the good and the beautiful are the beginning both of the knowledge and of the movement of many
things.

'Cause' means (1) that from which, as immanent material, a thing comes into being, e.g. the bronze is the
cause of the statue and the silver of the saucer, and so are the classes which include these. (2) The form or
pattern, i.e. the definition of the essence, and the classes which include this (e.g. the ratio 2:1 and number in
general are causes of the octave), and the parts included in the definition. (3) That from which the change or
the resting from change first begins; e.g. the adviser is a cause of the action, and the father a cause of the
child, and in general the maker a cause of the thing made and the change-producing of the changing. (4) The
end, i.e. that for the sake of which a thing is; e.g. health is the cause of walking. For 'Why does one walk?' we
say; 'that one may be healthy'; and in speaking thus we think we have given the cause. The same is true of all
the means that intervene before the end, when something else has put the process in motion, as e.g. thinning
or purging or drugs or instruments intervene before health is reached; for all these are for the sake of the end,
though they differ from one another in that some are instruments and others are actions.

These, then, are practically all the senses in which causes are spoken of, and as they are spoken of in several
senses it follows both that there are several causes of the same thing, and in no accidental sense (e.g. both the
art of sculpture and the bronze are causes of the statue not in respect of anything else but qua statue; not,
however, in the same way, but the one as matter and the other as source of the movement), and that things
can be causes of one another (e.g. exercise of good condition, and the latter of exercise; not, however, in the
same way, but the one as end and the other as source of movement). -Again, the same thing is the cause of
contraries; for that which when present causes a particular thing, we sometimes charge, when absent, with the
contrary, e.g. we impute the shipwreck to the absence of the steersman, whose presence was the cause of
safety; and both-the presence and the privation-are causes as sources of movement.

All the causes now mentioned fall under four senses which are the most obvious. For the letters are the cause
of syllables, and the material is the cause of manufactured things, and fire and earth and all such things are

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the causes of bodies, and the parts are causes of the whole, and the hypotheses are causes of the conclusion,
in the sense that they are that out of which these respectively are made; but of these some are cause as the
substratum (e.g. the parts), others as the essence (the whole, the synthesis, and the form). The semen, the
physician, the adviser, and in general the agent, are all sources of change or of rest. The remainder are causes
as the end and the good of the other things; for that for the sake of which other things are tends to be the best
and the end of the other things; let us take it as making no difference whether we call it good or apparent
good.

These, then, are the causes, and this is the number of their kinds, but the varieties of causes are many in
number, though when summarized these also are comparatively few. Causes are spoken of in many senses,
and even of those which are of the same kind some are causes in a prior and others in a posterior sense, e.g.
both 'the physician' and 'the professional man' are causes of health, and both 'the ratio 2:1' and 'number' are
causes of the octave, and the classes that include any particular cause are always causes of the particular
effect. Again, there are accidental causes and the classes which include these; e.g. while in one sense 'the
sculptor' causes the statue, in another sense 'Polyclitus' causes it, because the sculptor happens to be
Polyclitus; and the classes that include the accidental cause are also causes, e.g. 'man'-or in general
'animal'-is the cause of the statue, because Polyclitus is a man, and man is an animal. Of accidental causes
also some are more remote or nearer than others, as, for instance, if 'the white' and 'the musical' were called
causes of the statue, and not only 'Polyclitus' or 'man'. But besides all these varieties of causes, whether
proper or accidental, some are called causes as being able to act, others as acting; e.g. the cause of the house's
being built is a builder, or a builder who is building.-The same variety of language will be found with regard
to the effects of causes; e.g. a thing may be called the cause of this statue or of a statue or in general of an
image, and of this bronze or of bronze or of matter in general; and similarly in the case of accidental effects.
Again, both accidental and proper causes may be spoken of in combination; e.g. we may say not 'Polyclitus'
nor 'the sculptor' but 'Polyclitus the sculptor'. Yet all these are but six in number, while each is spoken of in
two ways; for (A) they are causes either as the individual, or as the genus, or as the accidental, or as the genus
that includes the accidental, and these either as combined, or as taken simply; and (B) all may be taken as
acting or as having a capacity. But they differ inasmuch as the acting causes, i.e. the individuals, exist, or do
not exist, simultaneously with the things of which they are causes, e.g. this particular man who is healing,
with this particular man who is recovering health, and this particular builder with this particular thing that is
being built; but the potential causes are not always in this case; for the house does not perish at the same time
as the builder.

'Element' means (1) the primary component immanent in a thing, and indivisible in kind into other kinds; e.g.
the elements of speech are the parts of which speech consists and into which it is ultimately divided, while
they are no longer divided into other forms of speech different in kind from them. If they are divided, their
parts are of the same kind, as a part of water is water (while a part of the syllable is not a syllable). Similarly
those who speak of the elements of bodies mean the things into which bodies are ultimately divided, while
they are no longer divided into other things differing in kind; and whether the things of this sort are one or
more, they call these elements. The so-called elements of geometrical proofs, and in general the elements of
demonstrations, have a similar character; for the primary demonstrations, each of which is implied in many
demonstrations, are called elements of demonstrations; and the primary syllogisms, which have three terms
and proceed by means of one middle, are of this nature.

(2) People also transfer the word 'element' from this meaning and apply it to that which, being one and small,
is useful for many purposes; for which reason what is small and simple and indivisible is called an element.
Hence come the facts that the most universal things are elements (because each of them being one and simple
is present in a plurality of things, either in all or in as many as possible), and that unity and the point are
thought by some to be first principles. Now, since the so-called genera are universal and indivisible (for there
is no definition of them), some say the genera are elements, and more so than the differentia, because the
genus is more universal; for where the differentia is present, the genus accompanies it, but where the genus is

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present, the differentia is not always so. It is common to all the meanings that the element of each thing is the
first component immanent in each.

'Nature' means (1) the genesis of growing things-the meaning which would be suggested if one were to
pronounce the 'u' in phusis long. (2) That immanent part of a growing thing, from which its growth first
proceeds. (3) The source from which the primary movement in each natural object is present in it in virtue of
its own essence. Those things are said to grow which derive increase from something else by contact and
either by organic unity, or by organic adhesion as in the case of embryos. Organic unity differs from contact;
for in the latter case there need not be anything besides the contact, but in organic unities there is something
identical in both parts, which makes them grow together instead of merely touching, and be one in respect of
continuity and quantity, though not of quality.-(4) 'Nature' means the primary material of which any natural
object consists or out of which it is made, which is relatively unshaped and cannot be changed from its own
potency, as e.g. bronze is said to be the nature of a statue and of bronze utensils, and wood the nature of
wooden things; and so in all other cases; for when a product is made out of these materials, the first matter is
preserved throughout. For it is in this way that people call the elements of natural objects also their nature,
some naming fire, others earth, others air, others water, others something else of the sort, and some naming
more than one of these, and others all of them.-(5) 'Nature' means the essence of natural objects, as with
those who say the nature is the primary mode of composition, or as Empedocles says:-

Nothing that is has a nature,
But only mixing and parting of the mixed,
And nature is but a name given them by men.

Hence as regards the things that are or come to be by nature, though that from which they naturally come to
be or are is already present, we say they have not their nature yet, unless they have their form or shape. That
which comprises both of these exists by nature, e.g. the animals and their parts; and not only is the first
matter nature (and this in two senses, either the first, counting from the thing, or the first in general; e.g. in
the case of works in bronze, bronze is first with reference to them, but in general perhaps water is first, if all
things that can be melted are water), but also the form or essence, which is the end of the process of
becoming. -(6) By an extension of meaning from this sense of 'nature' every essence in general has come to
be called a 'nature', because the nature of a thing is one kind of essence.

From what has been said, then, it is plain that nature in the primary and strict sense is the essence of things
which have in themselves, as such, a source of movement; for the matter is called the nature because it is
qualified to receive this, and processes of becoming and growing are called nature because they are
movements proceeding from this. And nature in this sense is the source of the movement of natural objects,
being present in them somehow, either potentially or in complete reality.

We call 'necessary' (1) (a) that without which, as a condition, a thing cannot live; e.g. breathing and food are
necessary for an animal; for it is incapable of existing without these; (b) the conditions without which good
cannot be or come to be, or without which we cannot get rid or be freed of evil; e.g. drinking the medicine is
necessary in order that we may be cured of disease, and a man's sailing to Aegina is necessary in order that he
may get his money. -(2) The compulsory and compulsion, i.e. that which impedes and tends to hinder,
contrary to impulse and purpose. For the compulsory is called necessary (whence the necessary is painful, as
Evenus says: 'For every necessary thing is ever irksome'), and compulsion is a form of necessity, as
Sophocles says: 'But force necessitates me to this act'. And necessity is held to be something that cannot be
persuaded-and rightly, for it is contrary to the movement which accords with purpose and with
reasoning.-(3) We say that that which cannot be otherwise is necessarily as it is. And from this sense of
'necessary' all the others are somehow derived; for a thing is said to do or suffer what is necessary in the
sense of compulsory, only when it cannot act according to its impulse because of the compelling
forces-which implies that necessity is that because of which a thing cannot be otherwise; and similarly as

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regards the conditions of life and of good; for when in the one case good, in the other life and being, are not
possible without certain conditions, these are necessary, and this kind of cause is a sort of necessity. Again,
demonstration is a necessary thing because the conclusion cannot be otherwise, if there has been
demonstration in the unqualified sense; and the causes of this necessity are the first premisses, i.e. the fact
that the propositions from which the syllogism proceeds cannot be otherwise.

Now some things owe their necessity to something other than themselves; others do not, but are themselves
the source of necessity in other things. Therefore the necessary in the primary and strict sense is the simple;
for this does not admit of more states than one, so that it cannot even be in one state and also in another; for if
it did it would already be in more than one. If, then, there are any things that are eternal and unmovable,
nothing compulsory or against their nature attaches to them.

'One' means (1) that which is one by accident, (2) that which is one by its own nature. (1) Instances of the
accidentally one are 'Coriscus and what is musical', and 'musical Coriscus' (for it is the same thing to say
'Coriscus and what is musical', and 'musical Coriscus'), and 'what is musical and what is just', and 'musical
Coriscus and just Coriscus'. For all of these are called one by virtue of an accident, 'what is just and what is
musical' because they are accidents of one substance, 'what is musical and Coriscus' because the one is an
accident of the other; and similarly in a sense 'musical Coriscus' is one with 'Coriscus' because one of the
parts of the phrase is an accident of the other, i.e. 'musical' is an accident of Coriscus; and 'musical Coriscus'
is one with just Coriscus' because one part of each is an accident of one and the same subject. The case is
similar if the accident is predicated of a genus or of any universal name, e.g. if one says that man is the same
as 'musical man'; for this is either because 'musical' is an accident of man, which is one substance, or because
both are accidents of some individual, e.g. Coriscus. Both, however, do not belong to him in the same way,
but one presumably as genus and included in his substance, the other as a state or affection of the substance.

The things, then, that are called one in virtue of an accident, are called so in this way. (2) Of things that are
called one in virtue of their own nature some (a) are so called because they are continuous, e.g. a bundle is
made one by a band, and pieces of wood are made one by glue; and a line, even if it is bent, is called one if it
is continuous, as each part of the body is, e.g. the leg or the arm. Of these themselves, the continuous by
nature are more one than the continuous by art. A thing is called continuous which has by its own nature one
movement and cannot have any other; and the movement is one when it is indivisible, and it is indivisible in
respect of time. Those things are continuous by their own nature which are one not merely by contact; for if
you put pieces of wood touching one another, you will not say these are one piece of wood or one body or
one continuum of any other sort. Things, then, that are continuous in any way called one, even if they admit
of being bent, and still more those which cannot be bent; e.g. the shin or the thigh is more one than the leg,
because the movement of the leg need not be one. And the straight line is more one than the bent; but that
which is bent and has an angle we call both one and not one, because its movement may be either
simultaneous or not simultaneous; but that of the straight line is always simultaneous, and no part of it which
has magnitude rests while another moves, as in the bent line.

(b)(i) Things are called one in another sense because their substratum does not differ in kind; it does not
differ in the case of things whose kind is indivisible to sense. The substratum meant is either the nearest to, or
the farthest from, the final state. For, one the one hand, wine is said to be one and water is said to be one, qua
indivisible in kind; and, on the other hand, all juices, e.g. oil and wine, are said to be one, and so are all things
that can be melted, because the ultimate substratum of all is the same; for all of these are water or air.

(ii) Those things also are called one whose genus is one though distinguished by opposite differentiae-these
too are all called one because the genus which underlies the differentiae is one (e.g. horse, man, and dog form
a unity, because all are animals), and indeed in a way similar to that in which the matter is one. These are
sometimes called one in this way, but sometimes it is the higher genus that is said to be the same (if they are
infimae species of their genus)-the genus above the proximate genera; e.g. the isosceles and the equilateral

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are one and the same figure because both are triangles; but they are not the same triangles.

(c) Two things are called one, when the definition which states the essence of one is indivisible from another
definition which shows us the other (though in itself every definition is divisible). Thus even that which has
increased or is diminishing is one, because its definition is one, as, in the case of plane figures, is the
definition of their form. In general those things the thought of whose essence is indivisible, and cannot
separate them either in time or in place or in definition, are most of all one, and of these especially those
which are substances. For in general those things that do not admit of division are called one in so far as they
do not admit of it; e.g. if two things are indistinguishable qua man, they are one kind of man; if qua animal,
one kind of animal; if qua magnitude, one kind of magnitude.-Now most things are called one because they
either do or have or suffer or are related to something else that is one, but the things that are primarily called
one are those whose substance is one,-and one either in continuity or in form or in definition; for we count as
more than one either things that are not continuous, or those whose form is not one, or those whose definition
is not one.

While in a sense we call anything one if it is a quantity and continuous, in a sense we do not unless it is a
whole, i.e. unless it has unity of form; e.g. if we saw the parts of a shoe put together anyhow we should not
call them one all the same (unless because of their continuity); we do this only if they are put together so as to
be a shoe and to have already a certain single form. This is why the circle is of all lines most truly one,
because it is whole and complete.

(3) The essence of what is one is to be some kind of beginning of number; for the first measure is the
beginning, since that by which we first know each class is the first measure of the class; the one, then, is the
beginning of the knowable regarding each class. But the one is not the same in all classes. For here it is a
quarter-tone, and there it is the vowel or the consonant; and there is another unit of weight and another of
movement. But everywhere the one is indivisible either in quantity or in kind. Now that which is indivisible
in quantity is called a unit if it is not divisible in any dimension and is without position, a point if it is not
divisible in any dimension and has position, a line if it is divisible in one dimension, a plane if in two, a body
if divisible in quantity in all — i.e. in three — dimensions. And, reversing the order, that which is divisible in
two dimensions is a plane, that which is divisible in one a line, that which is in no way divisible in quantity is
a point or a unit,-that which has not position a unit, that which has position a point.

Again, some things are one in number, others in species, others in genus, others by analogy; in number those
whose matter is one, in species those whose definition is one, in genus those to which the same figure of
predication applies, by analogy those which are related as a third thing is to a fourth. The latter kinds of unity
are always found when the former are; e.g. things that are one in number are also one in species, while things
that are one in species are not all one in number; but things that are one in species are all one in genus, while
things that are so in genus are not all one in species but are all one by analogy; while things that are one by
analogy are not all one in genus.

Evidently 'many' will have meanings opposite to those of 'one'; some things are many because they are not
continuous, others because their matter-either the proximate matter or the ultimate-is divisible in kind,
others because the definitions which state their essence are more than one.

Things are said to 'be' (1) in an accidental sense, (2) by their own nature.

(1) In an accidental sense, e.g. we say 'the righteous doer is musical', and 'the man is musical', and 'the
musician is a man', just as we say 'the musician builds', because the builder happens to be musical or the
musician to be a builder; for here 'one thing is another' means 'one is an accident of another'. So in the cases
we have mentioned; for when we say 'the man is musical' and 'the musician is a man', or 'he who is pale is
musical' or 'the musician is pale', the last two mean that both attributes are accidents of the same thing; the

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first that the attribute is an accident of that which is, while 'the musical is a man' means that 'musical' is an
accident of a man. (In this sense, too, the not-pale is said to be, because that of which it is an accident is.)
Thus when one thing is said in an accidental sense to be another, this is either because both belong to the
same thing, and this is, or because that to which the attribute belongs is, or because the subject which has as
an attribute that of which it is itself predicated, itself is.

(2) The kinds of essential being are precisely those that are indicated by the figures of predication; for the
senses of 'being' are just as many as these figures. Since, then, some predicates indicate what the subject is,
others its quality, others quantity, others relation, others activity or passivity, others its 'where', others its
'when', 'being' has a meaning answering to each of these. For there is no difference between 'the man is
recovering' and 'the man recovers', nor between 'the man is walking or cutting' and 'the man walks' or 'cuts';
and similarly in all other cases.

(3) Again, 'being' and 'is' mean that a statement is true, 'not being' that it is not true but falses-and this alike in
the case of affirmation and of negation; e.g. 'Socrates is musical' means that this is true, or 'Socrates is
not-pale' means that this is true; but 'the diagonal of the square is not commensurate with the side' means that
it is false to say it is.

(4) Again, 'being' and 'that which is' mean that some of the things we have mentioned 'are' potentially, others
in complete reality. For we say both of that which sees potentially and of that which sees actually, that it is
'seeing', and both of that which can actualize its knowledge and of that which is actualizing it, that it knows,
and both of that to which rest is already present and of that which can rest, that it rests. And similarly in the
case of substances; we say the Hermes is in the stone, and the half of the line is in the line, and we say of that
which is not yet ripe that it is corn. When a thing is potential and when it is not yet potential must be
explained elsewhere.

We call 'substance' (1) the simple bodies, i.e. earth and fire and water and everything of the sort, and in
general bodies and the things composed of them, both animals and divine beings, and the parts of these. All
these are called substance because they are not predicated of a subject but everything else is predicated of
them.-(2) That which, being present in such things as are not predicated of a subject, is the cause of their
being, as the soul is of the being of an animal.-(3) The parts which are present in such things, limiting them
and marking them as individuals, and by whose destruction the whole is destroyed, as the body is by the
destruction of the plane, as some say, and the plane by the destruction of the line; and in general number is
thought by some to be of this nature; for if it is destroyed, they say, nothing exists, and it limits all things.-(4)
The essence, the formula of which is a definition, is also called the substance of each thing.

It follows, then, that 'substance' has two senses, (A) ultimate substratum, which is no longer predicated of
anything else, and (B) that which, being a 'this', is also separable and of this nature is the shape or form of
each thing.

'The same' means (1) that which is the same in an accidental sense, e.g. 'the pale' and 'the musical' are the
same because they are accidents of the same thing, and 'a man' and 'musical' because the one is an accident of
the other; and 'the musical' is 'a man' because it is an accident of the man. (The complex entity is the same as
either of the simple ones and each of these is the same as it; for both 'the man' and 'the musical' are said to be
the same as 'the musical man', and this the same as they.) This is why all of these statements are made not
universally; for it is not true to say that every man is the same as 'the musical' (for universal attributes belong
to things in virtue of their own nature, but accidents do not belong to them in virtue of their own nature); but
of the individuals the statements are made without qualification. For 'Socrates' and 'musical Socrates' are
thought to be the same; but 'Socrates' is not predicable of more than one subject, and therefore we do not say
'every Socrates' as we say 'every man'.

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Some things are said to be the same in this sense, others (2) are the same by their own nature, in as many
senses as that which is one by its own nature is so; for both the things whose matter is one either in kind or in
number, and those whose essence is one, are said to be the same. Clearly, therefore, sameness is a unity of the
being either of more than one thing or of one thing when it is treated as more than one, ie. when we say a
thing is the same as itself; for we treat it as two.

Things are called 'other' if either their kinds or their matters or the definitions of their essence are more than
one; and in general 'other' has meanings opposite to those of 'the same'.

'Different' is applied (1) to those things which though other are the same in some respect, only not in number
but either in species or in genus or by analogy; (2) to those whose genus is other, and to contraries, and to an
things that have their otherness in their essence.

Those things are called 'like' which have the same attributes in every respect, and those which have more
attributes the same than different, and those whose quality is one; and that which shares with another thing
the greater number or the more important of the attributes (each of them one of two contraries) in respect of
which things are capable of altering, is like that other thing. The senses of 'unlike' are opposite to those of
'like'.

The term 'opposite' is applied to contradictories, and to contraries, and to relative terms, and to privation and
possession, and to the extremes from which and into which generation and dissolution take place; and the
attributes that cannot be present at the same time in that which is receptive of both, are said to be
opposed,-either themselves of their constituents. Grey and white colour do not belong at the same time to the
same thing; hence their constituents are opposed.

The term 'contrary' is applied (1) to those attributes differing in genus which cannot belong at the same time
to the same subject, (2) to the most different of the things in the same genus, (3) to the most different of the
attributes in the same recipient subject, (4) to the most different of the things that fall under the same faculty,
(5) to the things whose difference is greatest either absolutely or in genus or in species. The other things that
are called contrary are so called, some because they possess contraries of the above kind, some because they
are receptive of such, some because they are productive of or susceptible to such, or are producing or
suffering them, or are losses or acquisitions, or possessions or privations, of such. Since 'one' and 'being' have
many senses, the other terms which are derived from these, and therefore 'same', 'other', and 'contrary', must
correspond, so that they must be different for each category.

The term 'other in species' is applied to things which being of the same genus are not subordinate the one to
the other, or which being in the same genus have a difference, or which have a contrariety in their substance;
and contraries are other than one another in species (either all contraries or those which are so called in the
primary sense), and so are those things whose definitions differ in the infima species of the genus (e.g. man
and horse are indivisible in genus, but their definitions are different), and those which being in the same
substance have a difference. 'The same in species' has the various meanings opposite to these.

The words 'prior' and 'posterior' are applied (1) to some things (on the assumption that there is a first, i.e. a
beginning, in each class) because they are nearer some beginning determined either absolutely and by nature,
or by reference to something or in some place or by certain people; e.g. things are prior in place because they
are nearer either to some place determined by nature (e.g. the middle or the last place), or to some chance
object; and that which is farther is posterior.-Other things are prior in time; some by being farther from the
present, i.e. in the case of past events (for the Trojan war is prior to the Persian, because it is farther from the
present), others by being nearer the present, i.e. in the case of future events (for the Nemean games are prior
to the Pythian, if we treat the present as beginning and first point, because they are nearer the present). -Other
things are prior in movement; for that which is nearer the first mover is prior (e.g. the boy is prior to the

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man); and the prime mover also is a beginning absolutely. -Others are prior in power; for that which exceeds
in power, i.e. the more powerful, is prior; and such is that according to whose will the other-i.e. the
posterior-must follow, so that if the prior does not set it in motion the other does not move, and if it sets it in
motion it does move; and here will is a beginning. -Others are prior in arrangement; these are the things that
are placed at intervals in reference to some one definite thing according to some rule, e.g. in the chorus the
second man is prior to the third, and in the lyre the second lowest string is prior to the lowest; for in the one
case the leader and in the other the middle string is the beginning.

These, then, are called prior in this sense, but (2) in another sense that which is prior for knowledge is treated
as also absolutely prior; of these, the things that are prior in definition do not coincide with those that are
prior in relation to perception. For in definition universals are prior, in relation to perception individuals. And
in definition also the accident is prior to the whole, e.g. 'musical' to 'musical man', for the definition cannot
exist as a whole without the part; yet musicalness cannot exist unless there is some one who is musical.

(3) The attributes of prior things are called prior, e.g. straightness is prior to smoothness; for one is an
attribute of a line as such, and the other of a surface.

Some things then are called prior and posterior in this sense, others (4) in respect of nature and substance, i.e.
those which can be without other things, while the others cannot be without them,-a distinction which Plato
used. (If we consider the various senses of 'being', firstly the subject is prior, so that substance is prior;
secondly, according as potency or complete reality is taken into account, different things are prior, for some
things are prior in respect of potency, others in respect of complete reality, e.g. in potency the half line is
prior to the whole line, and the part to the whole, and the matter to the concrete substance, but in complete
reality these are posterior; for it is only when the whole has been dissolved that they will exist in complete
reality.) In a sense, therefore, all things that are called prior and posterior are so called with reference to this
fourth sense; for some things can exist without others in respect of generation, e.g. the whole without the
parts, and others in respect of dissolution, e.g. the part without the whole. And the same is true in all other
cases.

'Potency' means (1) a source of movement or change, which is in another thing than the thing moved or in the
same thing qua other; e.g. the art of building is a potency which is not in the thing built, while the art of
healing, which is a potency, may be in the man healed, but not in him qua healed. 'Potency' then means the
source, in general, of change or movement in another thing or in the same thing qua other, and also (2) the
source of a thing's being moved by another thing or by itself qua other. For in virtue of that principle, in
virtue of which a patient suffers anything, we call it 'capable' of suffering; and this we do sometimes if it
suffers anything at all, sometimes not in respect of everything it suffers, but only if it suffers a change for the
better — (3) The capacity of performing this well or according to intention; for sometimes we say of those
who merely can walk or speak but not well or not as they intend, that they cannot speak or walk. So too (4) in
the case of passivity — (5) The states in virtue of which things are absolutely impassive or unchangeable, or
not easily changed for the worse, are called potencies; for things are broken and crushed and bent and in
general destroyed not by having a potency but by not having one and by lacking something, and things are
impassive with respect to such processes if they are scarcely and slightly affected by them, because of a
'potency' and because they 'can' do something and are in some positive state.

'Potency' having this variety of meanings, so too the 'potent' or 'capable' in one sense will mean that which
can begin a movement (or a change in general, for even that which can bring things to rest is a 'potent' thing)
in another thing or in itself qua other; and in one sense that over which something else has such a potency;
and in one sense that which has a potency of changing into something, whether for the worse or for the better
(for even that which perishes is thought to be 'capable' of perishing, for it would not have perished if it had
not been capable of it; but, as a matter of fact, it has a certain disposition and cause and principle which fits it
to suffer this; sometimes it is thought to be of this sort because it has something, sometimes because it is

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deprived of something; but if privation is in a sense 'having' or 'habit', everything will be capable by having
something, so that things are capable both by having a positive habit and principle, and by having the
privation of this, if it is possible to have a privation; and if privation is not in a sense 'habit', 'capable' is used
in two distinct senses); and a thing is capable in another sense because neither any other thing, nor itself qua
other, has a potency or principle which can destroy it. Again, all of these are capable either merely because
the thing might chance to happen or not to happen, or because it might do so well. This sort of potency is
found even in lifeless things, e.g. in instruments; for we say one lyre can speak, and another cannot speak at
all, if it has not a good tone.

Incapacity is privation of capacity-i.e. of such a principle as has been described either in general or in the
case of something that would naturally have the capacity, or even at the time when it would naturally already
have it; for the senses in which we should call a boy and a man and a eunuch 'incapable of begetting' are
distinct.-Again, to either kind of capacity there is an opposite incapacity-both to that which only can produce
movement and to that which can produce it well.

Some things, then, are called adunata in virtue of this kind of incapacity, while others are so in another sense;
i.e. both dunaton and adunaton are used as follows. The impossible is that of which the contrary is of
necessity true, e.g. that the diagonal of a square is commensurate with the side is impossible, because such a
statement is a falsity of which the contrary is not only true but also necessary; that it is commensurate, then,
is not only false but also of necessity false. The contrary of this, the possible, is found when it is not
necessary that the contrary is false, e.g. that a man should be seated is possible; for that he is not seated is not
of necessity false. The possible, then, in one sense, as has been said, means that which is not of necessity
false; in one, that which is true; in one, that which may be true.-A 'potency' or 'power' in geometry is so
called by a change of meaning. -These senses of 'capable' or 'possible' involve no reference to potency. But
the senses which involve a reference to potency all refer to the primary kind of potency; and this is a source
of change in another thing or in the same thing qua other. For other things are called 'capable', some because
something else has such a potency over them, some because it has not, some because it has it in a particular
way. The same is true of the things that are incapable. Therefore the proper definition of the primary kind of
potency will be 'a source of change in another thing or in the same thing qua other'.

'Quantum' means that which is divisible into two or more constituent parts of which each is by nature a 'one'
and a 'this'. A quantum is a plurality if it is numerable, a magnitude if it is a measurable. 'Plurality' means that
which is divisible potentially into non-continuous parts, 'magnitude' that which is divisible into continuous
parts; of magnitude, that which is continuous in one dimension is length; in two breadth, in three depth. Of
these, limited plurality is number, limited length is a line, breadth a surface, depth a solid.

Again, some things are called quanta in virtue of their own nature, others incidentally; e.g. the line is a
quantum by its own nature, the musical is one incidentally. Of the things that are quanta by their own nature
some are so as substances, e.g. the line is a quantum (for 'a certain kind of quantum' is present in the
definition which states what it is), and others are modifications and states of this kind of substance, e.g. much
and little, long and short, broad and narrow, deep and shallow, heavy and light, and all other such attributes.
And also great and small, and greater and smaller, both in themselves and when taken relatively to each other,
are by their own nature attributes of what is quantitative; but these names are transferred to other things also.
Of things that are quanta incidentally, some are so called in the sense in which it was said that the musical
and the white were quanta, viz. because that to which musicalness and whiteness belong is a quantum, and
some are quanta in the way in which movement and time are so; for these also are called quanta of a sort and
continuous because the things of which these are attributes are divisible. I mean not that which is moved, but
the space through which it is moved; for because that is a quantum movement also is a quantum, and because
this is a quantum time is one.

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'Quality' means (1) the differentia of the essence, e.g. man is an animal of a certain quality because he is
two-footed, and the horse is so because it is four-footed; and a circle is a figure of particular quality because
it is without angles,-which shows that the essential differentia is a quality.-This, then, is one meaning of
quality-the differentia of the essence, but (2) there is another sense in which it applies to the unmovable
objects of mathematics, the sense in which the numbers have a certain quality, e.g. the composite numbers
which are not in one dimension only, but of which the plane and the solid are copies (these are those which
have two or three factors); and in general that which exists in the essence of numbers besides quantity is
quality; for the essence of each is what it is once, e.g. that of is not what it is twice or thrice, but what it is
once; for 6 is once 6.

(3) All the modifications of substances that move (e.g. heat and cold, whiteness and blackness, heaviness and
lightness, and the others of the sort) in virtue of which, when they change, bodies are said to alter. (4) Quality
in respect of virtue and vice, and in general, of evil and good.

Quality, then, seems to have practically two meanings, and one of these is the more proper. The primary
quality is the differentia of the essence, and of this the quality in numbers is a part; for it is a differentia of
essences, but either not of things that move or not of them qua moving. Secondly, there are the modifications
of things that move, qua moving, and the differentiae of movements. Virtue and vice fall among these
modifications; for they indicate differentiae of the movement or activity, according to which the things in
motion act or are acted on well or badly; for that which can be moved or act in one way is good, and that
which can do so in another — the contrary — way is vicious. Good and evil indicate quality especially in living
things, and among these especially in those which have purpose.

Things are 'relative' (1) as double to half, and treble to a third, and in general that which contains something
else many times to that which is contained many times in something else, and that which exceeds to that
which is exceeded; (2) as that which can heat to that which can be heated, and that which can cut to that
which can be cut, and in general the active to the passive; (3) as the measurable to the measure, and the
knowable to knowledge, and the perceptible to perception.

(1) Relative terms of the first kind are numerically related either indefinitely or definitely, to numbers
themselves or to 1. E.g. the double is in a definite numerical relation to 1, and that which is 'many times as
great' is in a numerical, but not a definite, relation to 1, i.e. not in this or in that numerical relation to it; the
relation of that which is half as big again as something else to that something is a definite numerical relation
to a number; that which is n+I/n times something else is in an indefinite relation to that something, as that
which is 'many times as great' is in an indefinite relation to 1 ; the relation of that which exceeds to that which
is exceeded is numerically quite indefinite; for number is always commensurate, and 'number' is not
predicated of that which is not commensurate, but that which exceeds is, in relation to that which is exceeded,
so much and something more; and this something is indefinite; for it can, indifferently, be either equal or not
equal to that which is exceeded.-All these relations, then, are numerically expressed and are determinations
of number, and so in another way are the equal and the like and the same. For all refer to unity. Those things
are the same whose substance is one; those are like whose quality is one; those are equal whose quantity is
one; and 1 is the beginning and measure of number, so that all these relations imply number, though not in
the same way.

(2) Things that are active or passive imply an active or a passive potency and the actualizations of the
potencies; e.g. that which is capable of heating is related to that which is capable of being heated, because it
can heat it, and, again, that which heats is related to that which is heated and that which cuts to that which is
cut, in the sense that they actually do these things. But numerical relations are not actualized except in the
sense which has been elsewhere stated; actualizations in the sense of movement they have not. Of relations
which imply potency some further imply particular periods of time, e.g. that which has made is relative to
that which has been made, and that which will make to that which will be made. For it is in this way that a

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father is called the father of his son; for the one has acted and the other has been acted on in a certain way.
Further, some relative terms imply privation of potency, i.e. 'incapable' and terms of this sort, e.g. 'invisible'.

Relative terms which imply number or potency, therefore, are all relative because their very essence includes
in its nature a reference to something else, not because something else involves a reference to it; but (3) that
which is measurable or knowable or thinkable is called relative because something else involves a reference
to it. For 'that which is thinkable' implies that the thought of it is possible, but the thought is not relative to
'that of which it is the thought'; for we should then have said the same thing twice. Similarly sight is the sight
of something, not 'of that of which it is the sight' (though of course it is true to say this); in fact it is relative to
colour or to something else of the sort. But according to the other way of speaking the same thing would be
said twice,-'the sight is of that of which it is.'

Things that are by their own nature called relative are called so sometimes in these senses, sometimes if the
classes that include them are of this sort; e.g. medicine is a relative term because its genus, science, is thought
to be a relative term. Further, there are the properties in virtue of which the things that have them are called
relative, e.g. equality is relative because the equal is, and likeness because the like is. Other things are relative
by accident; e.g. a man is relative because he happens to be double of something and double is a relative
term; or the white is relative, if the same thing happens to be double and white.

What is called 'complete' is (1) that outside which it is not possible to find any, even one, of its parts; e.g. the
complete time of each thing is that outside which it is not possible to find any time which is a part proper to
it.— (2) That which in respect of excellence and goodness cannot be excelled in its kind; e.g. we have a
complete doctor or a complete flute-player, when they lack nothing in respect of the form of their proper
excellence. And thus, transferring the word to bad things, we speak of a complete scandal-monger and a
complete thief; indeed we even call them good, i.e. a good thief and a good scandal-monger. And excellence
is a completion; for each thing is complete and every substance is complete, when in respect of the form of its
proper excellence it lacks no part of its natural magnitude.-(3) The things which have attained their end, this
being good, are called complete; for things are complete in virtue of having attained their end. Therefore,
since the end is something ultimate, we transfer the word to bad things and say a thing has been completely
spoilt, and completely destroyed, when it in no wise falls short of destruction and badness, but is at its last
point. This is why death, too, is by a figure of speech called the end, because both are last things. But the
ultimate purpose is also an end.-Things, then, that are called complete in virtue of their own nature are so
called in all these senses, some because in respect of goodness they lack nothing and cannot be excelled and
no part proper to them can be found outside them, others in general because they cannot be exceeded in their
several classes and no part proper to them is outside them; the others presuppose these first two kinds, and are
called complete because they either make or have something of the sort or are adapted to it or in some way or
other involve a reference to the things that are called complete in the primary sense.

'Limit' means (1) the last point of each thing, i.e. the first point beyond which it is not possible to find any
part, and the first point within which every part is; (2) the form, whatever it may be, of a spatial magnitude or
of a thing that has magnitude; (3) the end of each thing (and of this nature is that towards which the
movement and the action are, not that from which they are-though sometimes it is both, that from which and
that to which the movement is, i.e. the final cause); (4) the substance of each thing, and the essence of each;
for this is the limit of knowledge; and if of knowledge, of the object also. Evidently, therefore, 'limit' has as
many senses as 'beginning', and yet more; for the beginning is a limit, but not every limit is a beginning.

That in virtue of which' has several meanings:-(l) the form or substance of each thing, e.g. that in virtue of
which a man is good is the good itself, (2) the proximate subject in which it is the nature of an attribute to be
found, e.g. colour in a surface. That in virtue of which', then, in the primary sense is the form, and in a
secondary sense the matter of each thing and the proximate substratum of each.-In general 'that in virtue of
which' will found in the same number of senses as 'cause'; for we say indifferently (3) in virtue of what has he

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come?' or 'for what end has he come?'; and (4) in virtue of what has he inferred wrongly, or inferred?' or
'what is the cause of the inference, or of the wrong inference?'-Further (5) Kath' d is used in reference to
position, e.g. 'at which he stands' or 'along which he walks; for all such phrases indicate place and position.

Therefore 'in virtue of itself must likewise have several meanings. The following belong to a thing in virtue
of itself:— (1) the essence of each thing, e.g. Callias is in virtue of himself Callias and what it was to be
Callias;-(2) whatever is present in the 'what', e.g. Callias is in virtue of himself an animal. For 'animal' is
present in his definition; Callias is a particular animal.-(3) Whatever attribute a thing receives in itself
directly or in one of its parts; e.g. a surface is white in virtue of itself, and a man is alive in virtue of himself;
for the soul, in which life directly resides, is a part of the man.-(4) That which has no cause other than itself;
man has more than one cause — animal, two-footed — but yet man is man in virtue of himself.-(5) Whatever
attributes belong to a thing alone, and in so far as they belong to it merely by virtue of itself considered apart
by itself.

'Disposition' means the arrangement of that which has parts, in respect either of place or of potency or of
kind; for there must be a certain position, as even the word 'disposition' shows.

'Having' means (1) a kind of activity of the haver and of what he has-something like an action or movement.
For when one thing makes and one is made, between them there is a making; so too between him who has a
garment and the garment which he has there is a having. This sort of having, then, evidently we cannot have;
for the process will go on to infinity, if it is to be possible to have the having of what we have.-(2) 'Having'
or 'habit' means a disposition according to which that which is disposed is either well or ill disposed, and
either in itself or with reference to something else; e.g. health is a 'habit'; for it is such a disposition.-(3) We
speak of a 'habit' if there is a portion of such a disposition; and so even the excellence of the parts is a 'habit'
of the whole thing.

'Affection' means (1) a quality in respect of which a thing can be altered, e.g. white and black, sweet and
bitter, heaviness and lightness, and all others of the kind.-(2) The actualization of these-the already
accomplished alterations.-(3) Especially, injurious alterations and movements, and, above all painful
injuries.-(4) Misfortunes and painful experiences when on a large scale are called affections.

We speak of 'privation' (1) if something has not one of the attributes which a thing might naturally have, even
if this thing itself would not naturally have it; e.g. a plant is said to be 'deprived' of eyes.-(2) If, though either
the thing itself or its genus would naturally have an attribute, it has it not; e.g. a blind man and a mole are in
different senses 'deprived' of sight; the latter in contrast with its genus, the former in contrast with his own
normal nature.-(3) If, though it would naturally have the attribute, and when it would naturally have it, it has
it not; for blindness is a privation, but one is not 'blind' at any and every age, but only if one has not sight at
the age at which one would naturally have it. Similarly a thing is called blind if it has not sight in the medium
in which, and in respect of the organ in respect of which, and with reference to the object with reference to
which, and in the circumstances in which, it would naturally have it.— (4) The violent taking away of anything
is called privation.

Indeed there are just as many kinds of privations as there are of words with negative prefixes; for a thing is
called unequal because it has not equality though it would naturally have it, and invisible either because it has
no colour at all or because it has a poor colour, and apodous either because it has no feet at all or because it
has imperfect feet. Again, a privative term may be used because the thing has little of the attribute (and this
means having it in a sense imperfectly), e.g. 'kernel-less'; or because it has it not easily or not well (e.g. we
call a thing uncuttable not only if it cannot be cut but also if it cannot be cut easily or well); or because it has
not the attribute at all; for it is not the one-eyed man but he who is sightless in both eyes that is called blind.
This is why not every man is 'good' or 'bad', 'just' or 'unjust', but there is also an intermediate state.

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To 'have' or 'hold' means many things:-(l) to treat a thing according to one's own nature or according to one's
own impulse; so that fever is said to have a man, and tyrants to have their cities, and people to have the
clothes they wear.-(2) That in which a thing is present as in something receptive of it is said to have the
thing; e.g. the bronze has the form of the statue, and the body has the disease.-(3) As that which contains
holds the things contained; for a thing is said to be held by that in which it is as in a container; e.g. we say
that the vessel holds the liquid and the city holds men and the ship sailors; and so too that the whole holds the
parts.-(4) That which hinders a thing from moving or acting according to its own impulse is said to hold it, as
pillars hold the incumbent weights, and as the poets make Atlas hold the heavens, implying that otherwise
they would collapse on the earth, as some of the natural philosophers also say. In this way also that which
holds things together is said to hold the things it holds together, since they would otherwise separate, each
according to its own impulse.

'Being in something' has similar and corresponding meanings to 'holding' or 'having'.

To come from something' means (1) to come from something as from matter, and this in two senses, either in
respect of the highest genus or in respect of the lowest species; e.g. in a sense all things that can be melted
come from water, but in a sense the statue comes from bronze.-(2) As from the first moving principle; e.g.
'what did the fight come from?' From abusive language, because this was the origin of the fight.— (3) From the
compound of matter and shape, as the parts come from the whole, and the verse from the Iliad, and the stones
from the house; (in every such case the whole is a compound of matter and shape,) for the shape is the end,
and only that which attains an end is complete.-(4) As the form from its part, e.g. man from 'two-footed'and
syllable from 'letter'; for this is a different sense from that in which the statue comes from bronze; for the
composite substance comes from the sensible matter, but the form also comes from the matter of the
form.-Some things, then, are said to come from something else in these senses; but (5) others are so
described if one of these senses is applicable to a part of that other thing; e.g. the child comes from its father
and mother, and plants come from the earth, because they come from a part of those things.-(6) It means
coming after a thing in time, e.g. night comes from day and storm from fine weather, because the one comes
after the other. Of these things some are so described because they admit of change into one another, as in the
cases now mentioned; some merely because they are successive in time, e.g. the voyage took place 'from' the
equinox, because it took place after the equinox, and the festival of the Thargelia comes 'from' the Dionysia,
because after the Dionysia.

'Part' means (1) (a) that into which a quantum can in any way be divided; for that which is taken from a
quantum qua quantum is always called a part of it, e.g. two is called in a sense a part of three. It means (b), of
the parts in the first sense, only those which measure the whole; this is why two, though in one sense it is, in
another is not, called a part of three.-(2) The elements into which a kind might be divided apart from the
quantity are also called parts of it; for which reason we say the species are parts of the genus.-(3) The
elements into which a whole is divided, or of which it consists-the 'whole' meaning either the form or that
which has the form; e.g. of the bronze sphere or of the bronze cube both the bronze-i.e. the matter in which
the form is-and the characteristic angle are parts. -(4) The elements in the definition which explains a thing
are also parts of the whole; this is why the genus is called a part of the species, though in another sense the
species is part of the genus.

A whole' means (1) that from which is absent none of the parts of which it is said to be naturally a whole, and
(2) that which so contains the things it contains that they form a unity; and this in two senses-either as being
each severally one single thing, or as making up the unity between them. For (a) that which is true of a whole
class and is said to hold good as a whole (which implies that it is a kind whole) is true of a whole in the sense
that it contains many things by being predicated of each, and by all of them, e.g. man, horse, god, being
severally one single thing, because all are living things. But (b) the continuous and limited is a whole, when it
is a unity consisting of several parts, especially if they are present only potentially, but, failing this, even if
they are present actually. Of these things themselves, those which are so by nature are wholes in a higher

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degree than those which are so by art, as we said in the case of unity also, wholeness being in fact a sort of
oneness.

Again (3) of quanta that have a beginning and a middle and an end, those to which the position does not make
a difference are called totals, and those to which it does, wholes. Those which admit of both descriptions are
both wholes and totals. These are the things whose nature remains the same after transposition, but whose
form does not, e.g. wax or a coat; they are called both wholes and totals; for they have both characteristics.
Water and all liquids and number are called totals, but 'the whole number' or 'the whole water' one does not
speak of, except by an extension of meaning. To things, to which qua one the term 'total' is applied, the term
'all' is applied when they are treated as separate; 'this total number,' 'all these units.'

It is not any chance quantitative thing that can be said to be 'mutilated'; it must be a whole as well as
divisible. For not only is two not 'mutilated' if one of the two ones is taken away (for the part removed by
mutilation is never equal to the remainder), but in general no number is thus mutilated; for it is also necessary
that the essence remain; if a cup is mutilated, it must still be a cup; but the number is no longer the same.
Further, even if things consist of unlike parts, not even these things can all be said to be mutilated, for in a
sense a number has unlike parts (e.g. two and three) as well as like; but in general of the things to which their
position makes no difference, e.g. water or fire, none can be mutilated; to be mutilated, things must be such
as in virtue of their essence have a certain position. Again, they must be continuous; for a musical scale
consists of unlike parts and has position, but cannot become mutilated. Besides, not even the things that are
wholes are mutilated by the privation of any part. For the parts removed must be neither those which
determine the essence nor any chance parts, irrespective of their position; e.g. a cup is not mutilated if it is
bored through, but only if the handle or a projecting part is removed, and a man is mutilated not if the flesh or
the spleen is removed, but if an extremity is, and that not every extremity but one which when completely
removed cannot grow again. Therefore baldness is not a mutilation.

The term 'race' or 'genus' is used (1) if generation of things which have the same form is continuous, e.g.
'while the race of men lasts' means 'while the generation of them goes on continuously '.-(2) It is used with
reference to that which first brought things into existence; for it is thus that some are called Hellenes by race
and others Ionians, because the former proceed from Hellen and the latter from Ion as their first begetter. And
the word is used in reference to the begetter more than to the matter, though people also get a race-name
from the female, e.g. 'the descendants of Pyrrha'.-(3) There is genus in the sense in which 'plane' is the genus
of plane figures and solid' of solids; for each of the figures is in the one case a plane of such and such a kind,
and in the other a solid of such and such a kind; and this is what underlies the differentiae. Again (4) in
definitions the first constituent element, which is included in the 'what', is the genus, whose differentiae the
qualities are said to be 'Genus' then is used in all these ways, (1) in reference to continuous generation of the
same kind, (2) in reference to the first mover which is of the same kind as the things it moves, (3) as matter;
for that to which the differentia or quality belongs is the substratum, which we call matter.

Those things are said to be 'other in genus' whose proximate substratum is different, and which are not
analysed the one into the other nor both into the same thing (e.g. form and matter are different in genus); and
things which belong to different categories of being (for some of the things that are said to 'be' signify
essence, others a quality, others the other categories we have before distinguished); these also are not
analysed either into one another or into some one thing.

'The false' means (1) that which is false as a thing, and that (a) because it is not put together or cannot be put
together, e.g. 'that the diagonal of a square is commensurate with the side' or 'that you are sitting'; for one of
these is false always, and the other sometimes; it is in these two senses that they are non-existent, (b) There
are things which exist, but whose nature it is to appear either not to be such as they are or to be things that do
not exist, e.g. a sketch or a dream; for these are something, but are not the things the appearance of which
they produce in us. We call things false in this way, then,-either because they themselves do not exist, or

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because the appearance which results from them is that of something that does not exist.

(2) A false account is the account of non-existent objects, in so far as it is false. Hence every account is false
when applied to something other than that of which it is true; e.g. the account of a circle is false when applied
to a triangle. In a sense there is one account of each thing, i.e. the account of its essence, but in a sense there
are many, since the thing itself and the thing itself with an attribute are in a sense the same, e.g. Socrates and
musical Socrates (a false account is not the account of anything, except in a qualified sense). Hence
Antisthenes was too simple-minded when he claimed that nothing could be described except by the account
proper to it,-one predicate to one subject; from which the conclusion used to be drawn that there could be no
contradiction, and almost that there could be no error. But it is possible to describe each thing not only by the
account of itself, but also by that of something else. This may be done altogether falsely indeed, but there is
also a way in which it may be done truly; e.g. eight may be described as a double number by the use of the
definition of two.

These things, then, are called false in these senses, but (3) a false man is one who is ready at and fond of such
accounts, not for any other reason but for their own sake, and one who is good at impressing such accounts
on other people, just as we say things are which produce a false appearance. This is why the proof in the
Hippias that the same man is false and true is misleading. For it assumes that he is false who can deceive (i.e.
the man who knows and is wise); and further that he who is willingly bad is better. This is a false result of
induction-for a man who limps willingly is better than one who does so unwillingly-by 'limping' Plato
means 'mimicking a limp', for if the man were lame willingly, he would presumably be worse in this case as
in the corresponding case of moral character.

Accident' means (1) that which attaches to something and can be truly asserted, but neither of necessity nor
usually, e.g. if some one in digging a hole for a plant has found treasure. This-the finding of treasure-is for
the man who dug the hole an accident; for neither does the one come of necessity from the other or after the
other, nor, if a man plants, does he usually find treasure. And a musical man might be pale; but since this
does not happen of necessity nor usually, we call it an accident. Therefore since there are attributes and they
attach to subjects, and some of them attach to these only in a particular place and at a particular time,
whatever attaches to a subject, but not because it was this subject, or the time this time, or the place this
place, will be an accident. Therefore, too, there is no definite cause for an accident, but a chance cause, i.e. an
indefinite one. Going to Aegina was an accident for a man, if he went not in order to get there, but because he
was carried out of his way by a storm or captured by pirates. The accident has happened or exists,-not in
virtue of the subject's nature, however, but of something else; for the storm was the cause of his coming to a
place for which he was not sailing, and this was Aegina.

Accident' has also (2) another meaning, i.e. all that attaches to each thing in virtue of itself but is not in its
essence, as having its angles equal to two right angles attaches to the triangle. And accidents of this sort may
be eternal, but no accident of the other sort is. This is explained elsewhere.

Book VI

WE are seeking the principles and the causes of the things that are, and obviously of them qua being. For,
while there is a cause of health and of good condition, and the objects of mathematics have first principles
and elements and causes, and in general every science which is ratiocinative or at all involves reasoning deals
with causes and principles, more or less precise, all these sciences mark off some particular being-some
genus, and inquire into this, but not into being simply nor qua being, nor do they offer any discussion of the
essence of the things of which they treat; but starting from the essence-some making it plain to the senses,
others assuming it as a hypothesis-they then demonstrate, more or less cogently, the essential attributes of the
genus with which they deal. It is obvious, therefore, that such an induction yields no demonstration of
substance or of the essence, but some other way of exhibiting it. And similarly the sciences omit the question

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whether the genus with which they deal exists or does not exist, because it belongs to the same kind of
thinking to show what it is and that it is.

And since natural science, like other sciences, is in fact about one class of being, i.e. to that sort of substance
which has the principle of its movement and rest present in itself, evidently it is neither practical nor
productive. For in the case of things made the principle is in the maker-it is either reason or art or some
faculty, while in the case of things done it is in the doer-viz. will, for that which is done and that which is
willed are the same. Therefore, if all thought is either practical or productive or theoretical, physics must be a
theoretical science, but it will theorize about such being as admits of being moved, and about
substance-as-defined for the most part only as not separable from matter. Now, we must not fail to notice the
mode of being of the essence and of its definition, for, without this, inquiry is but idle. Of things defined, i.e.
of 'whats', some are like 'snub', and some like 'concave'. And these differ because 'snub' is bound up with
matter (for what is snub is a concave nose), while concavity is independent of perceptible matter. If then all
natural things are a analogous to the snub in their nature; e.g. nose, eye, face, flesh, bone, and, in general,
animal; leaf, root, bark, and, in general, plant (for none of these can be defined without reference to
movement-they always have matter), it is clear how we must seek and define the 'what' in the case of natural
objects, and also that it belongs to the student of nature to study even soul in a certain sense, i.e. so much of it
as is not independent of matter.

That physics, then, is a theoretical science, is plain from these considerations. Mathematics also, however, is
theoretical; but whether its objects are immovable and separable from matter, is not at present clear; still, it is
clear that some mathematical theorems consider them qua immovable and qua separable from matter. But if
there is something which is eternal and immovable and separable, clearly the knowledge of it belongs to a
theoretical science,-not, however, to physics (for physics deals with certain movable things) nor to
mathematics, but to a science prior to both. For physics deals with things which exist separately but are not
immovable, and some parts of mathematics deal with things which are immovable but presumably do not
exist separately, but as embodied in matter; while the first science deals with things which both exist
separately and are immovable. Now all causes must be eternal, but especially these; for they are the causes
that operate on so much of the divine as appears to us. There must, then, be three theoretical philosophies,
mathematics, physics, and what we may call theology, since it is obvious that if the divine is present
anywhere, it is present in things of this sort. And the highest science must deal with the highest genus. Thus,
while the theoretical sciences are more to be desired than the other sciences, this is more to be desired than
the other theoretical sciences. For one might raise the question whether first philosophy is universal, or deals
with one genus, i.e. some one kind of being; for not even the mathematical sciences are all alike in this
respect,-geometry and astronomy deal with a certain particular kind of thing, while universal mathematics
applies alike to all. We answer that if there is no substance other than those which are formed by nature,
natural science will be the first science; but if there is an immovable substance, the science of this must be
prior and must be first philosophy, and universal in this way, because it is first. And it will belong to this to
consider being qua being-both what it is and the attributes which belong to it qua being.

But since the unqualified term 'being' has several meanings, of which one was seen' to be the accidental, and
another the true ('non-being' being the false), while besides these there are the figures of predication (e.g. the
'what', quality, quantity, place, time, and any similar meanings which 'being' may have), and again besides all
these there is that which 'is' potentially or actually :-since 'being' has many meanings, we must say regarding
the accidental, that there can be no scientific treatment of it. This is confirmed by the fact that no science
practical, productive, or theoretical troubles itself about it. For on the one hand he who produces a house does
not produce all the attributes that come into being along with the house; for these are innumerable; the house
that has been made may quite well be pleasant for some people, hurtful for some, and useful to others, and
different-to put it shortly from all things that are; and the science of building does not aim at producing any
of these attributes. And in the same way the geometer does not consider the attributes which attach thus to
figures, nor whether 'triangle' is different from 'triangle whose angles are equal to two right angles'.-And this

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happens naturally enough; for the accidental is practically a mere name. And so Plato was in a sense not
wrong in ranking sophistic as dealing with that which is not. For the arguments of the sophists deal, we may
say, above all with the accidental; e.g. the question whether 'musical' and 'lettered' are different or the same,
and whether 'musical Coriscus' and 'Coriscus' are the same, and whether 'everything which is, but is not
eternal, has come to be', with the paradoxical conclusion that if one who was musical has come to be lettered,
he must also have been lettered and have come to be musical, and all the other arguments of this sort; the
accidental is obviously akin to non-being. And this is clear also from arguments such as the following: things
which are in another sense come into being and pass out of being by a process, but things which are
accidentally do not. But still we must, as far as we can, say further, regarding the accidental, what its nature is
and from what cause it proceeds; for it will perhaps at the same time become clear why there is no science of
it.

Since, among things which are, some are always in the same state and are of necessity (not necessity in the
sense of compulsion but that which we assert of things because they cannot be otherwise), and some are not
of necessity nor always, but for the most part, this is the principle and this the cause of the existence of the
accidental; for that which is neither always nor for the most part, we call accidental. For instance, if in the
dog-days there is wintry and cold weather, we say this is an accident, but not if there is sultry heat, because
the latter is always or for the most part so, but not the former. And it is an accident that a man is pale (for this
is neither always nor for the most part so), but it is not by accident that he is an animal. And that the builder
produces health is an accident, because it is the nature not of the builder but of the doctor to do this,-but the
builder happened to be a doctor. Again, a confectioner, aiming at giving pleasure, may make something
wholesome, but not in virtue of the confectioner's art; and therefore we say 'it was an accident', and while
there is a sense in which he makes it, in the unqualified sense he does not. For to other things answer faculties
productive of them, but to accidental results there corresponds no determinate art nor faculty; for of things
which are or come to be by accident, the cause also is accidental. Therefore, since not all things either are or
come to be of necessity and always, but, the majority of things are for the most part, the accidental must exist;
for instance a pale man is not always nor for the most part musical, but since this sometimes happens, it must
be accidental (if not, everything will be of necessity). The matter, therefore, which is capable of being
otherwise than as it usually is, must be the cause of the accidental. And we must take as our starting-point the
question whether there is nothing that is neither always nor for the most part. Surely this is impossible. There
is, then, besides these something which is fortuitous and accidental. But while the usual exists, can nothing be
said to be always, or are there eternal things? This must be considered later,' but that there is no science of the
accidental is obvious; for all science is either of that which is always or of that which is for the most part.
(For how else is one to learn or to teach another? The thing must be determined as occurring either always or
for the most part, e.g. that honey-water is useful for a patient in a fever is true for the most part.) But that
which is contrary to the usual law science will be unable to state, i.e. when the thing does not happen, e.g. 'on
the day of new moon'; for even that which happens on the day of new moon happens then either always or for
the most part; but the accidental is contrary to such laws. We have stated, then, what the accidental is, and
from what cause it arises, and that there is no science which deals with it.

That there are principles and causes which are generable and destructible without ever being in course of
being generated or destroyed, is obvious. For otherwise all things will be of necessity, since that which is
being generated or destroyed must have a cause which is not accidentally its cause. Will A exist or not? It
will if B happens; and if not, not. And B will exist if C happens. And thus if time is constantly subtracted
from a limited extent of time, one will obviously come to the present. This man, then, will die by violence, if
he goes out; and he will do this if he gets thirsty; and he will get thirsty if something else happens; and thus
we shall come to that which is now present, or to some past event. For instance, he will go out if he gets
thirsty; and he will get thirsty if he is eating pungent food; and this is either the case or not; so that he will of
necessity die, or of necessity not die. And similarly if one jumps over to past events, the same account will
hold good; for this-I mean the past condition-is already present in something. Everything, therefore, that will
be, will be of necessity; e.g. it is necessary that he who lives shall one day die; for already some condition has

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come into existence, e.g. the presence of contraries in the same body. But whether he is to die by disease or
by violence is not yet determined, but depends on the happening of something else. Clearly then the process
goes back to a certain starting-point, but this no longer points to something further. This then will be the
starting-point for the fortuitous, and will have nothing else as cause of its coming to be. But to what sort of
starting-point and what sort of cause we thus refer the fortuitous-whether to matter or to the purpose or to
the motive power, must be carefully considered.

Let us dismiss accidental being; for we have sufficiently determined its nature. But since that which is in the
sense of being true, or is not in the sense of being false, depends on combination and separation, and truth and
falsity together depend on the allocation of a pair of contradictory judgements (for the true judgement affirms
where the subject and predicate really are combined, and denies where they are separated, while the false
judgement has the opposite of this allocation; it is another question, how it happens that we think things
together or apart; by 'together' and 'apart' I mean thinking them so that there is no succession in the thoughts
but they become a unity); for falsity and truth are not in things-it is not as if the good were true, and the bad
were in itself false-but in thought; while with regard to simple concepts and 'whats' falsity and truth do not
exist even in thought — this being so, we must consider later what has to be discussed with regard to that
which is or is not in this sense. But since the combination and the separation are in thought and not in the
things, and that which is in this sense is a different sort of 'being' from the things that are in the full sense (for
the thought attaches or removes either the subject's 'what' or its having a certain quality or quantity or
something else), that which is accidentally and that which is in the sense of being true must be dismissed. For
the cause of the former is indeterminate, and that of the latter is some affection of the thought, and both are
related to the remaining genus of being, and do not indicate the existence of any separate class of being.
Therefore let these be dismissed, and let us consider the causes and the principles of being itself, qua being.
(It was clear in our discussion of the various meanings of terms, that 'being' has several meanings.)

Book VII

THERE are several senses in which a thing may be said to 'be', as we pointed out previously in our book on
the various senses of words;' for in one sense the 'being' meant is 'what a thing is' or a 'this', and in another
sense it means a quality or quantity or one of the other things that are predicated as these are. While 'being'
has all these senses, obviously that which 'is' primarily is the 'what', which indicates the substance of the
thing. For when we say of what quality a thing is, we say that it is good or bad, not that it is three cubits long
or that it is a man; but when we say what it is, we do not say 'white' or 'hot' or 'three cubits long', but 'a man'
or 'a 'god'. And all other things are said to be because they are, some of them, quantities of that which is in
this primary sense, others qualities of it, others affections of it, and others some other determination of it. And
so one might even raise the question whether the words 'to walk', 'to be healthy', 'to sit' imply that each of
these things is existent, and similarly in any other case of this sort; for none of them is either self-subsistent
or capable of being separated from substance, but rather, if anything, it is that which walks or sits or is
healthy that is an existent thing. Now these are seen to be more real because there is something definite which
underlies them (i.e. the substance or individual), which is implied in such a predicate; for we never use the
word 'good' or 'sitting' without implying this. Clearly then it is in virtue of this category that each of the
others also is. Therefore that which is primarily, i.e. not in a qualified sense but without qualification, must be
substance.

Now there are several senses in which a thing is said to be first; yet substance is first in every sense-(l) in
definition, (2) in order of knowledge, (3) in time. For (3) of the other categories none can exist independently,
but only substance. And (1) in definition also this is first; for in the definition of each term the definition of
its substance must be present. And (2) we think we know each thing most fully, when we know what it is, e.g.
what man is or what fire is, rather than when we know its quality, its quantity, or its place; since we know
each of these predicates also, only when we know what the quantity or the quality is.

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And indeed the question which was raised of old and is raised now and always, and is always the subject of
doubt, viz. what being is, is just the question, what is substance? For it is this that some assert to be one,
others more than one, and that some assert to be limited in number, others unlimited. And so we also must
consider chiefly and primarily and almost exclusively what that is which is in this sense.

Substance is thought to belong most obviously to bodies; and so we say that not only animals and plants and
their parts are substances, but also natural bodies such as fire and water and earth and everything of the sort,
and all things that are either parts of these or composed of these (either of parts or of the whole bodies), e.g.
the physical universe and its parts, stars and moon and sun. But whether these alone are substances, or there
are also others, or only some of these, or others as well, or none of these but only some other things, are
substances, must be considered. Some think the limits of body, i.e. surface, line, point, and unit, are
substances, and more so than body or the solid.

Further, some do not think there is anything substantial besides sensible things, but others think there are
eternal substances which are more in number and more real; e.g. Plato posited two kinds of substance-the
Forms and objects of mathematics-as well as a third kind, viz. the substance of sensible bodies. And
Speusippus made still more kinds of substance, beginning with the One, and assuming principles for each
kind of substance, one for numbers, another for spatial magnitudes, and then another for the soul; and by
going on in this way he multiplies the kinds of substance. And some say Forms and numbers have the same
nature, and the other things come after them-lines and planes-until we come to the substance of the material
universe and to sensible bodies.

Regarding these matters, then, we must inquire which of the common statements are right and which are not
right, and what substances there are, and whether there are or are not any besides sensible substances, and
how sensible substances exist, and whether there is a substance capable of separate existence (and if so why
and how) or no such substance, apart from sensible substances; and we must first sketch the nature of
substance.

The word 'substance' is applied, if not in more senses, still at least to four main objects; for both the essence
and the universal and the genus, are thought to be the substance of each thing, and fourthly the substratum.
Now the substratum is that of which everything else is predicated, while it is itself not predicated of anything
else. And so we must first determine the nature of this; for that which underlies a thing primarily is thought to
be in the truest sense its substance. And in one sense matter is said to be of the nature of substratum, in
another, shape, and in a third, the compound of these. (By the matter I mean, for instance, the bronze, by the
shape the pattern of its form, and by the compound of these the statue, the concrete whole.) Therefore if the
form is prior to the matter and more real, it will be prior also to the compound of both, for the same reason.

We have now outlined the nature of substance, showing that it is that which is not predicated of a stratum, but
of which all else is predicated. But we must not merely state the matter thus; for this is not enough. The
statement itself is obscure, and further, on this view, matter becomes substance. For if this is not substance, it
baffles us to say what else is. When all else is stripped off evidently nothing but matter remains. For while the
rest are affections, products, and potencies of bodies, length, breadth, and depth are quantities and not
substances (for a quantity is not a substance), but the substance is rather that to which these belong primarily.
But when length and breadth and depth are taken away we see nothing left unless there is something that is
bounded by these; so that to those who consider the question thus matter alone must seem to be substance. By
matter I mean that which in itself is neither a particular thing nor of a certain quantity nor assigned to any
other of the categories by which being is determined. For there is something of which each of these is
predicated, whose being is different from that of each of the predicates (for the predicates other than
substance are predicated of substance, while substance is predicated of matter). Therefore the ultimate
substratum is of itself neither a particular thing nor of a particular quantity nor otherwise positively
characterized; nor yet is it the negations of these, for negations also will belong to it only by accident.

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If we adopt this point of view, then, it follows that matter is substance. But this is impossible; for both
separability and 'thisness' are thought to belong chiefly to substance. And so form and the compound of form
and matter would be thought to be substance, rather than matter. The substance compounded of both, i.e. of
matter and shape, may be dismissed; for it is posterior and its nature is obvious. And matter also is in a sense
manifest. But we must inquire into the third kind of substance; for this is the most perplexing.

Some of the sensible substances are generally admitted to be substances, so that we must look first among
these. For it is an advantage to advance to that which is more knowable. For learning proceeds for all in this
way-through that which is less knowable by nature to that which is more knowable; and just as in conduct
our task is to start from what is good for each and make what is without qualification good good for each, so
it is our task to start from what is more knowable to oneself and make what is knowable by nature knowable
to oneself. Now what is knowable and primary for particular sets of people is often knowable to a very small
extent, and has little or nothing of reality. But yet one must start from that which is barely knowable but
knowable to oneself, and try to know what is knowable without qualification, passing, as has been said, by
way of those very things which one does know.

Since at the start we distinguished the various marks by which we determine substance, and one of these was
thought to be the essence, we must investigate this. And first let us make some linguistic remarks about it.
The essence of each thing is what it is said to be propter se. For being you is not being musical, since you are
not by your very nature musical. What, then, you are by your very nature is your essence.

Nor yet is the whole of this the essence of a thing; not that which is propter se as white is to a surface,
because being a surface is not identical with being white. But again the combination of both- 'being a white
surface'-is not the essence of surface, because 'surface' itself is added. The formula, therefore, in which the
term itself is not present but its meaning is expressed, this is the formula of the essence of each thing.
Therefore if to be a white surface is to be a smooth surface, to be white and to be smooth are one and the
same.

But since there are also compounds answering to the other categories (for there is a substratum for each
category, e.g. for quality, quantity, time, place, and motion), we must inquire whether there is a formula of
the essence of each of them, i.e. whether to these compounds also there belongs an essence, e.g. 'white man'.
Let the compound be denoted by 'cloak. What is the essence of cloak? But, it may be said, this also is not a
propter se expression. We reply that there are just two ways in which a predicate may fail to be true of a
subject propter se, and one of these results from the addition, and the other from the omission, of a
determinant. One kind of predicate is not propter se because the term that is being defined is combined with
another determinant, e.g. if in defining the essence of white one were to state the formula of white man; the
other because in the subject another determinant is combined with that which is expressed in the formula, e.g.
if 'cloak meant 'white man', and one were to define cloak as white; white man is white indeed, but its essence
is not to be white.

But is being-a-cloak an essence at all? Probably not. For the essence is precisely what something is; but
when an attribute is asserted of a subject other than itself, the complex is not precisely what some 'this' is, e.g.
white man is not precisely what some 'this' is, since thisness belongs only to substances. Therefore there is an
essence only of those things whose formula is a definition. But we have a definition not where we have a
word and a formula identical in meaning (for in that case all formulae or sets of words would be definitions;
for there will be some name for any set of words whatever, so that even the Iliad will be a definition), but
where there is a formula of something primary; and primary things are those which do not imply the
predication of one element in them of another element. Nothing, then, which is not a species of a genus will
have an essence-only species will have it, for these are thought to imply not merely that the subject
participates in the attribute and has it as an affection, or has it by accident; but for ever thing else as well, if it
has a name, there be a formula of its meaning-viz. that this attribute belongs to this subject; or instead of a

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simple formula we shall be able to give a more accurate one; but there will be no definition nor essence.

Or has 'definition', like 'what a thing is', several meanings? 'What a thing is' in one sense means substance and
the 'this', in another one or other of the predicates, quantity, quality, and the like. For as 'is' belongs to all
things, not however in the same sense, but to one sort of thing primarily and to others in a secondary way, so
too 'what a thing is' belongs in the simple sense to substance, but in a limited sense to the other categories.
For even of a quality we might ask what it is, so that quality also is a 'what a thing is',-not in the simple
sense, however, but just as, in the case of that which is not, some say, emphasizing the linguistic form, that
that is which is not is-not is simply, but is non-existent; so too with quality.

We must no doubt inquire how we should express ourselves on each point, but certainly not more than how
the facts actually stand. And so now also, since it is evident what language we use, essence will belong, just
as 'what a thing is' does, primarily and in the simple sense to substance, and in a secondary way to the other
categories also,-not essence in the simple sense, but the essence of a quality or of a quantity. For it must be
either by an equivocation that we say these are, or by adding to and taking from the meaning of 'are' (in the
way in which that which is not known may be said to be known),-the truth being that we use the word neither
ambiguously nor in the same sense, but just as we apply the word 'medical' by virtue of a reference to one and
the same thing, not meaning one and the same thing, nor yet speaking ambiguously; for a patient and an
operation and an instrument are called medical neither by an ambiguity nor with a single meaning, but with
reference to a common end. But it does not matter at all in which of the two ways one likes to describe the
facts; this is evident, that definition and essence in the primary and simple sense belong to substances. Still
they belong to other things as well, only not in the primary sense. For if we suppose this it does not follow
that there is a definition of every word which means the same as any formula; it must mean the same as a
particular kind of formula; and this condition is satisfied if it is a formula of something which is one, not by
continuity like the Iliad or the things that are one by being bound together, but in one of the main senses of
'one', which answer to the senses of 'is'; now 'that which is' in one sense denotes a 'this', in another a quantity,
in another a quality. And so there can be a formula or definition even of white man, but not in the sense in
which there is a definition either of white or of a substance.

It is a difficult question, if one denies that a formula with an added determinant is a definition, whether any of
the terms that are not simple but coupled will be definable. For we must explain them by adding a
determinant. E.g. there is the nose, and concavity, and snubness, which is compounded out of the two by the
presence of the one in the other, and it is not by accident that the nose has the attribute either of concavity or
of snubness, but in virtue of its nature; nor do they attach to it as whiteness does to Callias, or to man
(because Callias, who happens to be a man, is white), but as 'male' attaches to animal and 'equal' to quantity,
and as all so-called 'attributes propter se' attach to their subjects. And such attributes are those in which is
involved either the formula or the name of the subject of the particular attribute, and which cannot be
explained without this; e.g. white can be explained apart from man, but not female apart from animal.
Therefore there is either no essence and definition of any of these things, or if there is, it is in another sense,
as we have said.

But there is also a second difficulty about them. For if snub nose and concave nose are the same thing, snub
and concave will be the thing; but if snub and concave are not the same (because it is impossible to speak of
snubness apart from the thing of which it is an attribute propter se, for snubness is concavity-in-a-nose),
either it is impossible to say 'snub nose' or the same thing will have been said twice, concave-nose nose; for
snub nose will be concave-nose nose. And so it is absurd that such things should have an essence; if they
have, there will be an infinite regress; for in snub-nose nose yet another 'nose' will be involved.

Clearly, then, only substance is definable. For if the other categories also are definable, it must be by addition
of a determinant, e.g. the qualitative is defined thus, and so is the odd, for it cannot be defined apart from
number; nor can female be defined apart from animal. (When I say 'by addition' I mean the expressions in

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which it turns out that we are saying the same thing twice, as in these instances.) And if this is true, coupled
terms also, like 'odd number', will not be definable (but this escapes our notice because our formulae are not
accurate.)- But if these also are definable, either it is in some other way or, as we definition and essence must
be said to have more than one sense. Therefore in one sense nothing will have a definition and nothing will
have an essence, except substances, but in another sense other things will have them. Clearly, then, definition
is the formula of the essence, and essence belongs to substances either alone or chiefly and primarily and in
the unqualified sense.

We must inquire whether each thing and its essence are the same or different. This is of some use for the
inquiry concerning substance; for each thing is thought to be not different from its substance, and the essence
is said to be the substance of each thing.

Now in the case of accidental unities the two would be generally thought to be different, e.g. white man
would be thought to be different from the essence of white man. For if they are the same, the essence of man
and that of white man are also the same; for a man and a white man are the same thing, as people say, so that
the essence of white man and that of man would be also the same. But perhaps it does not follow that the
essence of accidental unities should be the same as that of the simple terms. For the extreme terms are not in
the same way identical with the middle term. But perhaps this might be thought to follow, that the extreme
terms, the accidents, should turn out to be the same, e.g. the essence of white and that of musical; but this is
not actually thought to be the case.

But in the case of so-called self-subsistent things, is a thing necessarily the same as its essence? E.g. if there
are some substances which have no other substances nor entities prior to them-substances such as some
assert the Ideas to be?-If the essence of good is to be different from good-itself, and the essence of animal
from animal-itself, and the essence of being from being-itself, there will, firstly, be other substances and
entities and Ideas besides those which are asserted, and, secondly, these others will be prior substances, if
essence is substance. And if the posterior substances and the prior are severed from each other, (a) there will
be no knowledge of the former, and (b) the latter will have no being. (By 'severed' I mean, if the good-itself
has not the essence of good, and the latter has not the property of being good.) For (a) there is knowledge of
each thing only when we know its essence. And (b) the case is the same for other things as for the good; so
that if the essence of good is not good, neither is the essence of reality real, nor the essence of unity one. And
all essences alike exist or none of them does; so that if the essence of reality is not real, neither is any of the
others. Again, that to which the essence of good does not belong is not good.-The good, then, must be one
with the essence of good, and the beautiful with the essence of beauty, and so with all things which do not
depend on something else but are self-subsistent and primary. For it is enough if they are this, even if they
are not Forms; or rather, perhaps, even if they are Forms. (At the same time it is clear that if there are Ideas
such as some people say there are, it will not be substratum that is substance; for these must be substances,
but not predicable of a substratum; for if they were they would exist only by being participated in.)

Each thing itself, then, and its essence are one and the same in no merely accidental way, as is evident both
from the preceding arguments and because to know each thing, at least, is just to know its essence, so that
even by the exhibition of instances it becomes clear that both must be one.

(But of an accidental term, e.g. 'the musical' or 'the white', since it has two meanings, it is not true to say that it
itself is identical with its essence; for both that to which the accidental quality belongs, and the accidental
quality, are white, so that in a sense the accident and its essence are the same, and in a sense they are not; for
the essence of white is not the same as the man or the white man, but it is the same as the attribute white.)

The absurdity of the separation would appear also if one were to assign a name to each of the essences; for
there would be yet another essence besides the original one, e.g. to the essence of horse there will belong a
second essence. Yet why should not some things be their essences from the start, since essence is substance?

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But indeed not only are a thing and its essence one, but the formula of them is also the same, as is clear even
from what has been said; for it is not by accident that the essence of one, and the one, are one. Further, if they
are to be different, the process will go on to infinity; for we shall have (1) the essence of one, and (2) the one,
so that to terms of the former kind the same argument will be applicable.

Clearly, then, each primary and self-subsistent thing is one and the same as its essence. The sophistical
objections to this position, and the question whether Socrates and to be Socrates are the same thing, are
obviously answered by the same solution; for there is no difference either in the standpoint from which the
question would be asked, or in that from which one could answer it successfully. We have explained, then, in
what sense each thing is the same as its essence and in what sense it is not.

Of things that come to be, some come to be by nature, some by art, some spontaneously. Now everything that
comes to be comes to be by the agency of something and from something and comes to be something. And
the something which I say it comes to be may be found in any category; it may come to be either a 'this' or of
some size or of some quality or somewhere.

Now natural comings to be are the comings to be of those things which come to be by nature; and that out of
which they come to be is what we call matter; and that by which they come to be is something which exists
naturally; and the something which they come to be is a man or a plant or one of the things of this kind,
which we say are substances if anything is-all things produced either by nature or by art have matter; for
each of them is capable both of being and of not being, and this capacity is the matter in each-and, in general,
both that from which they are produced is nature, and the type according to which they are produced is nature
(for that which is produced, e.g. a plant or an animal, has a nature), and so is that by which they are
produced — the so-called 'formal' nature, which is specifically the same (though this is in another individual);
for man begets man.

Thus, then, are natural products produced; all other productions are called 'makings'. And all makings
proceed either from art or from a faculty or from thought. Some of them happen also spontaneously or by
luck just as natural products sometimes do; for there also the same things sometimes are produced without
seed as well as from seed. Concerning these cases, then, we must inquire later, but from art proceed the things
of which the form is in the soul of the artist. (By form I mean the essence of each thing and its primary
substance.) For even contraries have in a sense the same form; for the substance of a privation is the opposite
substance, e.g. health is the substance of disease (for disease is the absence of health); and health is the
formula in the soul or the knowledge of it. The healthy subject is produced as the result of the following train
of thought:-since this is health, if the subject is to be healthy this must first be present, e.g. a uniform state of
body, and if this is to be present, there must be heat; and the physician goes on thinking thus until he reduces
the matter to a final something which he himself can produce. Then the process from this point onward, i.e.
the process towards health, is called a 'making'. Therefore it follows that in a sense health comes from health
and house from house, that with matter from that without matter; for the medical art and the building art are
the form of health and of the house, and when I speak of substance without matter I mean the essence.

Of the productions or processes one part is called thinking and the other making,-that which proceeds from
the starting-point and the form is thinking, and that which proceeds from the final step of the thinking is
making. And each of the other, intermediate, things is produced in the same way. I mean, for instance, if the
subject is to be healthy his bodily state must be made uniform. What then does being made uniform imply?
This or that. And this depends on his being made warm. What does this imply? Something else. And this
something is present potentially; and what is present potentially is already in the physician's power.

The active principle then and the starting point for the process of becoming healthy is, if it happens by art, the
form in the soul, and if spontaneously, it is that, whatever it is, which starts the making, for the man who
makes by art, as in healing the starting-point is perhaps the production of warmth (and this the physician

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produces by rubbing). Warmth in the body, then, is either a part of health or is followed (either directly or
through several intermediate steps) by something similar which is a part of health; and this, viz. that which
produces the part of health, is the limiting-point — and so too with a house (the stones are the limiting-point
here) and in all other cases. Therefore, as the saying goes, it is impossible that anything should be produced if
there were nothing existing before. Obviously then some part of the result will pre-exist of necessity; for the
matter is a part; for this is present in the process and it is this that becomes something. But is the matter an
element even in the formula? We certainly describe in both ways what brazen circles are; we describe both
the matter by saying it is brass, and the form by saying that it is such and such a figure; and figure is the
proximate genus in which it is placed. The brazen circle, then, has its matter in its formula.

As for that out of which as matter they are produced, some things are said, when they have been produced, to
be not that but 'thaten'; e.g. the statue is not gold but golden. And a healthy man is not said to be that from
which he has come. The reason is that though a thing comes both from its privation and from its substratum,
which we call its matter (e.g. what becomes healthy is both a man and an invalid), it is said to come rather
from its privation (e.g. it is from an invalid rather than from a man that a healthy subject is produced). And so
the healthy subject is not said to he an invalid, but to be a man, and the man is said to be healthy. But as for
the things whose privation is obscure and nameless, e.g. in brass the privation of a particular shape or in
bricks and timber the privation of arrangement as a house, the thing is thought to be produced from these
materials, as in the former case the healthy man is produced from an invalid. And so, as there also a thing is
not said to be that from which it comes, here the statue is not said to be wood but is said by a verbal change to
be wooden, not brass but brazen, not gold but golden, and the house is said to be not bricks but bricken
(though we should not say without qualification, if we looked at the matter carefully, even that a statue is
produced from wood or a house from bricks, because coming to be implies change in that from which a thing
comes to be, and not permanence). It is for this reason, then, that we use this way of speaking.

Since anything which is produced is produced by something (and this I call the starting-point of the
production), and from something (and let this be taken to be not the privation but the matter; for the meaning
we attach to this has already been explained), and since something is produced (and this is either a sphere or a
circle or whatever else it may chance to be), just as we do not make the substratum (the brass), so we do not
make the sphere, except incidentally, because the brazen sphere is a sphere and we make the forme. For to
make a 'this' is to make a 'this' out of the substratum in the full sense of the word. (I mean that to make the
brass round is not to make the round or the sphere, but something else, i.e. to produce this form in something
different from itself. For if we make the form, we must make it out of something else; for this was assumed.
E.g. we make a brazen sphere; and that in the sense that out of this, which is brass, we make this other, which
is a sphere.) If, then, we also make the substratum itself, clearly we shall make it in the same way, and the
processes of making will regress to infinity. Obviously then the form also, or whatever we ought to call the
shape present in the sensible thing, is not produced, nor is there any production of it, nor is the essence
produced; for this is that which is made to be in something else either by art or by nature or by some faculty.
But that there is a brazen sphere, this we make. For we make it out of brass and the sphere; we bring the form
into this particular matter, and the result is a brazen sphere. But if the essence of sphere in general is to be
produced, something must be produced out of something. For the product will always have to be divisible,
and one part must be this and another that; I mean the one must be matter and the other form. If, then, a
sphere is 'the figure whose circumference is at all points equidistant from the centre', part of this will be the
medium in which the thing made will be, and part will be in that medium, and the whole will be the thing
produced, which corresponds to the brazen sphere. It is obvious, then, from what has been said, that that
which is spoken of as form or substance is not produced, but the concrete thing which gets its name from this
is produced, and that in everything which is generated matter is present, and one part of the thing is matter
and the other form.

Is there, then, a sphere apart from the individual spheres or a house apart from the bricks? Rather we may say
that no 'this' would ever have been coming to be, if this had been so, but that the 'form' means the 'such', and

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is not a 'this'-a definite thing; but the artist makes, or the father begets, a 'such' out of a 'this'; and when it has
been begotten, it is a 'this such'. And the whole 'this', Callias or Socrates, is analogous to 'this brazen sphere',
but man and animal to 'brazen sphere' in general. Obviously, then, the cause which consists of the Forms
(taken in the sense in which some maintain the existence of the Forms, i.e. if they are something apart from
the individuals) is useless, at least with regard to comings-to-be and to substances; and the Forms need not,
for this reason at least, be self-subsistent substances. In some cases indeed it is even obvious that the begetter
is of the same kind as the begotten (not, however, the same nor one in number, but in form), i.e. in the case of
natural products (for man begets man), unless something happens contrary to nature, e.g. the production of a
mule by a horse. (And even these cases are similar; for that which would be found to be common to horse and
ass, the genus next above them, has not received a name, but it would doubtless be both in fact something
like a mule.) Obviously, therefore, it is quite unnecessary to set up a Form as a pattern (for we should have
looked for Forms in these cases if in any; for these are substances if anything is so); the begetter is adequate
to the making of the product and to the causing of the form in the matter. And when we have the whole, such
and such a form in this flesh and in these bones, this is Callias or Socrates; and they are different in virtue of
their matter (for that is different), but the same in form; for their form is indivisible.

The question might be raised, why some things are produced spontaneously as well as by art, e.g. health,
while others are not, e.g. a house. The reason is that in some cases the matter which governs the production in
the making and producing of any work of art, and in which a part of the product is present,-some matter is
such as to be set in motion by itself and some is not of this nature, and of the former kind some can move
itself in the particular way required, while other matter is incapable of this; for many things can be set in
motion by themselves but not in some particular way, e.g. that of dancing. The things, then, whose matter is
of this sort, e.g. stones, cannot be moved in the particular way required, except by something else, but in
another way they can move themselves-and so it is with fire. Therefore some things will not exist apart from
some one who has the art of making them, while others will; for motion will be started by these things which
have not the art but can themselves be moved by other things which have not the art or with a motion starting
from a part of the product.

And it is clear also from what has been said that in a sense every product of art is produced from a thing
which shares its name (as natural products are produced), or from a part of itself which shares its name (e.g.
the house is produced from a house, qua produced by reason; for the art of building is the form of the house),
or from something which contains a art of it, — if we exclude things produced by accident; for the cause of the
thing's producing the product directly per se is a part of the product. The heat in the movement caused heat in
the body, and this is either health, or a part of health, or is followed by a part of health or by health itself. And
so it is said to cause health, because it causes that to which health attaches as a consequence.

Therefore, as in syllogisms, substance is the starting-point of everything. It is from 'what a thing is' that
syllogisms start; and from it also we now find processes of production to start.

Things which are formed by nature are in the same case as these products of art. For the seed is productive in
the same way as the things that work by art; for it has the form potentially, and that from which the seed
comes has in a sense the same name as the offspring only in a sense, for we must not expect parent and
offspring always to have exactly the same name, as in the production of 'human being' from 'human' for a
'woman' also can be produced by a 'man'-unless the offspring be an imperfect form; which is the reason why
the parent of a mule is not a mule. The natural things which (like the artificial objects previously considered)
can be produced spontaneously are those whose matter can be moved even by itself in the way in which the
seed usually moves it; those things which have not such matter cannot be produced except from the parent
animals themselves.

But not only regarding substance does our argument prove that its form does not come to be, but the
argument applies to all the primary classes alike, i.e. quantity, quality, and the other categories. For as the

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brazen sphere comes to be, but not the sphere nor the brass, and so too in the case of brass itself, if it comes to
be, it is its concrete unity that comes to be (for the matter and the form must always exist before), so is it both
in the case of substance and in that of quality and quantity and the other categories likewise; for the quality
does not come to be, but the wood of that quality, and the quantity does not come to be, but the wood or the
animal of that size. But we may learn from these instances a peculiarity of substance, that there must exist
beforehand in complete reality another substance which produces it, e.g. an animal if an animal is produced;
but it is not necessary that a quality or quantity should pre-exist otherwise than potentially.

Since a definition is a formula, and every formula has parts, and as the formula is to the thing, so is the part of
the formula to the part of the thing, the question is already being asked whether the formula of the parts must
be present in the formula of the whole or not. For in some cases the formulae of the parts are seen to be
present, and in some not. The formula of the circle does not include that of the segments, but that of the
syllable includes that of the letters; yet the circle is divided into segments as the syllable is into letters. -And
further if the parts are prior to the whole, and the acute angle is a part of the right angle and the finger a part
of the animal, the acute angle will be prior to the right angle and finger to the man. But the latter are thought
to be prior; for in formula the parts are explained by reference to them, and in respect also of the power of
existing apart from each other the wholes are prior to the parts.

Perhaps we should rather say that 'part' is used in several senses. One of these is 'that which measures another
thing in respect of quantity'. But let this sense be set aside; let us inquire about the parts of which substance
consists. If then matter is one thing, form another, the compound of these a third, and both the matter and the
form and the compound are substance even the matter is in a sense called part of a thing, while in a sense it is
not, but only the elements of which the formula of the form consists. E.g. of concavity flesh (for this is the
matter in which it is produced) is not a part, but of snubness it is a part; and the bronze is a part of the
concrete statue, but not of the statue when this is spoken of in the sense of the form. (For the form, or the
thing as having form, should be said to be the thing, but the material element by itself must never be said to
be so.) And so the formula of the circle does not include that of the segments, but the formula of the syllable
includes that of the letters; for the letters are parts of the formula of the form, and not matter, but the
segments are parts in the sense of matter on which the form supervenes; yet they are nearer the form than the
bronze is when roundness is produced in bronze. But in a sense not even every kind of letter will be present
in the formula of the syllable, e.g. particular waxen letters or the letters as movements in the air; for in these
also we have already something that is part of the syllable only in the sense that it is its perceptible matter.
For even if the line when divided passes away into its halves, or the man into bones and muscles and flesh, it
does not follow that they are composed of these as parts of their essence, but rather as matter; and these are
parts of the concrete thing, but not also of the form, i.e. of that to which the formula refers; wherefore also
they are not present in the formulae. In one kind of formula, then, the formula of such parts will be present,
but in another it must not be present, where the formula does not refer to the concrete object. For it is for this
reason that some things have as their constituent principles parts into which they pass away, while some have
not. Those things which are the form and the matter taken together, e.g. the snub, or the bronze circle, pass
away into these materials, and the matter is a part of them; but those things which do not involve matter but
are without matter, and whose formulae are formulae of the form only, do not pass away,-either not at all or
at any rate not in this way. Therefore these materials are principles and parts of the concrete things, while of
the form they are neither parts nor principles. And therefore the clay statue is resolved into clay and the ball
into bronze and Callias into flesh and bones, and again the circle into its segments; for there is a sense of
'circle' in which involves matter. For 'circle' is used ambiguously, meaning both the circle, unqualified, and
the individual circle, because there is no name peculiar to the individuals.

The truth has indeed now been stated, but still let us state it yet more clearly, taking up the question again.
The parts of the formula, into which the formula is divided, are prior to it, either all or some of them. The
formula of the right angle, however, does not include the formula of the acute, but the formula of the acute
includes that of the right angle; for he who defines the acute uses the right angle; for the acute is 'less than a

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right angle'. The circle and the semicircle also are in a like relation; for the semicircle is defined by the circle;
and so is the finger by the whole body, for a finger is 'such and such a part of a man'. Therefore the parts
which are of the nature of matter, and into which as its matter a thing is divided, are posterior; but those
which are of the nature of parts of the formula, and of the substance according to its formula, are prior, either
all or some of them. And since the soul of animals (for this is the substance of a living being) is their
substance according to the formula, i.e. the form and the essence of a body of a certain kind (at least we shall
define each part, if we define it well, not without reference to its function, and this cannot belong to it without
perception), so that the parts of soul are prior, either all or some of them, to the concrete 'animal', and so too
with each individual animal; and the body and parts are posterior to this, the essential substance, and it is not
the substance but the concrete thing that is divided into these parts as its matter:-this being so, to the concrete
thing these are in a sense prior, but in a sense they are not. For they cannot even exist if severed from the
whole; for it is not a finger in any and every state that is the finger of a living thing, but a dead finger is a
finger only in name. Some parts are neither prior nor posterior to the whole, i.e. those which are dominant
and in which the formula, i.e. the essential substance, is immediately present, e.g. perhaps the heart or the
brain; for it does not matter in the least which of the two has this quality. But man and horse and terms which
are thus applied to individuals, but universally, are not substance but something composed of this particular
formula and this particular matter treated as universal; and as regards the individual, Socrates already
includes in him ultimate individual matter; and similarly in all other cases. 'A part' may be a part either of the
form (i.e. of the essence), or of the compound of the form and the matter, or of the matter itself. But only the
parts of the form are parts of the formula, and the formula is of the universal; for 'being a circle' is the same as
the circle, and 'being a soul' the same as the soul. But when we come to the concrete thing, e.g. this circle, i.e.
one of the individual circles, whether perceptible or intelligible (I mean by intelligible circles the
mathematical, and by perceptible circles those of bronze and of wood),-of these there is no definition, but
they are known by the aid of intuitive thinking or of perception; and when they pass out of this complete
realization it is not clear whether they exist or not; but they are always stated and recognized by means of the
universal formula. But matter is unknowable in itself. And some matter is perceptible and some intelligible,
perceptible matter being for instance bronze and wood and all matter that is changeable, and intelligible
matter being that which is present in perceptible things not qua perceptible, i.e. the objects of mathematics.

We have stated, then, how matters stand with regard to whole and part, and their priority and posteriority. But
when any one asks whether the right angle and the circle and the animal are prior, or the things into which
they are divided and of which they consist, i.e. the parts, we must meet the inquiry by saying that the question
cannot be answered simply. For if even bare soul is the animal or the living thing, or the soul of each
individual is the individual itself, and 'being a circle' is the circle, and 'being a right angle' and the essence of
the right angle is the right angle, then the whole in one sense must be called posterior to the art in one sense,
i.e. to the parts included in the formula and to the parts of the individual right angle (for both the material
right angle which is made of bronze, and that which is formed by individual lines, are posterior to their parts);
while the immaterial right angle is posterior to the parts included in the formula, but prior to those included in
the particular instance, and the question must not be answered simply. If, however, the soul is something
different and is not identical with the animal, even so some parts must, as we have maintained, be called prior
and others must not.

Another question is naturally raised, viz. what sort of parts belong to the form and what sort not to the form,
but to the concrete thing. Yet if this is not plain it is not possible to define any thing; for definition is of the
universal and of the form. If then it is not evident what sort of parts are of the nature of matter and what sort
are not, neither will the formula of the thing be evident. In the case of things which are found to occur in
specifically different materials, as a circle may exist in bronze or stone or wood, it seems plain that these, the
bronze or the stone, are no part of the essence of the circle, since it is found apart from them. Of things which
are not seen to exist apart, there is no reason why the same may not be true, just as if all circles that had ever
been seen were of bronze; for none the less the bronze would be no part of the form; but it is hard to eliminate
it in thought. E.g. the form of man is always found in flesh and bones and parts of this kind; are these then

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also parts of the form and the formula? No, they are matter; but because man is not found also in other
matters we are unable to perform the abstraction.

Since this is thought to be possible, but it is not clear when it is the case, some people already raise the
question even in the case of the circle and the triangle, thinking that it is not right to define these by reference
to lines and to the continuous, but that all these are to the circle or the triangle as flesh and bones are to man,
and bronze or stone to the statue; and they reduce all things to numbers, and they say the formula of 'line' is
that of 'two'. And of those who assert the Ideas some make 'two' the line-itself, and others make it the Form
of the line; for in some cases they say the Form and that of which it is the Form are the same, e.g. 'two' and
the Form of two; but in the case of 'line' they say this is no longer so.

It follows then that there is one Form for many things whose form is evidently different (a conclusion which
confronted the Pythagoreans also); and it is possible to make one thing the Form-itself of all, and to hold that
the others are not Forms; but thus all things will be one.

We have pointed out, then, that the question of definitions contains some difficulty, and why this is so. And
so to reduce all things thus to Forms and to eliminate the matter is useless labour; for some things surely are a
particular form in a particular matter, or particular things in a particular state. And the comparison which
Socrates the younger used to make in the case of 'animal' is not sound; for it leads away from the truth, and
makes one suppose that man can possibly exist without his parts, as the circle can without the bronze. But the
case is not similar; for an animal is something perceptible, and it is not possible to define it without reference
to movement-nor, therefore, without reference to the parts' being in a certain state. For it is not a hand in any
and every state that is a part of man, but only when it can fulfil its work, and therefore only when it is alive; if
it is not alive it is not a part.

Regarding the objects of mathematics, why are the formulae of the parts not parts of the formulae of the
wholes; e.g. why are not the semicircles included in the formula of the circle? It cannot be said, 'because
these parts are perceptible things'; for they are not. But perhaps this makes no difference; for even some
things which are not perceptible must have matter; indeed there is some matter in everything which is not an
essence and a bare form but a 'this'. The semicircles, then, will not be parts of the universal circle, but will be
parts of the individual circles, as has been said before; for while one kind of matter is perceptible, there is
another which is intelligible.

It is clear also that the soul is the primary substance and the body is matter, and man or animal is the
compound of both taken universally; and 'Socrates' or 'Coriscus', if even the soul of Socrates may be called
Socrates, has two meanings (for some mean by such a term the soul, and others mean the concrete thing), but
if 'Socrates' or 'Coriscus' means simply this particular soul and this particular body, the individual is
analogous to the universal in its composition.

Whether there is, apart from the matter of such substances, another kind of matter, and one should look for
some substance other than these, e.g. numbers or something of the sort, must be considered later. For it is for
the sake of this that we are trying to determine the nature of perceptible substances as well, since in a sense
the inquiry about perceptible substances is the work of physics, i.e. of second philosophy; for the physicist
must come to know not only about the matter, but also about the substance expressed in the formula, and
even more than about the other. And in the case of definitions, how the elements in the formula are parts of
the definition, and why the definition is one formula (for clearly the thing is one, but in virtue of what is the
thing one, although it has parts?),-this must be considered later.

What the essence is and in what sense it is independent, has been stated universally in a way which is true of
every case, and also why the formula of the essence of some things contains the parts of the thing defined,
while that of others does not. And we have stated that in the formula of the substance the material parts will

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not be present (for they are not even parts of the substance in that sense, but of the concrete substance; but of
this there is in a sense a formula, and in a sense there is not; for there is no formula of it with its matter, for
this is indefinite, but there is a formula of it with reference to its primary substance-e.g. in the case of man
the formula of the soul-, for the substance is the indwelling form, from which and the matter the so-called
concrete substance is derived; e.g. concavity is a form of this sort, for from this and the nose arise 'snub nose'
and 'snubness'); but in the concrete substance, e.g. a snub nose or Callias, the matter also will be present. And
we have stated that the essence and the thing itself are in some cases the same; ie. in the case of primary
substances, e.g. curvature and the essence of curvature if this is primary. (By a 'primary' substance I mean one
which does not imply the presence of something in something else, i.e. in something that underlies it which
acts as matter.) But things which are of the nature of matter, or of wholes that include matter, are not the
same as their essences, nor are accidental unities like that of 'Socrates' and 'musical'; for these are the same
only by accident.

Now let us treat first of definition, in so far as we have not treated of it in the Analytics; for the problem
stated in them is useful for our inquiries concerning substance. I mean this problem: -wherein can consist the
unity of that, the formula of which we call a definition, as for instance, in the case of man, 'two-footed
animal'; for let this be the formula of man. Why, then, is this one, and not many, viz. 'animal' and
'two-footed'? For in the case of 'man' and 'pale' there is a plurality when one term does not belong to the
other, but a unity when it does belong and the subject, man, has a certain attribute; for then a unity is
produced and we have 'the pale man'. In the present case, on the other hand, one does not share in the other;
the genus is not thought to share in its differentiae (for then the same thing would share in contraries; for the
differentiae by which the genus is divided are contrary). And even if the genus does share in them, the same
argument applies, since the differentiae present in man are many, e.g. endowed with feet, two-footed,
featherless. Why are these one and not many? Not because they are present in one thing; for on this principle
a unity can be made out of all the attributes of a thing. But surely all the attributes in the definition must be
one; for the definition is a single formula and a formula of substance, so that it must be a formula of some one
thing; for substance means a 'one' and a 'this', as we maintain.

We must first inquire about definitions reached by the method of divisions. There is nothing in the definition
except the first-named and the differentiae. The other genera are the first genus and along with this the
differentiae that are taken with it, e.g. the first may be 'animal', the next 'animal which is two-footed', and
again 'animal which is two-footed and featherless', and similarly if the definition includes more terms. And
in general it makes no difference whether it includes many or few terms,-nor, therefore, whether it includes
few or simply two; and of the two the one is differentia and the other genus; e.g. in 'two-footed animal'
'animal' is genus, and the other is differentia.

If then the genus absolutely does not exist apart from the species-of-a-genus, or if it exists but exists as
matter (for the voice is genus and matter, but its differentiae make the species, i.e. the letters, out of it),
clearly the definition is the formula which comprises the differentiae.

But it is also necessary that the division be by the differentia of the diferentia; e.g. 'endowed with feet' is a
differentia of 'animal'; again the differentia of 'animal endowed with feet' must be of it qua endowed with
feet. Therefore we must not say, if we are to speak rightly, that of that which is endowed with feet one part
has feathers and one is featherless (if we do this we do it through incapacity); we must divide it only into
cloven-footed and not cloven; for these are differentiae in the foot; cloven-footedness is a form of
footedness. And the process wants always to go on so till it reaches the species that contain no differences.
And then there will be as many kinds of foot as there are differentiae, and the kinds of animals endowed with
feet will be equal in number to the differentiae. If then this is so, clearly the last differentia will be the
substance of the thing and its definition, since it is not right to state the same things more than once in our
definitions; for it is superfluous. And this does happen; for when we say 'animal endowed with feet and
two-footed' we have said nothing other than 'animal having feet, having two feet'; and if we divide this by the

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proper division, we shall be saying the same thing more than once-as many times as there are differentiae.

If then a differentia of a differentia be taken at each step, one differentia-the last-will be the form and the
substance; but if we divide according to accidental qualities, e.g. if we were to divide that which is endowed
with feet into the white and the black, there will be as many differentiae as there are cuts. Therefore it is plain
that the definition is the formula which contains the differentiae, or, according to the right method, the last of
these. This would be evident, if we were to change the order of such definitions, e.g. of that of man, saying
'animal which is two-footed and endowed with feet'; for 'endowed with feet' is superfluous when
'two-footed' has been said. But there is no order in the substance; for how are we to think the one element
posterior and the other prior? Regarding the definitions, then, which are reached by the method of divisions,
let this suffice as our first attempt at stating their nature.

Let us return to the subject of our inquiry, which is substance. As the substratum and the essence and the
compound of these are called substance, so also is the universal. About two of these we have spoken; both
about the essence and about the substratum, of which we have said that it underlies in two senses, either being
a 'this'-which is the way in which an animal underlies its attributes-or as the matter underlies the complete
reality. The universal also is thought by some to be in the fullest sense a cause, and a principle; therefore let
us attack the discussion of this point also. For it seems impossible that any universal term should be the name
of a substance. For firstly the substance of each thing is that which is peculiar to it, which does not belong to
anything else; but the universal is common, since that is called universal which is such as to belong to more
than one thing. Of which individual then will this be the substance? Either of all or of none; but it cannot be
the substance of all. And if it is to be the substance of one, this one will be the others also; for things whose
substance is one and whose essence is one are themselves also one.

Further, substance means that which is not predicable of a subject, but the universal is predicable of some
subject always.

But perhaps the universal, while it cannot be substance in the way in which the essence is so, can be present
in this; e.g. 'animal' can be present in 'man' and 'horse'. Then clearly it is a formula of the essence. And it
makes no difference even if it is not a formula of everything that is in the substance; for none the less the
universal will be the substance of something, as 'man' is the substance of the individual man in whom it is
present, so that the same result will follow once more; for the universal, e.g. 'animal', will be the substance of
that in which it is present as something peculiar to it. And further it is impossible and absurd that the 'this', i.e.
the substance, if it consists of parts, should not consist of substances nor of what is a 'this', but of quality; for
that which is not substance, i.e. the quality, will then be prior to substance and to the 'this'. Which is
impossible; for neither in formula nor in time nor in coming to be can the modifications be prior to the
substance; for then they will also be separable from it. Further, Socrates will contain a substance present in a
substance, so that this will be the substance of two things. And in general it follows, if man and such things
are substance, that none of the elements in their formulae is the substance of anything, nor does it exist apart
from the species or in anything else; I mean, for instance, that no 'animal' exists apart from the particular
kinds of animal, nor does any other of the elements present in formulae exist apart.

If, then, we view the matter from these standpoints, it is plain that no universal attribute is a substance, and
this is plain also from the fact that no common predicate indicates a 'this', but rather a 'such'. If not, many
difficulties follow and especially the 'third man'.

The conclusion is evident also from the following consideration. A substance cannot consist of substances
present in it in complete reality; for things that are thus in complete reality two are never in complete reality
one, though if they are potentially two, they can be one (e.g. the double line consists of two
halves-potentially; for the complete realization of the halves divides them from one another); therefore if the
substance is one, it will not consist of substances present in it and present in this way, which Democritus

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describes rightly; he says one thing cannot be made out of two nor two out of one; for he identifies substances
with his indivisible magnitudes. It is clear therefore that the same will hold good of number, if number is a
synthesis of units, as is said by some; for two is either not one, or there is no unit present in it in complete
reality. But our result involves a difficulty. If no substance can consist of universals because a universal
indicates a 'such', not a 'this', and if no substance can be composed of substances existing in complete reality,
every substance would be incomposite, so that there would not even be a formula of any substance. But it is
thought by all and was stated long ago that it is either only, or primarily, substance that can defined; yet now
it seems that not even substance can. There cannot, then, be a definition of anything; or in a sense there can
be, and in a sense there cannot. And what we are saying will be plainer from what follows.

It is clear also from these very facts what consequence confronts those who say the Ideas are substances
capable of separate existence, and at the same time make the Form consist of the genus and the differentiae.
For if the Forms exist and 'animal' is present in 'man' and 'horse', it is either one and the same in number, or
different. (In formula it is clearly one; for he who states the formula will go through the formula in either
case.) If then there is a 'man-in-himself who is a 'this' and exists apart, the parts also of which he consists,
e.g. 'animal' and 'two-footed', must indicate 'thises', and be capable of separate existence, and substances;
therefore 'animal', as well as 'man', must be of this sort.

Now (1) if the 'animal' in 'the horse' and in 'man' is one and the same, as you are with yourself, (a) how will
the one in things that exist apart be one, and how will this 'animal' escape being divided even from itself?

Further, (b) if it is to share in 'two-footed' and 'many-footed', an impossible conclusion follows; for contrary
attributes will belong at the same time to it although it is one and a 'this'. If it is not to share in them, what is
the relation implied when one says the animal is two-footed or possessed of feet? But perhaps the two things
are 'put together' and are 'in contact', or are 'mixed'. Yet all these expressions are absurd.

But (2) suppose the Form to be different in each species. Then there will be practically an infinite number of
things whose substance is animal'; for it is not by accident that 'man' has 'animal' for one of its elements.
Further, many things will be 'animal-itself . For (i) the 'animal' in each species will be the substance of the
species; for it is after nothing else that the species is called; if it were, that other would be an element in 'man',
i.e. would be the genus of man. And further, (ii) all the elements of which 'man' is composed will be Ideas.
None of them, then, will be the Idea of one thing and the substance of another; this is impossible. The
'animal', then, present in each species of animals will be animal-itself. Further, from what is this 'animal' in
each species derived, and how will it be derived from animal-itself? Or how can this 'animal', whose essence
is simply animality, exist apart from animal-itself?

Further, (3)in the case of sensible things both these consequences and others still more absurd follow. If, then,
these consequences are impossible, clearly there are not Forms of sensible things in the sense in which some
maintain their existence.

Since substance is of two kinds, the concrete thing and the formula (I mean that one kind of substance is the
formula taken with the matter, while another kind is the formula in its generality), substances in the former
sense are capable of destruction (for they are capable also of generation), but there is no destruction of the
formula in the sense that it is ever in course of being destroyed (for there is no generation of it either; the
being of house is not generated, but only the being of this house), but without generation and destruction
formulae are and are not; for it has been shown that no one begets nor makes these. For this reason, also,
there is neither definition of nor demonstration about sensible individual substances, because they have
matter whose nature is such that they are capable both of being and of not being; for which reason all the
individual instances of them are destructible. If then demonstration is of necessary truths and definition is a
scientific process, and if, just as knowledge cannot be sometimes knowledge and sometimes ignorance, but
the state which varies thus is opinion, so too demonstration and definition cannot vary thus, but it is opinion

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that deals with that which can be otherwise than as it is, clearly there can neither be definition of nor
demonstration about sensible individuals. For perishing things are obscure to those who have the relevant
knowledge, when they have passed from our perception; and though the formulae remain in the soul
unchanged, there will no longer be either definition or demonstration. And so when one of the
definition-mongers defines any individual, he must recognize that his definition may always be overthrown;
for it is not possible to define such things.

Nor is it possible to define any Idea. For the Idea is, as its supporters say, an individual, and can exist apart;
and the formula must consist of words; and he who defines must not invent a word (for it would be
unknown), but the established words are common to all the members of a class; these then must apply to
something besides the thing defined; e.g. if one were defining you, he would say 'an animal which is lean' or
'pale', or something else which will apply also to some one other than you. If any one were to say that perhaps
all the attributes taken apart may belong to many subjects, but together they belong only to this one, we must
reply first that they belong also to both the elements; e.g. 'two-footed animal' belongs to animal and to the
two-footed. (And in the case of eternal entities this is even necessary, since the elements are prior to and
parts of the compound; nay more, they can also exist apart, if 'man' can exist apart. For either neither or both
can. If, then, neither can, the genus will not exist apart from the various species; but if it does, the differentia
will also.) Secondly, we must reply that 'animal' and 'two-footed' are prior in being to 'two-footed animal';
and things which are prior to others are not destroyed when the others are.

Again, if the Ideas consist of Ideas (as they must, since elements are simpler than the compound), it will be
further necessary that the elements also of which the Idea consists, e.g. 'animal' and 'two-footed', should be
predicated of many subjects. If not, how will they come to be known? For there will then be an Idea which
cannot be predicated of more subjects than one. But this is not thought possible-every Idea is thought to be
capable of being shared.

As has been said, then, the impossibility of defining individuals escapes notice in the case of eternal things,
especially those which are unique, like the sun or the moon. For people err not only by adding attributes
whose removal the sun would survive, e.g. 'going round the earth' or 'night-hidden' (for from their view it
follows that if it stands still or is visible, it will no longer be the sun; but it is strange if this is so; for 'the sun'
means a certain substance); but also by the mention of attributes which can belong to another subject; e.g. if
another thing with the stated attributes comes into existence, clearly it will be a sun; the formula therefore is
general. But the sun was supposed to be an individual, like Cleon or Socrates. After all, why does not one of
the supporters of the Ideas produce a definition of an Idea? It would become clear, if they tried, that what has
now been said is true.

Evidently even of the things that are thought to be substances, most are only potencies,-both the parts of
animals (for none of them exists separately; and when they are separated, then too they exist, all of them,
merely as matter) and earth and fire and air; for none of them is a unity, but as it were a mere heap, till they
are worked up and some unity is made out of them. One might most readily suppose the parts of living things
and the parts of the soul nearly related to them to turn out to be both, i.e. existent in complete reality as well
as in potency, because they have sources of movement in something in their joints; for which reason some
animals live when divided. Yet all the parts must exist only potentially, when they are one and continuous by
nature,-not by force or by growing into one, for such a phenomenon is an abnormality.

Since the term 'unity' is used like the term 'being', and the substance of that which is one is one, and things
whose substance is numerically one are numerically one, evidently neither unity nor being can be the
substance of things, just as being an element or a principle cannot be the substance, but we ask what, then, the
principle is, that we may reduce the thing to something more knowable. Now of these concepts 'being' and
'unity' are more substantial than 'principle' or 'element' or 'cause', but not even the former are substance, since
in general nothing that is common is substance; for substance does not belong to anything but to itself and to

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that which has it, of which it is the substance. Further, that which is one cannot be in many places at the same
time, but that which is common is present in many places at the same time; so that clearly no universal exists
apart from its individuals.

But those who say the Forms exist, in one respect are right, in giving the Forms separate existence, if they are
substances; but in another respect they are not right, because they say the one over many is a Form. The
reason for their doing this is that they cannot declare what are the substances of this sort, the imperishable
substances which exist apart from the individual and sensible substances. They make them, then, the same in
kind as the perishable things (for this kind of substance we know) — 'man-himself and 'horse-itself, adding
to the sensible things the word 'itself. Yet even if we had not seen the stars, none the less, I suppose, would
they have been eternal substances apart from those which we knew; so that now also if we do not know what
non-sensible substances there are, yet it is doubtless necessary that there should he some.-Clearly, then, no
universal term is the name of a substance, and no substance is composed of substances.

Let us state what, i.e. what kind of thing, substance should be said to be, taking once more another
starting-point; for perhaps from this we shall get a clear view also of that substance which exists apart from
sensible substances. Since, then, substance is a principle and a cause, let us pursue it from this starting-point.
The 'why' is always sought in this form — 'why does one thing attach to some other?' For to inquire why the
musical man is a musical man, is either to inquire — as we have said why the man is musical, or it is
something else. Now 'why a thing is itself is a meaningless inquiry (for (to give meaning to the question
'why') the fact or the existence of the thing must already be evident-e.g. that the moon is eclipsed-but the
fact that a thing is itself is the single reason and the single cause to be given in answer to all such questions as
why the man is man, or the musician musical', unless one were to answer 'because each thing is inseparable
from itself, and its being one just meant this'; this, however, is common to all things and is a short and easy
way with the question). But we can inquire why man is an animal of such and such a nature. This, then, is
plain, that we are not inquiring why he who is a man is a man. We are inquiring, then, why something is
predicable of something (that it is predicable must be clear; for if not, the inquiry is an inquiry into nothing).
E.g. why does it thunder? This is the same as 'why is sound produced in the clouds?' Thus the inquiry is about
the predication of one thing of another. And why are these things, i.e. bricks and stones, a house? Plainly we
are seeking the cause. And this is the essence (to speak abstractly), which in some cases is the end, e.g.
perhaps in the case of a house or a bed, and in some cases is the first mover; for this also is a cause. But while
the efficient cause is sought in the case of genesis and destruction, the final cause is sought in the case of
being also.

The object of the inquiry is most easily overlooked where one term is not expressly predicated of another
(e.g. when we inquire 'what man is'), because we do not distinguish and do not say definitely that certain
elements make up a certain whole. But we must articulate our meaning before we begin to inquire; if not, the
inquiry is on the border-line between being a search for something and a search for nothing. Since we must
have the existence of the thing as something given, clearly the question is why the matter is some definite
thing; e.g. why are these materials a house? Because that which was the essence of a house is present. And
why is this individual thing, or this body having this form, a man? Therefore what we seek is the cause, i.e.
the form, by reason of which the matter is some definite thing; and this is the substance of the thing.
Evidently, then, in the case of simple terms no inquiry nor teaching is possible; our attitude towards such
things is other than that of inquiry.

Since that which is compounded out of something so that the whole is one, not like a heap but like a
syllable-now the syllable is not its elements, ba is not the same as b and a, nor is flesh fire and earth (for
when these are separated the wholes, i.e. the flesh and the syllable, no longer exist, but the elements of the
syllable exist, and so do fire and earth); the syllable, then, is something-not only its elements (the vowel and
the consonant) but also something else, and the flesh is not only fire and earth or the hot and the cold, but also
something else:-if, then, that something must itself be either an element or composed of elements, (1) if it is

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an element the same argument will again apply; for flesh will consist of this and fire and earth and something
still further, so that the process will go on to infinity. But (2) if it is a compound, clearly it will be a
compound not of one but of more than one (or else that one will be the thing itself), so that again in this case
we can use the same argument as in the case of flesh or of the syllable. But it would seem that this 'other' is
something, and not an element, and that it is the cause which makes this thing flesh and that a syllable. And
similarly in all other cases. And this is the substance of each thing (for this is the primary cause of its being);
and since, while some things are not substances, as many as are substances are formed in accordance with a
nature of their own and by a process of nature, their substance would seem to be this kind of 'nature', which is
not an element but a principle. An element, on the other hand, is that into which a thing is divided and which
is present in it as matter; e.g. a and b are the elements of the syllable.

Book VIII

WE must reckon up the results arising from what has been said, and compute the sum of them, and put the
finishing touch to our inquiry. We have said that the causes, principles, and elements of substances are the
object of our search. And some substances are recognized by every one, but some have been advocated by
particular schools. Those generally recognized are the natural substances, i.e. fire, earth, water, air, the simple
bodies; second plants and their parts, and animals and the parts of animals; and finally the physical universe
and its parts; while some particular schools say that Forms and the objects of mathematics are substances. But
there are arguments which lead to the conclusion that there are other substances, the essence and the
substratum. Again, in another way the genus seems more substantial than the various species, and the
universal than the particulars. And with the universal and the genus the Ideas are connected; it is in virtue of
the same argument that they are thought to be substances. And since the essence is substance, and the
definition is a formula of the essence, for this reason we have discussed definition and essential predication.
Since the definition is a formula, and a formula has parts, we had to consider also with respect to the notion
of 'part', what are parts of the substance and what are not, and whether the parts of the substance are also parts
of the definition. Further, too, neither the universal nor the genus is a substance; we must inquire later into the
Ideas and the objects of mathematics; for some say these are substances as well as the sensible substances.

But now let us resume the discussion of the generally recognized substances. These are the sensible
substances, and sensible substances all have matter. The substratum is substance, and this is in one sense the
matter (and by matter I mean that which, not being a 'this' actually, is potentially a 'this'), and in another sense
the formula or shape (that which being a 'this' can be separately formulated), and thirdly the complex of these
two, which alone is generated and destroyed, and is, without qualification, capable of separate existence; for
of substances completely expressible in a formula some are separable and some are separable and some are
not.

But clearly matter also is substance; for in all the opposite changes that occur there is something which
underlies the changes, e.g. in respect of place that which is now here and again elsewhere, and in respect of
increase that which is now of one size and again less or greater, and in respect of alteration that which is now
healthy and again diseased; and similarly in respect of substance there is something that is now being
generated and again being destroyed, and now underlies the process as a 'this' and again underlies it in respect
of a privation of positive character. And in this change the others are involved. But in either one or two of the
others this is not involved; for it is not necessary if a thing has matter for change of place that it should also
have matter for generation and destruction.

The difference between becoming in the full sense and becoming in a qualified sense has been stated in our
physical works.

Since the substance which exists as underlying and as matter is generally recognized, and this that which
exists potentially, it remains for us to say what is the substance, in the sense of actuality, of sensible things.

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Democritus seems to think there are three kinds of difference between things; the underlying body, the
matter, is one and the same, but they differ either in rhythm, i.e. shape, or in turning, i.e. position, or in
inter-contact, i.e. order. But evidently there are many differences; for instance, some things are characterized
by the mode of composition of their matter, e.g. the things formed by blending, such as honey-water; and
others by being bound together, e.g. bundle; and others by being glued together, e.g. a book; and others by
being nailed together, e.g. a casket; and others in more than one of these ways; and others by position, e.g.
threshold and lintel (for these differ by being placed in a certain way); and others by time, e.g. dinner and
breakfast; and others by place, e.g. the winds; and others by the affections proper to sensible things, e.g.
hardness and softness, density and rarity, dryness and wetness; and some things by some of these qualities,
others by them all, and in general some by excess and some by defect. Clearly, then, the word 'is' has just as
many meanings; a thing is a threshold because it lies in such and such a position, and its being means its lying
in that position, while being ice means having been solidified in such and such a way. And the being of some
things will be defined by all these qualities, because some parts of them are mixed, others are blended, others
are bound together, others are solidified, and others use the other differentiae; e.g. the hand or the foot
requires such complex definition. We must grasp, then, the kinds of differentiae (for these will be the
principles of the being of things), e.g. the things characterized by the more and the less, or by the dense and
the rare, and by other such qualities; for all these are forms of excess and defect. And anything that is
characterized by shape or by smoothness and roughness is characterized by the straight and the curved. And
for other things their being will mean their being mixed, and their not being will mean the opposite.

It is clear, then, from these facts that, since its substance is the cause of each thing's being, we must seek in
these differentiae what is the cause of the being of each of these things. Now none of these differentiae is
substance, even when coupled with matter, yet it is what is analogous to substance in each case; and as in
substances that which is predicated of the matter is the actuality itself, in all other definitions also it is what
most resembles full actuality. E.g. if we had to define a threshold, we should say 'wood or stone in such and
such a position', and a house we should define as 'bricks and timbers in such and such a position',(or a
purpose may exist as well in some cases), and if we had to define ice we should say 'water frozen or solidified
in such and such a way', and harmony is 'such and such a blending of high and low'; and similarly in all other
cases.

Obviously, then, the actuality or the formula is different when the matter is different; for in some cases it is
the composition, in others the mixing, and in others some other of the attributes we have named. And so, of
the people who go in for defining, those who define a house as stones, bricks, and timbers are speaking of the
potential house, for these are the matter; but those who propose 'a receptacle to shelter chattels and living
beings', or something of the sort, speak of the actuality. Those who combine both of these speak of the third
kind of substance, which is composed of matter and form (for the formula that gives the differentiae seems to
be an account of the form or actuality, while that which gives the components is rather an account of the
matter); and the same is true of the kind of definitions which Archytas used to accept; they are accounts of
the combined form and matter. E.g. what is still weather? Absence of motion in a large expanse of air; air is
the matter, and absence of motion is the actuality and substance. What is a calm? Smoothness of sea; the
material substratum is the sea, and the actuality or shape is smoothness. It is obvious then, from what has
been said, what sensible substance is and how it exists-one kind of it as matter, another as form or actuality,
while the third kind is that which is composed of these two.

We must not fail to notice that sometimes it is not clear whether a name means the composite substance, or
the actuality or form, e.g. whether 'house' is a sign for the composite thing, 'a covering consisting of bricks
and stones laid thus and thus', or for the actuality or form, 'a covering', and whether a line is 'twoness in
length' or 'twoness', and whether an animal is soul in a body' or 'a soul'; for soul is the substance or actuality
of some body. Animal' might even be applied to both, not as something definable by one formula, but as
related to a single thing. But this question, while important for another purpose, is of no importance for the
inquiry into sensible substance; for the essence certainly attaches to the form and the actuality. For 'soul' and

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'to be soul' are the same, but 'to be man' and 'man' are not the same, unless even the bare soul is to be called
man; and thus on one interpretation the thing is the same as its essence, and on another it is not.

If we examine we find that the syllable does not consist of the letters + juxtaposition, nor is the house bricks
+ juxtaposition. And this is right; for the juxtaposition or mixing does not consist of those things of which it
is the juxtaposition or mixing. And the same is true in all other cases; e.g. if the threshold is characterized by
its position, the position is not constituted by the threshold, but rather the latter is constituted by the former.
Nor is man animal + biped, but there must be something besides these, if these are matter,-something which
is neither an element in the whole nor a compound, but is the substance; but this people eliminate, and state
only the matter. If, then, this is the cause of the thing's being, and if the cause of its being is its substance,
they will not be stating the substance itself.

(This, then, must either be eternal or it must be destructible without being ever in course of being destroyed,
and must have come to be without ever being in course of coming to be. But it has been proved and explained
elsewhere that no one makes or begets the form, but it is the individual that is made, i.e. the complex of form
and matter that is generated. Whether the substances of destructible things can exist apart, is not yet at all
clear; except that obviously this is impossible in some cases-in the case of things which cannot exist apart
from the individual instances, e.g. house or utensil. Perhaps, indeed, neither these things themselves, nor any
of the other things which are not formed by nature, are substances at all; for one might say that the nature in
natural objects is the only substance to be found in destructible things.)

Therefore the difficulty which used to be raised by the school of Antisthenes and other such uneducated
people has a certain timeliness. They said that the 'what' cannot be defined (for the definition so called is a
'long rigmarole') but of what sort a thing, e.g. silver, is, they thought it possible actually to explain, not saying
what it is, but that it is like tin. Therefore one kind of substance can be defined and formulated, i.e. the
composite kind, whether it be perceptible or intelligible; but the primary parts of which this consists cannot
be defined, since a definitory formula predicates something of something, and one part of the definition must
play the part of matter and the other that of form.

It is also obvious that, if substances are in a sense numbers, they are so in this sense and not, as some say, as
numbers of units. For a definition is a sort of number; for (1) it is divisible, and into indivisible parts (for
definitory formulae are not infinite), and number also is of this nature. And (2) as, when one of the parts of
which a number consists has been taken from or added to the number, it is no longer the same number, but a
different one, even if it is the very smallest part that has been taken away or added, so the definition and the
essence will no longer remain when anything has been taken away or added. And (3) the number must be
something in virtue of which it is one, and this these thinkers cannot state, what makes it one, if it is one (for
either it is not one but a sort of heap, or if it is, we ought to say what it is that makes one out of many); and
the definition is one, but similarly they cannot say what makes it one. And this is a natural result; for the
same reason is applicable, and substance is one in the sense which we have explained, and not, as some say,
by being a sort of unit or point; each is a complete reality and a definite nature. And (4) as number does not
admit of the more and the less, neither does substance, in the sense of form, but if any substance does, it is
only the substance which involves matter. Let this, then, suffice for an account of the generation and
destruction of so-called substances in what sense it is possible and in what sense impossible — and of the
reduction of things to number.

Regarding material substance we must not forget that even if all things come from the same first cause or
have the same things for their first causes, and if the same matter serves as starting-point for their generation,
yet there is a matter proper to each, e.g. for phlegm the sweet or the fat, and for bile the bitter, or something
else; though perhaps these come from the same original matter. And there come to be several matters for the
same thing, when the one matter is matter for the other; e.g. phlegm comes from the fat and from the sweet, if
the fat comes from the sweet; and it comes from bile by analysis of the bile into its ultimate matter. For one

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thing comes from another in two senses, either because it will be found at a later stage, or because it is
produced if the other is analysed into its original constituents. When the matter is one, different things may be
produced owing to difference in the moving cause; e.g. from wood may be made both a chest and a bed. But
some different things must have their matter different; e.g. a saw could not be made of wood, nor is this in the
power of the moving cause; for it could not make a saw of wool or of wood. But if, as a matter of fact, the
same thing can be made of different material, clearly the art, i.e. the moving principle, is the same; for if both
the matter and the moving cause were different, the product would be so too.

When one inquires into the cause of something, one should, since 'causes' are spoken of in several senses,
state all the possible causes, what is the material cause of man? Shall we say 'the menstrual fluid'? What is
moving cause? Shall we say 'the seed'? The formal cause? His essence. The final cause? His end. But perhaps
the latter two are the same.-It is the proximate causes we must state. What is the material cause? We must
name not fire or earth, but the matter peculiar to the thing.

Regarding the substances that are natural and generable, if the causes are really these and of this number and
we have to learn the causes, we must inquire thus, if we are to inquire rightly. But in the case of natural but
eternal substances another account must be given. For perhaps some have no matter, or not matter of this sort
but only such as can be moved in respect of place. Nor does matter belong to those things which exist by
nature but are not substances; their substratum is the substance. E.g what is the cause of eclipse? What is its
matter? There is none; the moon is that which suffers eclipse. What is the moving cause which extinguished
the light? The earth. The final cause perhaps does not exist. The formal principle is the definitory formula,
but this is obscure if it does not include the cause. E.g. what is eclipse? Deprivation of light. But if we add 'by
the earth's coming in between', this is the formula which includes the cause. In the case of sleep it is not clear
what it is that proximately has this affection. Shall we say that it is the animal? Yes, but the animal in virtue
of what, i.e. what is the proximate subject? The heart or some other part. Next, by what is it produced? Next,
what is the affection-that of the proximate subject, not of the whole animal? Shall we say that it is
immobility of such and such a kind? Yes, but to what process in the proximate subject is this due?

Since some things are and are not, without coming to be and ceasing to be, e.g. points, if they can be said to
be, and in general forms (for it is not 'white' comes to be, but the wood comes to be white, if everything that
comes to be comes from something and comes to be something), not all contraries can come from one
another, but it is in different senses that a pale man comes from a dark man, and pale comes from dark. Nor
has everything matter, but only those things which come to be and change into one another. Those things
which, without ever being in course of changing, are or are not, have no matter.

There is difficulty in the question how the matter of each thing is related to its contrary states. E.g. if the body
is potentially healthy, and disease is contrary to health, is it potentially both healthy and diseased? And is
water potentially wine and vinegar? We answer that it is the matter of one in virtue of its positive state and its
form, and of the other in virtue of the privation of its positive state and the corruption of it contrary to its
nature. It is also hard to say why wine is not said to be the matter of vinegar nor potentially vinegar (though
vinegar is produced from it), and why a living man is not said to be potentially dead. In fact they are not, but
the corruptions in question are accidental, and it is the matter of the animal that is itself in virtue of its
corruption the potency and matter of a corpse, and it is water that is the matter of vinegar. For the corpse
comes from the animal, and vinegar from wine, as night from day. And all the things which change thus into
one another must go back to their matter; e.g. if from a corpse is produced an animal, the corpse first goes
back to its matter, and only then becomes an animal; and vinegar first goes back to water, and only then
becomes wine.

To return to the difficulty which has been stated with respect both to definitions and to numbers, what is the
cause of their unity? In the case of all things which have several parts and in which the totality is not, as it
were, a mere heap, but the whole is something beside the parts, there is a cause; for even in bodies contact is

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the cause of unity in some cases, and in others viscosity or some other such quality. And a definition is a set
of words which is one not by being connected together, like the Iliad, but by dealing with one object.-What
then, is it that makes man one; why is he one and not many, e.g. animal + biped, especially if there are, as
some say, an animal-itself and a biped-itself? Why are not those Forms themselves the man, so that men
would exist by participation not in man, nor in-one Form, but in two, animal and biped, and in general man
would be not one but more than one thing, animal and biped?

Clearly, then, if people proceed thus in their usual manner of definition and speech, they cannot explain and
solve the difficulty. But if, as we say, one element is matter and another is form, and one is potentially and
the other actually, the question will no longer be thought a difficulty. For this difficulty is the same as would
arise if 'round bronze' were the definition of 'cloak'; for this word would be a sign of the definitory formula,
so that the question is, what is the cause of the unity of 'round' and 'bronze'? The difficulty disappears,
because the one is matter, the other form. What, then, causes this-that which was potentially to be
actually-except, in the case of things which are generated, the agent? For there is no other cause of the
potential sphere's becoming actually a sphere, but this was the essence of either. Of matter some is
intelligible, some perceptible, and in a formula there is always an element of matter as well as one of
actuality; e.g. the circle is 'a plane figure'. But of the things which have no matter, either intelligible or
perceptible, each is by its nature essentially a kind of unity, as it is essentially a kind of being-individual
substance, quality, or quantity (and so neither 'existent' nor 'one' is present in their definitions), and the
essence of each of them is by its very nature a kind of unity as it is a kind of being-and so none of these has
any reason outside itself, for being one, nor for being a kind of being; for each is by its nature a kind of being
and a kind of unity, not as being in the genus 'being' or 'one' nor in the sense that being and unity can exist
apart from particulars.

Owing to the difficulty about unity some speak of 'participation', and raise the question, what is the cause of
participation and what is it to participate; and others speak of 'communion', as Lycophron says knowledge is a
communion of knowing with the soul; and others say life is a 'composition' or 'connexion' of soul with body.
Yet the same account applies to all cases; for being healthy, too, will on this showing be either a 'communion'
or a 'connexion' or a 'composition' of soul and health, and the fact that the bronze is a triangle will be a
'composition' of bronze and triangle, and the fact that a thing is white will be a 'composition' of surface and
whiteness. The reason is that people look for a unifying formula, and a difference, between potency and
complete reality. But, as has been said, the proximate matter and the form are one and the same thing, the one
potentially, and the other actually. Therefore it is like asking what in general is the cause of unity and of a
thing's being one; for each thing is a unity, and the potential and the actual are somehow one. Therefore there
is no other cause here unless there is something which caused the movement from potency into actuality. And
all things which have no matter are without qualification essentially unities.

Book IX

WE have treated of that which is primarily and to which all the other categories of being are referred-i.e. of
substance. For it is in virtue of the concept of substance that the others also are said to be-quantity and
quality and the like; for all will be found to involve the concept of substance, as we said in the first part of our
work. And since 'being' is in one way divided into individual thing, quality, and quantity, and is in another
way distinguished in respect of potency and complete reality, and of function, let us now add a discussion of
potency and complete reality. And first let us explain potency in the strictest sense, which is, however, not the
most useful for our present purpose. For potency and actuality extend beyond the cases that involve a
reference to motion. But when we have spoken of this first kind, we shall in our discussions of actuality'
explain the other kinds of potency as well.

We have pointed out elsewhere that 'potency' and the word 'can' have several senses. Of these we may neglect
all the potencies that are so called by an equivocation. For some are called so by analogy, as in geometry we

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say one thing is or is not a 'power' of another by virtue of the presence or absence of some relation between
them. But all potencies that conform to the same type are originative sources of some kind, and are called
potencies in reference to one primary kind of potency, which is an originative source of change in another
thing or in the thing itself qua other. For one kind is a potency of being acted on, i.e. the originative source, in
the very thing acted on, of its being passively changed by another thing or by itself qua other; and another
kind is a state of insusceptibility to change for the worse and to destruction by another thing or by the thing
itself qua other by virtue of an originative source of change. In all these definitions is implied the formula if
potency in the primary sense.-And again these so-called potencies are potencies either of merely acting or
being acted on, or of acting or being acted on well, so that even in the formulae of the latter the formulae of
the prior kinds of potency are somehow implied.

Obviously, then, in a sense the potency of acting and of being acted on is one (for a thing may be 'capable'
either because it can itself be acted on or because something else can be acted on by it), but in a sense the
potencies are different. For the one is in the thing acted on; it is because it contains a certain originative
source, and because even the matter is an originative source, that the thing acted on is acted on, and one thing
by one, another by another; for that which is oily can be burnt, and that which yields in a particular way can
be crushed; and similarly in all other cases. But the other potency is in the agent, e.g. heat and the art of
building are present, one in that which can produce heat and the other in the man who can build. And so, in so
far as a thing is an organic unity, it cannot be acted on by itself; for it is one and not two different things. And
'impotence'and 'impotent' stand for the privation which is contrary to potency of this sort, so that every
potency belongs to the same subject and refers to the same process as a corresponding impotence. Privation
has several senses; for it means (1) that which has not a certain quality and (2) that which might naturally
have it but has not it, either (a) in general or (b) when it might naturally have it, and either (a) in some
particular way, e.g. when it has not it completely, or (b) when it has not it at all. And in certain cases if things
which naturally have a quality lose it by violence, we say they have suffered privation.

Since some such originative sources are present in soulless things, and others in things possessed of soul, and
in soul, and in the rational part of the soul, clearly some potencies will, be non-rational and some will be
non-rational and some will be accompanied by a rational formula. This is why all arts, i.e. all productive
forms of knowledge, are potencies; they are originative sources of change in another thing or in the artist
himself considered as other.

And each of those which are accompanied by a rational formula is alike capable of contrary effects, but one
non-rational power produces one effect; e.g. the hot is capable only of heating, but the medical art can
produce both disease and health. The reason is that science is a rational formula, and the same rational
formula explains a thing and its privation, only not in the same way; and in a sense it applies to both, but in a
sense it applies rather to the positive fact. Therefore such sciences must deal with contraries, but with one in
virtue of their own nature and with the other not in virtue of their nature; for the rational formula applies to
one object in virtue of that object's nature, and to the other, in a sense, accidentally. For it is by denial and
removal that it exhibits the contrary; for the contrary is the primary privation, and this is the removal of the
positive term. Now since contraries do not occur in the same thing, but science is a potency which depends on
the possession of a rational formula, and the soul possesses an originative source of movement; therefore,
while the wholesome produces only health and the calorific only heat and the frigorific only cold, the
scientific man produces both the contrary effects. For the rational formula is one which applies to both,
though not in the same way, and it is in a soul which possesses an originative source of movement; so that the
soul will start both processes from the same originative source, having linked them up with the same thing.
And so the things whose potency is according to a rational formula act contrariwise to the things whose
potency is non-rational; for the products of the former are included under one originative source, the rational
formula.

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It is obvious also that the potency of merely doing a thing or having it done to one is implied in that of doing
it or having it done well, but the latter is not always implied in the former: for he who does a thing well must
also do it, but he who does it merely need not also do it well.

There are some who say, as the Megaric school does, that a thing 'can' act only when it is acting, and when it
is not acting it 'cannot' act, e.g. that he who is not building cannot build, but only he who is building, when he
is building; and so in all other cases. It is not hard to see the absurdities that attend this view.

For it is clear that on this view a man will not be a builder unless he is building (for to be a builder is to be
able to build), and so with the other arts. If, then, it is impossible to have such arts if one has not at some time
learnt and acquired them, and it is then impossible not to have them if one has not sometime lost them (either
by forgetfulness or by some accident or by time; for it cannot be by the destruction of the object, for that lasts
for ever), a man will not have the art when he has ceased to use it, and yet he may immediately build again;
how then will he have got the art? And similarly with regard to lifeless things; nothing will be either cold or
hot or sweet or perceptible at all if people are not perceiving it; so that the upholders of this view will have to
maintain the doctrine of Protagoras. But, indeed, nothing will even have perception if it is not perceiving, i.e.
exercising its perception. If, then, that is blind which has not sight though it would naturally have it, when it
would naturally have it and when it still exists, the same people will be blind many times in the day-and deaf
too.

Again, if that which is deprived of potency is incapable, that which is not happening will be incapable of
happening; but he who says of that which is incapable of happening either that it is or that it will be will say
what is untrue; for this is what incapacity meant. Therefore these views do away with both movement and
becoming. For that which stands will always stand, and that which sits will always sit, since if it is sitting it
will not get up; for that which, as we are told, cannot get up will be incapable of getting up. But we cannot
say this, so that evidently potency and actuality are different (but these views make potency and actuality the
same, and so it is no small thing they are seeking to annihilate), so that it is possible that a thing may be
capable of being and not he, and capable of not being and yet he, and similarly with the other kinds of
predicate; it may be capable of walking and yet not walk, or capable of not walking and yet walk. And a thing
is capable of doing something if there will be nothing impossible in its having the actuality of that of which it
is said to have the capacity. I mean, for instance, if a thing is capable of sitting and it is open to it to sit, there
will be nothing impossible in its actually sitting; and similarly if it is capable of being moved or moving, or
of standing or making to stand, or of being or coming to be, or of not being or not coming to be.

The word 'actuality', which we connect with 'complete reality', has, in the main, been extended from
movements to other things; for actuality in the strict sense is thought to be identical with movement. And so
people do not assign movement to non-existent things, though they do assign some other predicates. E.g.
they say that non-existent things are objects of thought and desire, but not that they are moved; and this
because, while ex hypothesi they do not actually exist, they would have to exist actually if they were moved.
For of non-existent things some exist potentially; but they do not exist, because they do not exist in complete
reality.

If what we have described is identical with the capable or convertible with it, evidently it cannot be true to
say 'this is capable of being but will not be', which would imply that the things incapable of being would on
this showing vanish. Suppose, for instance, that a man-one who did not take account of that which is
incapable of being-were to say that the diagonal of the square is capable of being measured but will not be
measured, because a thing may well be capable of being or coming to be, and yet not be or be about to be.
But from the premisses this necessarily follows, that if we actually supposed that which is not, but is capable
of being, to be or to have come to be, there will be nothing impossible in this; but the result will be
impossible, for the measuring of the diagonal is impossible. For the false and the impossible are not the same;
that you are standing now is false, but that you should be standing is not impossible.

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At the same time it is clear that if, when A is real, B must be real, then, when A is possible, B also must be
possible. For if B need not be possible, there is nothing to prevent its not being possible. Now let A be
supposed possible. Then, when A was possible, we agreed that nothing impossible followed if A were
supposed to be real; and then B must of course be real. But we supposed B to be impossible. Let it be
impossible then. If, then, B is impossible, A also must be so. But the first was supposed impossible; therefore
the second also is impossible. If, then, A is possible, B also will be possible, if they were so related that if
A,is real, B must be real. If, then, A and B being thus related, B is not possible on this condition, and B will
not be related as was supposed. And if when A is possible, B must be possible, then if A is real, B also must
be real. For to say that B must be possible, if A is possible, means this, that if A is real both at the time when
and in the way in which it was supposed capable of being real, B also must then and in that way be real.

As all potencies are either innate, like the senses, or come by practice, like the power of playing the flute, or
by learning, like artistic power, those which come by practice or by rational formula we must acquire by
previous exercise but this is not necessary with those which are not of this nature and which imply passivity.

Since that which is 'capable' is capable of something and at some time in some way (with all the other
qualifications which must be present in the definition), and since some things can produce change according
to a rational formula and their potencies involve such a formula, while other things are nonrational and their
potencies are non-rational, and the former potencies must be in a living thing, while the latter can be both in
the living and in the lifeless; as regards potencies of the latter kind, when the agent and the patient meet in the
way appropriate to the potency in question, the one must act and the other be acted on, but with the former
kind of potency this is not necessary. For the nonrational potencies are all productive of one effect each, but
the rational produce contrary effects, so that if they produced their effects necessarily they would produce
contrary effects at the same time; but this is impossible. There must, then, be something else that decides; I
mean by this, desire or will. For whichever of two things the animal desires decisively, it will do, when it is
present, and meets the passive object, in the way appropriate to the potency in question. Therefore everything
which has a rational potency, when it desires that for which it has a potency and in the circumstances in
which it has the potency, must do this. And it has the potency in question when the passive object is present
and is in a certain state; if not it will not be able to act. (To add the qualification 'if nothing external prevents
it' is not further necessary; for it has the potency on the terms on which this is a potency of acting, and it is
this not in all circumstances but on certain conditions, among which will be the exclusion of external
hindrances; for these are barred by some of the positive qualifications.) And so even if one has a rational
wish, or an appetite, to do two things or contrary things at the same time, one will not do them; for it is not on
these terms that one has the potency for them, nor is it a potency of doing both at the same time, since one
will do the things which it is a potency of doing, on the terms on which one has the potency.

Since we have treated of the kind of potency which is related to movement, let us discuss actuality-what, and
what kind of thing, actuality is. For in the course of our analysis it will also become clear, with regard to the
potential, that we not only ascribe potency to that whose nature it is to move something else, or to be moved
by something else, either without qualification or in some particular way, but also use the word in another
sense, which is the reason of the inquiry in the course of which we have discussed these previous senses also.
Actuality, then, is the existence of a thing not in the way which we express by 'potentially'; we say that
potentially, for instance, a statue of Hermes is in the block of wood and the half-line is in the whole, because
it might be separated out, and we call even the man who is not studying a man of science, if he is capable of
studying; the thing that stands in contrast to each of these exists actually. Our meaning can be seen in the
particular cases by induction, and we must not seek a definition of everything but be content to grasp the
analogy, that it is as that which is building is to that which is capable of building, and the waking to the
sleeping, and that which is seeing to that which has its eyes shut but has sight, and that which has been
shaped out of the matter to the matter, and that which has been wrought up to the unwrought. Let actuality be
defined by one member of this antithesis, and the potential by the other. But all things are not said in the
same sense to exist actually, but only by analogy-as A is in B or to B, C is in D or to D; for some are as

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movement to potency, and the others as substance to some sort of matter.

But also the infinite and the void and all similar things are said to exist potentially and actually in a different
sense from that which applies to many other things, e.g. to that which sees or walks or is seen. For of the
latter class these predicates can at some time be also truly asserted without qualification; for the seen is so
called sometimes because it is being seen, sometimes because it is capable of being seen. But the infinite does
not exist potentially in the sense that it will ever actually have separate existence; it exists potentially only for
knowledge. For the fact that the process of dividing never comes to an end ensures that this activity exists
potentially, but not that the infinite exists separately.

Since of the actions which have a limit none is an end but all are relative to the end, e.g. the removing of fat,
or fat-removal, and the bodily parts themselves when one is making them thin are in movement in this way
(i.e. without being already that at which the movement aims), this is not an action or at least not a complete
one (for it is not an end); but that movement in which the end is present is an action. E.g. at the same time we
are seeing and have seen, are understanding and have understood, are thinking and have thought (while it is
not true that at the same time we are learning and have learnt, or are being cured and have been cured). At the
same time we are living well and have lived well, and are happy and have been happy. If not, the process
would have had sometime to cease, as the process of making thin ceases: but, as things are, it does not cease;
we are living and have lived. Of these processes, then, we must call the one set movements, and the other
actualities. For every movement is incomplete-making thin, learning, walking, building; these are
movements, and incomplete at that. For it is not true that at the same time a thing is walking and has walked,
or is building and has built, or is coming to be and has come to be, or is being moved and has been moved,
but what is being moved is different from what has been moved, and what is moving from what has moved.
But it is the same thing that at the same time has seen and is seeing, seeing, or is thinking and has thought.
The latter sort of process, then, I call an actuality, and the former a movement.

What, and what kind of thing, the actual is, may be taken as explained by these and similar considerations.
But we must distinguish when a thing exists potentially and when it does not; for it is not at any and every
time. E.g. is earth potentially a man? No-but rather when it has already become seed, and perhaps not even
then. It is just as it is with being healed; not everything can be healed by the medical art or by luck, but there
is a certain kind of thing which is capable of it, and only this is potentially healthy. And (1) the delimiting
mark of that which as a result of thought comes to exist in complete reality from having existed potentially is
that if the agent has willed it it comes to pass if nothing external hinders, while the condition on the other
side-viz. in that which is healed-is that nothing in it hinders the result. It is on similar terms that we have
what is potentially a house; if nothing in the thing acted on-i.e. in the matter-prevents it from becoming a
house, and if there is nothing which must be added or taken away or changed, this is potentially a house; and
the same is true of all other things the source of whose becoming is external. And (2) in the cases in which
the source of the becoming is in the very thing which comes to be, a thing is potentially all those things which
it will be of itself if nothing external hinders it. E.g. the seed is not yet potentially a man; for it must be
deposited in something other than itself and undergo a change. But when through its own motive principle it
has already got such and such attributes, in this state it is already potentially a man; while in the former state
it needs another motive principle, just as earth is not yet potentially a statue (for it must first change in order
to become brass.)

It seems that when we call a thing not something else but 'thaten'-e.g. a casket is not 'wood' but 'wooden', and
wood is not 'earth' but 'earthen', and again earth will illustrate our point if it is similarly not something else
but 'thaten'-that other thing is always potentially (in the full sense of that word) the thing which comes after it
in this series. E.g. a casket is not 'earthen' nor 'earth', but 'wooden'; for this is potentially a casket and this is
the matter of a casket, wood in general of a casket in general, and this particular wood of this particular
casket. And if there is a first thing, which is no longer, in reference to something else, called 'thaten', this is
prime matter; e.g. if earth is 'airy' and air is not 'fire' but 'fiery', fire is prime matter, which is not a 'this'. For

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the subject or substratum is differentiated by being a 'this' or not being one; i.e. the substratum of
modifications is, e.g. a man, i.e. a body and a soul, while the modification is 'musical' or 'pale'. (The subject is
called, when music comes to be present in it, not 'music' but 'musical', and the man is not 'paleness' but 'pale',
and not 'ambulation' or 'movement' but 'walking' or 'moving',-which is akin to the 'thaten'.) Wherever this is
so, then, the ultimate subject is a substance; but when this is not so but the predicate is a form and a 'this', the
ultimate subject is matter and material substance. And it is only right that 'thaten' should be used with
reference both to the matter and to the accidents; for both are indeterminates.

We have stated, then, when a thing is to be said to exist potentially and when it is not.

From our discussion of the various senses of 'prior', it is clear that actuality is prior to potency. And I mean by
potency not only that definite kind which is said to be a principle of change in another thing or in the thing
itself regarded as other, but in general every principle of movement or of rest. For nature also is in the same
genus as potency; for it is a principle of movement-not, however, in something else but in the thing itself qua
itself. To all such potency, then, actuality is prior both in formula and in substantiality; and in time it is prior
in one sense, and in another not.

(1) Clearly it is prior in formula; for that which is in the primary sense potential is potential because it is
possible for it to become active; e.g. I mean by 'capable of building' that which can build, and by 'capable of
seeing' that which can see, and by 'visible' that which can be seen. And the same account applies to all other
cases, so that the formula and the knowledge of the one must precede the knowledge of the other.

(2) In time it is prior in this sense: the actual which is identical in species though not in number with a
potentially existing thing is to it. I mean that to this particular man who now exists actually and to the corn
and to the seeing subject the matter and the seed and that which is capable of seeing, which are potentially a
man and corn and seeing, but not yet actually so, are prior in time; but prior in time to these are other actually
existing things, from which they were produced. For from the potentially existing the actually existing is
always produced by an actually existing thing, e.g. man from man, musician by musician; there is always a
first mover, and the mover already exists actually. We have said in our account of substance that everything
that is produced is something produced from something and by something, and that the same in species as it.

This is why it is thought impossible to be a builder if one has built nothing or a harper if one has never played
the harp; for he who learns to play the harp learns to play it by playing it, and all other learners do similarly.
And thence arose the sophistical quibble, that one who does not possess a science will be doing that which is
the object of the science; for he who is learning it does not possess it. But since, of that which is coming to
be, some part must have come to be, and, of that which, in general, is changing, some part must have changed
(this is shown in the treatise on movement), he who is learning must, it would seem, possess some part of the
science. But here too, then, it is clear that actuality is in this sense also, viz. in order of generation and of
time, prior to potency.

But (3) it is also prior in substantiality; firstly, (a) because the things that are posterior in becoming are prior
in form and in substantiality (e.g. man is prior to boy and human being to seed; for the one already has its
form, and the other has not), and because everything that comes to be moves towards a principle, i.e. an end
(for that for the sake of which a thing is, is its principle, and the becoming is for the sake of the end), and the
actuality is the end, and it is for the sake of this that the potency is acquired. For animals do not see in order
that they may have sight, but they have sight that they may see. And similarly men have the art of building
that they may build, and theoretical science that they may theorize; but they do not theorize that they may
have theoretical science, except those who are learning by practice; and these do not theorize except in a
limited sense, or because they have no need to theorize. Further, matter exists in a potential state, just because
it may come to its form; and when it exists actually, then it is in its form. And the same holds good in all
cases, even those in which the end is a movement. And so, as teachers think they have achieved their end

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when they have exhibited the pupil at work, nature does likewise. For if this is not the case, we shall have
Pauson's Hermes over again, since it will be hard to say about the knowledge, as about the figure in the
picture, whether it is within or without. For the action is the end, and the actuality is the action. And so even
the word 'actuality' is derived from 'action', and points to the complete reality.

And while in some cases the exercise is the ultimate thing (e.g. in sight the ultimate thing is seeing, and no
other product besides this results from sight), but from some things a product follows (e.g. from the art of
building there results a house as well as the act of building), yet none the less the act is in the former case the
end and in the latter more of an end than the potency is. For the act of building is realized in the thing that is
being built, and comes to be, and is, at the same time as the house.

Where, then, the result is something apart from the exercise, the actuality is in the thing that is being made,
e.g. the act of building is in the thing that is being built and that of weaving in the thing that is being woven,
and similarly in all other cases, and in general the movement is in the thing that is being moved; but where
there is no product apart from the actuality, the actuality is present in the agents, e.g. the act of seeing is in the
seeing subject and that of theorizing in the theorizing subject and the life is in the soul (and therefore
well-being also; for it is a certain kind of life).

Obviously, therefore, the substance or form is actuality. According to this argument, then, it is obvious that
actuality is prior in substantial being to potency; and as we have said, one actuality always precedes another
in time right back to the actuality of the eternal prime mover.

But (b) actuality is prior in a stricter sense also; for eternal things are prior in substance to perishable things,
and no eternal thing exists potentially. The reason is this. Every potency is at one and the same time a
potency of the opposite; for, while that which is not capable of being present in a subject cannot be present,
everything that is capable of being may possibly not be actual. That, then, which is capable of being may
either be or not be; the same thing, then, is capable both of being and of not being. And that which is capable
of not being may possibly not be; and that which may possibly not be is perishable, either in the full sense, or
in the precise sense in which it is said that it possibly may not be, i.e. in respect either of place or of quantity
or quality; 'in the full sense' means 'in respect of substance'. Nothing, then, which is in the full sense
imperishable is in the full sense potentially existent (though there is nothing to prevent its being so in some
respect, e.g. potentially of a certain quality or in a certain place); all imperishable things, then, exist actually.
Nor can anything which is of necessity exist potentially; yet these things are primary; for if these did not
exist, nothing would exist. Nor does eternal movement, if there be such, exist potentially; and, if there is an
eternal mobile, it is not in motion in virtue of a potentiality, except in respect of 'whence' and 'whither' (there
is nothing to prevent its having matter which makes it capable of movement in various directions). And so the
sun and the stars and the whole heaven are ever active, and there is no fear that they may sometime stand still,
as the natural philosophers fear they may. Nor do they tire in this activity; for movement is not for them, as it
is for perishable things, connected with the potentiality for opposites, so that the continuity of the movement
should be laborious; for it is that kind of substance which is matter and potency, not actuality, that causes
this.

Imperishable things are imitated by those that are involved in change, e.g. earth and fire. For these also are
ever active; for they have their movement of themselves and in themselves. But the other potencies,
according to our previous discussion, are all potencies for opposites; for that which can move another in this
way can also move it not in this way, i.e. if it acts according to a rational formula; and the same non-rational
potencies will produce opposite results by their presence or absence.

If, then, there are any entities or substances such as the dialecticians say the Ideas are, there must be
something much more scientific than science-itself and something more mobile than movement-itself ; for
these will be more of the nature of actualities, while science-itself and movement-itself are potencies for

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these.

Obviously, then, actuality is prior both to potency and to every principle of change.

That the actuality is also better and more valuable than the good potency is evident from the following
argument. Everything of which we say that it can do something, is alike capable of contraries, e.g. that of
which we say that it can be well is the same as that which can be ill, and has both potencies at once; for the
same potency is a potency of health and illness, of rest and motion, of building and throwing down, of being
built and being thrown down. The capacity for contraries, then, is present at the same time; but contraries
cannot be present at the same time, and the actualities also cannot be present at the same time, e.g. health and
illness. Therefore, while the good must be one of them, the capacity is both alike, or neither; the actuality,
then, is better. Also in the case of bad things the end or actuality must be worse than the potency; for that
which 'can' is both contraries alike. Clearly, then, the bad does not exist apart from bad things; for the bad is
in its nature posterior to the potency. And therefore we may also say that in the things which are from the
beginning, i.e. in eternal things, there is nothing bad, nothing defective, nothing perverted (for perversion is
something bad).

It is an activity also that geometrical constructions are discovered; for we find them by dividing. If the figures
had been already divided, the constructions would have been obvious; but as it is they are present only
potentially. Why are the angles of the triangle equal to two right angles? Because the angles about one point
are equal to two right angles. If, then, the line parallel to the side had been already drawn upwards, the reason
would have been evident to any one as soon as he saw the figure. Why is the angle in a semicircle in all cases
a right angle? If three lines are equal the two which form the base, and the perpendicular from the centre-the
conclusion is evident at a glance to one who knows the former proposition. Obviously, therefore, the
potentially existing constructions are discovered by being brought to actuality; the reason is that the
geometer's thinking is an actuality; so that the potency proceeds from an actuality; and therefore it is by
making constructions that people come to know them (though the single actuality is later in generation than
the corresponding potency). (See diagram.)

The terms 'being' and 'non-being' are employed firstly with reference to the categories, and secondly with
reference to the potency or actuality of these or their non-potency or nonactuality, and thirdly in the sense of
true and false. This depends, on the side of the objects, on their being combined or separated, so that he who
thinks the separated to be separated and the combined to be combined has the truth, while he whose thought
is in a state contrary to that of the objects is in error. This being so, when is what is called truth or falsity
present, and when is it not? We must consider what we mean by these terms. It is not because we think truly
that you are pale, that you are pale, but because you are pale we who say this have the truth. If, then, some
things are always combined and cannot be separated, and others are always separated and cannot be
combined, while others are capable either of combination or of separation, 'being' is being combined and one,
and 'not being' is being not combined but more than one. Regarding contingent facts, then, the same opinion
or the same statement comes to be false and true, and it is possible for it to be at one time correct and at
another erroneous; but regarding things that cannot be otherwise opinions are not at one time true and at
another false, but the same opinions are always true or always false.

But with regard to incomposites, what is being or not being, and truth or falsity? A thing of this sort is not
composite, so as to 'be' when it is compounded, and not to 'be' if it is separated, like 'that the wood is white' or
'that the diagonal is incommensurable'; nor will truth and falsity be still present in the same way as in the
previous cases. In fact, as truth is not the same in these cases, so also being is not the same; but (a) truth or
falsity is as follows — contact and assertion are truth (assertion not being the same as affirmation), and
ignorance is non-contact. For it is not possible to be in error regarding the question what a thing is, save in an
accidental sense; and the same holds good regarding non-composite substances (for it is not possible to be in
error about them). And they all exist actually, not potentially; for otherwise they would have come to be and

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ceased to be; but, as it is, being itself does not come to be (nor cease to be); for if it had done so it would have
had to come out of something. About the things, then, which are essences and actualities, it is not possible to
be in error, but only to know them or not to know them. But we do inquire what they are, viz. whether they
are of such and such a nature or not.

(b) As regards the 'being' that answers to truth and the 'non-being' that answers to falsity, in one case there is
truth if the subject and the attribute are really combined, and falsity if they are not combined; in the other
case, if the object is existent it exists in a particular way, and if it does not exist in this way does not exist at
all. And truth means knowing these objects, and falsity does not exist, nor error, but only ignorance-and not
an ignorance which is like blindness; for blindness is akin to a total absence of the faculty of thinking.

It is evident also that about unchangeable things there can be no error in respect of time, if we assume them to
be unchangeable. E.g. if we suppose that the triangle does not change, we shall not suppose that at one time
its angles are equal to two right angles while at another time they are not (for that would imply change). It is
possible, however, to suppose that one member of such a class has a certain attribute and another has not; e.g.
while we may suppose that no even number is prime, we may suppose that some are and some are not. But
regarding a numerically single number not even this form of error is possible; for we cannot in this case
suppose that one instance has an attribute and another has not, but whether our judgement be true or false, it
is implied that the fact is eternal.

BookX

WE have said previously, in our distinction of the various meanings of words, that 'one' has several
meanings; the things that are directly and of their own nature and not accidentally called one may be
summarized under four heads, though the word is used in more senses. (1) There is the continuous, either in
general, or especially that which is continuous by nature and not by contact nor by being together; and of
these, that has more unity and is prior, whose movement is more indivisible and simpler. (2) That which is a
whole and has a certain shape and form is one in a still higher degree; and especially if a thing is of this sort
by nature, and not by force like the things which are unified by glue or nails or by being tied together, i.e. if it
has in itself the cause of its continuity. A thing is of this sort because its movement is one and indivisible in
place and time; so that evidently if a thing has by nature a principle of movement that is of the first kind (i.e.
local movement) and the first in that kind (i.e. circular movement), this is in the primary sense one extended
thing. Some things, then, are one in this way, qua continuous or whole, and the other things that are one are
those whose definition is one. Of this sort are the things the thought of which is one, i.e. those the thought of
which is indivisible; and it is indivisible if the thing is indivisible in kind or in number. (3) In number, then,
the individual is indivisible, and (4) in kind, that which in intelligibility and in knowledge is indivisible, so
that that which causes substances to be one must be one in the primary sense. 'One', then, has all these
meanings-the naturally continuous and the whole, and the individual and the universal. And all these are one
because in some cases the movement, in others the thought or the definition is indivisible.

But it must be observed that the questions, what sort of things are said to be one, and what it is to be one and
what is the definition of it, should not be assumed to be the same. 'One' has all these meanings, and each of
the things to which one of these kinds of unity belongs will be one; but 'to be one' will sometimes mean being
one of these things, and sometimes being something else which is even nearer to the meaning of the word
'one' while these other things approximate to its application. This is also true of 'element' or 'cause', if one had
both to specify the things of which it is predicable and to render the definition of the word. For in a sense fire
is an element (and doubtless also 'the indefinite' or something else of the sort is by its own nature the
element), but in a sense it is not; for it is not the same thing to be fire and to be an element, but while as a
particular thing with a nature of its own fire is an element, the name 'element' means that it has this attribute,
that there is something which is made of it as a primary constituent. And so with 'cause' and 'one' and all such
terms. For this reason, too, 'to be one' means 'to be indivisible, being essentially one means a "this" and

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capable of being isolated either in place, or in form or thought'; or perhaps 'to be whole and indivisible'; but it
means especially 'to be the first measure of a kind', and most strictly of quantity; for it is from this that it has
been extended to the other categories. For measure is that by which quantity is known; and quantity qua
quantity is known either by a 'one' or by a number, and all number is known by a 'one'. Therefore all quantity
qua quantity is known by the one, and that by which quantities are primarily known is the one itself; and so
the one is the starting-point of number qua number. And hence in the other classes too 'measure' means that
by which each is first known, and the measure of each is a unit-in length, in breadth, in depth, in weight, in
speed. (The words 'weight' and 'speed' are common to both contraries; for each of them has two
meanings-'weight' means both that which has any amount of gravity and that which has an excess of gravity,
and 'speed' both that which has any amount of movement and that which has an excess of movement; for
even the slow has a certain speed and the comparatively light a certain weight.)

In all these, then, the measure and starting-point is something one and indivisible, since even in lines we treat
as indivisible the line a foot long. For everywhere we seek as the measure something one and indivisible; and
this is that which is simple either in quality or in quantity. Now where it is thought impossible to take away or
to add, there the measure is exact (hence that of number is most exact; for we posit the unit as indivisible in
every respect); but in all other cases we imitate this sort of measure. For in the case of a furlong or a talent or
of anything comparatively large any addition or subtraction might more easily escape our notice than in the
case of something smaller; so that the first thing from which, as far as our perception goes, nothing can be
subtracted, all men make the measure, whether of liquids or of solids, whether of weight or of size; and they
think they know the quantity when they know it by means of this measure. And indeed they know movement
too by the simple movement and the quickest; for this occupies least time. And so in astronomy a 'one' of this
sort is the starting-point and measure (for they assume the movement of the heavens to be uniform and the
quickest, and judge the others by reference to it), and in music the quarter-tone (because it is the least
interval), and in speech the letter. And all these are ones in this sense — not that 'one' is something predicable
in the same sense of all of these, but in the sense we have mentioned.

But the measure is not always one in number — sometimes there are several; e.g. the quarter-tones (not to the
ear, but as determined by the ratios) are two, and the articulate sounds by which we measure are more than
one, and the diagonal of the square and its side are measured by two quantities, and all spatial magnitudes
reveal similar varieties of unit. Thus, then, the one is the measure of all things, because we come to know the
elements in the substance by dividing the things either in respect of quantity or in respect of kind. And the
one is indivisible just because the first of each class of things is indivisible. But it is not in the same way that
every 'one' is indivisible e.g. a foot and a unit; the latter is indivisible in every respect, while the former must
be placed among things which are undivided to perception, as has been said already-only to perception, for
doubtless every continuous thing is divisible.

The measure is always homogeneous with the thing measured; the measure of spatial magnitudes is a spatial
magnitude, and in particular that of length is a length, that of breadth a breadth, that of articulate sound an
articulate sound, that of weight a weight, that of units a unit. (For we must state the matter so, and not say that
the measure of numbers is a number; we ought indeed to say this if we were to use the corresponding form of
words, but the claim does not really correspond-it is as if one claimed that the measure of units is units and
not a unit; number is a plurality of units.)

Knowledge, also, and perception, we call the measure of things for the same reason, because we come to
know something by them-while as a matter of fact they are measured rather than measure other things. But it
is with us as if some one else measured us and we came to know how big we are by seeing that he applied the
cubit-measure to such and such a fraction of us. But Protagoras says 'man is the measure of all things', as if
he had said 'the man who knows' or 'the man who perceives'; and these because they have respectively
knowledge and perception, which we say are the measures of objects. Such thinkers are saying nothing, then,
while they appear to be saying something remarkable.

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Evidently, then, unity in the strictest sense, if we define it according to the meaning of the word, is a measure,
and most properly of quantity, and secondly of quality. And some things will be one if they are indivisible in
quantity, and others if they are indivisible in quality; and so that which is one is indivisible, either absolutely
or qua one.

With regard to the substance and nature of the one we must ask in which of two ways it exists. This is the
very question that we reviewed in our discussion of problems, viz. what the one is and how we must conceive
of it, whether we must take the one itself as being a substance (as both the Pythagoreans say in earlier and
Plato in later times), or there is, rather, an underlying nature and the one should be described more intelligibly
and more in the manner of the physical philosophers, of whom one says the one is love, another says it is air,
and another the indefinite.

If, then, no universal can be a substance, as has been said our discussion of substance and being, and if being
itself cannot be a substance in the sense of a one apart from the many (for it is common to the many), but is
only a predicate, clearly unity also cannot be a substance; for being and unity are the most universal of all
predicates. Therefore, on the one hand, genera are not certain entities and substances separable from other
things; and on the other hand the one cannot be a genus, for the same reasons for which being and substance
cannot be genera.

Further, the position must be similar in all the kinds of unity. Now 'unity' has just as many meanings as
'being'; so that since in the sphere of qualities the one is something definite-some particular kind of
thing-and similarly in the sphere of quantities, clearly we must in every category ask what the one is, as we
must ask what the existent is, since it is not enough to say that its nature is just to be one or existent. But in
colours the one is a colour, e.g. white, and then the other colours are observed to be produced out of this and
black, and black is the privation of white, as darkness of light. Therefore if all existent things were colours,
existent things would have been a number, indeed, but of what? Clearly of colours; and the 'one' would have
been a particular 'one', i.e. white. And similarly if all existing things were tunes, they would have been a
number, but a number of quarter-tones, and their essence would not have been number; and the one would
have been something whose substance was not to be one but to be the quarter-tone. And similarly if all
existent things had been articulate sounds, they would have been a number of letters, and the one would have
been a vowel. And if all existent things were rectilinear figures, they would have been a number of figures,
and the one would have been the triangle. And the same argument applies to all other classes. Since,
therefore, while there are numbers and a one both in affections and in qualities and in quantities and in
movement, in all cases the number is a number of particular things and the one is one something, and its
substance is not just to be one, the same must be true of substances also; for it is true of all cases alike.

That the one, then, in every class is a definite thing, and in no case is its nature just this, unity, is evident; but
as in colours the one-itself which we must seek is one colour, so too in substance the one-itself is one
substance. That in a sense unity means the same as being is clear from the facts that its meanings correspond
to the categories one to one, and it is not comprised within any category (e.g. it is comprised neither in 'what
a thing is' nor in quality, but is related to them just as being is); that in 'one man' nothing more is predicated
than in 'man' (just as being is nothing apart from substance or quality or quantity); and that to be one is just to
be a particular thing.

The one and the many are opposed in several ways, of which one is the opposition of the one and plurality as
indivisible and divisible; for that which is either divided or divisible is called a plurality, and that which is
indivisible or not divided is called one. Now since opposition is of four kinds, and one of these two terms is
privative in meaning, they must be contraries, and neither contradictory nor correlative in meaning. And the
one derives its name and its explanation from its contrary, the indivisible from the divisible, because plurality
and the divisible is more perceptible than the indivisible, so that in definition plurality is prior to the
indivisible, because of the conditions of perception.

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To the one belong, as we indicated graphically in our distinction of the contraries, the same and the like and
the equal, and to plurality belong the other and the unlike and the unequal. 'The same' has several meanings;
(1) we sometimes mean 'the same numerically'; again, (2) we call a thing the same if it is one both in
definition and in number, e.g. you are one with yourself both in form and in matter; and again, (3) if the
definition of its primary essence is one; e.g. equal straight lines are the same, and so are equal and
equal-angled quadrilaterals; there are many such, but in these equality constitutes unity.

Things are like if, not being absolutely the same, nor without difference in respect of their concrete substance,
they are the same in form; e.g. the larger square is like the smaller, and unequal straight lines are like; they
are like, but not absolutely the same. Other things are like, if, having the same form, and being things in
which difference of degree is possible, they have no difference of degree. Other things, if they have a quality
that is in form one and same-e.g. whiteness-in a greater or less degree, are called like because their form is
one. Other things are called like if the qualities they have in common are more numerous than those in which
they differ-either the qualities in general or the prominent qualities; e.g. tin is like silver, qua white, and gold
is like fire, qua yellow and red.

Evidently, then, 'other' and 'unlike' also have several meanings. And the other in one sense is the opposite of
the same (so that everything is either the same as or other than everything else). In another sense things are
other unless both their matter and their definition are one (so that you are other than your neighbour). The
other in the third sense is exemplified in the objects of mathematics. 'Other or the same' can therefore be
predicated of everything with regard to everything else-but only if the things are one and existent, for 'other'
is not the contradictory of 'the same'; which is why it is not predicated of non-existent things (while 'not the
same' is so predicated). It is predicated of all existing things; for everything that is existent and one is by its
very nature either one or not one with anything else.

The other, then, and the same are thus opposed. But difference is not the same as otherness. For the other and
that which it is other than need not be other in some definite respect (for everything that is existent is either
other or the same), but that which is different is different from some particular thing in some particular
respect, so that there must be something identical whereby they differ. And this identical thing is genus or
species; for everything that differs differs either in genus or in species, in genus if the things have not their
matter in common and are not generated out of each other (i.e. if they belong to different figures of
predication), and in species if they have the same genus ('genus' meaning that identical thing which is
essentially predicated of both the different things).

Contraries are different, and contrariety is a kind of difference. That we are right in this supposition is shown
by induction. For all of these too are seen to be different; they are not merely other, but some are other in
genus, and others are in the same line of predication, and therefore in the same genus, and the same in genus.
We have distinguished elsewhere what sort of things are the same or other in genus.

Since things which differ may differ from one another more or less, there is also a greatest difference, and
this I call contrariety. That contrariety is the greatest difference is made clear by induction. For things which
differ in genus have no way to one another, but are too far distant and are not comparable; and for things that
differ in species the extremes from which generation takes place are the contraries, and the distance between
extremes-and therefore that between the contraries-is the greatest.

But surely that which is greatest in each class is complete. For that is greatest which cannot be exceeded, and
that is complete beyond which nothing can be found. For the complete difference marks the end of a series
(just as the other things which are called complete are so called because they have attained an end), and
beyond the end there is nothing; for in everything it is the extreme and includes all else, and therefore there is
nothing beyond the end, and the complete needs nothing further. From this, then, it is clear that contrariety is
complete difference; and as contraries are so called in several senses, their modes of completeness will

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answer to the various modes of contrariety which attach to the contraries.

This being so, it is clear that one thing have more than one contrary (for neither can there be anything more
extreme than the extreme, nor can there be more than two extremes for the one interval), and, to put the
matter generally, this is clear if contrariety is a difference, and if difference, and therefore also the complete
difference, must be between two things.

And the other commonly accepted definitions of contraries are also necessarily true. For not only is (1) the
complete difference the greatest difference (for we can get no difference beyond it of things differing either in
genus or in species; for it has been shown that there is no 'difference' between anything and the things outside
its genus, and among the things which differ in species the complete difference is the greatest); but also (2)
the things in the same genus which differ most are contrary (for the complete difference is the greatest
difference between species of the same genus); and (3) the things in the same receptive material which differ
most are contrary (for the matter is the same for contraries); and (4) of the things which fall under the same
faculty the most different are contrary (for one science deals with one class of things, and in these the
complete difference is the greatest).

The primary contrariety is that between positive state and privation-not every privation, however (for
'privation' has several meanings), but that which is complete. And the other contraries must be called so with
reference to these, some because they possess these, others because they produce or tend to produce them,
others because they are acquisitions or losses of these or of other contraries. Now if the kinds of opposition
are contradiction and privation and contrariety and relation, and of these the first is contradiction, and
contradiction admits of no intermediate, while contraries admit of one, clearly contradiction and contrariety
are not the same. But privation is a kind of contradiction; for what suffers privation, either in general or in
some determinate way, either that which is quite incapable of having some attribute or that which, being of
such a nature as to have it, has it not; here we have already a variety of meanings, which have been
distinguished elsewhere. Privation, therefore, is a contradiction or incapacity which is determinate or taken
along with the receptive material. This is the reason why, while contradiction does not admit of an
intermediate, privation sometimes does; for everything is equal or not equal, but not everything is equal or
unequal, or if it is, it is only within the sphere of that which is receptive of equality. If, then, the
comings-to-be which happen to the matter start from the contraries, and proceed either from the form and
the possession of the form or from a privation of the form or shape, clearly all contrariety must be privation,
but presumably not all privation is contrariety (the reason being that that has suffered privation may have
suffered it in several ways); for it is only the extremes from which changes proceed that are contraries.

And this is obvious also by induction. For every contrariety involves, as one of its terms, a privation, but not
all cases are alike; inequality is the privation of equality and unlikeness of likeness, and on the other hand
vice is the privation of virtue. But the cases differ in a way already described; in one case we mean simply
that the thing has suffered privation, in another case that it has done so either at a certain time or in a certain
part (e.g. at a certain age or in the dominant part), or throughout. This is why in some cases there is a mean
(there are men who are neither good nor bad), and in others there is not (a number must be either odd or
even). Further, some contraries have their subject defined, others have not. Therefore it is evident that one of
the contraries is always privative; but it is enough if this is true of the first-i.e. the generic-contraries, e.g. the
one and the many; for the others can be reduced to these.

Since one thing has one contrary, we might raise the question how the one is opposed to the many, and the
equal to the great and the small. For if we used the word 'whether' only in an antithesis such as 'whether it is
white or black', or 'whether it is white or not white' (we do not ask 'whether it is a man or white'), unless we
are proceeding on a prior assumption and asking something such as 'whether it was Cleon or Socrates that
came' as this is not a necessary disjunction in any class of things; yet even this is an extension from the case
of opposites; for opposites alone cannot be present together; and we assume this incompatibility here too in

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asking which of the two came; for if they might both have come, the question would have been absurd; but if
they might, even so this falls just as much into an antithesis, that of the 'one or many', i.e. 'whether both came
or one of the two':-if, then, the question 'whether' is always concerned with opposites, and we can ask
'whether it is greater or less or equal', what is the opposition of the equal to the other two? It is not contrary
either to one alone or to both; for why should it be contrary to the greater rather than to the less? Further, the
equal is contrary to the unequal. Therefore if it is contrary to the greater and the less, it will be contrary to
more things than one. But if the unequal means the same as both the greater and the less together, the equal
will be opposite to both (and the difficulty supports those who say the unequal is a 'two'), but it follows that
one thing is contrary to two others, which is impossible. Again, the equal is evidently intermediate between
the great and the small, but no contrariety is either observed to be intermediate, or, from its definition, can be
so; for it would not be complete if it were intermediate between any two things, but rather it always has
something intermediate between its own terms.

It remains, then, that it is opposed either as negation or as privation. It cannot be the negation or privation of
one of the two; for why of the great rather than of the small? It is, then, the privative negation of both. This is
why 'whether' is said with reference to both, not to one of the two (e.g. 'whether it is greater or equal' or
'whether it is equal or less'); there are always three cases. But it is not a necessary privation; for not
everything which is not greater or less is equal, but only the things which are of such a nature as to have these
attributes.

The equal, then, is that which is neither great nor small but is naturally fitted to be either great or small; and it
is opposed to both as a privative negation (and therefore is also intermediate). And that which is neither good
nor bad is opposed to both, but has no name; for each of these has several meanings and the recipient subject
is not one; but that which is neither white nor black has more claim to unity. Yet even this has not one name,
though the colours of which this negation is privatively predicated are in a way limited; for they must be
either grey or yellow or something else of the kind. Therefore it is an incorrect criticism that is passed by
those who think that all such phrases are used in the same way, so that that which is neither a shoe nor a hand
would be intermediate between a shoe and a hand, since that which is neither good nor bad is intermediate
between the good and the bad-as if there must be an intermediate in all cases. But this does not necessarily
follow. For the one phrase is a joint denial of opposites between which there is an intermediate and a certain
natural interval; but between the other two there is no 'difference'; for the things, the denials of which are
combined, belong to different classes, so that the substratum is not one.

We might raise similar questions about the one and the many. For if the many are absolutely opposed to the
one, certain impossible results follow. One will then be few, whether few be treated here as singular or plural;
for the many are opposed also to the few. Further, two will be many, since the double is multiple and 'double'
derives its meaning from 'two'; therefore one will be few; for what is that in comparison with which two are
many, except one, which must therefore be few? For there is nothing fewer. Further, if the much and the little
are in plurality what the long and the short are in length, and whatever is much is also many, and the many
are much (unless, indeed, there is a difference in the case of an easily-bounded continuum), the little (or few)
will be a plurality. Therefore one is a plurality if it is few; and this it must be, if two are many. But perhaps,
while the 'many' are in a sense said to be also 'much', it is with a difference; e.g. water is much but not many.
But 'many' is applied to the things that are divisible; in the one sense it means a plurality which is excessive
either absolutely or relatively (while 'few' is similarly a plurality which is deficient), and in another sense it
means number, in which sense alone it is opposed to the one. For we say 'one or many', just as if one were to
say 'one and ones' or 'white thing and white things', or to compare the things that have been measured with
the measure. It is in this sense also that multiples are so called. For each number is said to be many because it
consists of ones and because each number is measurable by one; and it is 'many' as that which is opposed to
one, not to the few. In this sense, then, even two is many-not, however, in the sense of a plurality which is
excessive either relatively or absolutely; it is the first plurality. But without qualification two is few; for it is
first plurality which is deficient (for this reason Anaxagoras was not right in leaving the subject with the

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statement that 'all things were together, boundless both in plurality and in smallness'-where for 'and in
smallness' he should have said 'and in fewness'; for they could not have been boundless in fewness), since it
is not one, as some say, but two, that make a few.

The one is opposed then to the many in numbers as measure to thing measurable; and these are opposed as
are the relatives which are not from their very nature relatives. We have distinguished elsewhere the two
senses in which relatives are so called:-(l) as contraries; (2) as knowledge to thing known, a term being
called relative because another is relative to it. There is nothing to prevent one from being fewer than
something, e.g. than two; for if one is fewer, it is not therefore few. Plurality is as it were the class to which
number belongs; for number is plurality measurable by one, and one and number are in a sense opposed, not
as contrary, but as we have said some relative terms are opposed; for inasmuch as one is measure and the
other measurable, they are opposed. This is why not everything that is one is a number; i.e. if the thing is
indivisible it is not a number. But though knowledge is similarly spoken of as relative to the knowable, the
relation does not work out similarly; for while knowledge might be thought to be the measure, and the
knowable the thing measured, the fact that all knowledge is knowable, but not all that is knowable is
knowledge, because in a sense knowledge is measured by the knowable.-Plurality is contrary neither to the
few (the many being contrary to this as excessive plurality to plurality exceeded), nor to the one in every
sense; but in the one sense these are contrary, as has been said, because the former is divisible and the latter
indivisible, while in another sense they are relative as knowledge is to knowable, if plurality is number and
the one is a measure.

Since contraries admit of an intermediate and in some cases have it, intermediates must be composed of the
contraries. For (1) all intermediates are in the same genus as the things between which they stand. For we call
those things intermediates, into which that which changes must change first; e.g. if we were to pass from the
highest string to the lowest by the smallest intervals, we should come sooner to the intermediate notes, and in
colours if we were to pass from white to black, we should come sooner to crimson and grey than to black;
and similarly in all other cases. But to change from one genus to another genus is not possible except in an
incidental way, as from colour to figure. Intermediates, then, must be in the same genus both as one another
and as the things they stand between.

But (2) all intermediates stand between opposites of some kind; for only between these can change take place
in virtue of their own nature (so that an intermediate is impossible between things which are not opposite; for
then there would be change which was not from one opposite towards the other). Of opposites,
contradictories admit of no middle term; for this is what contradiction is-an opposition, one or other side of
which must attach to anything whatever, i.e. which has no intermediate. Of other opposites, some are relative,
others privative, others contrary. Of relative terms, those which are not contrary have no intermediate; the
reason is that they are not in the same genus. For what intermediate could there be between knowledge and
knowable? But between great and small there is one.

(3) If intermediates are in the same genus, as has been shown, and stand between contraries, they must be
composed of these contraries. For either there will be a genus including the contraries or there will be none.
And if (a) there is to be a genus in such a way that it is something prior to the contraries, the differentiae
which constituted the contrary species-of-a-genus will be contraries prior to the species; for species are
composed of the genus and the differentiae. (E.g. if white and black are contraries, and one is a piercing
colour and the other a compressing colour, these differentiae-'piercing' and 'compressing'-are prior; so that
these are prior contraries of one another.) But, again, the species which differ contrariwise are the more truly
contrary species. And the other.species, i.e. the intermediates, must be composed of their genus and their
differentiae. (E.g. all colours which are between white and black must be said to be composed of the genus,
i.e. colour, and certain differentiae. But these differentiae will not be the primary contraries; otherwise every
colour would be either white or black. They are different, then, from the primary contraries; and therefore
they will be between the primary contraries; the primary differentiae are 'piercing' and 'compressing'.)

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Therefore it is (b) with regard to these contraries which do not fall within a genus that we must first ask of
what their intermediates are composed. (For things which are in the same genus must be composed of terms
in which the genus is not an element, or else be themselves incomposite.) Now contraries do not involve one
another in their composition, and are therefore first principles; but the intermediates are either all
incomposite, or none of them. But there is something compounded out of the contraries, so that there can be a
change from a contrary to it sooner than to the other contrary; for it will have less of the quality in question
than the one contrary and more than the other. This also, then, will come between the contraries. All the other
intermediates also, therefore, are composite; for that which has more of a quality than one thing and less than
another is compounded somehow out of the things than which it is said to have more and less respectively of
the quality. And since there are no other things prior to the contraries and homogeneous with the
intermediates, all intermediates must be compounded out of the contraries. Therefore also all the inferior
classes, both the contraries and their intermediates, will be compounded out of the primary contraries.
Clearly, then, intermediates are (1) all in the same genus and (2) intermediate between contraries, and (3) all
compounded out of the contraries.

That which is other in species is other than something in something, and this must belong to both; e.g. if it is
an animal other in species, both are animals. The things, then, which are other in species must be in the same
genus. For by genus I mean that one identical thing which is predicated of both and is differentiated in no
merely accidental way, whether conceived as matter or otherwise. For not only must the common nature
attach to the different things, e.g. not only must both be animals, but this very animality must also be
different for each (e.g. in the one case equinity, in the other humanity), and so this common nature is
specifically different for each from what it is for the other. One, then, will be in virtue of its own nature one
sort of animal, and the other another, e.g. one a horse and the other a man. This difference, then, must be an
otherness of the genus. For I give the name of 'difference in the genus' an otherness which makes the genus
itself other.

This, then, will be a contrariety (as can be shown also by induction). For all things are divided by opposites,
and it has been proved that contraries are in the same genus. For contrariety was seen to be complete
difference; and all difference in species is a difference from something in something; so that this is the same
for both and is their genus. (Hence also all contraries which are different in species and not in genus are in the
same line of predication, and other than one another in the highest degree-for the difference is complete-,
and cannot be present along with one another.) The difference, then, is a contrariety.

This, then, is what it is to be 'other in species'-to have a contrariety, being in the same genus and being
indivisible (and those things are the same in species which have no contrariety, being indivisible); we say
'being indivisible', for in the process of division contrarieties arise in the intermediate stages before we come
to the indivisibles. Evidently, therefore, with reference to that which is called the genus, none of the
species-of-a-genus is either the same as it or other than it in species (and this is fitting; for the matter is
indicated by negation, and the genus is the matter of that of which it is called the genus, not in the sense in
which we speak of the genus or family of the Heraclidae, but in that in which the genus is an element in a
thing's nature), nor is it so with reference to things which are not in the same genus, but it will differ in genus
from them, and in species from things in the same genus. For a thing's difference from that from which it
differs in species must be a contrariety; and this belongs only to things in the same genus.

One might raise the question, why woman does not differ from man in species, when female and male are
contrary and their difference is a contrariety; and why a female and a male animal are not different in species,
though this difference belongs to animal in virtue of its own nature, and not as paleness or darkness does;
both 'female' and 'male' belong to it qua animal. This question is almost the same as the other, why one
contrariety makes things different in species and another does not, e.g. 'with feet' and 'with wings' do, but
paleness and darkness do not. Perhaps it is because the former are modifications peculiar to the genus, and
the latter are less so. And since one element is definition and one is matter, contrarieties which are in the

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definition make a difference in species, but those which are in the thing taken as including its matter do not
make one. And so paleness in a man, or darkness, does not make one, nor is there a difference in species
between the pale man and the dark man, not even if each of them be denoted by one word. For man is here
being considered on his material side, and matter does not create a difference; for it does not make individual
men species of man, though the flesh and the bones of which this man and that man consist are other. The
concrete thing is other, but not other in species, because in the definition there is no contrariety. This is the
ultimate indivisible kind. Callias is definition + matter, the pale man, then, is so also, because it is the
individual Callias that is pale; man, then, is pale only incidentally. Neither do a brazen and a wooden circle,
then, differ in species; and if a brazen triangle and a wooden circle differ in species, it is not because of the
matter, but because there is a contrariety in the definition. But does the matter not make things other in
species, when it is other in a certain way, or is there a sense in which it does? For why is this horse other than
this man in species, although their matter is included with their definitions? Doubtless because there is a
contrariety in the definition. For while there is a contrariety also between pale man and dark horse, and it is a
contrariety in species, it does not depend on the paleness of the one and the darkness of the other, since even
if both had been pale, yet they would have been other in species. But male and female, while they are
modifications peculiar to 'animal', are so not in virtue of its essence but in the matter, ie. the body. This is
why the same seed becomes female or male by being acted on in a certain way. We have stated, then, what it
is to be other in species, and why some things differ in species and others do not.

Since contraries are other in form, and the perishable and the imperishable are contraries (for privation is a
determinate incapacity), the perishable and the imperishable must be different in kind.

Now so far we have spoken of the general terms themselves, so that it might be thought not to be necessary
that every imperishable thing should be different from every perishable thing in form, just as not every pale
thing is different in form from every dark thing. For the same thing can be both, and even at the same time if
it is a universal (e.g. man can be both pale and dark), and if it is an individual it can still be both; for the same
man can be, though not at the same time, pale and dark. Yet pale is contrary to dark.

But while some contraries belong to certain things by accident (e.g. both those now mentioned and many
others), others cannot, and among these are 'perishable' and 'imperishable'. For nothing is by accident
perishable. For what is accidental is capable of not being present, but perishableness is one of the attributes
that belong of necessity to the things to which they belong; or else one and the same thing may be perishable
and imperishable, if perishableness is capable of not belonging to it. Perishableness then must either be the
essence or be present in the essence of each perishable thing. The same account holds good for
imperishableness also; for both are attributes which are present of necessity. The characteristics, then, in
respect of which and in direct consequence of which one thing is perishable and another imperishable, are
opposite, so that the things must be different in kind.

Evidently, then, there cannot be Forms such as some maintain, for then one man would be perishable and
another imperishable. Yet the Forms are said to be the same in form with the individuals and not merely to
have the same name; but things which differ in kind are farther apart than those which differ in form.

Book XI

THAT Wisdom is a science of first principles is evident from the introductory chapters, in which we have
raised objections to the statements of others about the first principles; but one might ask the question whether
Wisdom is to be conceived as one science or as several. If as one, it may be objected that one science always
deals with contraries, but the first principles are not contrary. If it is not one, what sort of sciences are those
with which it is to be identified?

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Further, is it the business of one science, or of more than one, to examine the first principles of
demonstration? If of one, why of this rather than of any other? If of more, what sort of sciences must these be
said to be?

Further, does Wisdom investigate all substances or not? If not all, it is hard to say which; but if, being one, it
investigates them all, it is doubtful how the same science can embrace several subject-matters.

Further, does it deal with substances only or also with their attributes? If in the case of attributes
demonstration is possible, in that of substances it is not. But if the two sciences are different, what is each of
them and which is Wisdom? If we think of it as demonstrative, the science of the attributes is Wisdom, but if
as dealing with what is primary, the science of substances claims the tide.

But again the science we are looking for must not be supposed to deal with the causes which have been
mentioned in the Physics. For (A) it does not deal with the final cause (for that is the nature of the good, and
this is found in the field of action and movement; and it is the first mover-for that is the nature of the end-but
in the case of things unmovable there is nothing that moved them first), and (B) in general it is hard to say
whether perchance the science we are now looking for deals with perceptible substances or not with them, but
with certain others. If with others, it must deal either with the Forms or with the objects of mathematics. Now
(a) evidently the Forms do not exist. (But it is hard to say, even if one suppose them to exist, why in the
world the same is not true of the other things of which there are Forms, as of the objects of mathematics. I
mean that these thinkers place the objects of mathematics between the Forms and perceptible things, as a kind
of third set of things apart both from the Forms and from the things in this world; but there is not a third man
or horse besides the ideal and the individuals. If on the other hand it is not as they say, with what sort of
things must the mathematician be supposed to deal? Certainly not with the things in this world; for none of
these is the sort of thing which the mathematical sciences demand.) Nor (b) does the science which we are
now seeking treat of the objects of mathematics; for none of them can exist separately. But again it does not
deal with perceptible substances; for they are perishable.

In general one might raise the question, to what kind of science it belongs to discuss the difficulties about the
matter of the objects of mathematics. Neither to physics (because the whole inquiry of the physicist is about
the things that have in themselves a principle, of movement and rest), nor yet to the science which inquires
into demonstration and science; for this is just the subject which it investigates. It remains then that it is the
philosophy which we have set before ourselves that treats of those subjects.

One might discuss the question whether the science we are seeking should be said to deal with the principles
which are by some called elements; all men suppose these to be present in composite things. But it might be
thought that the science we seek should treat rather of universals; for every definition and every science is of
universals and not of infimae species, so that as far as this goes it would deal with the highest genera. These
would turn out to be being and unity; for these might most of all be supposed to contain all things that are,
and to be most like principles because they are by nature; for if they perish all other things are destroyed with
them; for everything is and is one. But inasmuch as, if one is to suppose them to be genera, they must be
predicable of their differentiae, and no genus is predicable of any of its differentiae, in this way it would seem
that we should not make them genera nor principles. Further, if the simpler is more of a principle than the less
simple, and the ultimate members of the genus are simpler than the genera (for they are indivisible, but the
genera are divided into many and differing species), the species might seem to be the principles, rather than
the genera. But inasmuch as the species are involved in the destruction of the genera, the genera are more like
principles; for that which involves another in its destruction is a principle of it. These and others of the kind
are the subjects that involve difficulties.

Further, must we suppose something apart from individual things, or is it these that the science we are
seeking treats of? But these are infinite in number. Yet the things that are apart from the individuals are

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genera or species; but the science we now seek treats of neither of these. The reason why this is impossible
has been stated. Indeed, it is in general hard to say whether one must assume that there is a separable
substance besides the sensible substances (i.e. the substances in this world), or that these are the real things
and Wisdom is concerned with them. For we seem to seek another kind of substance, and this is our problem,
i.e. to see if there is something which can exist apart by itself and belongs to no sensible thing.-Further, if
there is another substance apart from and corresponding to sensible substances, which kinds of sensible
substance must be supposed to have this corresponding to them? Why should one suppose men or horses to
have it, more than either the other animals or even all lifeless things? On the other hand to set up other and
eternal substances equal in number to the sensible and perishable substances would seem to fall beyond the
bounds of probability. -But if the principle we now seek is not separable from corporeal things, what has a
better claim to the name matter? This, however, does not exist in actuality, but exists in potency. And it
would seem rather that the form or shape is a more important principle than this; but the form is perishable,
so that there is no eternal substance at all which can exist apart and independent. But this is paradoxical; for
such a principle and substance seems to exist and is sought by nearly all the most refined thinkers as
something that exists; for how is there to be order unless there is something eternal and independent and
permanent?

Further, if there is a substance or principle of such a nature as that which we are now seeking, and if this is
one for all things, and the same for eternal and for perishable things, it is hard to say why in the world, if
there is the same principle, some of the things that fall under the principle are eternal, and others are not
eternal; this is paradoxical. But if there is one principle of perishable and another of eternal things, we shall
be in a like difficulty if the principle of perishable things, as well as that of eternal, is eternal; for why, if the
principle is eternal, are not the things that fall under the principle also eternal? But if it is perishable another
principle is involved to account for it, and another to account for that, and this will go on to infinity.

If on the other hand we are to set up what are thought to be the most unchangeable principles, being and
unity, firstly, if each of these does not indicate a 'this' or substance, how will they be separable and
independent? Yet we expect the eternal and primary principles to be so. But if each of them does signify a
'this' or substance, all things that are are substances; for being is predicated of all things (and unity also of
some); but that all things that are are substance is false. Further, how can they be right who say that the first
principle is unity and this is substance, and generate number as the first product from unity and from matter,
assert that number is substance? How are we to think of 'two', and each of the other numbers composed of
units, as one? On this point neither do they say anything nor is it easy to say anything. But if we are to
suppose lines or what comes after these (I mean the primary surfaces) to be principles, these at least are not
separable substances, but sections and divisions-the former of surfaces, the latter of bodies (while points are
sections and divisions of lines); and further they are limits of these same things; and all these are in other
things and none is separable. Further, how are we to suppose that there is a substance of unity and the point?
Every substance comes into being by a gradual process, but a point does not; for the point is a division.

A further difficulty is raised by the fact that all knowledge is of universals and of the 'such', but substance is
not a universal, but is rather a 'this'-a separable thing, so that if there is knowledge about the first principles,
the question arises, how are we to suppose the first principle to be substance?

Further, is there anything apart from the concrete thing (by which I mean the matter and that which is joined
with it), or not? If not, we are met by the objection that all things that are in matter are perishable. But if there
is something, it must be the form or shape. Now it is hard to determine in which cases this exists apart and in
which it does not; for in some cases the form is evidently not separable, e.g. in the case of a house.

Further, are the principles the same in kind or in number? If they are one in number, all things will be the
same.

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Since the science of the philosopher treats of being qua being universally and not in respect of a part of it, and
'being' has many senses and is not used in one only, it follows that if the word is used equivocally and in
virtue of nothing common to its various uses, being does not fall under one science (for the meanings of an
equivocal term do not form one genus); but if the word is used in virtue of something common, being will fall
under one science. The term seems to be used in the way we have mentioned, like 'medical' and 'healthy'. For
each of these also we use in many senses. Terms are used in this way by virtue of some kind of reference, in
the one case to medical science, in the other to health, in others to something else, but in each case to one
identical concept. For a discussion and a knife are called medical because the former proceeds from medical
science, and the latter is useful to it. And a thing is called healthy in a similar way; one thing because it is
indicative of health, another because it is productive of it. And the same is true in the other cases. Everything
that is, then, is said to 'be' in this same way; each thing that is is said to 'be' because it is a modification of
being qua being or a permanent or a transient state or a movement of it, or something else of the sort. And
since everything that is may be referred to something single and common, each of the contrarieties also may
be referred to the first differences and contrarieties of being, whether the first differences of being are
plurality and unity, or likeness and unlikeness, or some other differences; let these be taken as already
discussed. It makes no difference whether that which is be referred to being or to unity. For even if they are
not the same but different, at least they are convertible; for that which is one is also somehow being, and that
which is being is one.

But since every pair of contraries falls to be examined by one and the same science, and in each pair one term
is the privative of the other though one might regarding some contraries raise the question, how they can be
privately related, viz. those which have an intermediate, e.g. unjust and just-in all such cases one must
maintain that the privation is not of the whole definition, but of the infima species, if the just man is 'by virtue
of some permanent disposition obedient to the laws', the unjust man will not in every case have the whole
definition denied of him, but may be merely 'in some respect deficient in obedience to the laws', and in this
respect the privation will attach to him; and similarly in all other cases.

As the mathematician investigates abstractions (for before beginning his investigation he strips off all the
sensible qualities, e.g. weight and lightness, hardness and its contrary, and also heat and cold and the other
sensible contrarieties, and leaves only the quantitative and continuous, sometimes in one, sometimes in two,
sometimes in three dimensions, and the attributes of these qua quantitative and continuous, and does not
consider them in any other respect, and examines the relative positions of some and the attributes of these,
and the commensurabilities and incommensurabilities of others, and the ratios of others; but yet we posit one
and the same science of all these things — geometry) — the same is true with regard to being. For the
attributes of this in so far as it is being, and the contrarieties in it qua being, it is the business of no other
science than philosophy to investigate; for to physics one would assign the study of things not qua being, but
rather qua sharing in movement; while dialectic and sophistic deal with the attributes of things that are, but
not of things qua being, and not with being itself in so far as it is being; therefore it remains that it is the
philosopher who studies the things we have named, in so far as they are being. Since all that is is to 'be' in
virtue of something single and common, though the term has many meanings, and contraries are in the same
case (for they are referred to the first contrarieties and differences of being), and things of this sort can fall
under one science, the difficulty we stated at the beginning appears to be solved,-! mean the question how
there can be a single science of things which are many and different in genus.

Since even the mathematician uses the common axioms only in a special application, it must be the business
of first philosophy to examine the principles of mathematics also. That when equals are taken from equals the
remainders are equal, is common to all quantities, but mathematics studies a part of its proper matter which it
has detached, e.g. lines or angles or numbers or some other kind of quantity-not, however, qua being but in
so far as each of them is continuous in one or two or three dimensions; but philosophy does not inquire about
particular subjects in so far as each of them has some attribute or other, but speculates about being, in so far
as each particular thing is.-Physics is in the same position as mathematics; for physics studies the attributes

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and the principles of the things that are, qua moving and not qua being (whereas the primary science, we have
said, deals with these, only in so far as the underlying subjects are existent, and not in virtue of any other
character); and so both physics and mathematics must be classed as parts of Wisdom.

There is a principle in things, about which we cannot be deceived, but must always, on the contrary recognize
the truth,-viz. that the same thing cannot at one and the same time be and not be, or admit any other similar
pair of opposites. About such matters there is no proof in the full sense, though there is proof ad hominem.
For it is not possible to infer this truth itself from a more certain principle, yet this is necessary if there is to
be completed proof of it in the full sense. But he who wants to prove to the asserter of opposites that he is
wrong must get from him an admission which shall be identical with the principle that the same thing cannot
be and not be at one and the same time, but shall not seem to be identical; for thus alone can his thesis be
demonstrated to the man who asserts that opposite statements can be truly made about the same subject.
Those, then, who are to join in argument with one another must to some extent understand one another; for if
this does not happen how are they to join in argument with one another? Therefore every word must be
intelligible and indicate something, and not many things but only one; and if it signifies more than one thing,
it must be made plain to which of these the word is being applied. He, then, who says 'this is and is not'
denies what he affirms, so that what the word signifies, he says it does not signify; and this is impossible.
Therefore if 'this is' signifies something, one cannot truly assert its contradictory.

Further, if the word signifies something and this is asserted truly, this connexion must be necessary; and it is
not possible that that which necessarily is should ever not be; it is not possible therefore to make the opposed
affirmations and negations truly of the same subject. Further, if the affirmation is no more true than the
negation, he who says 'man' will be no more right than he who says 'not-man'. It would seem also that in
saying the man is not a horse one would be either more or not less right than in saying he is not a man, so that
one will also be right in saying that the same person is a horse; for it was assumed to be possible to make
opposite statements equally truly. It follows then that the same person is a man and a horse, or any other
animal.

While, then, there is no proof of these things in the full sense, there is a proof which may suffice against one
who will make these suppositions. And perhaps if one had questioned Heraclitus himself in this way one
might have forced him to confess that opposite statements can never be true of the same subjects. But, as it is,
he adopted this opinion without understanding what his statement involves. But in any case if what is said by
him is true, not even this itself will be true-viz. that the same thing can at one and the same time both be and
not be. For as, when the statements are separated, the affirmation is no more true than the negation, in the
same way-the combined and complex statement being like a single affirmation-the whole taken as an
affirmation will be no more true than the negation. Further, if it is not possible to affirm anything truly, this
itself will be false-the assertion that there is no true affirmation. But if a true affirmation exists, this appears
to refute what is said by those who raise such objections and utterly destroy rational discourse.

The saying of Protagoras is like the views we have mentioned; he said that man is the measure of all things,
meaning simply that that which seems to each man also assuredly is. If this is so, it follows that the same
thing both is and is not, and is bad and good, and that the contents of all other opposite statements are true,
because often a particular thing appears beautiful to some and the contrary of beautiful to others, and that
which appears to each man is the measure. This difficulty may be solved by considering the source of this
opinion. It seems to have arisen in some cases from the doctrine of the natural philosophers, and in others
from the fact that all men have not the same views about the same things, but a particular thing appears
pleasant to some and the contrary of pleasant to others.

That nothing comes to be out of that which is not, but everything out of that which is, is a dogma common to
nearly all the natural philosophers. Since, then, white cannot come to be if the perfectly white and in no
respect not-white existed before, that which becomes white must come from that which is not white; so that

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it must come to be out of that which is not (so they argue), unless the same thing was at the beginning white
and not-white. But it is not hard to solve this difficulty; for we have said in our works on physics in what
sense things that come to be come to be from that which is not, and in what sense from that which is.

But to attend equally to the opinions and the fancies of disputing parties is childish; for clearly one of them
must be mistaken. And this is evident from what happens in respect of sensation; for the same thing never
appears sweet to some and the contrary of sweet to others, unless in the one case the sense-organ which
discriminates the aforesaid flavours has been perverted and injured. And if this is so the one party must be
taken to be the measure, and the other must not. And say the same of good and bad, and beautiful and ugly,
and all other such qualities. For to maintain the view we are opposing is just like maintaining that the things
that appear to people who put their finger under their eye and make the object appear two instead of one must
be two (because they appear to be of that number) and again one (for to those who do not interfere with their
eye the one object appears one).

In general, it is absurd to make the fact that the things of this earth are observed to change and never to
remain in the same state, the basis of our judgement about the truth. For in pursuing the truth one must start
from the things that are always in the same state and suffer no change. Such are the heavenly bodies; for these
do not appear to be now of one nature and again of another, but are manifestly always the same and share in
no change.

Further, if there is movement, there is also something moved, and everything is moved out of something and
into something; it follows that that that which is moved must first be in that out of which it is to be moved,
and then not be in it, and move into the other and come to be in it, and that the contradictory statements are
not true at the same time, as these thinkers assert they are.

And if the things of this earth continuously flow and move in respect of quantity-if one were to suppose this,
although it is not true-why should they not endure in respect of quality? For the assertion of contradictory
statements about the same thing seems to have arisen largely from the belief that the quantity of bodies does
not endure, which, our opponents hold, justifies them in saying that the same thing both is and is not four
cubits long. But essence depends on quality, and this is of determinate nature, though quantity is of
indeterminate.

Further, when the doctor orders people to take some particular food, why do they take it? In what respect is
'this is bread' truer than 'this is not bread'? And so it would make no difference whether one ate or not. But as
a matter of fact they take the food which is ordered, assuming that they know the truth about it and that it is
bread. Yet they should not, if there were no fixed constant nature in sensible things, but all natures moved
and flowed for ever.

Again, if we are always changing and never remain the same, what wonder is it if to us, as to the sick, things
never appear the same? (For to them also, because they are not in the same condition as when they were well,
sensible qualities do not appear alike; yet, for all that, the sensible things themselves need not share in any
change, though they produce different, and not identical, sensations in the sick. And the same must surely
happen to the healthy if the afore-said change takes place.) But if we do not change but remain the same,
there will be something that endures.

As for those to whom the difficulties mentioned are suggested by reasoning, it is not easy to solve the
difficulties to their satisfaction, unless they will posit something and no longer demand a reason for it; for it is
only thus that all reasoning and all proof is accomplished; if they posit nothing, they destroy discussion and
all reasoning. Therefore with such men there is no reasoning. But as for those who are perplexed by the
traditional difficulties, it is easy to meet them and to dissipate the causes of their perplexity. This is evident
from what has been said.

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It is manifest, therefore, from these arguments that contradictory statements cannot be truly made about the
same subject at one time, nor can contrary statements, because every contrariety depends on privation. This is
evident if we reduce the definitions of contraries to their principle.

Similarly, no intermediate between contraries can be predicated of one and the same subject, of which one of
the contraries is predicated. If the subject is white we shall be wrong in saying it is neither black nor white,
for then it follows that it is and is not white; for the second of the two terms we have put together is true of it,
and this is the contradictory of white.

We could not be right, then, in accepting the views either of Heraclitus or of Anaxagoras. If we were, it
would follow that contraries would be predicated of the same subject; for when Anaxagoras says that in
everything there is a part of everything, he says nothing is sweet any more than it is bitter, and so with any
other pair of contraries, since in everything everything is present not potentially only, but actually and
separately. And similarly all statements cannot be false nor all true, both because of many other difficulties
which might be adduced as arising from this position, and because if all are false it will not be true to say
even this, and if all are true it will not be false to say all are false.

Every science seeks certain principles and causes for each of its objects-e.g. medicine and gymnastics and
each of the other sciences, whether productive or mathematical. For each of these marks off a certain class of
things for itself and busies itself about this as about something existing and real,-not however qua real; the
science that does this is another distinct from these. Of the sciences mentioned each gets somehow the 'what'
in some class of things and tries to prove the other truths, with more or less precision. Some get the 'what'
through perception, others by hypothesis; so that it is clear from an induction of this sort that there is no
demonstration, of the substance or 'what'.

There is a science of nature, and evidently it must be different both from practical and from productive
science. For in the case of productive science the principle of movement is in the producer and not in the
product, and is either an art or some other faculty. And similarly in practical science the movement is not in
the thing done, but rather in the doers. But the science of the natural philosopher deals with the things that
have in themselves a principle of movement. It is clear from these facts, then, that natural science must be
neither practical nor productive, but theoretical (for it must fall into some one of these classes). And since
each of the sciences must somehow know the 'what' and use this as a principle, we must not fall to observe
how the natural philosopher should define things and how he should state the definition of the
essence-whether as akin to 'snub' or rather to 'concave'. For of these the definition of 'snub' includes the
matter of the thing, but that of 'concave' is independent of the matter; for snubness is found in a nose, so that
we look for its definition without eliminating the nose, for what is snub is a concave nose. Evidently then the
definition of flesh also and of the eye and of the other parts must always be stated without eliminating the
matter.

Since there is a science of being qua being and capable of existing apart, we must consider whether this is to
be regarded as the same as physics or rather as different. Physics deals with the things that have a principle of
movement in themselves; mathematics is theoretical, and is a science that deals with things that are at rest,
but its subjects cannot exist apart. Therefore about that which can exist apart and is unmovable there is a
science different from both of these, if there is a substance of this nature (I mean separable and unmovable),
as we shall try to prove there is. And if there is such a kind of thing in the world, here must surely be the
divine, and this must be the first and most dominant principle. Evidently, then, there are three kinds of
theoretical sciences-physics, mathematics, theology. The class of theoretical sciences is the best, and of these
themselves the last named is best; for it deals with the highest of existing things, and each science is called
better or worse in virtue of its proper object.

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One might raise the question whether the science of being qua being is to be regarded as universal or not.
Each of the mathematical sciences deals with some one determinate class of things, but universal
mathematics applies alike to all. Now if natural substances are the first of existing things, physics must be the
first of sciences; but if there is another entity and substance, separable and unmovable, the knowledge of it
must be different and prior to physics and universal because it is prior.

Since 'being' in general has several senses, of which one is 'being by accident', we must consider first that
which 'is' in this sense. Evidently none of the traditional sciences busies itself about the accidental. For
neither does architecture consider what will happen to those who are to use the house (e.g. whether they have
a painful life in it or not), nor does weaving, or shoemaking, or the confectioner's art, do the like; but each of
these sciences considers only what is peculiar to it, i.e. its proper end. And as for the argument that 'when he
who is musical becomes lettered he'll be both at once, not having been both before; and that which is, not
always having been, must have come to be; therefore he must have at once become musical and lettered',-this
none of the recognized sciences considers, but only sophistic; for this alone busies itself about the accidental,
so that Plato is not far wrong when he says that the sophist spends his time on non-being.

That a science of the accidental is not even possible will be evident if we try to see what the accidental really
is. We say that everything either is always and of necessity (necessity not in the sense of violence, but that
which we appeal to in demonstrations), or is for the most part, or is neither for the most part, nor always and
of necessity, but merely as it chances; e.g. there might be cold in the dogdays, but this occurs neither always
and of necessity, nor for the most part, though it might happen sometimes. The accidental, then, is what
occurs, but not always nor of necessity, nor for the most part. Now we have said what the accidental is, and it
is obvious why there is no science of such a thing; for all science is of that which is always or for the most
part, but the accidental is in neither of these classes.

Evidently there are not causes and principles of the accidental, of the same kind as there are of the essential;
for if there were, everything would be of necessity. If A is when B is, and B is when C is, and if C exists not
by chance but of necessity, that also of which C was cause will exist of necessity, down to the last causatum
as it is called (but this was supposed to be accidental). Therefore all things will be of necessity, and chance
and the possibility of a thing's either occurring or not occurring are removed entirely from the range of
events. And if the cause be supposed not to exist but to be coming to be, the same results will follow;
everything will occur of necessity. For to-morrow's eclipse will occur if A occurs, and A if B occurs, and B
if C occurs; and in this way if we subtract time from the limited time between now and to-morrow we shall
come sometime to the already existing condition. Therefore since this exists, everything after this will occur
of necessity, so that all things occur of necessity.

As to that which 'is' in the sense of being true or of being by accident, the former depends on a combination
in thought and is an affection of thought (which is the reason why it is the principles, not of that which 'is' in
this sense, but of that which is outside and can exist apart, that are sought); and the latter is not necessary but
indeterminate (I mean the accidental); and of such a thing the causes are unordered and indefinite.

Adaptation to an end is found in events that happen by nature or as the result of thought. It is 'luck' when one
of these events happens by accident. For as a thing may exist, so it may be a cause, either by its own nature or
by accident. Luck is an accidental cause at work in such events adapted to an end as are usually effected in
accordance with purpose. And so luck and thought are concerned with the same sphere; for purpose cannot
exist without thought. The causes from which lucky results might happen are indeterminate; and so luck is
obscure to human calculation and is a cause by accident, but in the unqualified sense a cause of nothing. It is
good or bad luck when the result is good or evil; and prosperity or misfortune when the scale of the results is
large.

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Since nothing accidental is prior to the essential, neither are accidental causes prior. If, then, luck or
spontaneity is a cause of the material universe, reason and nature are causes before it.

Some things are only actually, some potentially, some potentially and actually, what they are, viz. in one case
a particular reality, in another, characterized by a particular quantity, or the like. There is no movement apart
from things; for change is always according to the categories of being, and there is nothing common to these
and in no one category. But each of the categories belongs to all its subjects in either of two ways (e.g.
'this-ness'-for one kind of it is 'positive form', and the other is 'privation'; and as regards quality one kind is
'white' and the other 'black', and as regards quantity one kind is 'complete' and the other 'incomplete', and as
regards spatial movement one is 'upwards' and the other 'downwards', or one thing is 'light' and another
'heavy'); so that there are as many kinds of movement and change as of being. There being a distinction in
each class of things between the potential and the completely real, I call the actuality of the potential as such,
movement. That what we say is true, is plain from the following facts. When the 'buildable', in so far as it is
what we mean by 'buildable', exists actually, it is being built, and this is the process of building. Similarly
with learning, healing, walking, leaping, ageing, ripening. Movement takes when the complete reality itself
exists, and neither earlier nor later. The complete reality, then, of that which exists potentially, when it is
completely real and actual, not qua itself, but qua movable, is movement. By qua I mean this: bronze is
potentially a statue; but yet it is not the complete reality of bronze qua bronze that is movement. For it is not
the same thing to be bronze and to be a certain potency. If it were absolutely the same in its definition, the
complete reality of bronze would have been a movement. But it is not the same. (This is evident in the case of
contraries; for to be capable of being well and to be capable of being ill are not the same-for if they were,
being well and being ill would have been the same-it is that which underlies and is healthy or diseased,
whether it is moisture or blood, that is one and the same.) And since it is not. the same, as colour and the
visible are not the same, it is the complete reality of the potential, and as potential, that is movement. That it
is this, and that movement takes place when the complete reality itself exists, and neither earlier nor later, is
evident. For each thing is capable of being sometimes actual, sometimes not, e.g. the buildable qua buildable;
and the actuality of the buildable qua buildable is building. For the actuality is either this-the act of
building-or the house. But when the house exists, it is no longer buildable; the buildable is what is being
built. The actuality, then, must be the act of building, and this is a movement. And the same account applies
to all other movements.

That what we have said is right is evident from what all others say about movement, and from the fact that it
is not easy to define it otherwise. For firstly one cannot put it in any class. This is evident from what people
say. Some call it otherness and inequality and the unreal; none of these, however, is necessarily moved, and
further, change is not either to these or from these any more than from their opposites. The reason why people
put movement in these classes is that it is thought to be something indefinite, and the principles in one of the
two 'columns of contraries' are indefinite because they are privative, for none of them is either a 'this' or a
'such' or in any of the other categories. And the reason why movement is thought to be indefinite is that it
cannot be classed either with the potency of things or with their actuality; for neither that which is capable of
being of a certain quantity, nor that which is actually of a certain quantity, is of necessity moved, and
movement is thought to be an actuality, but incomplete; the reason is that the potential, whose actuality it is,
is incomplete. And therefore it is hard to grasp what movement is; for it must be classed either under
privation or under potency or under absolute actuality, but evidently none of these is possible. Therefore what
remains is that it must be what we said-both actuality and the actuality we have described-which is hard to
detect but capable of existing.

And evidently movement is in the movable; for it is the complete realization of this by that which is capable
of causing movement. And the actuality of that which is capable of causing movement is no other than that of
the movable. For it must be the complete reality of both. For while a thing is capable of causing movement
because it can do this, it is a mover because it is active; but it is on the movable that it is capable of acting, so
that the actuality of both is one, just as there is the same interval from one to two as from two to one, and as

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the steep ascent and the steep descent are one, but the being of them is not one; the case of the mover and the
moved is similar.

The infinite is either that which is incapable of being traversed because it is not its nature to be traversed (this
corresponds to the sense in which the voice is 'invisible'), or that which admits only of incomplete traverse or
scarcely admits of traverse, or that which, though it naturally admits of traverse, is not traversed or limited;
further, a thing may be infinite in respect of addition or of subtraction, or both. The infinite cannot be a
separate, independent thing. For if it is neither a spatial magnitude nor a plurality, but infinity itself is its
substance and not an accident of it, it will be indivisible; for the divisible is either magnitude or plurality. But
if indivisible, it is not infinite, except as the voice is invisible; but people do not mean this, nor are we
examining this sort of infinite, but the infinite as untraversable. Further, how can an infinite exist by itself,
unless number and magnitude also exist by themselvess-since infinity is an attribute of these? Further, if the
infinite is an accident of something else, it cannot be qua infinite an element in things, as the invisible is not
an element in speech, though the voice is invisible. And evidently the infinite cannot exist actually. For then
any part of it that might be taken would be infinite (for 'to be infinite' and 'the infinite' are the same, if the
infinite is substance and not predicated of a subject). Therefore it is either indivisible, or if it is partible, it is
divisible into infinites; but the same thing cannot be many infinites (as a part of air is air, so a part of the
infinite would be infinite, if the infinite is substance and a principle). Therefore it must be impartible and
indivisible. But the actually infinite cannot be indivisible; for it must be of a certain quantity. Therefore
infinity belongs to its subject incidentally. But if so, then (as we have said) it cannot be it that is a principle,
but that of which it is an accident-the air or the even number.

This inquiry is universal; but that the infinite is not among sensible things, is evident from the following
argument. If the definition of a body is 'that which is bounded by planes', there cannot be an infinite body
either sensible or intelligible; nor a separate and infinite number, for number or that which has a number is
numerable. Concretely, the truth is evident from the following argument. The infinite can neither be
composite nor simple. For (a) it cannot be a composite body, since the elements are limited in multitude. For
the contraries must be equal and no one of them must be infinite; for if one of the two bodies falls at all short
of the other in potency, the finite will be destroyed by the infinite. And that each should be infinite is
impossible. For body is that which has extension in all directions, and the infinite is the boundlessly
extended, so that if the infinite is a body it will be infinite in every direction. Nor (b) can the infinite body be
one and simple-neither, as some say, something apart from the elements, from which they generate these (for
there is no such body apart from the elements; for everything can be resolved into that of which it consists,
but no such product of analysis is observed except the simple bodies), nor fire nor any other of the elements.
For apart from the question how any of them could be infinite, the All, even if it is finite, cannot either be or
become any one of them, as Heraclitus says all things sometime become fire. The same argument applies to
this as to the One which the natural philosophers posit besides the elements. For everything changes from
contrary to contrary, e.g. from hot to cold.

Further, a sensible body is somewhere, and whole and part have the same proper place, e.g. the whole earth
and part of the earth. Therefore if (a) the infinite body is homogeneous, it will be unmovable or it will be
always moving. But this is impossible; for why should it rather rest, or move, down, up, or anywhere, rather
than anywhere else? E.g. if there were a clod which were part of an infinite body, where will this move or
rest? The proper place of the body which is homogeneous with it is infinite. Will the clod occupy the whole
place, then? And how? (This is impossible.) What then is its rest or its movement? It will either rest
everywhere, and then it cannot move; or it will move everywhere, and then it cannot be still. But (b) if the All
has unlike parts, the proper places of the parts are unlike also, and, firstly, the body of the All is not one
except by contact, and, secondly, the parts will be either finite or infinite in variety of kind. Finite they cannot
be; for then those of one kind will be infinite in quantity and those of another will not (if the All is infinite),
e.g. fire or water would be infinite, but such an infinite element would be destruction to the contrary
elements. But if the parts are infinite and simple, their places also are infinite and there will be an infinite

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number of elements; and if this is impossible, and the places are finite, the All also must be limited.

In general, there cannot be an infinite body and also a proper place for bodies, if every sensible body has
either weight or lightness. For it must move either towards the middle or upwards, and the infinite either the
whole or the half of it-cannot do either; for how will you divide it? Or how will part of the infinite be down
and part up, or part extreme and part middle? Further, every sensible body is in a place, and there are six
kinds of place, but these cannot exist in an infinite body. In general, if there cannot be an infinite place, there
cannot be an infinite body; (and there cannot be an infinite place,) for that which is in a place is somewhere,
and this means either up or down or in one of the other directions, and each of these is a limit.

The infinite is not the same in the sense that it is a single thing whether exhibited in distance or in movement
or in time, but the posterior among these is called infinite in virtue of its relation to the prior; i.e. a movement
is called infinite in virtue of the distance covered by the spatial movement or alteration or growth, and a time
is called infinite because of the movement which occupies it.

Of things which change, some change in an accidental sense, like that in which 'the musical' may be said to
walk, and others are said, without qualification, to change, because something in them changes, i.e. the things
that change in parts; the body becomes healthy, because the eye does. But there is something which is by its
own nature moved directly, and this is the essentially movable. The same distinction is found in the case of
the mover; for it causes movement either in an accidental sense or in respect of a part of itself or essentially.
There is something that directly causes movement; and there is something that is moved, also the time in
which it is moved, and that from which and that into which it is moved. But the forms and the affections and
the place, which are the terminals of the movement of moving things, are unmovable, e.g. knowledge or heat;
it is not heat that is a movement, but heating. Change which is not accidental is found not in all things, but
between contraries, and their intermediates, and between contradictories. We may convince ourselves of this
by induction.

That which changes changes either from positive into positive, or from negative into negative, or from
positive into negative, or from negative into positive. (By positive I mean that which is expressed by an
affirmative term.) Therefore there must be three changes; that from negative into negative is not change,
because (since the terms are neither contraries nor contradictories) there is no opposition. The change from
the negative into the positive which is its contradictory is generation-absolute change absolute generation,
and partial change partial generation; and the change from positive to negative is destruction-absolute change
absolute destruction, and partial change partial destruction. If, then, 'that which is not' has several senses, and
movement can attach neither to that which implies putting together or separating, nor to that which implies
potency and is opposed to that which is in the full sense (true, the not-white or not-good can be moved
incidentally, for the not-white might be a man; but that which is not a particular thing at all can in no wise be
moved), that which is not cannot be moved (and if this is so, generation cannot be movement; for that which
is not is generated; for even if we admit to the full that its generation is accidental, yet it is true to say that
'not-being' is predicable of that which is generated absolutely). Similarly rest cannot be long to that which is
not. These consequences, then, turn out to be awkward, and also this, that everything that is moved is in a
place, but that which is not is not in a place; for then it would be somewhere. Nor is destruction movement;
for the contrary of movement is rest, but the contrary of destruction is generation. Since every movement is a
change, and the kinds of change are the three named above, and of these those in the way of generation and
destruction are not movements, and these are the changes from a thing to its contradictory, it follows that
only the change from positive into positive is movement. And the positives are either contrary or intermediate
(for even privation must be regarded as contrary), and are expressed by an affirmative term, e.g. 'naked' or
'toothless' or 'black'.

If the categories are classified as substance, quality, place, acting or being acted on, relation, quantity, there
must be three kinds of movement-of quality, of quantity, of place. There is no movement in respect of

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substance (because there is nothing contrary to substance), nor of relation (for it is possible that if one of two
things in relation changes, the relative term which was true of the other thing ceases to be true, though this
other does not change at all,-so that their movement is accidental), nor of agent and patient, or mover and
moved, because there is no movement of movement nor generation of generation, nor, in general, change of
change. For there might be movement of movement in two senses; (1) movement might be the subject
moved, as a man is moved because he changes from pale to dark,-so that on this showing movement, too,
may be either heated or cooled or change its place or increase. But this is impossible; for change is not a
subject. Or (2) some other subject might change from change into some other form of existence (e.g. a man
from disease into health). But this also is not possible except incidentally. For every movement is change
from something into something. (And so are generation and destruction; only, these are changes into things
opposed in certain ways while the other, movement, is into things opposed in another way.) A thing changes,
then, at the same time from health into illness, and from this change itself into another. Clearly, then, if it has
become ill, it will have changed into whatever may be the other change concerned (though it may be at rest),
and, further, into a determinate change each time; and that new change will be from something definite into
some other definite thing; therefore it will be the opposite change, that of growing well. We answer that this
happens only incidentally; e.g. there is a change from the process of recollection to that of forgetting, only
because that to which the process attaches is changing, now into a state of knowledge, now into one of
ignorance.

Further, the process will go on to infinity, if there is to be change of change and coming to be of coming to
be. What is true of the later, then, must be true of the earlier; e.g. if the simple coming to be was once coming
to be, that which comes to be something was also once coming to be; therefore that which simply comes to be
something was not yet in existence, but something which was coming to be coming to be something was
already in existence. And this was once coming to be, so that at that time it was not yet coming to be
something else. Now since of an infinite number of terms there is not a first, the first in this series will not
exist, and therefore no following term exist. Nothing, then, can either come term wi to be or move or change.
Further, that which is capable of a movement is also capable of the contrary movement and rest, and that
which comes to be also ceases to be. Therefore that which is coming to be is ceasing to be when it has come
to be coming to be; for it cannot cease to be as soon as it is coming to be coming to be, nor after it has come
to be; for that which is ceasing to be must be. Further, there must be a matter underlying that which comes to
be and changes. What will this be, then,-what is it that becomes movement or becoming, as body or soul is
that which suffers alteration? And; again, what is it that they move into? For it must be the movement or
becoming of something from something into something. How, then, can this condition be fulfilled? There can
be no learning of learning, and therefore no becoming of becoming. Since there is not movement either of
substance or of relation or of activity and passivity, it remains that movement is in respect of quality and
quantity and place; for each of these admits of contrariety. By quality I mean not that which is in the
substance (for even the differentia is a quality), but the passive quality, in virtue of which a thing is said to be
acted on or to be incapable of being acted on. The immobile is either that which is wholly incapable of being
moved, or that which is moved with difficulty in a long time or begins slowly, or that which is of a nature to
be moved and can be moved but is not moved when and where and as it would naturally be moved. This
alone among immobiles I describe as being at rest; for rest is contrary to movement, so that it must be a
privation in that which is receptive of movement.

Things which are in one proximate place are together in place, and things which are in different places are
apart: things whose extremes are together touch: that at which a changing thing, if it changes continuously
according to its nature, naturally arrives before it arrives at the extreme into which it is changing, is between.
That which is most distant in a straight line is contrary in place. That is successive which is after the
beginning (the order being determined by position or form or in some other way) and has nothing of the same
class between it and that which it succeeds, e.g. lines in the case of a line, units in that of a unit, or a house in
that of a house. (There is nothing to prevent a thing of some other class from being between.) For the
successive succeeds something and is something later; 'one' does not succeed 'two', nor the first day of the

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month the second. That which, being successive, touches, is contiguous. (Since all change is between
opposites, and these are either contraries or contradictories, and there is no middle term for contradictories,
clearly that which is between is between contraries.) The continuous is a species of the contiguous. I call two
things continuous when the limits of each, with which they touch and by which they are kept together,
become one and the same, so that plainly the continuous is found in the things out of which a unity naturally
arises in virtue of their contact. And plainly the successive is the first of these concepts (for the successive
does not necessarily touch, but that which touches is successive; and if a thing is continuous, it touches, but if
it touches, it is not necessarily continuous; and in things in which there is no touching, there is no organic
unity); therefore a point is not the same as a unit; for contact belongs to points, but not to units, which have
only succession; and there is something between two of the former, but not between two of the latter.

Book XII

The subject of our inquiry is substance; for the principles and the causes we are seeking are those of
substances. For if the universe is of the nature of a whole, substance is its first part; and if it coheres merely
by virtue of serial succession, on this view also substance is first, and is succeeded by quality, and then by
quantity. At the same time these latter are not even being in the full sense, but are qualities and movements of
it,-or else even the not-white and the not-straight would be being; at least we say even these are, e.g. 'there
is a not-white'. Further, none of the categories other than substance can exist apart. And the early
philosophers also in practice testify to the primacy of substance; for it was of substance that they sought the
principles and elements and causes. The thinkers of the present day tend to rank universals as substances (for
genera are universals, and these they tend to describe as principles and substances, owing to the abstract
nature of their inquiry); but the thinkers of old ranked particular things as substances, e.g. fire and earth, not
what is common to both, body.

There are three kinds of substance-one that is sensible (of which one subdivision is eternal and another is
perishable; the latter is recognized by all men, and includes e.g. plants and animals), of which we must grasp
the elements, whether one or many; and another that is immovable, and this certain thinkers assert to be
capable of existing apart, some dividing it into two, others identifying the Forms and the objects of
mathematics, and others positing, of these two, only the objects of mathematics. The former two kinds of
substance are the subject of physics (for they imply movement); but the third kind belongs to another science,
if there is no principle common to it and to the other kinds.

Sensible substance is changeable. Now if change proceeds from opposites or from intermediates, and not
from all opposites (for the voice is not-white, (but it does not therefore change to white)), but from the
contrary, there must be something underlying which changes into the contrary state; for the contraries do not
change. Further, something persists, but the contrary does not persist; there is, then, some third thing besides
the contraries, viz. the matter. Now since changes are of four kinds-either in respect of the 'what' or of the
quality or of the quantity or of the place, and change in respect of 'thisness' is simple generation and
destruction, and change in quantity is increase and diminution, and change in respect of an affection is
alteration, and change of place is motion, changes will be from given states into those contrary to them in
these several respects. The matter, then, which changes must be capable of both states. And since that which
'is' has two senses, we must say that everything changes from that which is potentially to that which is
actually, e.g. from potentially white to actually white, and similarly in the case of increase and diminution.
Therefore not only can a thing come to be, incidentally, out of that which is not, but also all things come to be
out of that which is, but is potentially, and is not actually. And this is the 'One' of Anaxagoras; for instead of
'all things were together'-and the 'Mixture' of Empedocles and Anaximander and the account given by
Democritus-it is better to say 'all things were together potentially but not actually'. Therefore these thinkers
seem to have had some notion of matter. Now all things that change have matter, but different matter; and of
eternal things those which are not generable but are movable in space have matter-not matter for generation,
however, but for motion from one place to another.

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One might raise the question from what sort of non-being generation proceeds; for 'non-being' has three
senses. If, then, one form of non-being exists potentially, still it is not by virtue of a potentiality for any and
every thing, but different things come from different things; nor is it satisfactory to say that 'all things were
together'; for they differ in their matter, since otherwise why did an infinity of things come to be, and not one
thing? For 'reason' is one, so that if matter also were one, that must have come to be in actuality which the
matter was in potency. The causes and the principles, then, are three, two being the pair of contraries of
which one is definition and form and the other is privation, and the third being the matter.

Note, next, that neither the matter nor the form comes to be-and I mean the last matter and form. For
everything that changes is something and is changed by something and into something. That by which it is
changed is the immediate mover; that which is changed, the matter; that into which it is changed, the form.
The process, then, will go on to infinity, if not only the bronze comes to be round but also the round or the
bronze comes to be; therefore there must be a stop.

Note, next, that each substance comes into being out of something that shares its name. (Natural objects and
other things both rank as substances.) For things come into being either by art or by nature or by luck or by
spontaneity. Now art is a principle of movement in something other than the thing moved, nature is a
principle in the thing itself (for man begets man), and the other causes are privations of these two.

There are three kinds of substance-the matter, which is a 'this' in appearance (for all things that are
characterized by contact and not, by organic unity are matter and substratum, e.g. fire, flesh, head; for these
are all matter, and the last matter is the matter of that which is in the full sense substance); the nature, which
is a 'this' or positive state towards which movement takes place; and again, thirdly, the particular substance
which is composed of these two, e.g. Socrates or Callias. Now in some cases the 'this' does not exist apart
from the composite substance, e.g. the form of house does not so exist, unless the art of building exists apart
(nor is there generation and destruction of these forms, but it is in another way that the house apart from its
matter, and health, and all ideals of art, exist and do not exist); but if the 'this' exists apart from the concrete
thing, it is only in the case of natural objects. And so Plato was not far wrong when he said that there are as
many Forms as there are kinds of natural object (if there are Forms distinct from the things of this earth). The
moving causes exist as things preceding the effects, but causes in the sense of definitions are simultaneous
with their effects. For when a man is healthy, then health also exists; and the shape of a bronze sphere exists
at the same time as the bronze sphere. (But we must examine whether any form also survives afterwards. For
in some cases there is nothing to prevent this; e.g. the soul may be of this sort-not all soul but the reason; for
presumably it is impossible that all soul should survive.) Evidently then there is no necessity, on this ground
at least, for the existence of the Ideas. For man is begotten by man, a given man by an individual father; and
similarly in the arts; for the medical art is the formal cause of health.

The causes and the principles of different things are in a sense different, but in a sense, if one speaks
universally and analogically, they are the same for all. For one might raise the question whether the principles
and elements are different or the same for substances and for relative terms, and similarly in the case of each
of the categories. But it would be paradoxical if they were the same for all. For then from the same elements
will proceed relative terms and substances. What then will this common element be? For (1) (a) there is
nothing common to and distinct from substance and the other categories, viz. those which are predicated; but
an element is prior to the things of which it is an element. But again (b) substance is not an element in
relative terms, nor is any of these an element in substance. Further, (2) how can all things have the same
elements? For none of the elements can be the same as that which is composed of elements, e.g. b or a cannot
be the same as ba. (None, therefore, of the intelligibles, e.g. being or unity, is an element; for these are
predicable of each of the compounds as well.) None of the elements, then, will be either a substance or a
relative term; but it must be one or other. All things, then, have not the same elements.

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Or, as we are wont to put it, in a sense they have and in a sense they have not; e.g. perhaps the elements of
perceptible bodies are, as form, the hot, and in another sense the cold, which is the privation; and, as matter,
that which directly and of itself potentially has these attributes; and substances comprise both these and the
things composed of these, of which these are the principles, or any unity which is produced out of the hot and
the cold, e.g. flesh or bone; for the product must be different from the elements. These things then have the
same elements and principles (though specifically different things have specifically different elements); but
all things have not the same elements in this sense, but only analogically; i.e. one might say that there are
three principles-the form, the privation, and the matter. But each of these is different for each class; e.g. in
colour they are white, black, and surface, and in day and night they are light, darkness, and air.

Since not only the elements present in a thing are causes, but also something external, i.e. the moving cause,
clearly while 'principle' and 'element' are different both are causes, and 'principle' is divided into these two
kinds; and that which acts as producing movement or rest is a principle and a substance. Therefore
analogically there are three elements, and four causes and principles; but the elements are different in
different things, and the proximate moving cause is different for different things. Health, disease, body; the
moving cause is the medical art. Form, disorder of a particular kind, bricks; the moving cause is the building
art. And since the moving cause in the case of natural things is-for man, for instance, man, and in the
products of thought the form or its contrary, there will be in a sense three causes, while in a sense there are
four. For the medical art is in some sense health, and the building art is the form of the house, and man begets
man; further, besides these there is that which as first of all things moves all things.

Some things can exist apart and some cannot, and it is the former that are substances. And therefore all things
have the same causes, because, without substances, modifications and movements do not exist. Further, these
causes will probably be soul and body, or reason and desire and body.

And in yet another way, analogically identical things are principles, i.e. actuality and potency; but these also
are not only different for different things but also apply in different ways to them. For in some cases the same
thing exists at one time actually and at another potentially, e.g. wine or flesh or man does so. (And these too
fall under the above-named causes. For the form exists actually, if it can exist apart, and so does the complex
of form and matter, and the privation, e.g. darkness or disease; but the matter exists potentially; for this is that
which can become qualified either by the form or by the privation.) But the distinction of actuality and
potentiality applies in another way to cases where the matter of cause and of effect is not the same, in some of
which cases the form is not the same but different; e.g. the cause of man is (1) the elements in man (viz. fire
and earth as matter, and the peculiar form), and further (2) something else outside, i.e. the father, and (3)
besides these the sun and its oblique course, which are neither matter nor form nor privation of man nor of the
same species with him, but moving causes.

Further, one must observe that some causes can be expressed in universal terms, and some cannot. The
proximate principles of all things are the 'this' which is proximate in actuality, and another which is proximate
in potentiality. The universal causes, then, of which we spoke do not exist. For it is the individual that is the
originative principle of the individuals. For while man is the originative principle of man universally, there is
no universal man, but Peleus is the originative principle of Achilles, and your father of you, and this
particular b of this particular ba, though b in general is the originative principle of ba taken without
qualification.

Further, if the causes of substances are the causes of all things, yet different things have different causes and
elements, as was said; the causes of things that are not in the same class, e.g. of colours and sounds, of
substances and quantities, are different except in an analogical sense; and those of things in the same species
are different, not in species, but in the sense that the causes of different individuals are different, your matter
and form and moving cause being different from mine, while in their universal definition they are the same.
And if we inquire what are the principles or elements of substances and relations and qualities-whether they

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are the same or different-clearly when the names of the causes are used in several senses the causes of each
are the same, but when the senses are distinguished the causes are not the same but different, except that in
the following senses the causes of all are the same. They are (1) the same or analogous in this sense, that
matter, form, privation, and the moving cause are common to all things; and (2) the causes of substances may
be treated as causes of all things in this sense, that when substances are removed all things are removed;
further, (3) that which is first in respect of complete reality is the cause of all things. But in another sense
there are different first causes, viz. all the contraries which are neither generic nor ambiguous terms; and,
further, the matters of different things are different. We have stated, then, what are the principles of sensible
things and how many they are, and in what sense they are the same and in what sense different.

Since there were three kinds of substance, two of them physical and one unmovable, regarding the latter we
must assert that it is necessary that there should be an eternal unmovable substance. For substances are the
first of existing things, and if they are all destructible, all things are destructible. But it is impossible that
movement should either have come into being or cease to be (for it must always have existed), or that time
should. For there could not be a before and an after if time did not exist. Movement also is continuous, then,
in the sense in which time is; for time is either the same thing as movement or an attribute of movement. And
there is no continuous movement except movement in place, and of this only that which is circular is
continuous.

But if there is something which is capable of moving things or acting on them, but is not actually doing so,
there will not necessarily be movement; for that which has a potency need not exercise it. Nothing, then, is
gained even if we suppose eternal substances, as the believers in the Forms do, unless there is to be in them
some principle which can cause change; nay, even this is not enough, nor is another substance besides the
Forms enough; for if it is not to act, there will be no movement. Further even if it acts, this will not be
enough, if its essence is potency; for there will not be eternal movement, since that which is potentially may
possibly not be. There must, then, be such a principle, whose very essence is actuality. Further, then, these
substances must be without matter; for they must be eternal, if anything is eternal. Therefore they must be
actuality.

Yet there is a difficulty; for it is thought that everything that acts is able to act, but that not everything that is
able to act acts, so that the potency is prior. But if this is so, nothing that is need be; for it is possible for all
things to be capable of existing but not yet to exist.

Yet if we follow the theologians who generate the world from night, or the natural philosophers who say that
'all things were together', the same impossible result ensues. For how will there be movement, if there is no
actually existing cause? Wood will surely not move itself-the carpenter's art must act on it; nor will the
menstrual blood nor the earth set themselves in motion, but the seeds must act on the earth and the semen on
the menstrual blood.

This is why some suppose eternal actuality-e.g. Leucippus and Plato; for they say there is always movement.
But why and what this movement is they do say, nor, if the world moves in this way or that, do they tell us
the cause of its doing so. Now nothing is moved at random, but there must always be something present to
move it; e.g. as a matter of fact a thing moves in one way by nature, and in another by force or through the
influence of reason or something else. (Further, what sort of movement is primary? This makes a vast
difference.) But again for Plato, at least, it is not permissible to name here that which he sometimes supposes
to be the source of movement-that which moves itself; for the soul is later, and coeval with the heavens,
according to his account. To suppose potency prior to actuality, then, is in a sense right, and in a sense not;
and we have specified these senses. That actuality is prior is testified by Anaxagoras (for his 'reason' is
actuality) and by Empedocles in his doctrine of love and strife, and by those who say that there is always
movement, e.g. Leucippus. Therefore chaos or night did not exist for an infinite time, but the same things
have always existed (either passing through a cycle of changes or obeying some other law), since actuality is

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prior to potency. If, then, there is a constant cycle, something must always remain, acting in the same way.
And if there is to be generation and destruction, there must be something else which is always acting in
different ways. This must, then, act in one way in virtue of itself, and in another in virtue of something
else-either of a third agent, therefore, or of the first. Now it must be in virtue of the first. For otherwise this
again causes the motion both of the second agent and of the third. Therefore it is better to say 'the first'. For it
was the cause of eternal uniformity; and something else is the cause of variety, and evidently both together
are the cause of eternal variety. This, accordingly, is the character which the motions actually exhibit. What
need then is there to seek for other principles?

Since (1) this is a possible account of the matter, and (2) if it were not true, the world would have proceeded
out of night and 'all things together' and out of non-being, these difficulties may be taken as solved. There is,
then, something which is always moved with an unceasing motion, which is motion in a circle; and this is
plain not in theory only but in fact. Therefore the first heaven must be eternal. There is therefore also
something which moves it. And since that which moves and is moved is intermediate, there is something
which moves without being moved, being eternal, substance, and actuality. And the object of desire and the
object of thought move in this way; they move without being moved. The primary objects of desire and of
thought are the same. For the apparent good is the object of appetite, and the real good is the primary object
of rational wish. But desire is consequent on opinion rather than opinion on desire; for the thinking is the
starting-point. And thought is moved by the object of thought, and one of the two columns of opposites is in
itself the object of thought; and in this, substance is first, and in substance, that which is simple and exists
actually. (The one and the simple are not the same; for 'one' means a measure, but 'simple' means that the
thing itself has a certain nature.) But the beautiful, also, and that which is in itself desirable are in the same
column; and the first in any class is always best, or analogous to the best.

That a final cause may exist among unchangeable entities is shown by the distinction of its meanings. For the
final cause is (a) some being for whose good an action is done, and (b) something at which the action aims;
and of these the latter exists among unchangeable entities though the former does not. The final cause, then,
produces motion as being loved, but all other things move by being moved. Now if something is moved it is
capable of being otherwise than as it is. Therefore if its actuality is the primary form of spatial motion, then in
so far as it is subject to change, in this respect it is capable of being otherwise,-in place, even if not in
substance. But since there is something which moves while itself unmoved, existing actually, this can in no
way be otherwise than as it is. For motion in space is the first of the kinds of change, and motion in a circle
the first kind of spatial motion; and this the first mover produces. The first mover, then, exists of necessity;
and in so far as it exists by necessity, its mode of being is good, and it is in this sense a first principle. For the
necessary has all these senses-that which is necessary perforce because it is contrary to the natural impulse,
that without which the good is impossible, and that which cannot be otherwise but can exist only in a single
way.

On such a principle, then, depend the heavens and the world of nature. And it is a life such as the best which
we enjoy, and enjoy for but a short time (for it is ever in this state, which we cannot be), since its actuality is
also pleasure. (And for this reason are waking, perception, and thinking most pleasant, and hopes and
memories are so on account of these.) And thinking in itself deals with that which is best in itself, and that
which is thinking in the fullest sense with that which is best in the fullest sense. And thought thinks on itself
because it shares the nature of the object of thought; for it becomes an object of thought in coming into
contact with and thinking its objects, so that thought and object of thought are the same. For that which is
capable of receiving the object of thought, i.e. the essence, is thought. But it is active when it possesses this
object. Therefore the possession rather than the receptivity is the divine element which thought seems to
contain, and the act of contemplation is what is most pleasant and best. If, then, God is always in that good
state in which we sometimes are, this compels our wonder; and if in a better this compels it yet more. And
God is in a better state. And life also belongs to God; for the actuality of thought is life, and God is that
actuality; and God's self-dependent actuality is life most good and eternal. We say therefore that God is a

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living being, eternal, most good, so that life and duration continuous and eternal belong to God; for this is
God.

Those who suppose, as the Pythagoreans and Speusippus do, that supreme beauty and goodness are not
present in the beginning, because the beginnings both of plants and of animals are causes, but beauty and
completeness are in the effects of these, are wrong in their opinion. For the seed comes from other individuals
which are prior and complete, and the first thing is not seed but the complete being; e.g. we must say that
before the seed there is a man,-not the man produced from the seed, but another from whom the seed comes.

It is clear then from what has been said that there is a substance which is eternal and unmovable and separate
from sensible things. It has been shown also that this substance cannot have any magnitude, but is without
parts and indivisible (for it produces movement through infinite time, but nothing finite has infinite power;
and, while every magnitude is either infinite or finite, it cannot, for the above reason, have finite magnitude,
and it cannot have infinite magnitude because there is no infinite magnitude at all). But it has also been
shown that it is impassive and unalterable; for all the other changes are posterior to change of place.

It is clear, then, why these things are as they are. But we must not ignore the question whether we have to
suppose one such substance or more than one, and if the latter, how many; we must also mention, regarding
the opinions expressed by others, that they have said nothing about the number of the substances that can
even be clearly stated. For the theory of Ideas has no special discussion of the subject; for those who speak of
Ideas say the Ideas are numbers, and they speak of numbers now as unlimited, now as limited by the number
10; but as for the reason why there should be just so many numbers, nothing is said with any demonstrative
exactness. We however must discuss the subject, starting from the presuppositions and distinctions we have
mentioned. The first principle or primary being is not movable either in itself or accidentally, but produces
the primary eternal and single movement. But since that which is moved must be moved by something, and
the first mover must be in itself unmovable, and eternal movement must be produced by something eternal
and a single movement by a single thing, and since we see that besides the simple spatial movement of the
universe, which we say the first and unmovable substance produces, there are other spatial movements-those
of the planets-which are eternal (for a body which moves in a circle is eternal and unresting; we have proved
these points in the physical treatises), each of these movements also must be caused by a substance both
unmovable in itself and eternal. For the nature of the stars is eternal just because it is a certain kind of
substance, and the mover is eternal and prior to the moved, and that which is prior to a substance must be a
substance. Evidently, then, there must be substances which are of the same number as the movements of the
stars, and in their nature eternal, and in themselves unmovable, and without magnitude, for the reason before
mentioned. That the movers are substances, then, and that one of these is first and another second according
to the same order as the movements of the stars, is evident. But in the number of the movements we reach a
problem which must be treated from the standpoint of that one of the mathematical sciences which is most
akin to philosophy-viz. of astronomy; for this science speculates about substance which is perceptible but
eternal, but the other mathematical sciences, i.e. arithmetic and geometry, treat of no substance. That the
movements are more numerous than the bodies that are moved is evident to those who have given even
moderate attention to the matter; for each of the planets has more than one movement. But as to the actual
number of these movements, we now-to give some notion of the subject-quote what some of the
mathematicians say, that our thought may have some definite number to grasp; but, for the rest, we must
partly investigate for ourselves, Partly learn from other investigators, and if those who study this subject form
an opinion contrary to what we have now stated, we must esteem both parties indeed, but follow the more
accurate.

Eudoxus supposed that the motion of the sun or of the moon involves, in either case, three spheres, of which
the first is the sphere of the fixed stars, and the second moves in the circle which runs along the middle of the
zodiac, and the third in the circle which is inclined across the breadth of the zodiac; but the circle in which
the moon moves is inclined at a greater angle than that in which the sun moves. And the motion of the planets

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involves, in each case, four spheres, and of these also the first and second are the same as the first two
mentioned above (for the sphere of the fixed stars is that which moves all the other spheres, and that which is
placed beneath this and has its movement in the circle which bisects the zodiac is common to all), but the
poles of the third sphere of each planet are in the circle which bisects the zodiac, and the motion of the fourth
sphere is in the circle which is inclined at an angle to the equator of the third sphere; and the poles of the third
sphere are different for each of the other planets, but those of Venus and Mercury are the same.

Callippus made the position of the spheres the same as Eudoxus did, but while he assigned the same number
as Eudoxus did to Jupiter and to Saturn, he thought two more spheres should be added to the sun and two to
the moon, if one is to explain the observed facts; and one more to each of the other planets.

But it is necessary, if all the spheres combined are to explain the observed facts, that for each of the planets
there should be other spheres (one fewer than those hitherto assigned) which counteract those already
mentioned and bring back to the same position the outermost sphere of the star which in each case is situated
below the star in question; for only thus can all the forces at work produce the observed motion of the planets.
Since, then, the spheres involved in the movement of the planets themselves are — eight for Saturn and Jupiter
and twenty-five for the others, and of these only those involved in the movement of the lowest-situated
planet need not be counteracted the spheres which counteract those of the outermost two planets will be six in
number, and the spheres which counteract those of the next four planets will be sixteen; therefore the number
of all the spheres — both those which move the planets and those which counteract these — will be fifty-five.
And if one were not to add to the moon and to the sun the movements we mentioned, the whole set of spheres
will be forty-seven in number.

Let this, then, be taken as the number of the spheres, so that the unmovable substances and principles also
may probably be taken as just so many; the assertion of necessity must be left to more powerful thinkers. But
if there can be no spatial movement which does not conduce to the moving of a star, and if further every
being and every substance which is immune from change and in virtue of itself has attained to the best must
be considered an end, there can be no other being apart from these we have named, but this must be the
number of the substances. For if there are others, they will cause change as being a final cause of movement;
but there cannot he other movements besides those mentioned. And it is reasonable to infer this from a
consideration of the bodies that are moved; for if everything that moves is for the sake of that which is
moved, and every movement belongs to something that is moved, no movement can be for the sake of itself
or of another movement, but all the movements must be for the sake of the stars. For if there is to be a
movement for the sake of a movement, this latter also will have to be for the sake of something else; so that
since there cannot be an infinite regress, the end of every movement will be one of the divine bodies which
move through the heaven.

(Evidently there is but one heaven. For if there are many heavens as there are many men, the moving
principles, of which each heaven will have one, will be one in form but in number many. But all things that
are many in number have matter; for one and the same definition, e.g. that of man, applies to many things,
while Socrates is one. But the primary essence has not matter; for it is complete reality. So the unmovable
first mover is one both in definition and in number; so too, therefore, is that which is moved always and
continuously; therefore there is one heaven alone.) Our forefathers in the most remote ages have handed
down to their posterity a tradition, in the form of a myth, that these bodies are gods, and that the divine
encloses the whole of nature. The rest of the tradition has been added later in mythical form with a view to
the persuasion of the multitude and to its legal and utilitarian expediency; they say these gods are in the form
of men or like some of the other animals, and they say other things consequent on and similar to these which
we have mentioned. But if one were to separate the first point from these additions and take it alone-that they
thought the first substances to be gods, one must regard this as an inspired utterance, and reflect that, while
probably each art and each science has often been developed as far as possible and has again perished, these
opinions, with others, have been preserved until the present like relics of the ancient treasure. Only thus far,

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then, is the opinion of our ancestors and of our earliest predecessors clear to us.

The nature of the divine thought involves certain problems; for while thought is held to be the most divine of
things observed by us, the question how it must be situated in order to have that character involves
difficulties. For if it thinks of nothing, what is there here of dignity? It is just like one who sleeps. And if it
thinks, but this depends on something else, then (since that which is its substance is not the act of thinking,
but a potency) it cannot be the best substance; for it is through thinking that its value belongs to it. Further,
whether its substance is the faculty of thought or the act of thinking, what does it think of? Either of itself or
of something else; and if of something else, either of the same thing always or of something different. Does it
matter, then, or not, whether it thinks of the good or of any chance thing? Are there not some things about
which it is incredible that it should think? Evidently, then, it thinks of that which is most divine and precious,
and it does not change; for change would be change for the worse, and this would be already a movement.
First, then, if 'thought' is not the act of thinking but a potency, it would be reasonable to suppose that the
continuity of its thinking is wearisome to it. Secondly, there would evidently be something else more
precious than thought, viz. that which is thought of. For both thinking and the act of thought will belong even
to one who thinks of the worst thing in the world, so that if this ought to be avoided (and it ought, for there
are even some things which it is better not to see than to see), the act of thinking cannot be the best of things.
Therefore it must be of itself that the divine thought thinks (since it is the most excellent of things), and its
thinking is a thinking on thinking.

But evidently knowledge and perception and opinion and understanding have always something else as their
object, and themselves only by the way. Further, if thinking and being thought of are different, in respect of
which does goodness belong to thought? For to he an act of thinking and to he an object of thought are not
the same thing. We answer that in some cases the knowledge is the object. In the productive sciences it is the
substance or essence of the object, matter omitted, and in the theoretical sciences the definition or the act of
thinking is the object. Since, then, thought and the object of thought are not different in the case of things that
have not matter, the divine thought and its object will be the same, i.e. the thinking will be one with the
object of its thought.

A further question is left-whether the object of the divine thought is composite; for if it were, thought would
change in passing from part to part of the whole. We answer that everything which has not matter is
indivisible-as human thought, or rather the thought of composite beings, is in a certain period of time (for it
does not possess the good at this moment or at that, but its best, being something different from it, is attained
only in a whole period of time), so throughout eternity is the thought which has itself for its object.

We must consider also in which of two ways the nature of the universe contains the good, and the highest
good, whether as something separate and by itself, or as the order of the parts. Probably in both ways, as an
army does; for its good is found both in its order and in its leader, and more in the latter; for he does not
depend on the order but it depends on him. And all things are ordered together somehow, but not all
alike,-both fishes and fowls and plants; and the world is not such that one thing has nothing to do with
another, but they are connected. For all are ordered together to one end, but it is as in a house, where the
freemen are least at liberty to act at random, but all things or most things are already ordained for them, while
the slaves and the animals do little for the common good, and for the most part live at random; for this is the
sort of principle that constitutes the nature of each. I mean, for instance, that all must at least come to be
dissolved into their elements, and there are other functions similarly in which all share for the good of the
whole.

We must not fail to observe how many impossible or paradoxical results confront those who hold different
views from our own, and what are the views of the subtler thinkers, and which views are attended by fewest
difficulties. All make all things out of contraries. But neither 'all things' nor 'out of contraries' is right; nor do
these thinkers tell us how all the things in which the contraries are present can be made out of the contraries;

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for contraries are not affected by one another. Now for us this difficulty is solved naturally by the fact that
there is a third element. These thinkers however make one of the two contraries matter; this is done for
instance by those who make the unequal matter for the equal, or the many matter for the one. But this also is
refuted in the same way; for the one matter which underlies any pair of contraries is contrary to nothing.
Further, all things, except the one, will, on the view we are criticizing, partake of evil; for the bad itself is one
of the two elements. But the other school does not treat the good and the bad even as principles; yet in all
things the good is in the highest degree a principle. The school we first mentioned is right in saying that it is a
principle, but how the good is a principle they do not say-whether as end or as mover or as form.

Empedocles also has a paradoxical view; for he identifies the good with love, but this is a principle both as
mover (for it brings things together) and as matter (for it is part of the mixture). Now even if it happens that
the same thing is a principle both as matter and as mover, still the being, at least, of the two is not the same.
In which respect then is love a principle? It is paradoxical also that strife should be imperishable; the nature
of his 'evil' is just strife.

Anaxagoras makes the good a motive principle; for his 'reason' moves things. But it moves them for an end,
which must be something other than it, except according to our way of stating the case; for, on our view, the
medical art is in a sense health. It is paradoxical also not to suppose a contrary to the good, i.e. to reason. But
all who speak of the contraries make no use of the contraries, unless we bring their views into shape. And
why some things are perishable and others imperishable, no one tells us; for they make all existing things out
of the same principles. Further, some make existing things out of the nonexistent; and others to avoid the
necessity of this make all things one.

Further, why should there always be becoming, and what is the cause of becoming ?— this no one tells us. And
those who suppose two principles must suppose another, a superior principle, and so must those who believe
in the Forms; for why did things come to participate, or why do they participate, in the Forms? And all other
thinkers are confronted by the necessary consequence that there is something contrary to Wisdom, i.e. to the
highest knowledge; but we are not. For there is nothing contrary to that which is primary; for all contraries
have matter, and things that have matter exist only potentially; and the ignorance which is contrary to any
knowledge leads to an object contrary to the object of the knowledge; but what is primary has no contrary.

Again, if besides sensible things no others exist, there will be no first principle, no order, no becoming, no
heavenly bodies, but each principle will have a principle before it, as in the accounts of the theologians and
all the natural philosophers. But if the Forms or the numbers are to exist, they will be causes of nothing; or if
not that, at least not of movement. Further, how is extension, i.e. a continuum, to be produced out of
unextended parts? For number will not, either as mover or as form, produce a continuum. But again there
cannot be any contrary that is also essentially a productive or moving principle; for it would be possible for it
not to be. Or at least its action would be posterior to its potency. The world, then, would not be eternal. But it
is; one of these premisses, then, must be denied. And we have said how this must be done. Further, in virtue
of what the numbers, or the soul and the body, or in general the form and the thing, are one-of this no one
tells us anything; nor can any one tell, unless he says, as we do, that the mover makes them one. And those
who say mathematical number is first and go on to generate one kind of substance after another and give
different principles for each, make the substance of the universe a mere series of episodes (for one substance
has no influence on another by its existence or nonexistence), and they give us many governing principles;
but the world refuses to be governed badly.

'The rule of many is not good; one ruler let there be.'

Book XIII

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WE have stated what is the substance of sensible things, dealing in the treatise on physics with matter, and
later with the substance which has actual existence. Now since our inquiry is whether there is or is not
besides the sensible substances any which is immovable and eternal, and, if there is, what it is, we must first
consider what is said by others, so that, if there is anything which they say wrongly, we may not be liable to
the same objections, while, if there is any opinion common to them and us, we shall have no private
grievance against ourselves on that account; for one must be content to state some points better than one's
predecessors, and others no worse.

Two opinions are held on this subject; it is said that the objects of mathematics-i.e. numbers and lines and
the like-are substances, and again that the Ideas are substances. And (1) since some recognize these as two
different classes-the Ideas and the mathematical numbers, and (2) some recognize both as having one nature,
while (3) some others say that the mathematical substances are the only substances, we must consider first the
objects of mathematics, not qualifying them by any other characteristic-not asking, for instance, whether
they are in fact Ideas or not, or whether they are the principles and substances of existing things or not, but
only whether as objects of mathematics they exist or not, and if they exist, how they exist. Then after this we
must separately consider the Ideas themselves in a general way, and only as far as the accepted mode of
treatment demands; for most of the points have been repeatedly made even by the discussions outside our
school, and, further, the greater part of our account must finish by throwing light on that inquiry, viz. when
we examine whether the substances and the principles of existing things are numbers and Ideas; for after the
discussion of the Ideas this remans as a third inquiry.

If the objects of mathematics exist, they must exist either in sensible objects, as some say, or separate from
sensible objects (and this also is said by some); or if they exist in neither of these ways, either they do not
exist, or they exist only in some special sense. So that the subject of our discussion will be not whether they
exist but how they exist.

That it is impossible for mathematical objects to exist in sensible things, and at the same time that the
doctrine in question is an artificial one, has been said already in our discussion of difficulties we have pointed
out that it is impossible for two solids to be in the same place, and also that according to the same argument
the other powers and characteristics also should exist in sensible things and none of them separately. This we
have said already. But, further, it is obvious that on this theory it is impossible for any body whatever to be
divided; for it would have to be divided at a plane, and the plane at a line, and the line at a point, so that if the
point cannot be divided, neither can the line, and if the line cannot, neither can the plane nor the solid. What
difference, then, does it make whether sensible things are such indivisible entities, or, without being so
themselves, have indivisible entities in them? The result will be the same; if the sensible entities are divided
the others will be divided too, or else not even the sensible entities can be divided.

But, again, it is not possible that such entities should exist separately. For if besides the sensible solids there
are to be other solids which are separate from them and prior to the sensible solids, it is plain that besides the
planes also there must be other and separate planes and points and lines; for consistency requires this. But if
these exist, again besides the planes and lines and points of the mathematical solid there must be others which
are separate. (For incomposites are prior to compounds; and if there are, prior to the sensible bodies, bodies
which are not sensible, by the same argument the planes which exist by themselves must be prior to those
which are in the motionless solids. Therefore these will be planes and lines other than those that exist along
with the mathematical solids to which these thinkers assign separate existence; for the latter exist along with
the mathematical solids, while the others are prior to the mathematical solids.) Again, therefore, there will be,
belonging to these planes, lines, and prior to them there will have to be, by the same argument, other lines
and points; and prior to these points in the prior lines there will have to be other points, though there will be
no others prior to these. Now (1) the accumulation becomes absurd; for we find ourselves with one set of
solids apart from the sensible solids; three sets of planes apart from the sensible planes-those which exist
apart from the sensible planes, and those in the mathematical solids, and those which exist apart from those in

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the mathematical solids; four sets of lines, and five sets of points. With which of these, then, will the
mathematical sciences deal? Certainly not with the planes and lines and points in the motionless solid; for
science always deals with what is prior. And (the same account will apply also to numbers; for there will be a
different set of units apart from each set of points, and also apart from each set of realities, from the objects of
sense and again from those of thought; so that there will be various classes of mathematical numbers.

Again, how is it possible to solve the questions which we have already enumerated in our discussion of
difficulties? For the objects of astronomy will exist apart from sensible things just as the objects of geometry
will; but how is it possible that a heaven and its parts-or anything else which has movement-should exist
apart? Similarly also the objects of optics and of harmonics will exist apart; for there will be both voice and
sight besides the sensible or individual voices and sights. Therefore it is plain that the other senses as well,
and the other objects of sense, will exist apart; for why should one set of them do so and another not? And if
this is so, there will also be animals existing apart, since there will be senses.

Again, there are certain mathematical theorems that are universal, extending beyond these substances. Here
then we shall have another intermediate substance separate both from the Ideas and from the intermediates,-a
substance which is neither number nor points nor spatial magnitude nor time. And if this is impossible,
plainly it is also impossible that the former entities should exist separate from sensible things.

And, in general, conclusion contrary alike to the truth and to the usual views follow, if one is to suppose the
objects of mathematics to exist thus as separate entities. For because they exist thus they must be prior to
sensible spatial magnitudes, but in truth they must be posterior; for the incomplete spatial magnitude is in the
order of generation prior, but in the order of substance posterior, as the lifeless is to the living.

Again, by virtue of what, and when, will mathematical magnitudes be one? For things in our perceptible
world are one in virtue of soul, or of a part of soul, or of something else that is reasonable enough; when
these are not present, the thing is a plurality, and splits up into parts. But in the case of the subjects of
mathematics, which are divisible and are quantities, what is the cause of their being one and holding
together?

Again, the modes of generation of the objects of mathematics show that we are right. For the dimension first
generated is length, then comes breadth, lastly depth, and the process is complete. If, then, that which is
posterior in the order of generation is prior in the order of substantiality, the solid will be prior to the plane
and the line. And in this way also it is both more complete and more whole, because it can become animate.
How, on the other hand, could a line or a plane be animate? The supposition passes the power of our senses.

Again, the solid is a sort of substance; for it already has in a sense completeness. But how can lines be
substances? Neither as a form or shape, as the soul perhaps is, nor as matter, like the solid; for we have no
experience of anything that can be put together out of lines or planes or points, while if these had been a sort
of material substance, we should have observed things which could be put together out of them.

Grant, then, that they are prior in definition. Still not all things that are prior in definition are also prior in
substantiality. For those things are prior in substantiality which when separated from other things surpass
them in the power of independent existence, but things are prior in definition to those whose definitions are
compounded out of their definitions; and these two properties are not coextensive. For if attributes do not
exist apart from the substances (e.g. a 'mobile' or a pale'), pale is prior to the pale man in definition, but not in
substantiality. For it cannot exist separately, but is always along with the concrete thing; and by the concrete
thing I mean the pale man. Therefore it is plain that neither is the result of abstraction prior nor that which is
produced by adding determinants posterior; for it is by adding a determinant to pale that we speak of the pale
man.

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It has, then, been sufficiently pointed out that the objects of mathematics are not substances in a higher
degree than bodies are, and that they are not prior to sensibles in being, but only in definition, and that they
cannot exist somewhere apart. But since it was not possible for them to exist in sensibles either, it is plain that
they either do not exist at all or exist in a special sense and therefore do not 'exist' without qualification. For
'exist' has many senses.

For just as the universal propositions of mathematics deal not with objects which exist separately, apart from
extended magnitudes and from numbers, but with magnitudes and numbers, not however qua such as to have
magnitude or to be divisible, clearly it is possible that there should also be both propositions and
demonstrations about sensible magnitudes, not however qua sensible but qua possessed of certain definite
qualities. For as there are many propositions about things merely considered as in motion, apart from what
each such thing is and from their accidents, and as it is not therefore necessary that there should be either a
mobile separate from sensibles, or a distinct mobile entity in the sensibles, so too in the case of mobiles there
will be propositions and sciences, which treat them however not qua mobile but only qua bodies, or again
only qua planes, or only qua lines, or qua divisibles, or qua indivisibles having position, or only qua
indivisibles. Thus since it is true to say without qualification that not only things which are separable but also
things which are inseparable exist (for instance, that mobiles exist), it is true also to say without qualification
that the objects of mathematics exist, and with the character ascribed to them by mathematicians. And as it is
true to say of the other sciences too, without qualification, that they deal with such and such a subject-not
with what is accidental to it (e.g. not with the pale, if the healthy thing is pale, and the science has the healthy
as its subject), but with that which is the subject of each science-with the healthy if it treats its object qua
healthy, with man if qua man:-so too is it with geometry; if its subjects happen to be sensible, though it does
not treat them qua sensible, the mathematical sciences will not for that reason be sciences of sensibles-nor,
on the other hand, of other things separate from sensibles. Many properties attach to things in virtue of their
own nature as possessed of each such character; e.g. there are attributes peculiar to the animal qua female or
qua male (yet there is no 'female' nor 'male' separate from animals); so that there are also attributes which
belong to things merely as lengths or as planes. And in proportion as we are dealing with things which are
prior in definition and simpler, our knowledge has more accuracy, i.e. simplicity. Therefore a science which
abstracts from spatial magnitude is more precise than one which takes it into account; and a science is most
precise if it abstracts from movement, but if it takes account of movement, it is most precise if it deals with
the primary movement, for this is the simplest; and of this again uniform movement is the simplest form.

The same account may be given of harmonics and optics; for neither considers its objects qua sight or qua
voice, but qua lines and numbers; but the latter are attributes proper to the former. And mechanics too
proceeds in the same way. Therefore if we suppose attributes separated from their fellow attributes and make
any inquiry concerning them as such, we shall not for this reason be in error, any more than when one draws
a line on the ground and calls it a foot long when it is not; for the error is not included in the premisses.

Each question will be best investigated in this way-by setting up by an act of separation what is not separate,
as the arithmetician and the geometer do. For a man qua man is one indivisible thing; and the arithmetician
supposed one indivisible thing, and then considered whether any attribute belongs to a man qua indivisible.
But the geometer treats him neither qua man nor qua indivisible, but as a solid. For evidently the properties
which would have belonged to him even if perchance he had not been indivisible, can belong to him even
apart from these attributes. Thus, then, geometers speak correctly; they talk about existing things, and their
subjects do exist; for being has two forms-it exists not only in complete reality but also materially.

Now since the good and the beautiful are different (for the former always implies conduct as its subject, while
the beautiful is found also in motionless things), those who assert that the mathematical sciences say nothing
of the beautiful or the good are in error. For these sciences say and prove a great deal about them; if they do
not expressly mention them, but prove attributes which are their results or their definitions, it is not true to
say that they tell us nothing about them. The chief forms of beauty are order and symmetry and definiteness,

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which the mathematical sciences demonstrate in a special degree. And since these (e.g. order and
definiteness) are obviously causes of many things, evidently these sciences must treat this sort of causative
principle also (i.e. the beautiful) as in some sense a cause. But we shall speak more plainly elsewhere about
these matters.

So much then for the objects of mathematics; we have said that they exist and in what sense they exist, and in
what sense they are prior and in what sense not prior. Now, regarding the Ideas, we must first examine the
ideal theory itself, not connecting it in any way with the nature of numbers, but treating it in the form in
which it was originally understood by those who first maintained the existence of the Ideas. The supporters of
the ideal theory were led to it because on the question about the truth of things they accepted the Heraclitean
sayings which describe all sensible things as ever passing away, so that if knowledge or thought is to have an
object, there must be some other and permanent entities, apart from those which are sensible; for there could
be no knowledge of things which were in a state of flux. But when Socrates was occupying himself with the
excellences of character, and in connexion with them became the first to raise the problem of universal
definition (for of the physicists Democritus only touched on the subject to a small extent, and defined, after a
fashion, the hot and the cold; while the Pythagoreans had before this treated of a few things, whose
definitions-e.g. those of opportunity, justice, or marriage-they connected with numbers; but it was natural
that Socrates should be seeking the essence, for he was seeking to syllogize, and 'what a thing is' is the
starting-point of syllogisms; for there was as yet none of the dialectical power which enables people even
without knowledge of the essence to speculate about contraries and inquire whether the same science deals
with contraries; for two things may be fairly ascribed to Socrates-inductive arguments and universal
definition, both of which are concerned with the starting-point of science):-but Socrates did not make the
universals or the definitions exist apart: they, however, gave them separate existence, and this was the kind of
thing they called Ideas. Therefore it followed for them, almost by the same argument, that there must be Ideas
of all things that are spoken of universally, and it was almost as if a man wished to count certain things, and
while they were few thought he would not be able to count them, but made more of them and then counted
them; for the Forms are, one may say, more numerous than the particular sensible things, yet it was in
seeking the causes of these that they proceeded from them to the Forms. For to each thing there answers an
entity which has the same name and exists apart from the substances, and so also in the case of all other
groups there is a one over many, whether these be of this world or eternal.

Again, of the ways in which it is proved that the Forms exist, none is convincing; for from some no inference
necessarily follows, and from some arise Forms even of things of which they think there are no Forms. For
according to the arguments from the sciences there will be Forms of all things of which there are sciences,
and according to the argument of the 'one over many' there will be Forms even of negations, and according to
the argument that thought has an object when the individual object has perished, there will be Forms of
perishable things; for we have an image of these. Again, of the most accurate arguments, some lead to Ideas
of relations, of which they say there is no independent class, and others introduce the 'third man'.

And in general the arguments for the Forms destroy things for whose existence the believers in Forms are
more zealous than for the existence of the Ideas; for it follows that not the dyad but number is first, and that
prior to number is the relative, and that this is prior to the absolute-besides all the other points on which
certain people, by following out the opinions held about the Forms, came into conflict with the principles of
the theory.

Again, according to the assumption on the belief in the Ideas rests, there will be Forms not only of substances
but also of many other things; for the concept is single not only in the case of substances, but also in that of
non-substances, and there are sciences of other things than substance; and a thousand other such difficulties
confront them. But according to the necessities of the case and the opinions about the Forms, if they can be
shared in there must be Ideas of substances only. For they are not shared in incidentally, but each Form must
be shared in as something not predicated of a subject. (By 'being shared in incidentally' I mean that if a thing

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shares in 'double itself, it shares also in 'eternal', but incidentally; for 'the double' happens to be eternal.)
Therefore the Forms will be substance. But the same names indicate substance in this and in the ideal world
(or what will be the meaning of saying that there is something apart from the particulars-the one over
many?). And if the Ideas and the things that share in them have the same form, there will be something
common: for why should '2' be one and the same in the perishable 2's, or in the 2's which are many but
eternal, and not the same in the '2 itself as in the individual 2? But if they have not the same form, they will
have only the name in common, and it is as if one were to call both Callias and a piece of wood a 'man',
without observing any community between them.

But if we are to suppose that in other respects the common definitions apply to the Forms, e.g. that 'plane
figure' and the other parts of the definition apply to the circle itself, but 'what really is' has to be added, we
must inquire whether this is not absolutely meaningless. For to what is this to be added? To 'centre' or to
'plane' or to all the parts of the definition? For all the elements in the essence are Ideas, e.g. 'animal' and
'two-footed'. Further, there must be some Ideal answering to 'plane' above, some nature which will be present
in all the Forms as their genus.

Above all one might discuss the question what in the world the Forms contribute to sensible things, either to
those that are eternal or to those that come into being and cease to be; for they cause neither movement nor
any change in them. But again they help in no wise either towards the knowledge of other things (for they are
not even the substance of these, else they would have been in them), or towards their being, if they are not in
the individuals which share in them; though if they were, they might be thought to be causes, as white causes
whiteness in a white object by entering into its composition. But this argument, which was used first by
Anaxagoras, and later by Eudoxus in his discussion of difficulties and by certain others, is very easily upset;
for it is easy to collect many and insuperable objections to such a view.

But, further, all other things cannot come from the Forms in any of the usual senses of 'from'. And to say that
they are patterns and the other things share in them is to use empty words and poetical metaphors. For what is
it that works, looking to the Ideas? And any thing can both be and come into being without being copied from
something else, so that, whether Socrates exists or not, a man like Socrates might come to be. And evidently
this might be so even if Socrates were eternal. And there will be several patterns of the same thing, and
therefore several Forms; e.g. 'animal' and 'two-footed', and also 'man-himself, will be Forms of man. Again,
the Forms are patterns not only of sensible things, but of Forms themselves also; i.e. the genus is the pattern
of the various forms-of-a-genus; therefore the same thing will be pattern and copy.

Again, it would seem impossible that substance and that whose substance it is should exist apart; how,
therefore, could the Ideas, being the substances of things, exist apart?

In the Phaedo the case is stated in this way-that the Forms are causes both of being and of becoming. Yet
though the Forms exist, still things do not come into being, unless there is something to originate movement;
and many other things come into being (e.g. a house or a ring) of which they say there are no Forms. Clearly
therefore even the things of which they say there are Ideas can both be and come into being owing to such
causes as produce the things just mentioned, and not owing to the Forms. But regarding the Ideas it is
possible, both in this way and by more abstract and accurate arguments, to collect many objections like those
we have considered.

Since we have discussed these points, it is well to consider again the results regarding numbers which
confront those who say that numbers are separable substances and first causes of things. If number is an
entity and its substance is nothing other than just number, as some say, it follows that either (1) there is a first
in it and a second, each being different in species,-and either (a) this is true of the units without exception,
and any unit is inassociable with any unit, or (b) they are all without exception successive, and any of them
are associable with any, as they say is the case with mathematical number; for in mathematical number no

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one unit is in any way different from another. Or (c) some units must be associable and some not; e.g.
suppose that 2 is first after 1, and then comes 3 and then the rest of the number series, and the units in each
number are associable, e.g. those in the first 2 are associable with one another, and those in the first 3 with
one another, and so with the other numbers; but the units in the '2-itself are inassociable with those in the
'3-itself ; and similarly in the case of the other successive numbers. And so while mathematical number is
counted thus- after 1, 2 (which consists of another 1 besides the former 1), and 3 which consists of another 1
besides these two), and the other numbers similarly, ideal number is counted thus-after 1, a distinct 2 which
does not include the first 1, and a 3 which does not include the 2 and the rest of the number series similarly.
Or (2) one kind of number must be like the first that was named, one like that which the mathematicians
speak of, and that which we have named last must be a third kind.

Again, these kinds of numbers must either be separable from things, or not separable but in objects of
perception (not however in the way which we first considered, in the sense that objects of perception consists
of numbers which are present in them)-either one kind and not another, or all of them.

These are of necessity the only ways in which the numbers can exist. And of those who say that the 1 is the
beginning and substance and element of all things, and that number is formed from the 1 and something else,
almost every one has described number in one of these ways; only no one has said all the units are
inassociable. And this has happened reasonably enough; for there can be no way besides those mentioned.
Some say both kinds of number exist, that which has a before and after being identical with the Ideas, and
mathematical number being different from the Ideas and from sensible things, and both being separable from
sensible things; and others say mathematical number alone exists, as the first of realities, separate from
sensible things. And the Pythagoreans, also, believe in one kind of number-the mathematical; only they say it
is not separate but sensible substances are formed out of it. For they construct the whole universe out of
numbers-only not numbers consisting of abstract units; they suppose the units to have spatial magnitude. But
how the first 1 was constructed so as to have magnitude, they seem unable to say.

Another thinker says the first kind of number, that of the Forms, alone exists, and some say mathematical
number is identical with this.

The case of lines, planes, and solids is similar. For some think that those which are the objects of
mathematics are different from those which come after the Ideas; and of those who express themselves
otherwise some speak of the objects of mathematics and in a mathematical way-viz. those who do not make
the Ideas numbers nor say that Ideas exist; and others speak of the objects of mathematics, but not
mathematically; for they say that neither is every spatial magnitude divisible into magnitudes, nor do any two
units taken at random make 2. All who say the 1 is an element and principle of things suppose numbers to
consist of abstract units, except the Pythagoreans; but they suppose the numbers to have magnitude, as has
been said before. It is clear from this statement, then, in how many ways numbers may be described, and that
all the ways have been mentioned; and all these views are impossible, but some perhaps more than others.

First, then, let us inquire if the units are associable or inassociable, and if inassociable, in which of the two
ways we distinguished. For it is possible that any unity is inassociable with any, and it is possible that those
in the 'itself are inassociable with those in the 'itself, and, generally, that those in each ideal number are
inassociable with those in other ideal numbers. Now (1) all units are associable and without difference, we
get mathematical number-only one kind of number, and the Ideas cannot be the numbers. For what sort of
number will man-himself or animal-itself or any other Form be? There is one Idea of each thing e.g. one of
man-himself and another one of animal-itself; but the similar and undifferentiated numbers are infinitely
many, so that any particular 3 is no more man-himself than any other 3. But if the Ideas are not numbers,
neither can they exist at all. For from what principles will the Ideas come? It is number that comes from the 1
and the indefinite dyad, and the principles or elements are said to be principles and elements of number, and
the Ideas cannot be ranked as either prior or posterior to the numbers.

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But (2) if the units are inassociable, and inassociable in the sense that any is inassociable with any other,
number of this sort cannot be mathematical number; for mathematical number consists of undifferentiated
units, and the truths proved of it suit this character. Nor can it be ideal number. For 2 will not proceed
immediately from 1 and the indefinite dyad, and be followed by the successive numbers, as they say '2,3,4'
for the units in the ideal are generated at the same time, whether, as the first holder of the theory said, from
unequals (coming into being when these were equalized) or in some other way-since, if one unit is to be prior
to the other, it will be prior also to 2 the composed of these; for when there is one thing prior and another
posterior, the resultant of these will be prior to one and posterior to the other. Again, since the 1 -itself is first,
and then there is a particular 1 which is first among the others and next after the 1 -itself, and again a third
which is next after the second and next but one after the first 1 ,-so the units must be prior to the numbers
after which they are named when we count them; e.g. there will be a third unit in 2 before 3 exists, and a
fourth and a fifth in 3 before the numbers 4 and 5 exist.-Now none of these thinkers has said the units are
inassociable in this way, but according to their principles it is reasonable that they should be so even in this
way, though in truth it is impossible. For it is reasonable both that the units should have priority and
posteriority if there is a first unit or first 1, and also that the 2's should if there is a first 2; for after the first it
is reasonable and necessary that there should be a second, and if a second, a third, and so with the others
successively. (And to say both things at the same time, that a unit is first and another unit is second after the
ideal 1, and that a 2 is first after it, is impossible.) But they make a first unit or 1, but not also a second and a
third, and a first 2, but not also a second and a third. Clearly, also, it is not possible, if all the units are
inassociable, that there should be a 2-itself and a 3— itself; and so with the other numbers. For whether the
units are undifferentiated or different each from each, number must be counted by addition, e.g. 2 by adding
another 1 to the one, 3 by adding another 1 to the two, and similarly. This being so, numbers cannot be
generated as they generate them, from the 2 and the 1 ; for 2 becomes part of 3 and 3 of 4 and the same
happens in the case of the succeeding numbers, but they say 4 came from the first 2 and the indefinite which
makes it two 2's other than the 2-itself; if not, the 2-itself will be a part of 4 and one other 2 will be added.
And similarly 2 will consist of the 1— itself and another 1 ; but if this is so, the other element cannot be an
indefinite 2; for it generates one unit, not, as the indefinite 2 does, a definite 2.

Again, besides the 3— itself and the 2-itself how can there be other 3's and 2's? And how do they consist of
prior and posterior units? All this is absurd and fictitious, and there cannot be a first 2 and then a 3— itself. Yet
there must, if the 1 and the indefinite dyad are to be the elements. But if the results are impossible, it is also
impossible that these are the generating principles.

If the units, then, are differentiated, each from each, these results and others similar to these follow of
necessity. But (3) if those in different numbers are differentiated, but those in the same number are alone
undifferentiated from one another, even so the difficulties that follow are no less. E.g. in the 10— itself their
are ten units, and the 10 is composed both of them and of two 5's. But since the 10— itself is not any chance
number nor composed of any chance 5's — or, for that matter, units — the units in this 10 must differ. For if
they do not differ, neither will the 5's of which the 10 consists differ; but since these differ, the units also will
differ. But if they differ, will there be no other 5's in the 10 but only these two, or will there be others? If
there are not, this is paradoxical; and if there are, what sort of 10 will consist of them? For there is no other in
the 10 but the 10 itself. But it is actually necessary on their view that the 4 should not consist of any chance
2's; for the indefinite as they say, received the definite 2 and made two 2's; for its nature was to double what it
received.

Again, as to the 2 being an entity apart from its two units, and the 3 an entity apart from its three units, how is
this possible? Either by one's sharing in the other, as 'pale man' is different from 'pale' and 'man' (for it shares
in these), or when one is a differentia of the other, as 'man' is different from 'animal' and 'two-footed'.

Again, some things are one by contact, some by intermixture, some by position; none of which can belong to
the units of which the 2 or the 3 consists; but as two men are not a unity apart from both, so must it be with

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the units. And their being indivisible will make no difference to them; for points too are indivisible, but yet a
pair of them is nothing apart from the two.

But this consequence also we must not forget, that it follows that there are prior and posterior 2 and similarly
with the other numbers. For let the 2's in the 4 be simultaneous; yet these are prior to those in the 8 and as the
2 generated them, they generated the 4's in the 8— itself. Therefore if the first 2 is an Idea, these 2's also will
be Ideas of some kind. And the same account applies to the units; for the units in the first 2 generate the four
in 4, so that all the units come to be Ideas and an Idea will be composed of Ideas. Clearly therefore those
things also of which these happen to be the Ideas will be composite, e.g. one might say that animals are
composed of animals, if there are Ideas of them.

In general, to differentiate the units in any way is an absurdity and a fiction; and by a fiction I mean a forced
statement made to suit a hypothesis. For neither in quantity nor in quality do we see unit differing from unit,
and number must be either equal or unequal-all number but especially that which consists of abstract
units-so that if one number is neither greater nor less than another, it is equal to it; but things that are equal
and in no wise differentiated we take to be the same when we are speaking of numbers. If not, not even the 2
in the 10— itself will be undifferentiated, though they are equal; for what reason will the man who alleges that
they are not differentiated be able to give?

Again, if every unit + another unit makes two, a unit from the 2-itself and one from the 3— itself will make a
2. Now (a) this will consist of differentiated units; and will it be prior to the 3 or posterior? It rather seems
that it must be prior; for one of the units is simultaneous with the 3 and the other is simultaneous with the 2.
And we, for our part, suppose that in general 1 and 1, whether the things are equal or unequal, is 2, e.g. the
good and the bad, or a man and a horse; but those who hold these views say that not even two units are 2.

If the number of the 3— itself is not greater than that of the 2, this is surprising; and if it is greater, clearly there
is also a number in it equal to the 2, so that this is not different from the 2-itself. But this is not possible, if
there is a first and a second number.

Nor will the Ideas be numbers. For in this particular point they are right who claim that the units must be
different, if there are to be Ideas; as has been said before. For the Form is unique; but if the units are not
different, the 2's and the 3's also will not be different. This is also the reason why they must say that when we
count thus-'l,2'-we do not proceed by adding to the given number; for if we do, neither will the numbers be
generated from the indefinite dyad, nor can a number be an Idea; for then one Idea will be in another, and all
Forms will be parts of one Form. And so with a view to their hypothesis their statements are right, but as a
whole they are wrong; for their view is very destructive, since they will admit that this question itself affords
some difficulty-whether, when we count and say -1,2,3-we count by addition or by separate portions. But
we do both; and so it is absurd to reason back from this problem to so great a difference of essence.

First of all it is well to determine what is the differentia of a number-and of a unit, if it has a differentia.
Units must differ either in quantity or in quality; and neither of these seems to be possible. But number qua
number differs in quantity. And if the units also did differ in quantity, number would differ from number,
though equal in number of units. Again, are the first units greater or smaller, and do the later ones increase or
diminish? All these are irrational suppositions. But neither can they differ in quality. For no attribute can
attach to them; for even to numbers quality is said to belong after quantity. Again, quality could not come to
them either from the 1 or the dyad; for the former has no quality, and the latter gives quantity; for this entity
is what makes things to be many. If the facts are really otherwise, they should state this quite at the beginning
and determine if possible, regarding the differentia of the unit, why it must exist, and, failing this, what
differentia they mean.

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Evidently then, if the Ideas are numbers, the units cannot all be associable, nor can they be inassociable in
either of the two ways. But neither is the way in which some others speak about numbers correct. These are
those who do not think there are Ideas, either without qualification or as identified with certain numbers, but
think the objects of mathematics exist and the numbers are the first of existing things, and the 1— itself is the
starting-point of them. It is paradoxical that there should be a 1 which is first of l's, as they say, but not a 2
which is first of 2's, nor a 3 of 3's; for the same reasoning applies to all. If, then, the facts with regard to
number are so, and one supposes mathematical number alone to exist, the 1 is not the starting-point (for this
sort of 1 must differ from the-other units; and if this is so, there must also be a 2 which is first of 2's, and
similarly with the other successive numbers). But if the 1 is the starting-point, the truth about the numbers
must rather be what Plato used to say, and there must be a first 2 and 3 and numbers must not be associable
with one another. But if on the other hand one supposes this, many impossible results, as we have said,
follow. But either this or the other must be the case, so that if neither is, number cannot exist separately.

It is evident, also, from this that the third version is the worst,-the view ideal and mathematical number is the
same. For two mistakes must then meet in the one opinion. (1) Mathematical number cannot be of this sort,
but the holder of this view has to spin it out by making suppositions peculiar to himself. And (2) he must also
admit all the consequences that confront those who speak of number in the sense of 'Forms'.

The Pythagorean version in one way affords fewer difficulties than those before named, but in another way
has others peculiar to itself. For not thinking of number as capable of existing separately removes many of the
impossible consequences; but that bodies should be composed of numbers, and that this should be
mathematical number, is impossible. For it is not true to speak of indivisible spatial magnitudes; and however
much there might be magnitudes of this sort, units at least have not magnitude; and how can a magnitude be
composed of indivisibles? But arithmetical number, at least, consists of units, while these thinkers identify
number with real things; at any rate they apply their propositions to bodies as if they consisted of those
numbers.

If, then, it is necessary, if number is a self-subsistent real thing, that it should exist in one of these ways
which have been mentioned, and if it cannot exist in any of these, evidently number has no such nature as
those who make it separable set up for it.

Again, does each unit come from the great and the small, equalized, or one from the small, another from the
great? (a) If the latter, neither does each thing contain all the elements, nor are the units without difference;
for in one there is the great and in another the small, which is contrary in its nature to the great. Again, how is
it with the units in the 3— itself? One of them is an odd unit. But perhaps it is for this reason that they give
1— itself the middle place in odd numbers, (b) But if each of the two units consists of both the great and the
small, equalized, how will the 2 which is a single thing, consist of the great and the small? Or how will it
differ from the unit? Again, the unit is prior to the 2; for when it is destroyed the 2 is destroyed. It must, then,
be the Idea of an Idea since it is prior to an Idea, and it must have come into being before it. From what, then?
Not from the indefinite dyad, for its function was to double.

Again, number must be either infinite or finite; for these thinkers think of number as capable of existing
separately, so that it is not possible that neither of those alternatives should be true. Clearly it cannot be
infinite; for infinite number is neither odd nor even, but the generation of numbers is always the generation
either of an odd or of an even number; in one way, when 1 operates on an even number, an odd number is
produced; in another way, when 2 operates, the numbers got from 1 by doubling are produced; in another
way, when the odd numbers operate, the other even numbers are produced. Again, if every Idea is an Idea of
something, and the numbers are Ideas, infinite number itself will be an Idea of something, either of some
sensible thing or of something else. Yet this is not possible in view of their thesis any more than it is
reasonable in itself, at least if they arrange the Ideas as they do.

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But if number is finite, how far does it go? With regard to this not only the fact but the reason should be
stated. But if number goes only up to 10 as some say, firstly the Forms will soon run short; e.g. if 3 is
man-himself, what number will be the horse-itself? The series of the numbers which are the several
things-themselves goes up to 10. It must, then, be one of the numbers within these limits; for it is these that
are substances and Ideas. Yet they will run short; for the various forms of animal will outnumber them. At the
same time it is clear that if in this way the 3 is man-himself, the other 3's are so also (for those in identical
numbers are similar), so that there will be an infinite number of men; if each 3 is an Idea, each of the numbers
will be man-himself, and if not, they will at least be men. And if the smaller number is part of the greater
(being number of such a sort that the units in the same number are associable), then if the 4-itself is an Idea
of something, e.g. of 'horse' or of 'white', man will be a part of horse, if man is It is paradoxical also that there
should be an Idea of 10 but not of 1 1, nor of the succeeding numbers. Again, there both are and come to be
certain things of which there are no Forms; why, then, are there not Forms of them also? We infer that the
Forms are not causes. Again, it is paradoxical-if the number series up to 10 is more of a real thing and a
Form than 10 itself. There is no generation of the former as one thing, and there is of the latter. But they try to
work on the assumption that the series of numbers up to 10 is a complete series. At least they generate the
derivatives-e.g. the void, proportion, the odd, and the others of this kind-within the decade. For some things,
e.g. movement and rest, good and bad, they assign to the originative principles, and the others to the numbers.
This is why they identify the odd with 1 ; for if the odd implied 3 how would 5 be odd? Again, spatial
magnitudes and all such things are explained without going beyond a definite number; e.g. the first, the
indivisible, line, then the 2 these entities also extend only up to 10.

Again, if number can exist separately, one might ask which is prior- 1, or 3 or 2? Inasmuch as the number is
composite, 1 is prior, but inasmuch as the universal and the form is prior, the number is prior; for each of the
units is part of the number as its matter, and the number acts as form. And in a sense the right angle is prior to
the acute, because it is determinate and in virtue of its definition; but in a sense the acute is prior, because it is
a part and the right angle is divided into acute angles. As matter, then, the acute angle and the element and the
unit are prior, but in respect of the form and of the substance as expressed in the definition, the right angle,
and the whole consisting of the matter and the form, are prior; for the concrete thing is nearer to the form and
to what is expressed in the definition, though in generation it is later. How then is 1 the starting-point?
Because it is not divisiable, they say; but both the universal, and the particular or the element, are indivisible.
But they are starting-points in different ways, one in definition and the other in time. In which way, then, is 1
the starting-point? As has been said, the right angle is thought to be prior to the acute, and the acute to the
right, and each is one. Accordingly they make 1 the starting-point in both ways. But this is impossible. For
the universal is one as form or substance, while the element is one as a part or as matter. For each of the two
is in a sense one-in truth each of the two units exists potentially (at least if the number is a unity and not like
a heap, i.e. if different numbers consist of differentiated units, as they say), but not in complete reality; and
the cause of the error they fell into is that they were conducting their inquiry at the same time from the
standpoint of mathematics and from that of universal definitions, so that (1) from the former standpoint they
treated unity, their first principle, as a point; for the unit is a point without position. They put things together
out of the smallest parts, as some others also have done. Therefore the unit becomes the matter of numbers
and at the same time prior to 2; and again posterior, 2 being treated as a whole, a unity, and a form. But (2)
because they were seeking the universal they treated the unity which can be predicated of a number, as in this
sense also a part of the number. But these characteristics cannot belong at the same time to the same thing.

If the 1— itself must be unitary (for it differs in nothing from other l's except that it is the starting-point), and
the 2 is divisible but the unit is not, the unit must be liker the 1— itself than the 2 is. But if the unit is liker it, it
must be liker to the unit than to the 2; therefore each of the units in 2 must be prior to the 2. But they deny
this; at least they generate the 2 first. Again, if the 2-itself is a unity and the 3— itself is one also, both form a
2. From what, then, is this 2 produced?

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Since there is not contact in numbers, but succession, viz. between the units between which there is nothing,
e.g. between those in 2 or in 3 one might ask whether these succeed the 1— itself or not, and whether, of the
terms that succeed it, 2 or either of the units in 2 is prior.

Similar difficulties occur with regard to the classes of things posterior to number ,-the line, the plane, and the
solid. For some construct these out of the species of the 'great and small'; e.g. lines from the 'long and short',
planes from the 'broad and narrow', masses from the 'deep and shallow'; which are species of the 'great and
small'. And the originative principle of such things which answers to the 1 different thinkers describe in
different ways, And in these also the impossibilities, the fictions, and the contradictions of all probability are
seen to be innumerable. For (i) geometrical classes are severed from one another, unless the principles of
these are implied in one another in such a way that the 'broad and narrow' is also 'long and short' (but if this is
so, the plane will be line and the solid a plane; again, how will angles and figures and such things be
explained?). And (ii) the same happens as in regard to number; for 'long and short', are attributes of
magnitude, but magnitude does not consist of these, any more than the line consists of 'straight and curved',
or solids of 'smooth and rough.

(All these views share a difficulty which occurs with regard to species-of-a-genus, when one posits the
universals, viz. whether it is animal-itself or something other than animal-itself that is in the particular
animal. True, if the universal is not separable from sensible things, this will present no difficulty; but if the 1
and the numbers are separable, as those who express these views say, it is not easy to solve the difficulty, if
one may apply the words 'not easy' to the impossible. For when we apprehend the unity in 2, or in general in a
number, do we apprehend a thing-itself or something else?).

Some, then, generate spatial magnitudes from matter of this sort, others from the point -and the point is
thought by them to be not 1 but something like 1-and from other matter like plurality, but not identical with
it; about which principles none the less the same difficulties occur. For if the matter is one, line and
plane-and soli will be the same; for from the same elements will come one and the same thing. But if the
matters are more than one, and there is one for the line and a second for the plane and another for the solid,
they either are implied in one another or not, so that the same results will follow even so; for either the plane
will not contain a line or it will he a line.

Again, how number can consist of the one and plurality, they make no attempt to explain; but however they
express themselves, the same objections arise as confront those who construct number out of the one and the
indefinite dyad. For the one view generates number from the universally predicated plurality, and not from a
particular plurality; and the other generates it from a particular plurality, but the first; for 2 is said to be a 'first
plurality'. Therefore there is practically no difference, but the same difficulties will follow,-is it intermixture
or position or blending or generation? and so on. Above all one might press the question 'if each unit is one,
what does it come from?' Certainly each is not the one-itself. It must, then, come from the one itself and
plurality, or a part of plurality. To say that the unit is a plurality is impossible, for it is indivisible; and to
generate it from a part of plurality involves many other objections; for (a) each of the parts must be
indivisible (or it will be a plurality and the unit will be divisible) and the elements will not be the one and
plurality; for the single units do not come from plurality and the one. Again, (,the holder of this view does
nothing but presuppose another number; for his plurality of indivisibles is a number. Again, we must inquire,
in view of this theory also, whether the number is infinite or finite. For there was at first, as it seems, a
plurality that was itself finite, from which and from the one comes the finite number of units. And there is
another plurality that is plurality-itself and infinite plurality; which sort of plurality, then, is the element
which co-operates with the one? One might inquire similarly about the point, i.e. the element out of which
they make spatial magnitudes. For surely this is not the one and only point; at any rate, then, let them say out
of what each of the points is formed. Certainly not of some distance + the point-itself. Nor again can there be
indivisible parts of a distance, as the elements out of which the units are said to be made are indivisible parts
of plurality; for number consists of indivisibles, but spatial magnitudes do not.

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All these objections, then, and others of the sort make it evident that number and spatial magnitudes cannot
exist apart from things. Again, the discord about numbers between the various versions is a sign that it is the
incorrectness of the alleged facts themselves that brings confusion into the theories. For those who make the
objects of mathematics alone exist apart from sensible things, seeing the difficulty about the Forms and their
fictitiousness, abandoned ideal number and posited mathematical. But those who wished to make the Forms
at the same time also numbers, but did not see, if one assumed these principles, how mathematical number
was to exist apart from ideal, made ideal and mathematical number the same-in words, since in fact
mathematical number has been destroyed; for they state hypotheses peculiar to themselves and not those of
mathematics. And he who first supposed that the Forms exist and that the Forms are numbers and that the
objects of mathematics exist, naturally separated the two. Therefore it turns out that all of them are right in
some respect, but on the whole not right. And they themselves confirm this, for their statements do not agree
but conflict. The cause is that their hypotheses and their principles are false. And it is hard to make a good
case out of bad materials, according to Epicharmus: 'as soon as 'tis said, 'tis seen to be wrong.'

But regarding numbers the questions we have raised and the conclusions we have reached are sufficient (for
while he who is already convinced might be further convinced by a longer discussion, one not yet convinced
would not come any nearer to conviction); regarding the first principles and the first causes and elements, the
views expressed by those who discuss only sensible substance have been partly stated in our works on nature,
and partly do not belong to the present inquiry; but the views of those who assert that there are other
substances besides the sensible must be considered next after those we have been mentioning. Since, then,
some say that the Ideas and the numbers are such substances, and that the elements of these are elements and
principles of real things, we must inquire regarding these what they say and in what sense they say it.

Those who posit numbers only, and these mathematical, must be considered later; but as regards those who
believe in the Ideas one might survey at the same time their way of thinking and the difficulty into which they
fall. For they at the same time make the Ideas universal and again treat them as separable and as individuals.
That this is not possible has been argued before. The reason why those who described their substances as
universal combined these two characteristics in one thing, is that they did not make substances identical with
sensible things. They thought that the particulars in the sensible world were a state of flux and none of them
remained, but that the universal was apart from these and something different. And Socrates gave the impulse
to this theory, as we said in our earlier discussion, by reason of his definitions, but he did not separate
universals from individuals; and in this he thought rightly, in not separating them. This is plain from the
results; for without the universal it is not possible to get knowledge, but the separation is the cause of the
objections that arise with regard to the Ideas. His successors, however, treating it as necessary, if there are to
be any substances besides the sensible and transient substances, that they must be separable, had no others,
but gave separate existence to these universally predicated substances, so that it followed that universals and
individuals were almost the same sort of thing. This in itself, then, would be one difficulty in the view we
have mentioned.

Let us now mention a point which presents a certain difficulty both to those who believe in the Ideas and to
those who do not, and which was stated before, at the beginning, among the problems. If we do not suppose
substances to be separate, and in the way in which individual things are said to be separate, we shall destroy
substance in the sense in which we understand 'substance'; but if we conceive substances to be separable, how
are we to conceive their elements and their principles?

If they are individual and not universal, (a) real things will be just of the same number as the elements, and
(b) the elements will not be knowable. For (a) let the syllables in speech be substances, and their elements
elements of substances; then there must be only one 'ba' and one of each of the syllables, since they are not
universal and the same in form but each is one in number and a 'this' and not a kind possessed of a common
name (and again they suppose that the just what a thing is' is in each case one). And if the syllables are
unique, so too are the parts of which they consist; there will not, then, be more a's than one, nor more than

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one of any of the other elements, on the same principle on which an identical syllable cannot exist in the
plural number. But if this is so, there will not be other things existing besides the elements, but only the
elements.

(b) Again, the elements will not be even knowable; for they are not universal, and knowledge is of universals.
This is clear from demonstrations and from definitions; for we do not conclude that this triangle has its angles
equal to two right angles, unless every triangle has its angles equal to two right angles, nor that this man is an
animal, unless every man is an animal.

But if the principles are universal, either the substances composed of them are also universal, or
non-substance will be prior to substance; for the universal is not a substance, but the element or principle is
universal, and the element or principle is prior to the things of which it is the principle or element.

All these difficulties follow naturally, when they make the Ideas out of elements and at the same time claim
that apart from the substances which have the same form there are Ideas, a single separate entity. But if, e.g.
in the case of the elements of speech, the a's and the b's may quite well be many and there need be no a-itself
and b-itself besides the many, there may be, so far as this goes, an infinite number of similar syllables. The
statement that an knowledge is universal, so that the principles of things must also be universal and not
separate substances, presents indeed, of all the points we have mentioned, the greatest difficulty, but yet the
statement is in a sense true, although in a sense it is not. For knowledge, like the verb 'to know', means two
things, of which one is potential and one actual. The potency, being, as matter, universal and indefinite, deals
with the universal and indefinite; but the actuality, being definite, deals with a definite object, being a 'this', it
deals with a 'this'. But per accidens sight sees universal colour, because this individual colour which it sees is
colour; and this individual a which the grammarian investigates is an a. For if the principles must be
universal, what is derived from them must also be universal, as in demonstrations; and if this is so, there will
be nothing capable of separate existence-i.e. no substance. But evidently in a sense knowledge is universal,
and in a sense it is not.

Book XIV

REGARDING this kind of substance, what we have said must be taken as sufficient. All philosophers make
the first principles contraries: as in natural things, so also in the case of unchangeable substances. But since
there cannot be anything prior to the first principle of all things, the principle cannot be the principle and yet
be an attribute of something else. To suggest this is like saying that the white is a first principle, not qua
anything else but qua white, but yet that it is predicable of a subject, i.e. that its being white presupposes its
being something else; this is absurd, for then that subject will be prior. But all things which are generated
from their contraries involve an underlying subject; a subject, then, must be present in the case of contraries,
if anywhere. All contraries, then, are always predicable of a subject, and none can exist apart, but just as
appearances suggest that there is nothing contrary to substance, argument confirms this. No contrary, then, is
the first principle of all things in the full sense; the first principle is something different.

But these thinkers make one of the contraries matter, some making the unequal which they take to be the
essence of plurality-matter for the One, and others making plurality matter for the One. (The former generate
numbers out of the dyad of the unequal, i.e. of the great and small, and the other thinker we have referred to
generates them out of plurality, while according to both it is generated by the essence of the One.) For even
the philosopher who says the unequal and the One are the elements, and the unequal is a dyad composed of
the great and small, treats the unequal, or the great and the small, as being one, and does not draw the
distinction that they are one in definition, but not in number. But they do not describe rightly even the
principles which they call elements, for some name the great and the small with the One and treat these three
as elements of numbers, two being matter, one the form; while others name the many and few, because the
great and the small are more appropriate in their nature to magnitude than to number; and others name rather

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the universal character common to these-'that which exceeds and that which is exceeded'. None of these
varieties of opinion makes any difference to speak of, in view of some of the consequences; they affect only
the abstract objections, which these thinkers take care to avoid because the demonstrations they themselves
offer are abstract,-with this exception, that if the exceeding and the exceeded are the principles, and not the
great and the small, consistency requires that number should come from the elements before does; for number
is more universal than as the exceeding and the exceeded are more universal than the great and the small. But
as it is, they say one of these things but do not say the other. Others oppose the different and the other to the
One, and others oppose plurality to the One. But if, as they claim, things consist of contraries, and to the One
either there is nothing contrary, or if there is to be anything it is plurality, and the unequal is contrary to the
equal, and the different to the same, and the other to the thing itself, those who oppose the One to plurality
have most claim to plausibility, but even their view is inadequate, for the One would on their view be a few;
for plurality is opposed to fewness, and the many to the few.

'The one' evidently means a measure. And in every case there is some underlying thing with a distinct nature
of its own, e.g. in the scale a quarter-tone, in spatial magnitude a finger or a foot or something of the sort, in
rhythms a beat or a syllable; and similarly in gravity it is a definite weight; and in the same way in all cases,
in qualities a quality, in quantities a quantity (and the measure is indivisible, in the former case in kind, and in
the latter to the sense); which implies that the one is not in itself the substance of anything. And this is
reasonable; for 'the one' means the measure of some plurality, and 'number' means a measured plurality and a
plurality of measures. (Thus it is natural that one is not a number; for the measure is not measures, but both
the measure and the one are starting-points.) The measure must always be some identical thing predicable of
all the things it measures, e.g. if the things are horses, the measure is 'horse', and if they are men, 'man'. If
they are a man, a horse, and a god, the measure is perhaps 'living being', and the number of them will be a
number of living beings. If the things are 'man' and 'pale' and 'walking', these will scarcely have a number,
because all belong to a subject which is one and the same in number, yet the number of these will be a
number of 'kinds' or of some such term.

Those who treat the unequal as one thing, and the dyad as an indefinite compound of great and small, say
what is very far from being probable or possible. For (a) these are modifications and accidents, rather than
substrata, of numbers and magnitudes-the many and few of number, and the great and small of
magnitude-like even and odd, smooth and rough, straight and curved. Again, (b) apart from this mistake, the
great and the small, and so on, must be relative to something; but what is relative is least of all things a kind
of entity or substance, and is posterior to quality and quantity; and the relative is an accident of quantity, as
was said, not its matter, since something with a distinct nature of its own must serve as matter both to the
relative in general and to its parts and kinds. For there is nothing either great or small, many or few, or, in
general, relative to something else, which without having a nature of its own is many or few, great or small,
or relative to something else. A sign that the relative is least of all a substance and a real thing is the fact that
it alone has no proper generation or destruction or movement, as in respect of quantity there is increase and
diminution, in respect of quality alteration, in respect of place locomotion, in respect of substance simple
generation and destruction. In respect of relation there is no proper change; for, without changing, a thing will
be now greater and now less or equal, if that with which it is compared has changed in quantity. And (c) the
matter of each thing, and therefore of substance, must be that which is potentially of the nature in question;
but the relative is neither potentially nor actually substance. It is strange, then, or rather impossible, to make
not-substance an element in, and prior to, substance; for all the categories are posterior to substance. Again,
(d) elements are not predicated of the things of which they are elements, but many and few are predicated
both apart and together of number, and long and short of the line, and both broad and narrow apply to the
plane. If there is a plurality, then, of which the one term, viz. few, is always predicated, e.g. 2 (which cannot
be many, for if it were many, 1 would be few), there must be also one which is absolutely many, e.g. 10 is
many (if there is no number which is greater than 10), or 10,000. How then, in view of this, can number
consist of few and many? Either both ought to be predicated of it, or neither; but in fact only the one or the
other is predicated.

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We must inquire generally, whether eternal things can consist of elements. If they do, they will have matter;
for everything that consists of elements is composite. Since, then, even if a thing exists for ever, out of that of
which it consists it would necessarily also, if it had come into being, have come into being, and since
everything comes to be what it comes to be out of that which is it potentially (for it could not have come to be
out of that which had not this capacity, nor could it consist of such elements), and since the potential can be
either actual or not,-this being so, however everlasting number or anything else that has matter is, it must be
capable of not existing, just as that which is any number of years old is as capable of not existing as that
which is a day old; if this is capable of not existing, so is that which has lasted for a time so long that it has no
limit. They cannot, then, be eternal, since that which is capable of not existing is not eternal, as we had
occasion to show in another context. If that which we are now saying is true universally-that no substance is
eternal unless it is actuality-and if the elements are matter that underlies substance, no eternal substance can
have elements present in it, of which it consists.

There are some who describe the element which acts with the One as an indefinite dyad, and object to 'the
unequal', reasonably enough, because of the ensuing difficulties; but they have got rid only of those
objections which inevitably arise from the treatment of the unequal, i.e. the relative, as an element; those
which arise apart from this opinion must confront even these thinkers, whether it is ideal number, or
mathematical, that they construct out of those elements.

There are many causes which led them off into these explanations, and especially the fact that they framed
the difficulty in an obsolete form. For they thought that all things that are would be one (viz. Being itself), if
one did not join issue with and refute the saying of Parmenides:

'For never will this he proved, that things that are not are.'

They thought it necessary to prove that that which is not is; for only thus-of that which is and something
else-could the things that are be composed, if they are many.

But, first, if 'being' has many senses (for it means sometimes substance, sometimes that it is of a certain
quality, sometimes that it is of a certain quantity, and at other times the other categories), what sort of 'one',
then, are all the things that are, if non-being is to be supposed not to be? Is it the substances that are one, or
the affections and similarly the other categories as well, or all together-so that the 'this' and the 'such' and the
'so much' and the other categories that indicate each some one class of being will all be one? But it is strange,
or rather impossible, that the coming into play of a single thing should bring it about that part of that which is
is a 'this', part a 'such', part a 'so much', part a 'here'.

Secondly, of what sort of non-being and being do the things that are consist? For 'nonbeing' also has many
senses, since 'being' has; and 'not being a man' means not being a certain substance, 'not being straight' not
being of a certain quality, 'not being three cubits long' not being of a certain quantity. What sort of being and
non-being, then, by their union pluralize the things that are? This thinker means by the non-being the union
of which with being pluralizes the things that are, the false and the character of falsity. This is also why it
used to be said that we must assume something that is false, as geometers assume the line which is not a foot
long to be a foot long. But this cannot be so. For neither do geometers assume anything false (for the
enunciation is extraneous to the inference), nor is it non-being in this sense that the things that are are
generated from or resolved into. But since 'non-being' taken in its various cases has as many senses as there
are categories, and besides this the false is said not to be, and so is the potential, it is from this that generation
proceeds, man from that which is not man but potentially man, and white from that which is not white but
potentially white, and this whether it is some one thing that is generated or many.

The question evidently is, how being, in the sense of 'the substances', is many; for the things that are
generated are numbers and lines and bodies. Now it is strange to inquire how being in the sense of the 'what'

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is many, and not how either qualities or quantities are many. For surely the indefinite dyad or 'the great and
the small' is not a reason why there should be two kinds of white or many colours or flavours or shapes; for
then these also would be numbers and units. But if they had attacked these other categories, they would have
seen the cause of the plurality in substances also; for the same thing or something analogous is the cause.
This aberration is the reason also why in seeking the opposite of being and the one, from which with being
and the one the things that are proceed, they posited the relative term (i.e. the unequal), which is neither the
contrary nor the contradictory of these, and is one kind of being as 'what' and quality also are.

They should have asked this question also, how relative terms are many and not one. But as it is, they inquire
how there are many units besides the first 1 , but do not go on to inquire how there are many unequals besides
the unequal. Yet they use them and speak of great and small, many and few (from which proceed numbers),
long and short (from which proceeds the line), broad and narrow (from which proceeds the plane), deep and
shallow (from which proceed solids); and they speak of yet more kinds of relative term. What is the reason,
then, why there is a plurality of these?

It is necessary, then, as we say, to presuppose for each thing that which is it potentially; and the holder of
these views further declared what that is which is potentially a 'this' and a substance but is not in itself
being-viz. that it is the relative (as if he had said 'the qualitative'), which is neither potentially the one or
being, nor the negation of the one nor of being, but one among beings. And it was much more necessary, as
we said, if he was inquiring how beings are many, not to inquire about those in the same category-how there
are many substances or many qualities-but how beings as a whole are many; for some are substances, some
modifications, some relations. In the categories other than substance there is yet another problem involved in
the existence of plurality. Since they are not separable from substances, qualities and quantities are many just
because their substratum becomes and is many; yet there ought to be a matter for each category; only it
cannot be separable from substances. But in the case of 'thises', it is possible to explain how the 'this' is many
things, unless a thing is to be treated as both a 'this' and a general character. The difficulty arising from the
facts about substances is rather this, how there are actually many substances and not one.

But further, if the 'this' and the quantitative are not the same, we are not told how and why the things that are
are many, but how quantities are many. For all 'number' means a quantity, and so does the 'unit', unless it
means a measure or the quantitatively indivisible. If, then, the quantitative and the 'what' are different, we are
not told whence or how the 'what' is many; but if any one says they are the same, he has to face many
inconsistencies.

One might fix one's attention also on the question, regarding the numbers, what justifies the belief that they
exist. To the believer in Ideas they provide some sort of cause for existing things, since each number is an
Idea, and the Idea is to other things somehow or other the cause of their being; for let this supposition be
granted them. But as for him who does not hold this view because he sees the inherent objections to the Ideas
(so that it is not for this reason that he posits numbers), but who posits mathematical number, why must we
believe his statement that such number exists, and of what use is such number to other things? Neither does
he who says it exists maintain that it is the cause of anything (he rather says it is a thing existing by itself),
nor is it observed to be the cause of anything; for the theorems of arithmeticians will all be found true even of
sensible things, as was said before.

As for those, then, who suppose the Ideas to exist and to be numbers, by their assumption in virtue of the
method of setting out each term apart from its instances-of the unity of each general term they try at least to
explain somehow why number must exist. Since their reasons, however, are neither conclusive nor in
themselves possible, one must not, for these reasons at least, assert the existence of number. Again, the
Pythagoreans, because they saw many attributes of numbers belonging te sensible bodies, supposed real
things to be numbers-not separable numbers, however, but numbers of which real things consist. But why?
Because the attributes of numbers are present in a musical scale and in the heavens and in many other things.

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Those, however, who say that mathematical number alone exists cannot according to their hypotheses say
anything of this sort, but it used to be urged that these sensible things could not be the subject of the sciences.
But we maintain that they are, as we said before. And it is evident that the objects of mathematics do not exist
apart; for if they existed apart their attributes would not have been present in bodies. Now the Pythagoreans
in this point are open to no objection; but in that they construct natural bodies out of numbers, things that
have lightness and weight out of things that have not weight or lightness, they seem to speak of another
heaven and other bodies, not of the sensible. But those who make number separable assume that it both exists
and is separable because the axioms would not be true of sensible things, while the statements of mathematics
are true and 'greet the soul'; and similarly with the spatial magnitudes of mathematics. It is evident, then, both
that the rival theory will say the contrary of this, and that the difficulty we raised just now, why if numbers
are in no way present in sensible things their attributes are present in sensible things, has to be solved by
those who hold these views.

There are some who, because the point is the limit and extreme of the line, the line of the plane, and the plane
of the solid, think there must be real things of this sort. We must therefore examine this argument too, and see
whether it is not remarkably weak. For (i) extremes are not substances, but rather all these things are limits.
For even walking, and movement in general, has a limit, so that on their theory this will be a 'this' and a
substance. But that is absurd. Not but what (ii) even if they are substances, they will all be the substances of
the sensible things in this world; for it is to these that the argument applied. Why then should they be capable
of existing apart?

Again, if we are not too easily satisfied, we may, regarding all number and the objects of mathematics, press
this difficulty, that they contribute nothing to one another, the prior to the posterior; for if number did not
exist, none the less spatial magnitudes would exist for those who maintain the existence of the objects of
mathematics only, and if spatial magnitudes did not exist, soul and sensible bodies would exist. But the
observed facts show that nature is not a series of episodes, like a bad tragedy. As for the believers in the
Ideas, this difficulty misses them; for they construct spatial magnitudes out of matter and number, lines out of
the number planes doubtless out of solids out of or they use other numbers, which makes no difference. But
will these magnitudes be Ideas, or what is their manner of existence, and what do they contribute to things?
These contribute nothing, as the objects of mathematics contribute nothing. But not even is any theorem true
of them, unless we want to change the objects of mathematics and invent doctrines of our own. But it is not
hard to assume any random hypotheses and spin out a long string of conclusions. These thinkers, then, are
wrong in this way, in wanting to unite the objects of mathematics with the Ideas. And those who first posited
two kinds of number, that of the Forms and that which is mathematical, neither have said nor can say how
mathematical number is to exist and of what it is to consist. For they place it between ideal and sensible
number. If (i) it consists of the great and small, it will be the same as the other-ideal-number (he makes
spatial magnitudes out of some other small and great). And if (ii) he names some other element, he will be
making his elements rather many. And if the principle of each of the two kinds of number is a 1, unity will be
something common to these, and we must inquire how the one is these many things, while at the same time
number, according to him, cannot be generated except from one and an indefinite dyad.

All this is absurd, and conflicts both with itself and with the probabilities, and we seem to see in it Simonides
'long rigmarole' for the long rigmarole comes into play, like those of slaves, when men have nothing sound to
say. And the very elements-the great and the small-seem to cry out against the violence that is done to them;
for they cannot in any way generate numbers other than those got from 1 by doubling.

It is strange also to attribute generation to things that are eternal, or rather this is one of the things that are
impossible. There need be no doubt whether the Pythagoreans attribute generation to them or not; for they
say plainly that when the one had been constructed, whether out of planes or of surface or of seed or of
elements which they cannot express, immediately the nearest part of the unlimited began to be constrained
and limited by the limit. But since they are constructing a world and wish to speak the language of natural

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science, it is fair to make some examination of their physical theories, but to let them off from the present
inquiry; for we are investigating the principles at work in unchangeable things, so that it is numbers of this
kind whose genesis we must study.

These thinkers say there is no generation of the odd number, which evidently implies that there is generation
of the even; and some present the even as produced first from unequals-the great and the small-when these
are equalized. The inequality, then, must belong to them before they are equalized. If they had always been
equalized, they would not have been unequal before; for there is nothing before that which is always.
Therefore evidently they are not giving their account of the generation of numbers merely to assist
contemplation of their nature.

A difficulty, and a reproach to any one who finds it no difficulty, are contained in the question how the
elements and the principles are related to the good and the beautiful; the difficulty is this, whether any of the
elements is such a thing as we mean by the good itself and the best, or this is not so, but these are later in
origin than the elements. The theologians seem to agree with some thinkers of the present day, who answer
the question in the negative, and say that both the good and the beautiful appear in the nature of things only
when that nature has made some progress. (This they do to avoid a real objection which confronts those who
say, as some do, that the one is a first principle. The objection arises not from their ascribing goodness to the
first principle as an attribute, but from their making the one a principle-and a principle in the sense of an
element-and generating number from the one.) The old poets agree with this inasmuch as they say that not
those who are first in time, e.g. Night and Heaven or Chaos or Ocean, reign and rule, but Zeus. These poets,
however, are led to speak thus only because they think of the rulers of the world as changing; for those of
them who combine the two characters in that they do not use mythical language throughout, e.g. Pherecydes
and some others, make the original generating agent the Best, and so do the Magi, and some of the later sages
also, e.g. both Empedocles and Anaxagoras, of whom one made love an element, and the other made reason a
principle. Of those who maintain the existence of the unchangeable substances some say the One itself is the
good itself; but they thought its substance lay mainly in its unity.

This, then, is the problem,-which of the two ways of speaking is right. It would be strange if to that which is
primary and eternal and most self-sufficient this very quality — self-sufficiency and
self-maintenance — belongs primarily in some other way than as a good. But indeed it can be for no other
reason indestructible or self-sufficient than because its nature is good. Therefore to say that the first principle
is good is probably correct; but that this principle should be the One or, if not that, at least an element, and an
element of numbers, is impossible. Powerful objections arise, to avoid which some have given up the theory
(viz. those who agree that the One is a first principle and element, but only of mathematical number). For on
this view all the units become identical with species of good, and there is a great profusion of goods. Again, if
the Forms are numbers, all the Forms are identical with species of good. But let a man assume Ideas of
anything he pleases. If these are Ideas only of goods, the Ideas will not be substances; but if the Ideas are also
Ideas of substances, all animals and plants and all individuals that share in Ideas will be good.

These absurdities follow, and it also follows that the contrary element, whether it is plurality or the unequal,
i.e. the great and small, is the bad-itself. (Hence one thinker avoided attaching the good to the One, because
it would necessarily follow, since generation is from contraries, that badness is the fundamental nature of
plurality; while others say inequality is the nature of the bad.) It follows, then, that all things partake of the
bad except one — the One itself, and that numbers partake of it in a more undiluted form than spatial
magnitudes, and that the bad is the space in which the good is realized, and that it partakes in and desires that
which tends to destroy it; for contrary tends to destroy contrary. And if, as we were saying, the matter is that
which is potentially each thing, e.g. that of actual fire is that which is potentially fire, the bad will be just the
potentially good.

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All these objections, then, follow, partly because they make every principle an element, partly because they
make contraries principles, partly because they make the One a principle, partly because they treat the
numbers as the first substances, and as capable of existing apart, and as Forms.

If, then, it is equally impossible not to put the good among the first principles and to put it among them in this
way, evidently the principles are not being correctly described, nor are the first substances. Nor does any one
conceive the matter correctly if he compares the principles of the universe to that of animals and plants, on
the ground that the more complete always comes from the indefinite and incomplete-which is what leads this
thinker to say that this is also true of the first principles of reality, so that the One itself is not even an existing
thing. This is incorrect, for even in this world of animals and plants the principles from which these come are
complete; for it is a man that produces a man, and the seed is not first.

It is out of place, also, to generate place simultaneously with the mathematical solids (for place is peculiar to
the individual things, and hence they are separate in place; but mathematical objects are nowhere), and to say
that they must be somewhere, but not say what kind of thing their place is.

Those who say that existing things come from elements and that the first of existing things are the numbers,
should have first distinguished the senses in which one thing comes from another, and then said in which
sense number comes from its first principles.

By intermixture? But (1) not everything is capable of intermixture, and (2) that which is produced by it is
different from its elements, and on this view the one will not remain separate or a distinct entity; but they
want it to be so.

By juxtaposition, like a syllable? But then (1) the elements must have position; and (2) he who thinks of
number will be able to think of the unity and the plurality apart; number then will be this-a unit and plurality,
or the one and the unequal.

Again, coming from certain things means in one sense that these are still to be found in the product, and in
another that they are not; which sense does number come from these elements? Only things that are generated
can come from elements which are present in them. Does number come, then, from its elements as from
seed? But nothing can be excreted from that which is indivisible. Does it come from its contrary, its contrary
not persisting? But all things that come in this way come also from something else which does persist. Since,
then, one thinker places the 1 as contrary to plurality, and another places it as contrary to the unequal, treating
the 1 as equal, number must be being treated as coming from contraries. There is, then, something else that
persists, from which and from one contrary the compound is or has come to be. Again, why in the world do
the other things that come from contraries, or that have contraries, perish (even when all of the contrary is
used to produce them), while number does not? Nothing is said about this. Yet whether present or not present
in the compound the contrary destroys it, e.g. 'strife' destroys the 'mixture' (yet it should not; for it is not to
that that is contrary).

Once more, it has not been determined at all in which way numbers are the causes of substances and of
being-whether (1) as boundaries (as points are of spatial magnitudes). This is how Eurytus decided what was
the number of what (e.g. one of man and another of horse), viz. by imitating the figures of living things with
pebbles, as some people bring numbers into the forms of triangle and square. Or (2) is it because harmony is
a ratio of numbers, and so is man and everything else? But how are the attributes-white and sweet and
hot-numbers? Evidently it is not the numbers that are the essence or the causes of the form; for the ratio is
the essence, while the number the causes of the form; for the ratio is the essence, while the number is the
matter. E.g. the essence of flesh or bone is number only in this way, 'three parts of fire and two of earth'. And
a number, whatever number it is, is always a number of certain things, either of parts of fire or earth or of
units; but the essence is that there is so much of one thing to so much of another in the mixture; and this is no

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longer a number but a ratio of mixture of numbers, whether these are corporeal or of any other kind.

Number, then, whether it be number in general or the number which consists of abstract units, is neither the
cause as agent, nor the matter, nor the ratio and form of things. Nor, of course, is it the final cause.

One might also raise the question what the good is that things get from numbers because their composition is
expressible by a number, either by one which is easily calculable or by an odd number. For in fact
honey-water is no more wholesome if it is mixed in the proportion of three times three, but it would do more
good if it were in no particular ratio but well diluted than if it were numerically expressible but strong. Again,
the ratios of mixtures are expressed by the adding of numbers, not by mere numbers; e.g. it is 'three parts to
two', not 'three times two'. For in any multiplication the genus of the things multiplied must be the same;
therefore the product 1X2X3 must be measurable by 1, and 4X5X6 by 4 and therefore all products into which
the same factor enters must be measurable by that factor. The number of fire, then, cannot be 2X5X3X6 and
at the same time that of water 2X3.

If all things must share in number, it must follow that many things are the same, and the same number must
belong to one thing and to another. Is number the cause, then, and does the thing exist because of its number,
or is this not certain? E.g. the motions of the sun have a number, and again those of the moon,-yes, and the
life and prime of each animal. Why, then, should not some of these numbers be squares, some cubes, and
some equal, others double? There is no reason why they should not, and indeed they must move within these
limits, since all things were assumed to share in number. And it was assumed that things that differed might
fall under the same number. Therefore if the same number had belonged to certain things, these would have
been the same as one another, since they would have had the same form of number; e.g. sun and moon would
have been the same. But why need these numbers be causes? There are seven vowels, the scale consists of
seven strings, the Pleiades are seven, at seven animals lose their teeth (at least some do, though some do not),
and the champions who fought against Thebes were seven. Is it then because the number is the kind of
number it is, that the champions were seven or the Pleiad consists of seven stars? Surely the champions were
seven because there were seven gates or for some other reason, and the Pleiad we count as seven, as we count
the Bear as twelve, while other peoples count more stars in both. Nay they even say that X, Ps and Z are
concords and that because there are three concords, the double consonants also are three. They quite neglect
the fact that there might be a thousand such letters; for one symbol might be assigned to GP. But if they say
that each of these three is equal to two of the other letters, and no other is so, and if the cause is that there are
three parts of the mouth and one letter is in each applied to sigma, it is for this reason that there are only
three, not because the concords are three; since as a matter of fact the concords are more than three, but of
double consonants there cannot be more.

These people are like the old-fashioned Homeric scholars, who see small resemblances but neglect great
ones. Some say that there are many such cases, e.g. that the middle strings are represented by nine and eight,
and that the epic verse has seventeen syllables, which is equal in number to the two strings, and that the
scansion is, in the right half of the line nine syllables, and in the left eight. And they say that the distance in
the letters from alpha to omega is equal to that from the lowest note of the flute to the highest, and that the
number of this note is equal to that of the whole choir of heaven. It may be suspected that no one could find
difficulty either in stating such analogies or in finding them in eternal things, since they can be found even in
perishable things.

But the lauded characteristics of numbers, and the contraries of these, and generally the mathematical
relations, as some describe them, making them causes of nature, seem, when we inspect them in this way, to
vanish; for none of them is a cause in any of the senses that have been distinguished in reference to the first
principles. In a sense, however, they make it plain that goodness belongs to numbers, and that the odd, the
straight, the square, the potencies of certain numbers, are in the column of the beautiful. For the seasons and a
particular kind of number go together; and the other agreements that they collect from the theorems of

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mathematics all have this meaning. Hence they are like coincidences. For they are accidents, but the things
that agree are all appropriate to one another, and one by analogy. For in each category of being an analogous
term is found-as the straight is in length, so is the level in surface, perhaps the odd in number, and the white
in colour.

Again, it is not the ideal numbers that are the causes of musical phenomena and the like (for equal ideal
numbers differ from one another in form; for even the units do); so that we need not assume Ideas for this
reason at least.

These, then, are the results of the theory, and yet more might be brought together. The fact that our opponnts
have much trouble with the generation of numbers and can in no way make a system of them, seems to
indicate that the objects of mathematics are not separable from sensible things, as some say, and that they are
not the first principles. -THE END-

Metaphysics 130

METEOROLOGY

by Aristotle

METEOROLOGY

Table of Contents

METEOROLOGY. 1

by Aristotle 1

Book 1 2

_1 2

2 2

_3 2

A 5

_5 6

_6 6

J 8

1 9

_9 10

JO 11

11 12

V2 12

±3 13

14 15

Book II . 17

_1 17

2 19

3. 21

A 24

_5 25

6 27

1_ 29

1 30

1 33

Book III 34

J. 34

2 36

_3 37

A 38

_5 40

6 41

Book IV 42

_1 42

2 43

3. 44

A 46

_5 46

6 47

1_ 48

A 49

_9 50

JO 53

11 54

12 55

METEOROLOGY

by Aristotle

translated by E. W. Webster

• Book I

• 1

• 2

• 3

•4

•5

•6

•7

•8

•9

• 10

•11

•12

•13

• 14

• Book II

• 1

•2

•3

•4

•5

•6

•7

•8

•9

• Book III

• 1

•2

•3

•4

•5

•6

• Book IV

• 1

• 2

• 3

•4

•5

•6

METEOROLOGY

•7
•8
•9

• 10

•11

• 12

Book I

WE have already discussed the first causes of nature, and all natural motion, also the stars ordered in the
motion of the heavens, and the physical element-enumerating and specifying them and showing how they
change into one another-and becoming and perishing in general. There remains for consideration a part of
this inquiry which all our predecessors called meteorology. It is concerned with events that are natural,
though their order is less perfect than that of the first of the elements of bodies. They take place in the region
nearest to the motion of the stars. Such are the milky way, and comets, and the movements of meteors. It
studies also all the affections we may call common to air and water, and the kinds and parts of the earth and
the affections of its parts. These throw light on the causes of winds and earthquakes and all the consequences
the motions of these kinds and parts involve. Of these things some puzzle us, while others admit of
explanation in some degree. Further, the inquiry is concerned with the falling of thunderbolts and with
whirlwinds and fire-winds, and further, the recurrent affections produced in these same bodies by concretion.
When the inquiry into these matters is concluded let us consider what account we can give, in accordance
with the method we have followed, of animals and plants, both generally and in detail. When that has been
done we may say that the whole of our original undertaking will have been carried out.

After this introduction let us begin by discussing our immediate subject.

We have already laid down that there is one physical element which makes up the system of the bodies that
move in a circle, and besides this four bodies owing their existence to the four principles, the motion of these
latter bodies being of two kinds: either from the centre or to the centre. These four bodies are fire, air, water,
earth. Fire occupies the highest place among them all, earth the lowest, and two elements correspond to these
in their relation to one another, air being nearest to fire, water to earth. The whole world surrounding the
earth, then, the affections of which are our subject, is made up of these bodies. This world necessarily has a
certain continuity with the upper motions: consequently all its power and order is derived from them. (For the
originating principle of all motion is the first cause. Besides, that clement is eternal and its motion has no
limit in space, but is always complete; whereas all these other bodies have separate regions which limit one
another.) So we must treat fire and earth and the elements like them as the material causes of the events in
this world (meaning by material what is subject and is affected), but must assign causality in the sense of the
originating principle of motion to the influence of the eternally moving bodies.

Let us first recall our original principles and the distinctions already drawn and then explain the 'milky way'
and comets and the other phenomena akin to these.

Book I

METEOROLOGY

Fire, air, water, earth, we assert, originate from one another, and each of them exists potentially in each, as all
things do that can be resolved into a common and ultimate substrate.

The first difficulty is raised by what is called the air. What are we to take its nature to be in the world
surrounding the earth? And what is its position relatively to the other physical elements. (For there is no
question as to the relation of the bulk of the earth to the size of the bodies which exist around it, since
astronomical demonstrations have by this time proved to us that it is actually far smaller than some individual
stars. As for the water, it is not observed to exist collectively and separately, nor can it do so apart from that
volume of it which has its seat about the earth: the sea, that is, and rivers, which we can see, and any
subterranean water that may be hidden from our observation.) The question is really about that which lies
between the earth and the nearest stars. Are we to consider it to be one kind of body or more than one? And if
more than one, how many are there and what are the bounds of their regions?

We have already described and characterized the first element, and explained that the whole world of the
upper motions is full of that body.

This is an opinion we are not alone in holding: it appears to be an old assumption and one which men have
held in the past, for the word ether has long been used to denote that element. Anaxagoras, it is true, seems to
me to think that the word means the same as fire. For he thought that the upper regions were full of fire, and
that men referred to those regions when they spoke of ether. In the latter point he was right, for men seem to
have assumed that a body that was eternally in motion was also divine in nature; and, as such a body was
different from any of the terrestrial elements, they determined to call it 'ether'.

For the um opinions appear in cycles among men not once nor twice, but infinitely often.

Now there are some who maintain that not only the bodies in motion but that which contains them is pure
fire, and the interval between the earth and the stars air: but if they had considered what is now satisfactorily
established by mathematics, they might have given up this puerile opinion. For it is altogether childish to
suppose that the moving bodies are all of them of a small size, because they so to us, looking at them from
the earth.

This a matter which we have already discussed in our treatment of the upper region, but we may return to the
point now.

If the intervals were full of fire and the bodies consisted of fire every one of the other elements would long
ago have vanished.

However, they cannot simply be said to be full of air either; for even if there were two elements to fill the
space between the earth and the heavens, the air would far exceed the quantitu required to maintain its proper
proportion to the other elements. For the bulk of the earth (which includes the whole volume of water) is
infinitesimal in comparison with the whole world that surrounds it. Now we find that the excess in volume is
not proportionately great where water dissolves into air or air into fire. Whereas the proportion between any
given small quantity of water and the air that is generated from it ought to hold good between the total
amount of air and the total amount of water. Nor does it make any difference if any one denies that the
elements originate from one another, but asserts that they are equal in power. For on this view it is certain
amounts of each that are equal in power, just as would be the case if they actually originated from one
another.

So it is clear that neither air nor fire alone fills the intermediate space.

Book I

METEOROLOGY

It remains to explain, after a preliminary discussion of difficulties, the relation of the two elements air and
fire to the position of the first element, and the reason why the stars in the upper region impart heat to the
earth and its neighbourhood. Let us first treat of the air, as we proposed, and then go on to these questions.

Since water is generated from air, and air from water, why are clouds not formed in the upper air? They ought
to form there the more, the further from the earth and the colder that region is. For it is neither appreciably
near to the heat of the stars, nor to the rays relected from the earth. It is these that dissolve any formation by
their heat and so prevent clouds from forming near the earth. For clouds gather at the point where the
reflected rays disperse in the infinity of space and are lost. To explain this we must suppose either that it is
not all air which water is generated, or, if it is produced from all air alike, that what immediately surrounds
the earth is not mere air, but a sort of vapour, and that its vaporous nature is the reason why it condenses back
to water again. But if the whole of that vast region is vapour, the amount of air and of water will be
disproportionately great. For the spaces left by the heavenly bodies must be filled by some element. This
cannot be fire, for then all the rest would have been dried up. Consequently, what fills it must be air and the
water that surrounds the whole earth-vapour being water dissolved.

After this exposition of the difficulties involved, let us go on to lay down the truth, with a view at once to
what follows and to what has already been said. The upper region as far as the moon we affirm to consist of a
body distinct both from fire and from air, but varying degree of purity and in kind, especially towards its limit
on the side of the air, and of the world surrounding the earth. Now the circular motion of the first element and
of the bodies it contains dissolves, and inflames by its motion, whatever part of the lower world is nearest to
it, and so generates heat. From another point of view we may look at the motion as follows. The body that
lies below the circular motion of the heavens is, in a sort, matter, and is potentially hot, cold, dry, moist, and
possessed of whatever other qualities are derived from these. But it actually acquires or retains one of these in
virtue of motion or rest, the cause and principle of which has already been explained. So at the centre and
round it we get earth and water, the heaviest and coldest elements, by themselves; round them and contiguous
with them, air and what we commonly call fire. It is not really fire, for fire is an excess of heat and a sort of
ebullition; but in reality, of what we call air, the part surrounding the earth is moist and warm, because it
contains both vapour and a dry exhalation from the earth. But the next part, above that, is warm and dry. For
vapour is naturally moist and cold, but the exhalation warm and dry; and vapour is potentially like water, the
exhalation potentially like fire. So we must take the reason why clouds are not formed in the upper region to
be this: that it is filled not with mere air but rather with a sort of fire.

However, it may well be that the formation of clouds in that upper region is also prevented by the circular
motion. For the air round the earth is necessarily all of it in motion, except that which is cut off inside the
circumference which makes the earth a complete sphere. In the case of winds it is actually observable that
they originate in marshy districts of the earth; and they do not seem to blow above the level of the highest
mountains. It is the revolution of the heaven which carries the air with it and causes its circular motion, fire
being continuous with the upper element and air with fire. Thus its motion is a second reason why that air is
not condensed into water.

But whenever a particle of air grows heavy, the warmth in it is squeezed out into the upper region and it
sinks, and other particles in turn are carried up together with the fiery exhalation. Thus the one region is
always full of air and the other of fire, and each of them is perpetually in a state of change.

So much to explain why clouds are not formed and why the air is not condensed into water, and what account
must be given of the space between the stars and the earth, and what is the body that fills it.

As for the heat derived from the sun, the right place for a special and scientific account of it is in the treatise
about sense, since heat is an affection of sense, but we may now explain how it can be produced by the
heavenly bodies which are not themselves hot.

Book I 4

METEOROLOGY

We see that motion is able to dissolve and inflame the air; indeed, moving bodies are often actually found to
melt. Now the sun's motion alone is sufficient to account for the origin of terrestrial warmth and heat. For a
motion that is to have this effect must be rapid and near, and that of the stars is rapid but distant, while that of
the moon is near but slow, whereas the sun's motion combines both conditions in a sufficient degree. That
most heat should be generated where the sun is present is easy to understand if we consider the analogy of
terrestrial phenomena, for here, too, it is the air that is nearest to a thing in rapid motion which is heated most.
This is just what we should expect, as it is the nearest air that is most dissolved by the motion of a solid body.

This then is one reason why heat reaches our world. Another is that the fire surrounding the air is often
scattered by the motion of the heavens and driven downwards in spite of itself.

Shooting-stars further suffix to prove that the celestial sphere is not hot or fiery: for they do not occur in that
upper region but below: yet the more and the faster a thing moves, the more apt it is to take fire. Besides, the
sun, which most of all the stars is considered to be hot, is really white and not fiery in colour.

Having determined these principles let us explain the cause of the appearance in the sky of burning flames
and of shooting-stars, and of 'torches', and 'goats', as some people call them. All these phenomena are one
and the same thing, and are due to the same cause, the difference between them being one of degree.

The explanation of these and many other phenomena is this. When the sun warms the earth the evaporation
which takes place is necessarily of two kinds, not of one only as some think. One kind is rather of the nature
of vapour, the other of the nature of a windy exhalation. That which rises from the moisture contained in the
earth and on its surface is vapour, while that rising from the earth itself, which is dry, is like smoke. Of these
the windy exhalation, being warm, rises above the moister vapour, which is heavy and sinks below the other.
Hence the world surrounding the earth is ordered as follows. First below the circular motion comes the warm
and dry element, which we call fire, for there is no word fully adequate to every state of the fumid
evaporation: but we must use this terminology since this element is the most inflammable of all bodies.
Below this comes air. We must think of what we just called fire as being spread round the terrestrial sphere
on the outside like a kind of fuel, so that a little motion often makes it burst into flame just as smoke does: for
flame is the ebullition of a dry exhalation. So whenever the circular motion stirs this stuff up in any way, it
catches fire at the point at which it is most inflammable. The result differs according to the disposition and
quantity of the combustible material. If this is broad and long, we often see a flame burning as in a field of
stubble: if it burns lengthwise only, we see what are called 'torches' and 'goats' and shooting-stars. Now when
the inflammable material is longer than it is broad sometimes it seems to throw off sparks as it burns. (This
happens because matter catches fire at the sides in small portions but continuously with the main body.) Then
it is called a 'goat'. When this does not happen it is a 'torch'. But if the whole length of the exhalation is
scattered in small parts and in many directions and in breadth and depth alike, we get what are called
shooting-stars.

The cause of these shooting-stars is sometimes the motion which ignites the exhalation. At other times the air
is condensed by cold and squeezes out and ejects the hot element; making their motion look more like that of
a thing thrown than like a running fire. For the question might be raised whether the 'shooting' of a 'star' is the
same thing as when you put an exhalation below a lamp and it lights the lower lamp from the flame above.
For here too the flame passes wonderfully quickly and looks like a thing thrown, and not as if one thing after
another caught fire. Or is a 'star' when it 'shoots' a single body that is thrown? Apparently both cases occur:
sometimes it is like the flame from the lamp and sometimes bodies are projected by being squeezed out (like
fruit stones from one's fingers) and so are seen to fall into the sea and on the dry land, both by night and by
day when the sky is clear. They are thrown downwards because the condensation which propels them inclines

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downwards. Thunderbolts fall downwards for the same reason: their origin is never combustion but ejection
under pressure, since naturally all heat tends upwards.

When the phenomenon is formed in the upper region it is due to the combustion of the exhalation. When it
takes place at a lower level it is due to the ejection of the exhalation by the condensing and cooling of the
moister evaporation: for this latter as it condenses and inclines downward contracts, and thrusts out the hot
element and causes it to be thrown downwards. The motion is upwards or downwards or sideways according
to the way in which the evaporation lies, and its disposition in respect of breadth and depth. In most cases the
direction is sideways because two motions are involved, a compulsory motion downwards and a natural
motion upwards, and under these circumstances an object always moves obliquely. Hence the motion of
'shooting-stars' is generally oblique.

So the material cause of all these phenomena is the exhalation, the efficient cause sometimes the upper
motion, sometimes the contraction and condensation of the air. Further, all these things happen below the
moon. This is shown by their apparent speed, which is equal to that of things thrown by us; for it is because
they are close to us, that these latter seem far to exceed in speed the stars, the sun, and the moon.

Sometimes on a fine night we see a variety of appearances that form in the sky: 'chasms' for instance and
'trenches' and blood-red colours. These, too, have the same cause. For we have seen that the upper air
condenses into an inflammable condition and that the combustion sometimes takes on the appearance of a
burning flame, sometimes that of moving torches and stars. So it is not surprising that this same air when
condensing should assume a variety of colours. For a weak light shining through a dense air, and the air when
it acts as a mirror, will cause all kinds of colours to appear, but especially crimson and purple. For these
colours generally appear when fire-colour and white are combined by superposition. Thus on a hot day, or
through a smoky, medium, the stars when they rise and set look crimson. The light will also create colours by
reflection when the mirror is such as to reflect colour only and not shape.

These appearances do not persist long, because the condensation of the air is transient.

'Chasms' get their appearance of depth from light breaking out of a dark blue or black mass of air. When the
process of condensation goes further in such a case we often find 'torches' ejected. When the 'chasm' contracts
it presents the appearance of a 'trench'.

In general, white in contrast with black creates a variety of colours; like flame, for instance, through a
medium of smoke. But by day the sun obscures them, and, with the exception of crimson, the colours are not
seen at night because they are dark.

These then must be taken to be the causes of 'shooting-stars' and the phenomena of combustion and also of
the other transient appearances of this kind.

Let us go on to explain the nature of comets and the 'milky way', after a preliminary discussion of the views
of others.

Anaxagoras and Democritus declare that comets are a conjunction of the planets approaching one another and
so appearing to touch one another.

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Some of the Italians called Pythagoreans say that the comet is one of the planets, but that it appears at great
intervals of time and only rises a little above the horizon. This is the case with Mercury too; because it only
rises a little above the horizon it often fails to be seen and consequently appears at great intervals of time.

A view like theirs was also expressed by Hippocrates of Chios and his pupil Aeschylus. Only they say that
the tail does not belong to the comet iself, but is occasionally assumed by it on its course in certain situations,
when our sight is reflected to the sun from the moisture attracted by the comet. It appears at greater intervals
than the other stars because it is slowest to get clear of the sun and has been left behind by the sun to the
extent of the whole of its circle before it reappears at the same point. It gets clear of the sun both towards the
north and towards the south. In the space between the tropics it does not draw water to itself because that
region is dried up by the sun on its course. When it moves towards the south it has no lack of the necessary
moisture, but because the segment of its circle which is above the horizon is small, and that below it many
times as large, it is impossible for the sun to be reflected to our sight, either when it approaches the southern
tropic, or at the summer solstice. Hence in these regions it does not develop a tail at all. But when it is visible
in the north it assumes a tail because the arc above the horizon is large and that below it small. For under
these circumstances there is nothing to prevent our vision from being reflected to the sun.

These views involve impossibilities, some of which are common to all of them, while others are peculiar to
some only.

This is the case, first, with those who say that the comet is one of the planets. For all the planets appear in the
circle of the zodiac, whereas many comets have been seen outside that circle. Again more comets than one
have often appeared simultaneously. Besides, if their tail is due to reflection, as Aeschylus and Hippocrates
say, this planet ought sometimes to be visible without a tail since, as they it does not possess a tail in every
place in which it appears. But, as a matter of fact, no planet has been observed besides the five. And all of
them are often visible above the horizon together at the same time. Further, comets are often found to appear,
as well when all the planets are visible as when some are not, but are obscured by the neighbourhood of the
sun. Moreover the statement that a comet only appears in the north, with the sun at the summer solstice, is not
true either. The great comet which appeared at the time of the earthquake in Achaea and the tidal wave rose
due west; and many have been known to appear in the south. Again in the archonship of Euclees, son of
Molon, at Athens there appeared a comet in the north in the month Gamelion, the sun being about the winter
solstice. Yet they themselves admit that reflection over so great a space is an impossibility.

An objection that tells equally against those who hold this theory and those who say that comets are a
coalescence of the planets is, first, the fact that some of the fixed stars too get a tail. For this we must not only
accept the authority of the Egyptians who assert it, but we have ourselves observed the fact. For a star in the
thigh of the Dog had a tail, though a faint one. If you fixed your sight on it its light was dim, but if you just
glanced at it, it appeared brighter. Besides, all the comets that have been seen in our day have vanished
without setting, gradually fading away above the horizon; and they have not left behind them either one or
more stars. For instance the great comet we mentioned before appeared to the west in winter in frosty weather
when the sky was clear, in the archonship of Asteius. On the first day it set before the sun and was then not
seen. On the next day it was seen, being ever so little behind the sun and immediately setting. But its light
extended over a third part of the sky like a leap, so that people called it a 'path'. This comet receded as far as
Orion's belt and there dissolved. Democritus however, insists upon the truth of his view and affirms that
certain stars have been seen when comets dissolve. But on his theory this ought not to occur occasionally but
always. Besides, the Egyptians affirm that conjunctions of the planets with one another, and with the fixed
stars, take place, and we have ourselves observed Jupiter coinciding with one of the stars in the Twins and
hiding it, and yet no comet was formed. Further, we can also give a rational proof of our point. It is true that
some stars seem to be bigger than others, yet each one by itself looks indivisible. Consequently, just as, if
they really had been indivisible, their conjunction could not have created any greater magnitude, so now that
they are not in fact indivisible but look as if they were, their conjunction will not make them look any bigger.

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Enough has been said, without further argument, to show that the causes brought forward to explain comets
are false.

We consider a satisfactory explanation of phenomena inaccessible to observation to have been given when
our account of them is free from impossibilities. The observations before us suggest the following account of
the phenomena we are now considering. We know that the dry and warm exhalation is the outermost part of
the terrestrial world which falls below the circular motion. It, and a great part of the air that is continuous
with it below, is carried round the earth by the motion of the circular revolution. In the course of this motion
it often ignites wherever it may happen to be of the right consistency, and this we maintain to be the cause of
the 'shooting' of scattered 'stars'. We may say, then, that a comet is formed when the upper motion introduces
into a gathering of this kind a fiery principle not of such excessive strength as to burn up much of the material
quickly, nor so weak as soon to be extinguished, but stronger and capable of burning up much material, and
when exhalation of the right consistency rises from below and meets it. The kind of comet varies according to
the shape which the exhalation happens to take. If it is diffused equally on every side the star is said to be
fringed, if it stretches out in one direction it is called bearded. We have seen that when a fiery principle of this
kind moves we seem to have a shooting-star: similarly when it stands still we seem to have a star standing
still. We may compare these phenomena to a heap or mass of chaff into which a torch is thrust, or a spark
thrown. That is what a shooting-star is like. The fuel is so inflammable that the fire runs through it quickly in
a line. Now if this fire were to persist instead of running through the fuel and perishing away, its course
through the fuel would stop at the point where the latter was densest, and then the whole might begin to
move. Such is a comet-like a shooting-star that contains its beginning and end in itself.

When the matter begins to gather in the lower region independently the comet appears by itself. But when the
exhalation is constituted by one of the fixed stars or the planets, owing to their motion, one of them becomes
a comet. The fringe is not close to the stars themselves. Just as haloes appear to follow the sun and the moon
as they move, and encircle them, when the air is dense enough for them to form along under the sun's course,
so too the fringe. It stands in the relation of a halo to the stars, except that the colour of the halo is due to
reflection, whereas in the case of comets the colour is something that appears actually on them.

Now when this matter gathers in relation to a star the comet necessarily appears to follow the same course as
the star. But when the comet is formed independently it falls behind the motion of the universe, like the rest
of the terrestrial world. It is this fact, that a comet often forms independently, indeed oftener than round one
of the regular stars, that makes it impossible to maintain that a comet is a sort of reflection, not indeed, as
Hippocrates and his school say, to the sun, but to the very star it is alleged to accompany-in fact, a kind of
halo in the pure fuel of fire.

As for the halo we shall explain its cause later.

The fact that comets when frequent foreshadow wind and drought must be taken as an indication of their fiery
constitution. For their origin is plainly due to the plentiful supply of that secretion. Hence the air is
necessarily drier and the moist evaporation is so dissolved and dissipated by the quantity of the hot exhalation
as not readily to condense into water.-But this phenomenon too shall be explained more clearly later when
the time comes to speak of the winds.-So when there are many comets and they are dense, it is as we say,
and the years are clearly dry and windy. When they are fewer and fainter this effect does not appear in the
same degree, though as a rule the is found to be excessive either in duration or strength. For instance when
the stone at Aegospotami fell out of the air-it had been carried up by a wind and fell down in the
daytime-then too a comet happened to have appeared in the west. And at the time of the great comet the
winter was dry and north winds prevailed, and the wave was due to an opposition of winds. For in the gulf a

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north wind blew and outside it a violent south wind. Again in the archonship of Nicomachus a comet
appeared for a few days about the equinoctial circle (this one had not risen in the west), and simultaneously
with it there happened the storm at Corinth.

That there are few comets and that they appear rarely and outside the tropic circles more than within them is
due to the motion of the sun and the stars. For this motion does not only cause the hot principle to be secreted
but also dissolves it when it is gathering. But the chief reason is that most of this stuff collects in the region of
the milky way.

Let us now explain the origin, cause, and nature of the milky way. And here too let us begin by discussing the
statements of others on the subject.

(1) Of the so-called Pythagoreans some say that this is the path of one of the stars that fell from heaven at the
time of Phaethon's downfall. Others say that the sun used once to move in this circle and that this region was
scorched or met with some other affection of this kind, because of the sun and its motion.

But it is absurd not to see that if this were the reason the circle of the Zodiac ought to be affected in the same
way, and indeed more so than that of the milky way, since not the sun only but all the planets move in it. We
can see the whole of this circle (half of it being visible at any time of the night), but it shows no signs of any
such affection except where a part of it touches the circle of the milky way.

(2) Anaxagoras, Democritus, and their schools say that the milky way is the light of certain stars. For, they
say, when the sun passes below the earth some of the stars are hidden from it. Now the light of those on
which the sun shines is invisible, being obscured by the of the sun. But the milky way is the peculiar light of
those stars which are shaded by the earth from the sun's rays.

This, too, is obviously impossible. The milky way is always unchanged and among the same constellations
(for it is clearly a greatest circle), whereas, since the sun does not remain in the same place, what is hidden
from it differs at different times. Consequently with the change of the sun's position the milky way ought to
change its position too: but we find that this does not happen. Besides, if astronomical demonstrations are
correct and the size of the sun is greater than that of the earth and the distance of the stars from the earth
many times greater than that of the sun (just as the sun is further from the earth than the moon), then the cone
made by the rays of the sun would terminate at no great distance from the earth, and the shadow of the earth
(what we call night) would not reach the stars. On the contrary, the sun shines on all the stars and the earth
screens none of them.

(3) There is a third theory about the milky way. Some say that it is a reflection of our sight to the sun, just as
they say that the comet is.

But this too is impossible. For if the eye and the mirror and the whole of the object were severally at rest,
then the same part of the image would appear at the same point in the mirror. But if the mirror and the object
move, keeping the same distance from the eye which is at rest, but at different rates of speed and so not
always at the same interval from one another, then it is impossible for the same image always to appear in the
same part of the mirror. Now the constellations included in the circle of the milky way move; and so does the
sun, the object to which our sight is reflected; but we stand still. And the distance of those two from us is
constant and uniform, but their distance from one another varies. For the Dolphin sometimes rises at
midnight, sometimes in the morning. But in each case the same parts of the milky way are found near it. But
if it were a reflection and not a genuine affection of these this ought not to be the case.

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Again, we can see the milky way reflected at night in water and similar mirrors. But under these
circumstances it is impossible for our sight to be reflected to the sun.

These considerations show that the milky way is not the path of one of the planets, nor the light of
imperceptible stars, nor a reflection. And those are the chief theories handed down by others hitherto.

Let us recall our fundamental principle and then explain our views. We have already laid down that the
outermost part of what is called the air is potentially fire and that therefore when the air is dissolved by
motion, there is separated off a kind of matter-and of this matter we assert that comets consist. We must
suppose that what happens is the same as in the case of the comets when the matter does not form
independently but is formed by one of the fixed stars or the planets. Then these stars appear to be fringed,
because matter of this kind follows their course. In the same way, a certain kind of matter follows the sun,
and we explain the halo as a reflection from it when the air is of the right constitution. Now we must assume
that what happens in the case of the stars severally happens in the case of the whole of the heavens and all the
upper motion. For it is natural to suppose that, if the motion of a single star excites a flame, that of all the
stars should have a similar result, and especially in that region in which the stars are biggest and most
numerous and nearest to one another. Now the circle of the zodiac dissolves this kind of matter because of the
motion of the sun and the planets, and for this reason most comets are found outside the tropic circles. Again,
no fringe appears round the sun or moon: for they dissolve such matter too quickly to admit of its formation.
But this circle in which the milky way appears to our sight is the greatest circle, and its position is such that it
extends far outside the tropic circles. Besides the region is full of the biggest and brightest constellations and
also of what called 'scattered' stars (you have only to look to see this clearly). So for these reasons all this
matter is continually and ceaselessly collecting there. A proof of the theory is this: In the circle itself the light
is stronger in that half where the milky way is divided, and in it the constellations are more numerous and
closer to one another than in the other half; which shows that the cause of the light is the motion of the
constellations and nothing else. For if it is found in the circle in which there are most constellations and at
that point in the circle at which they are densest and contain the biggest and the most stars, it is natural to
suppose that they are the true cause of the affection in question. The circle and the constellations in it may be
seen in the diagram. The so-called 'scattered' stars it is not possible to set down in the same way on the
sphere because none of them have an evident permanent position; but if you look up to the sky the point is
clear. For in this circle alone are the intervals full of these stars: in the other circles there are obvious gaps.
Hence if we accept the cause assigned for the appearance of comets as plausible we must assume that the
same kind of thing holds good of the milky way. For the fringe which in the former case is an affection of a
single star here forms in the same way in relation to a whole circle. So if we are to define the milky way we
may call it 'a fringe attaching to the greatest circle, and due to the matter secreted'. This, as we said before,
explains why there are few comets and why they appear rarely; it is because at each revolution of the heavens
this matter has always been and is always being separated off and gathered into this region.

We have now explained the phenomena that occur in that part of the terrestrial world which is continuous
with the motions of the heavens, namely, shooting-stars and the burning flame, comets and the milky way,
these being the chief affections that appear in that region.

Let us go on to treat of the region which follows next in order after this and which immediately surrounds the
earth. It is the region common to water and air, and the processes attending the formation of water above take
place in it. We must consider the principles and causes of all these phenomena too as before. The efficient
and chief and first cause is the circle in which the sun moves. For the sun as it approaches or recedes,
obviously causes dissipation and condensation and so gives rise to generation and destruction. Now the earth
remains but the moisture surrounding it is made to evaporate by the sun's rays and the other heat from above,

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and rises. But when the heat which was raising it leaves it, in part dispersing to the higher region, in part
quenched through rising so far into the upper air, then the vapour cools because its heat is gone and because
the place is cold, and condenses again and turns from air into water. And after the water has formed it falls
down again to the earth.

The exhalation of water is vapour: air condensing into water is cloud. Mist is what is left over when a cloud
condenses into water, and is therefore rather a sign of fine weather than of rain; for mist might be called a
barren cloud. So we get a circular process that follows the course of the sun. For according as the sun moves
to this side or that, the moisture in this process rises or falls. We must think of it as a river flowing up and
down in a circle and made up partly of air, partly of water. When the sun is near, the stream of vapour flows
upwards; when it recedes, the stream of water flows down: and the order of sequence, at all events, in this
process always remains the same. So if 'Oceanus' had some secret meaning in early writers, perhaps they may
have meant this river that flows in a circle about the earth.

So the moisture is always raised by the heat and descends to the earth again when it gets cold. These
processes and, in some cases, their varieties are distinguished by special names. When the water falls in small
drops it is called a drizzle; when the drops are larger it is rain.

Some of the vapour that is formed by day does not rise high because the ratio of the fire that is raising it to
the water that is being raised is small. When this cools and descends at night it is called dew and hoar-frost.
When the vapour is frozen before it has condensed to water again it is hoar-frost; and this appears in winter
and is commoner in cold places. It is dew when the vapour has condensed into water and the heat is not so
great as to dry up the moisture that has been raised nor the cold sufficient (owing to the warmth of the climate
or season) for the vapour itself to freeze. For dew is more commonly found when the season or the place is
warm, whereas the opposite, as has been said, is the case with hoar-frost. For obviously vapour is warmer
than water, having still the fire that raised it: consequently more cold is needed to freeze it.

Both dew and hoar-frost are found when the sky is clear and there is no wind. For the vapour could not be
raised unless the sky were clear, and if a wind were blowing it could not condense.

The fact that hoar-frost is not found on mountains contributes to prove that these phenomena occur because
the vapour does not rise high. One reason for this is that it rises from hollow and watery places, so that the
heat that is raising it, bearing as it were too heavy a burden cannot lift it to a great height but soon lets it fall
again. A second reason is that the motion of the air is more pronounced at a height, and this dissolves a
gathering of this kind.

Everywhere, except in Pontus, dew is found with south winds and not with north winds. There the opposite is
the case and it is found with north winds and not with south. The reason is the same as that which explains
why dew is found in warm weather and not in cold. For the south wind brings warm, and the north, wintry
weather. For the north wind is cold and so quenches the heat of the evaporation. But in Pontus the south wind
does not bring warmth enough to cause evaporation, whereas the coldness of the north wind concentrates the
heat by a sort of recoil, so that there is more evaporation and not less. This is a thing which we can often
observe in other places too. Wells, for instance, give off more vapour in a north than in a south wind. Only
the north winds quench the heat before any considerable quantity of vapour has gathered, while in a south
wind the evaporation is allowed to accumulate.

Water, once formed, does not freeze on the surface of the earth, in the way that it does in the region of the
clouds.

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From the latter there fall three bodies condensed by cold, namely rain, snow, hail. Two of these correspond to
the phenomena on the lower level and are due to the same causes, differing from them only in degree and
quantity.

Snow and hoar-frost are one and the same thing, and so are rain and dew: only there is a great deal of the
former and little of the latter. For rain is due to the cooling of a great amount of vapour, for the region from
which and the time during which the vapour is collected are considerable. But of dew there is little: for the
vapour collects for it in a single day and from a small area, as its quick formation and scanty quantity show.

The relation of hoar-frost and snow is the same: when cloud freezes there is snow, when vapour freezes there
is hoar-frost. Hence snow is a sign of a cold season or country. For a great deal of heat is still present and
unless the cold were overpowering it the cloud would not freeze. For there still survives in it a great deal of
the heat which caused the moisture to rise as vapour from the earth.

Hail on the other hand is found in the upper region, but the corresponding phenomenon in the vaporous
region near the earth is lacking. For, as we said, to snow in the upper region corresponds hoar-frost in the
lower, and to rain in the upper region, dew in the lower. But there is nothing here to correspond to hail in the
upper region. Why this is so will be clear when we have explained the nature of hail.

But we must go on to collect the facts bearing on the origin of it, both those which raise no difficulties and
those which seem paradoxical.

Hail is ice, and water freezes in winter; yet hailstorms occur chiefly in spring and autumn and less often in the
late summer, but rarely in winter and then only when the cold is less intense. And in general hailstorms occur
in warmer, and snow in colder places. Again, there is a difficulty about water freezing in the upper region. It
cannot have frozen before becoming water: and water cannot remain suspended in the air for any space of
time. Nor can we say that the case is like that of particles of moisture which are carried up owing to their
small size and rest on the iar (the water swimming on the air just as small particles of earth and gold often
swim on water). In that case large drops are formed by the union of many small, and so fall down. This
cannot take place in the case of hail, since solid bodies cannot coalesce like liquid ones. Clearly then drops of
that size were suspended in the air or else they could not have been so large when frozen.

Some think that the cause and origin of hail is this. The cloud is thrust up into the upper atmosphere, which is
colder because the reflection of the sun's rays from the earth ceases there, and upon its arrival there the water
freezes. They think that this explains why hailstorms are commoner in summer and in warm countries; the
heat is greater and it thrusts the clouds further up from the earth. But the fact is that hail does not occur at all
at a great height: yet it ought to do so, on their theory, just as we see that snow falls most on high mountains.
Again clouds have often been observed moving with a great noise close to the earth, terrifying those who
heard and saw them as portents of some catastrophe. Sometimes, too, when such clouds have been seen,
without any noise, there follows a violent hailstorm, and the stones are of incredible size, and angular in
shape. This shows that they have not been falling for long and that they were frozen near to the earth, and not
as that theory would have it. Moreover, where the hailstones are large, the cause of their freezing must be
present in the highest degree: for hail is ice as every one can see. Now those hailstones are large which are
angular in shape. And this shows that they froze close to the earth, for those that fall far are worn away by the
length of their fall and become round and smaller in size.

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It clearly follows that the congelation does not take place because the cloud is thrust up into the cold upper
region.

Now we see that warm and cold react upon one another by recoil. Hence in warm weather the lower parts of
the earth are cold and in a frost they are warm. The same thing, we must suppose, happens in the air, so that
in the warmer seasons the cold is concentrated by the surrounding heat and causes the cloud to go over into
water suddenly. (For this reason rain-drops are much larger on warm days than in winter, and showers more
violent. A shower is said to be more violent in proportion as the water comes down in a body, and this
happens when the condensation takes place quickly,-though this is just the opposite of what Anaxagoras
says. He says that this happens when the cloud has risen into the cold air; whereas we say that it happens
when the cloud has descended into the warm air, and that the more the further the cloud has descended). But
when the cold has been concentrated within still more by the outer heat, it freezes the water it has formed and
there is hail. We get hail when the process of freezing is quicker than the descent of the water. For if the
water falls in a certain time and the cold is sufficient to freeze it in less, there is no difficulty about its having
frozen in the air, provided that the freezing takes place in a shorter time than its fall. The nearer to the earth,
and the more suddenly, this process takes place, the more violent is the rain that results and the larger the
raindrops and the hailstones because of the shortness of their fall. For the same reason large raindrops do not
fall thickly. Hail is rarer in summer than in spring and autumn, though commoner than in winter, because the
air is drier in summer, whereas in spring it is still moist, and in autumn it is beginning to grow moist. It is for
the same reason that hailstorms sometimes occur in the late summer as we have said.

The fact that the water has previously been warmed contributes to its freezing quickly: for so it cools sooner.
Hence many people, when they want to cool hot water quickly, begin by putting it in the sun. So the
inhabitants of Pontus when they encamp on the ice to fish (they cut a hole in the ice and then fish) pour warm
water round their reeds that it may freeze the quicker, for they use the ice like lead to fix the reeds. Now it is
in hot countries and seasons that the water which forms soon grows warm.

It is for the same reason that rain falls in summer and not in winter in Arabia and Ethiopia too, and that in
torrents and repeatedly on the same day. For the concentration or recoil due to the extreme heat of the country
cools the clouds quickly.

So much for an account of the nature and causes of rain, dew, snow, hoar-frost, and hail.

Let us explain the nature of winds, and all windy vapours, also of rivers and of the sea. But here, too, we must
first discuss the difficulties involved: for, as in other matters, so in this no theory has been handed down to us
that the most ordinary man could not have thought of.

Some say that what is called air, when it is in motion and flows, is wind, and that this same air when it
condenses again becomes cloud and water, implying that the nature of wind and water is the same. So they
define wind as a motion of the air. Hence some, wishing to say a clever thing, assert that all the winds are one
wind, because the air that moves is in fact all of it one and the same; they maintain that the winds appear to
differ owing to the region from which the air may happen to flow on each occasion, but really do not differ at
all. This is just like thinking that all rivers are one and the same river, and the ordinary unscientific view is
better than a scientific theory like this. If all rivers flow from one source, and the same is true in the case of
the winds, there might be some truth in this theory; but if it is no more true in the one case than in the other,
this ingenious idea is plainly false. What requires investigation is this: the nature of wind and how it
originates, its efficient cause and whence they derive their source; whether one ought to think of the wind as
issuing from a sort of vessel and flowing until the vessel is empty, as if let out of a wineskin, or, as painters

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represent the winds, as drawing their source from themselves.

We find analogous views about the origin of rivers. It is thought that the water is raised by the sun and
descends in rain and gathers below the earth and so flows from a great reservoir, all the rivers from one, or
each from a different one. No water at all is generated, but the volume of the rivers consists of the water that
is gathered into such reservoirs in winter. Hence rivers are always fuller in winter than in summer, and some
are perennial, others not. Rivers are perennial where the reservoir is large and so enough water has collected
in it to last out and not be used up before the winter rain returns. Where the reservoirs are smaller there is less
water in the rivers, and they are dried up and their vessel empty before the fresh rain comes on.

But if any one will picture to himself a reservoir adequate to the water that is continuously flowing day by
day, and consider the amount of the water, it is obvious that a receptacle that is to contain all the water that
flows in the year would be larger than the earth, or, at any rate, not much smaller.

Though it is evident that many reservoirs of this kind do exist in many parts of the earth, yet it is
unreasonable for any one to refuse to admit that air becomes water in the earth for the same reason as it does
above it. If the cold causes the vaporous air to condense into water above the earth we must suppose the cold
in the earth to produce this same effect, and recognize that there not only exists in it and flows out of it
actually formed water, but that water is continually forming in it too.

Again, even in the case of the water that is not being formed from day to day but exists as such, we must not
suppose as some do that rivers have their source in definite subterranean lakes. On the contrary, just as above
the earth small drops form and these join others, till finally the water descends in a body as rain, so too we
must suppose that in the earth the water at first trickles together little by little, and that the sources of the
rivers drip, as it were, out of the earth and then unite. This is proved by facts. When men construct an
aqueduct they collect the water in pipes and trenches, as if the earth in the higher ground were sweating the
water out. Hence, too, the head-waters of rivers are found to flow from mountains, and from the greatest
mountains there flow the most numerous and greatest rivers. Again, most springs are in the neighbourhood of
mountains and of high ground, whereas if we except rivers, water rarely appears in the plains. For mountains
and high ground, suspended over the country like a saturated sponge, make the water ooze out and trickle
together in minute quantities but in many places. They receive a great deal of water falling as rain (for it
makes no difference whether a spongy receptacle is concave and turned up or convex and turned down: in
either case it will contain the same volume of matter) and, they also cool the vapour that rises and condense it
back into water.

Hence, as we said, we find that the greatest rivers flow from the greatest mountains. This can be seen by
looking at itineraries: what is recorded in them consists either of things which the writer has seen himself or
of such as he has compiled after inquiry from those who have seen them.

In Asia we find that the most numerous and greatest rivers flow from the mountain called Parnassus,
admittedly the greatest of all mountains towards the south-east. When you have crossed it you see the outer
ocean, the further limit of which is unknown to the dwellers in our world. Besides other rivers there flow
from it the Bactrus, the Choaspes, the Araxes: from the last a branch separates off and flows into lake
Maeotis as the Tanais. From it, too, flows the Indus, the volume of whose stream is greatest of all rivers.
From the Caucasus flows the Phasis, and very many other great rivers besides. Now the Caucasus is the
greatest of the mountains that lie to the northeast, both as regards its extent and its height. A proof of its
height is the fact that it can be seen from the so-called 'deeps' and from the entrance to the lake. Again, the
sun shines on its peaks for a third part of the night before sunrise and again after sunset. Its extent is proved
by the fact that thought contains many inhabitable regions which are occupied by many nations and in which
there are said to be great lakes, yet they say that all these regions are visible up to the last peak. From Pyrene
(this is a mountain towards the west in Celtice) there flow the Istrus and the Tartessus. The latter flows

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outside the pillars, while the Istrus flows through all Europe into the Euxine. Most of the remaining rivers
flow northwards from the Hercynian mountains, which are the greatest in height and extent about that region.
In the extreme north, beyond furthest Scythia, are the mountains called Rhipae. The stories about their size
are altogether too fabulous: however, they say that the most and (after the Istrus) the greatest rivers flow from
them. So, too, in Libya there flow from the Aethiopian mountains the Aegon and the Nyses; and from the
so-called Silver Mountain the two greatest of named rivers, the river called Chremetes that flows into the
outer ocean, and the main source of the Nile. Of the rivers in the Greek world, the Achelous flows from
Pindus, the Inachus from the same mountain; the Strymon, the Nestus, and the Hebrus all three from
Scombrus; many rivers, too, flow from Rhodope.

All other rivers would be found to flow in the same way, but we have mentioned these as examples. Even
where rivers flow from marshes, the marshes in almost every case are found to lie below mountains or
gradually rising ground.

It is clear then that we must not suppose rivers to originate from definite reservoirs: for the whole earth, we
might almost say, would not be sufficient (any more than the region of the clouds would be) if we were to
suppose that they were fed by actually existing water only and it were not the case that as some water passed
out of existence some more came into existence, but rivers always drew their stream from an existing store.
Secondly, the fact that rivers rise at the foot of mountains proves that a place transmits the water it contains
by gradual percolation of many drops, little by little, and that this is how the sources of rivers originate.
However, there is nothing impossible about the existence of such places containing a quantity of water like
lakes: only they cannot be big enough to produce the supposed effect. To think that they are is just as absurd
as if one were to suppose that rivers drew all their water from the sources we see (for most rivers do flow
from springs). So it is no more reasonable to suppose those lakes to contain the whole volume of water than
these springs.

That there exist such chasms and cavities in the earth we are taught by the rivers that are swallowed up. They
are found in many parts of the earth: in the Peloponnesus, for instance, there are many such rivers in Arcadia.
The reason is that Arcadia is mountainous and there are no channels from its valleys to the sea. So these
places get full of water, and this, having no outlet, under the pressure of the water that is added above, finds a
way out for itself underground. In Greece this kind of thing happens on quite a small scale, but the lake at the
foot of the Caucasus, which the inhabitants of these parts call a sea, is considerable. Many great rivers fall
into it and it has no visible outlet but issues below the earth off the land of the Coraxi about the so-called
'deeps of Pontus'. This is a place of unfathomable depth in the sea: at any rate no one has yet been able to find
bottom there by sounding. At this spot, about three hundred stadia from land, there comes up sweet water
over a large area, not all of it together but in three places. And in Liguria a river equal in size to the Rhodanus
is swallowed up and appears again elsewhere: the Rhodanus being a navigable river.

The same parts of the earth are not always moist or dry, but they change according as rivers come into
existence and dry up. And so the relation of land to sea changes too and a place does not always remain land
or sea throughout all time, but where there was dry land there comes to be sea, and where there is now sea,
there one day comes to be dry land. But we must suppose these changes to follow some order and cycle. The
principle and cause of these changes is that the interior of the earth grows and decays, like the bodies of
plants and animals. Only in the case of these latter the process does not go on by parts, but each of them
necessarily grows or decays as a whole, whereas it does go on by parts in the case of the earth. Here the
causes are cold and heat, which increase and diminish on account of the sun and its course. It is owing to
them that the parts of the earth come to have a different character, that some parts remain moist for a certain
time, and then dry up and grow old, while other parts in their turn are filled with life and moisture. Now when

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places become drier the springs necessarily give out, and when this happens the rivers first decrease in size
and then finally become dry; and when rivers change and disappear in one part and come into existence
correspondingly in another, the sea must needs be affected.

If the sea was once pushed out by rivers and encroached upon the land anywhere, it necessarily leaves that
place dry when it recedes; again, if the dry land has encroached on the sea at all by a process of silting set up
by the rivers when at their full, the time must come when this place will be flooded again.

But the whole vital process of the earth takes place so gradually and in periods of time which are so immense
compared with the length of our life, that these changes are not observed, and before their course can be
recorded from beginning to end whole nations perish and are destroyed. Of such destructions the most utter
and sudden are due to wars; but pestilence or famine cause them too. Famines, again, are either sudden and
severe or else gradual. In the latter case the disappearance of a nation is not noticed because some leave the
country while others remain; and this goes on until the land is unable to maintain any inhabitants at all. So a
long period of time is likely to elapse from the first departure to the last, and no one remembers and the lapse
of time destroys all record even before the last inhabitants have disappeared. In the same way a nation must
be supposed to lose account of the time when it first settled in a land that was changing from a marshy and
watery state and becoming dry. Here, too, the change is gradual and lasts a long time and men do not
remember who came first, or when, or what the land was like when they came. This has been the case with
Egypt. Here it is obvious that the land is continually getting drier and that the whole country is a deposit of
the river Nile. But because the neighbouring peoples settled in the land gradually as the marshes dried, the
lapse of time has hidden the beginning of the process. However, all the mouths of the Nile, with the single
exception of that at Canopus, are obviously artificial and not natural. And Egypt was nothing more than what
is called Thebes, as Homer, too, shows, modern though he is in relation to such changes. For Thebes is the
place that he mentions; which implies that Memphis did not yet exist, or at any rate was not as important as it
is now. That this should be so is natural, since the lower land came to be inhabited later than that which lay
higher. For the parts that lie nearer to the place where the river is depositing the silt are necessarily marshy
for a longer time since the water always lies most in the newly formed land. But in time this land changes its
character, and in its turn enjoys a period of prosperity. For these places dry up and come to be in good
condition while the places that were formerly well-tempered some day grow excessively dry and deteriorate.
This happened to the land of Argos and Mycenae in Greece. In the time of the Trojan wars the Argive land
was marshy and could only support a small population, whereas the land of Mycenae was in good condition
(and for this reason Mycenae was the superior). But now the opposite is the case, for the reason we have
mentioned: the land of Mycenae has become completely dry and barren, while the Argive land that was
formerly barren owing to the water has now become fruitful. Now the same process that has taken place in
this small district must be supposed to be going on over whole countries and on a large scale.

Men whose outlook is narrow suppose the cause of such events to be change in the universe, in the sense of a
coming to be of the world as a whole. Hence they say that the sea being dried up and is growing less, because
this is observed to have happened in more places now than formerly. But this is only partially true. It is true
that many places are now dry, that formerly were covered with water. But the opposite is true too: for if they
look they will find that there are many places where the sea has invaded the land. But we must not suppose
that the cause of this is that the world is in process of becoming. For it is absurd to make the universe to be in
process because of small and trifling changes, when the bulk and size of the earth are surely as nothing in
comparison with the whole world. Rather we must take the cause of all these changes to be that, just as winter
occurs in the seasons of the year, so in determined periods there comes a great winter of a great year and with
it excess of rain. But this excess does not always occur in the same place. The deluge in the time of
Deucalion, for instance, took place chiefly in the Greek world and in it especially about ancient Hellas, the
country about Dodona and the Achelous, a river which has often changed its course. Here the Selli dwelt and
those who were formerly called Graeci and now Hellenes. When, therefore, such an excess of rain occurs we
must suppose that it suffices for a long time. We have seen that some say that the size of the subterranean

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cavities is what makes some rivers perennial and others not, whereas we maintain that the size of the
mountains is the cause, and their density and coldness; for great, dense, and cold mountains catch and keep
and create most water: whereas if the mountains that overhang the sources of rivers are small or porous and
stony and clayey, these rivers run dry earlier. We must recognize the same kind of thing in this case too.
Where such abundance of rain falls in the great winter it tends to make the moisture of those places almost
everlasting. But as time goes on places of the latter type dry up more, while those of the former, moist type,
do so less: until at last the beginning of the same cycle returns.

Since there is necessarily some change in the whole world, but not in the way of coming into existence or
perishing (for the universe is permanent), it must be, as we say, that the same places are not for ever moist
through the presence of sea and rivers, nor for ever dry. And the facts prove this. The whole land of the
Egyptians, whom we take to be the most ancient of men, has evidently gradually come into existence and
been produced by the river. This is clear from an observation of the country, and the facts about the Red Sea
suffice to prove it too. One of their kings tried to make a canal to it (for it would have been of no little
advantage to them for the whole region to have become navigable; Sesostris is said to have been the first of
the ancient kings to try), but he found that the sea was higher than the land. So he first, and Darius afterwards,
stopped making the canal, lest the sea should mix with the river water and spoil it. So it is clear that all this
part was once unbroken sea. For the same reason Libya-the country of Ammon-is, strangely enough, lower
and hollower than the land to the seaward of it. For it is clear that a barrier of silt was formed and after it
lakes and dry land, but in course of time the water that was left behind in the lakes dried up and is now all
gone. Again the silting up of the lake Maeotis by the rivers has advanced so much that the limit to the size of
the ships which can now sail into it to trade is much lower than it was sixty years ago. Hence it is easy to
infer that it, too, like most lakes, was originally produced by the rivers and that it must end by drying up
entirely.

Again, this process of silting up causes a continuous current through the Bosporus; and in this case we can
directly observe the nature of the process. Whenever the current from the Asiatic shore threw up a sandbank,
there first formed a small lake behind it. Later it dried up and a second sandbank formed in front of the first
and a second lake. This process went on uniformly and without interruption. Now when this has been
repeated often enough, in the course of time the strait must become like a river, and in the end the river itself
must dry up.

So it is clear, since there will be no end to time and the world is eternal, that neither the Tanais nor the Nile
has always been flowing, but that the region whence they flow was once dry: for their effect may be fulfilled,
but time cannot. And this will be equally true of all other rivers. But if rivers come into existence and perish
and the same parts of the earth were not always moist, the sea must needs change correspondingly. And if the
sea is always advancing in one place and receding in another it is clear that the same parts of the whole earth
are not always either sea or land, but that all this changes in course of time.

So we have explained that the same parts of the earth are not always land or sea and why that is so: and also
why some rivers are perennial and others not.

Book II

LET us explain the nature of the sea and the reason why such a large mass of water is salt and the way in
which it originally came to be.

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The old writers who invented theogonies say that the sea has springs, for they want earth and sea to have
foundations and roots of their own. Presumably they thought that this view was grander and more impressive
as implying that our earth was an important part of the universe. For they believed that the whole world had
been built up round our earth and for its sake, and that the earth was the most important and primary part of
it. Others, wiser in human knowledge, give an account of its origin. At first, they say, the earth was
surrounded by moisture. Then the sun began to dry it up, part of it evaporated and is the cause of winds and
the turnings back of the sun and the moon, while the remainder forms the sea. So the sea is being dried up
and is growing less, and will end by being some day entirely dried up. Others say that the sea is a kind of
sweat exuded by the earth when the sun heats it, and that this explains its saltness: for all sweat is salt. Others
say that the saltness is due to the earth. Just as water strained through ashes becomes salt, so the sea owes its
saltness to the admixture of earth with similar properties.

We must now consider the facts which prove that the sea cannot possibly have springs. The waters we find on
the earth either flow or are stationary. All flowing water has springs. (By a spring, as we have explained
above, we must not understand a source from which waters are ladled as it were from a vessel, but a first
point at which the water which is continually forming and percolating gathers.) Stationary water is either that
which has collected and has been left standing, marshy pools, for instance, and lakes, which differ merely in
size, or else it comes from springs. In this case it is always artificial, I mean as in the case of wells, otherwise
the spring would have to be above the outlet. Hence the water from fountains and rivers flows of itself,
whereas wells need to be worked artificially. All the waters that exist belong to one or other of these classes.

On the basis of this division we can sec that the sea cannot have springs. For it falls under neither of the two
classes; it does not flow and it is not artificial; whereas all water from springs must belong to one or other of
them. Natural standing water from springs is never found on such a large scale.

Again, there are several seas that have no communication with one another at all. The Red Sea, for instance,
communicates but slightly with the ocean outside the straits, and the Hyrcanian and Caspian seas are distinct
from this ocean and people dwell all round them. Hence, if these seas had had any springs anywhere they
must have been discovered.

It is true that in straits, where the land on either side contracts an open sea into a small space, the sea appears
to flow. But this is because it is swinging to and fro. In the open sea this motion is not observed, but where
the land narrows and contracts the sea the motion that was imperceptible in the open necessarily strikes the
attention.

The whole of the Mediterranean does actually flow. The direction of this flow is determined by the depth of
the basins and by the number of rivers. Maeotis flows into Pontus and Pontus into the Aegean. After that the
flow of the remaining seas is not so easy to observe. The current of Maeotis and Pontus is due to the number
of rivers (more rivers flow into the Euxine and Maeotis than into the whole Mediterranean with its much
larger basin), and to their own shallowness. For we find the sea getting deeper and deeper. Pontus is deeper
than Maeotis, the Aegean than Pontus, the Sicilian sea than the Aegean; the Sardinian and Tyrrhenic being
the deepest of all. (Outside the pillars of Heracles the sea is shallow owing to the mud, but calm, for it lies in
a hollow.) We see, then, that just as single rivers flow from mountains, so it is with the earth as a whole: the
greatest volume of water flows from the higher regions in the north. Their alluvium makes the northern seas
shallow, while the outer seas are deeper. Some further evidence of the height of the northern regions of the
earth is afforded by the view of many of the ancient meteorologists. They believed that the sun did not pass
below the earth, but round its northern part, and that it was the height of this which obscured the sun and
caused night.

So much to prove that there cannot be sources of the sea and to explain its observed flow.

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We must now discuss the origin of the sea, if it has an origin, and the cause of its salt and bitter taste.

What made earlier writers consider the sea to be the original and main body of water is this. It seems
reasonable to suppose that to be the case on the analogy of the other elements. Each of them has a main bulk
which by reason of its mass is the origin of that element, and any parts which change and mix with the other
elements come from it. Thus the main body of fire is in the upper region; that of air occupies the place next
inside the region of fire; while the mass of the earth is that round which the rest of the elements are seen to
lie. So we must clearly look for something analogous in the case of water. But here we can find no such
single mass, as in the case of the other elements, except the sea. River water is not a unity, nor is it stable, but
is seen to be in a continuous process of becoming from day to day. It was this difficulty which made people
regard the sea as the origin and source of moisture and of all water. And so we find it maintained that rivers
not only flow into the sea but originate from it, the salt water becoming sweet by filtration.

But this view involves another difficulty. If this body of water is the origin and source of all water, why is it
salt and not sweet? The reason for this, besides answering this question, will ensure our having a right first
conception of the nature of the sea.

The earth is surrounded by water, just as that is by the sphere of air, and that again by the sphere called that of
fire (which is the outermost both on the common view and on ours). Now the sun, moving as it does, sets up
processes of change and becoming and decay, and by its agency the finest and sweetest water is every day
carried up and is dissolved into vapour and rises to the upper region, where it is condensed again by the cold
and so returns to the earth. This, as we have said before, is the regular course of nature.

Hence all my predecessors who supposed that the sun was nourished by moisture are absurdly mistaken.
Some go on to say that the solstices are due to this, the reason being that the same places cannot always
supply the sun with nourishment and that without it he must perish. For the fire we are familiar with lives as
long as it is fed, and the only food for fire is moisture. As if the moisture that is raised could reach the sun! or
this ascent were really like that performed by flame as it comes into being, and to which they supposed the
case of the sun to be analogous! Really there is no similarity. A flame is a process of becoming, involving a
constant interchange of moist and dry. It cannot be said to be nourished since it scarcely persists as one and
the same for a moment. This cannot be true of the sun; for if it were nourished like that, as they say it is, we
should obviously not only have a new sun every day, as Heraclitus says, but a new sun every moment. Again,
when the sun causes the moisture to rise, this is like fire heating water. So, as the fire is not fed by the water
above it, it is absurd to suppose that the sun feeds on that moisture, even if its heat made all the water in the
world evaporate. Again, it is absurd, considering the number and size of the stars, that these thinkers should
consider the sun only and overlook the question how the rest of the heavenly bodies subsist. Again, they are
met by the same difficulty as those who say that at first the earth itself was moist and the world round the
earth was warmed by the sun, and so air was generated and the whole firmament grew, and the air caused
winds and solstices. The objection is that we always plainly see the water that has been carried up coming
down again. Even if the same amount does not come back in a year or in a given country, yet in a certain
period all that has been carried up is returned. This implies that the celestial bodies do not feed on it, and that
we cannot distinguish between some air which preserves its character once it is generated and some other
which is generated but becomes water again and so perishes; on the contrary, all the moisture alike is
dissolved and all of it condensed back into water.

The drinkable, sweet water, then, is light and is all of it drawn up: the salt water is heavy and remains behind,
but not in its natural place. For this is a question which has been sufficiently discussed (I mean about the
natural place that water, like the other elements, must in reason have), and the answer is this. The place which

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we see the sea filling is not its natural place but that of water. It seems to belong to the sea because the weight
of the salt water makes it remain there, while the sweet, drinkable water which is light is carried up. The same
thing happens in animal bodies. Here, too, the food when it enters the body is sweet, yet the residuum and
dregs of liquid food are found to be bitter and salt. This is because the sweet and drinkable part of it has been
drawn away by the natural animal heat and has passed into the flesh and the other parts of the body according
to their several natures. Now just as here it would be wrong for any one to refuse to call the belly the place of
liquid food because that disappears from it soon, and to call it the place of the residuum because this is seen
to remain, so in the case of our present subject. This place, we say, is the place of water. Hence all rivers and
all the water that is generated flow into it: for water flows into the deepest place, and the deepest part of the
earth is filled by the sea. Only all the light and sweet part of it is quickly carried off by the sun, while herest
remains for the reason we have explained. It is quite natural that some people should have been puzzled by
the old question why such a mass of water leaves no trace anywhere (for the sea does not increase though
innumerable and vast rivers are flowing into it every day.) But if one considers the matter the solution is easy.
The same amount of water does not take as long to dry up when it is spread out as when it is gathered in a
body, and indeed the difference is so great that in the one case it might persist the whole day long while in the
other it might all disappear in a moment-as for instance if one were to spread out a cup of water over a large
table. This is the case with the rivers: all the time they are flowing their water forms a compact mass, but
when it arrives at a vast wide place it quickly and imperceptibly evaporates.

But the theory of the Phaedo about rivers and the sea is impossible. There it is said that the earth is pierced by
intercommunicating channels and that the original head and source of all waters is what is called Tartarus-a
mass of water about the centre, from which all waters, flowing and standing, are derived. This primary and
original water is always surging to and fro, and so it causes the rivers to flow on this side of the earth's centre
and on that; for it has no fixed seat but is always oscillating about the centre. Its motion up and down is what
fills rivers. Many of these form lakes in various places (our sea is an instance of one of these), but all of them
come round again in a circle to the original source of their flow, many at the same point, but some at a point
opposite to that from which they issued; for instance, if they started from the other side of the earth's centre,
they might return from this side of it. They descend only as far as the centre, for after that all motion is
upwards. Water gets its tastes and colours from the kind of earth the rivers happened to flow through.

But on this theory rivers do not always flow in the same sense. For since they flow to the centre from which
they issue forth they will not be flowing down any more than up, but in whatever direction the surging of
Tartarus inclines to. But at this rate we shall get the proverbial rivers flowing upwards, which is impossible.
Again, where is the water that is generated and what goes up again as vapour to come from? For this must all
of it simply be ignored, since the quantity of water is always the same and all the water that flows out from
the original source flows back to it again. This itself is not true, since all rivers are seen to end in the sea
except where one flows into another. Not one of them ends in the earth, but even when one is swallowed up it
comes to the surface again. And those rivers are large which flow for a long distance through a lowying
country, for by their situation and length they cut off the course of many others and swallow them up. This is
why the Istrus and the Nile are the greatest of the rivers which flow into our sea. Indeed, so many rivers fall
into them that there is disagreement as to the sources of them both. All of which is plainly impossible on the
theory, and the more so as it derives the sea from Tartarus.

Enough has been said to prove that this is the natural place of water and not of the sea, and to explain why
sweet water is only found in rivers, while salt water is stationary, and to show that the sea is the end rather
than the source of water, analogous to the residual matter of all food, and especially liquid food, in animal
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We must now explain why the sea is salt, and ask whether it eternally exists as identically the same body, or
whether it did not exist at all once and some day will exist no longer, but will dry up as some people think.

Every one admits this, that if the whole world originated the sea did too; for they make them come into being
at the same time. It follows that if the universe is eternal the same must be true of the sea. Any one who
thinks like Democritus that the sea is diminishing and will disappear in the end reminds us of Aesop's tales.
His story was that Charybdis had twice sucked in the sea: the first time she made the mountains visible; the
second time the islands; and when she sucks it in for the last time she will dry it up entirely. Such a tale is
appropriate enough to Aesop in a rage with the ferryman, but not to serious inquirers. Whatever made the sea
remain at first, whether it was its weight, as some even of those who hold these views say (for it is easy to see
the cause here), or some other reason-clearly the same thing must make it persist for ever. They must either
deny that the water raised by the sun will return at all, or, if it does, they must admit that the sea persists for
ever or as long as this process goes on, and again, that for the same period of time that sweet water must have
been carried up beforehand. So the sea will never dry up: for before that can happen the water that has gone
up beforehand will return to it: for if you say that this happens once you must admit its recurrence. If you stop
the sun's course there is no drying agency. If you let it go on it will draw up the sweet water as we have said
whenever it approaches, and let it descend again when it recedes. This notion about the sea is derived from
the fact that many places are found to be drier now than they once were. Why this is so we have explained.
The phenomenon is due to temporary excess of rain and not to any process of becoming in which the universe
or its parts are involved. Some day the opposite will take place and after that the earth will grow dry once
again. We must recognize that this process always goes on thus in a cycle, for that is more satisfactory than to
suppose a change in the whole world in order to explain these facts. But we have dwelt longer on this point
than it deserves.

To return to the saltness of the sea: those who create the sea once for all, or indeed generate it at all, cannot
account for its saltness. It makes no difference whether the sea is the residue of all the moisture that is about
the earth and has been drawn up by the sun, or whether all the flavour existing in the whole mass of sweet
water is due to the admixture of a certain kind of earth. Since the total volume of the sea is the same once the
water that evaporated has returned, it follows that it must either have been salt at first too, or, if not at first,
then not now either. If it was salt from the very beginning, then we want to know why that was so; and why,
if salt water was drawn up then, that is not the case now.

Again, if it is maintained that an admixture of earth makes the sea salt (for they say that earth has many
flavours and is washed down by the rivers and so makes the sea salt by its admixture), it is strange that rivers
should not be salt too. How can the admixture of this earth have such a striking effect in a great quantity of
water and not in each river singly? For the sea, differing in nothing from rivers but in being salt, is evidently
simply the totality of river water, and the rivers are the vehicle in which that earth is carried to their common
destination.

It is equally absurd to suppose that anything has been explained by calling the sea 'the sweat of the earth', like
Empedicles. Metaphors are poetical and so that expression of his may satisfy the requirements of a poem, but
as a scientific theory it is unsatisfactory. Even in the case of the body it is a question how the sweet liquid
drunk becomes salt sweat whether it is merely by the departure of some element in it which is sweetest, or by
the admixture of something, as when water is strained through ashes. Actually the saltness seems to be due to
the same cause as in the case of the residual liquid that gathers in the bladder. That, too, becomes bitter and
salt though the liquid we drink and that contained in our food is sweet. If then the bitterness is due in these
cases (as with the water strained through lye) to the presence of a certain sort of stuff that is carried along by
the urine (as indeed we actually find a salt deposit settling in chamber-pots) and is secreted from the flesh in

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sweat (as if the departing moisture were washing the stuff out of the body), then no doubt the admixture of
something earthy with the water is what makes the sea salt.

Now in the body stuff of this kind, viz. the sediment of food, is due to failure to digest: but how there came to
be any such thing in the earth requires explanation. Besides, how can the drying and warming of the earth
cause the secretion such a great quantity of water; especially as that must be a mere fragment of what is left in
the earth? Again, waiving the question of quantity, why does not the earth sweat now when it happens to be
in process of drying? If it did so then, it ought to do so now. But it does not: on the contrary, when it is dry it
graws moist, but when it is moist it does not secrete anything at all. How then was it possible for the earth at
the beginning when it was moist to sweat as it grew dry? Indeed, the theory that maintains that most of the
moisture departed and was drawn up by the sun and that what was left over is the sea is more reasonable; but
for the earth to sweat when it is moist is impossible.

Since all the attempts to account for the saltness of the sea seem unsuccessful let us explain it by the help of
the principle we have used already.

Since we recognize two kinds of evaporation, one moist, the other dry, it is clear that the latter must be
recognized as the source of phenomena like those we are concerned with.

But there is a question which we must discuss first. Does the sea always remain numerically one and
consisting of the same parts, or is it, too, one in form and volume while its parts are in continual change, like
air and sweet water and fire? All of these are in a constant state of change, but the form and the quantity of
each of them are fixed, just as they are in the case of a flowing river or a burning flame. The answer is clear,
and there is no doubt that the same account holds good of all these things alike. They differ in that some of
them change more rapidly or more slowly than others; and they all are involved in a process of perishing and
becoming which yet affects them all in a regular course.

This being so we must go on to try to explain why the sea is salt. There are many facts which make it clear
that this taste is due to the admixture of something. First, in animal bodies what is least digested, the residue
of liquid food, is salt and bitter, as we said before. All animal excreta are undigested, but especially that
which gathers in the bladder (its extreme lightness proves this; for everything that is digested is condensed),
and also sweat; in these then is excreted (along with other matter) an identical substance to which this flavour
is due. The case of things burnt is analogous. What heat fails to assimilate becomes the excrementary residue
in animal bodies, and, in things burnt, ashes. That is why some people say that it was burnt earth that made
the sea salt. To say that it was burnt earth is absurd; but to say that it was something like burnt earth is true.
We must suppose that just as in the cases we have described, so in the world as a whole, everything that
grows and is naturally generated always leaves an undigested residue, like that of things burnt, consisting of
this sort of earth. All the earthy stuff in the dry exhalation is of this nature, and it is the dry exhalation which
accounts for its great quantity. Now since, as we have said, the moist and the dry evaporations are mixed,
some quantity of this stuff must always be included in the clouds and the water that are formed by
condensation, and must redescend to the earth in rain. This process must always go on with such regularity as
the sublunary world admits of. and it is the answer to the question how the sea comes to be salt.

It also explains why rain that comes from the south, and the first rains of autumn, are brackish. The south is
the warmest of winds and it blows from dry and hot regions. Hence it carries little moist vapour and that is
why it is hot. (It makes no difference even if this is not its true character and it is originally a cold wind, for it
becomes warm on its way by incorporating with itself a great quantity of dry evaporation from the places it
passes over.) The north wind, on the other hand, comb ing from moist regions, is full of vapour and therefore
cold. It is dry in our part of the world because it drives the clouds away before it, but in the south it is rainy;
just as the south is a dry wind in Libya. So the south wind charges the rain that falls with a great quantity of
this stuff. Autumn rain is brackish because the heaviest water must fall first; so that that which contains the

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greatest quantity of this kind of earth descends quickest.

This, too, is why the sea is warm. Everything that has been exposed to fire contains heat potentially, as we
see in the case of lye and ashes and the dry and liquid excreta of animals. Indeed those animals which are
hottest in the belly have the hottest excreta.

The action of this cause is continually making the sea more salt, but some part of its saltness is always being
drawn up with the sweet water. This is less than the sweet water in the same ratio in which the salt and
brackish element in rain is less than the sweet, and so the saltness of the sea remains constant on the whole.
Salt water when it turns into vapour becomes sweet, and the vapour does not form salt water when it
condenses again. This I know by experiment. The same thing is true in every case of the kind: wine and all
fluids that evaporate and condense back into a liquid state become water. They all are water modified by a
certain admixture, the nature of which determines their flavour. But this subject must be considered on
another more suitable occasion.

For the present let us say this. The sea is there and some of it is continually being drawn up and becoming
sweet; this returns from above with the rain. But it is now different from what it was when it was drawn up,
and its weight makes it sink below the sweet water. This process prevents the sea, as it does rivers, from
drying up except from local causes (this must happen to sea and rivers alike). On the other hand the parts
neither of the earth nor of the sea remain constant but only their whole bulk. For the same thing is true of the
earth as of the sea: some of it is carried up and some comes down with the rain, and both that which remains
on the surface and that which comes down again change their situations.

There is more evidence to prove that saltness is due to the admixture of some substance, besides that which
we have adduced. Make a vessel of wax and put it in the sea, fastening its mouth in such a way as to prevent
any water getting in. Then the water that percolates through the wax sides of the vessel is sweet, the earthy
stuff, the admixture of which makes the water salt, being separated off as it were by a filter. It is this stuff
which make salt water heavy (it weighs more than fresh water) and thick. The difference in consistency is
such that ships with the same cargo very nearly sink in a river when they are quite fit to navigate in the sea.
This circumstance has before now caused loss to shippers freighting their ships in a river. That the thicker
consistency is due to an admixture of something is proved by the fact that if you make strong brine by the
admixture of salt, eggs, even when they are full, float in it. It almost becomes like mud; such a quantity of
earthy matter is there in the sea. The same thing is done in salting fish.

Again if, as is fabled, there is a lake in Palestine, such that if you bind a man or beast and throw it in it floats
and does not sink, this would bear out what we have said. They say that this lake is so bitter and salt that no
fish live in it and that if you soak clothes in it and shake them it cleans them. The following facts all of them
support our theory that it is some earthy stuff in the water which makes it salt. In Chaonia there is a spring of
brackish water that flows into a neighbouring river which is sweet but contains no fish. The local story is that
when Heracles came from Erytheia driving the oxen and gave the inhabitants the choice, they chose salt in
preference to fish. They get the salt from the spring. They boil off some of the water and let the rest stand;
when it has cooled and the heat and moisture have evaporated together it gives them salt, not in lumps but
loose and light like snow. It is weaker than ordinary salt and added freely gives a sweet taste, and it is not as
white as salt generally is. Another instance of this is found in Umbria. There is a place there where reeds and
rushes grow. They burn some of these, put the ashes into water and boil it off. When a little water is left and
has cooled it gives a quantity of salt.

Most salt rivers and springs must once have been hot. Then the original fire in them was extinguished but the
earth through which they percolate preserves the character of lye or ashes. Springs and rivers with all kinds of
flavours are found in many places. These flavours must in every case be due to the fire that is or was in them,
for if you expose earth to different degrees of heat it assumes various kinds and shades of flavour. It becomes

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full of alum and lye and other things of the kind, and the fresh water percolates through these and changes its
character. Sometimes it becomes acid as in Sicania, a part of Sicily. There they get a salt and acid water
which they use as vinegar to season some of their dishes. In the neighbourhood of Lyncus, too, there is a
spring of acid water, and in Scythia a bitter spring. The water from this makes the whole of the river into
which it flows bitter. These differences are explained by a knowledge of the particular mixtures that
determine different savours. But these have been explained in another treatise.

We have now given an account of waters and the sea, why they persist, how they change, what their nature is,
and have explained most of their natural operations and affections.

Let us proceed to the theory of winds. Its basis is a distinction we have already made. We recognize two
kinds of evaporation, one moist, the other dry. The former is called vapour: for the other there is no general
name but we must call it a sort of smoke, applying to the whole of it a word that is proper to one of its forms.
The moist cannot exist without the dry nor the dry without the moist: whenever we speak of either we mean
that it predominates. Now when the sun in its circular course approaches, it draws up by its heat the moist
evaporation: when it recedes the cold makes the vapour that had been raised condense back into water which
falls and is distributed through the earth. (This explains why there is more rain in winter and more by night
than by day: though the fact is not recognized because rain by night is more apt to escape observation than by
day.) But there is a great quantity of fire and heat in the earth, and the sun not only draws up the moisture that
lies on the surface of it, but warms and dries the earth itself. Consequently, since there are two kinds of
evaporation, as we have said, one like vapour, the other like smoke, both of them are necessarily generated.
That in which moisture predominates is the source of rain, as we explained before, while the dry evaporation
is the source and substance of all winds. That things must necessarily take this course is clear from the
resulting phenomena themselves, for the evaporation that is to produce them must necessarily differ; and the
sun and the warmth in the earth not only can but must produce these evaporations.

Since the two evaporations are specifically distinct, wind and rain obviously differ and their substance is not
the same, as those say who maintain that one and the same air when in motion is wind, but when it condenses
again is water. Air, as we have explained in an earlier book, is made up of these as constituents. Vapour is
moist and cold (for its fluidity is due to its moistness, and because it derives from water it is naturally cold,
like water that has not been warmed): whereas the smoky evaporation is hot and dry. Hence each contributes
a part, and air is moist and hot. It is absurd that this air that surrounds us should become wind when in
motion, whatever be the source of its motion on the contrary the case of winds is like that of rivers. We do
not call water that flows anyhow a river, even if there is a great quantity of it, but only if the flow comes from
a spring. So too with the winds; a great quantity of air might be moved by the fall of some large object
without flowing from any source or spring.

The facts bear out our theory. It is because the evaporation takes place uninterruptedly but differs in degree
and quantity that clouds and winds appear in their natural proportion according to the season; and it is
because there is now a great excess of the vaporous, now of the dry and smoky exhalation, that some years
are rainy and wet, others windy and dry. Sometimes there is much drought or rain, and it prevails over a great
and continuous stretch of country. At other times it is local; the surrounding country often getting seasonable
or even excessive rains while there is drought in a certain part; or, contrariwise, all the surrounding country
gets little or even no rain while a certain part gets rain in abundance. The reason for all this is that while the
same affection is generally apt to prevail over a considerable district because adjacent places (unless there is
something special to differentiate them) stand in the same relation to the sun, yet on occasion the dry
evaporation will prevail in one part and the moist in another, or conversely. Again the reason for this latter is
that each evaporation goes over to that of the neighbouring district: for instance, the dry evaporation

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circulates in its own place while the moist migrates to the next district or is even driven by winds to some
distant place: or else the moist evaporation remains and the dry moves away. Just as in the case of the body
when the stomach is dry the lower belly is often in the contrary state, and when it is dry the stomach is moist
and cold, so it often happens that the evaporations reciprocally take one another's place and interchange.

Further, after rain wind generally rises in those places where the rain fell, and when rain has come on the
wind ceases. These are necessary effects of the principles we have explained. After rain the earth is being
dried by its own heat and that from above and gives off the evaporation which we saw to be the material
cause of. wind. Again, suppose this secretion is present and wind prevails; the heat is continually being
thrown off, rising to the upper region, and so the wind ceases; then the fall in temperature makes vapour form
and condense into water. Water also forms and cools the dry evaporation when the clouds are driven together
and the cold concentrated in them. These are the causes that make wind cease on the advent of rain, and rain
fall on the cessation of wind.

The cause of the predominance of winds from the north and from the south is the same. (Most winds, as a
matter of fact, are north winds or south winds.) These are the only regions which the sun does not visit: it
approaches them and recedes from them, but its course is always over the-west and the east. Hence clouds
collect on either side, and when the sun approaches it provokes the moist evaporation, and when it recedes to
the opposite side there are storms and rain. So summer and winter are due to the sun's motion to and from the
solstices, and water ascends and falls again for the same reason. Now since most rain falls in those regions
towards which and from which the sun turns and these are the north and the south, and since most
evaporation must take place where there is the greatest rainfall, just as green wood gives most smoke, and
since this evaporation is wind, it is natural that the most and most important winds should come from these
quarters. (The winds from the north are called Boreae, those from the south Noti.)

The course of winds is oblique: for though the evaporation rises straight up from the earth, they blow round it
because all the surrounding air follows the motion of the heavens. Hence the question might be asked
whether winds originate from above or from below. The motion comes from above: before we feel the wind
blowing the air betrays its presence if there are clouds or a mist, for their motion shows that the wind has
begun to blow before it has actually reached us; and this implies that the source of winds is above. But since
wind is defined as 'a quantity of dry evaporation from the earth moving round the earth', it is clear that while
the origin of the motion is from above, the matter and the generation of wind come from below. The oblique
movement of the rising evaporation is caused from above: for the motion of the heavens determines the
processes that are at a distance from the earth, and the motion from below is vertical and every cause is more
active where it is nearest to the effect; but in its generation and origin wind plainly derives from the earth.

The facts bear out the view that winds are formed by the gradual union of many evaporations just as rivers
derive their sources from the water that oozes from the earth. Every wind is weakest in the spot from which it
blows; as they proceed and leave their source at a distance they gather strength. Thus the winter in the north
is windless and calm: that is, in the north itself; but, the breeze that blows from there so gently as to escape
observation becomes a great wind as it passes on.

We have explained the nature and origin of wind, the occurrence of drought and rains, the reason why rain
stops wind and wind rises after rain, the prevalence of north and south winds and also why wind moves in the
way it does.

The sun both checks the formation of winds and stimulates it. When the evaporation is small in amount and
faint the sun wastes it and dissipates by its greater heat the lesser heat contained in the evaporation. It also

METEOROLOGY

dries up the earth, the source of the evaporation, before the latter has appeared in bulk: just as, when you
throw a little fuel into a great fire, it is often burnt up before giving off any smoke. In these ways the sun
checks winds and prevents them from rising at all: it checks them by wasting the evaporation, and prevents
their rising by drying up the earth quickly. Hence calm is very apt to prevail about the rising of Orion and
lasts until the coming of the Etesiae and their 'forerunners'.

Calm is due to two causes. Either cold quenches the evaporation, for instance a sharp frost: or excessive heat
wastes it. In the intermediate periods, too, the causes are generally either that the evaporation has not had
time to develop or that it has passed away and there is none as yet to replace it.

Both the setting and the rising of Orion are considered to be treacherous and stormy, because they place at a
change of season (namely of summer or winter; and because the size of the constellation makes its rise last
over many days) and a state of change is always indefinite and therefore liable to disturbance.

The Etesiae blow after the summer solstice and the rising of the dog-star: not at the time when the sun is
closest nor when it is distant; and they blow by day and cease at night. The reason is that when the sun is near
it dries up the earth before evaporation has taken place, but when it has receded a little its heat and the
evaporation are present in the right proportion; so the ice melts and the earth, dried by its own heat and that of
the sun, smokes and vapours. They abate at night because the cold pf the nights checks the melting of the ice.
What is frozen gives off no evaporation, nor does that which contains no dryness at all: it is only where
something dry contains moisture that it gives off evaporation under the influence of heat.

The question is sometimes asked: why do the north winds which we call the Etesiae blow continuously after
the summer solstice, when there are no corresponding south winds after the winter solstice? The facts are
reasonable enough: for the so-called 'white south winds' do blow at the corresponding season, though they
are not equally continuous and so escape observation and give rise to this inquiry. The reason for this is that
the north wind I from the arctic regions which are full of water and snow. The sun thaws them and so the
Etesiae blow: after rather than at the summer solstice. (For the greatest heat is developed not when the sun is
nearest to the north, but when its heat has been felt for a considerable period and it has not yet receded far.
The 'bird winds' blow in the same way after the winter solstice. They, too, are weak Etesiae, but they blow
less and later than the Etesiae. They begin to blow only on the seventieth day because the sun is distant and
therefore weaker. They do not blow so continuously because only things on the surface of the earth and
offering little resistance evaporate then, the thoroughly frozen parts requiring greater heat to melt them. So
they blow intermittently till the true Etesiae come on again at the summer solstice: for from that time onwards
the wind tends to blow continuously.) But the south wind blows from the tropic of Cancer and not from the
antarctic region.

There are two inhabitable sections of the earth: one near our upper, or nothern pole, the other near the other
or southern pole; and their shape is like that of a tambourine. If you draw lines from the centre of the earth
they cut out a drum-shaped figure. The lines form two cones; the base of the one is the tropic, of the other the
ever visible circle, their vertex is at the centre of the earth. Two other cones towards the south pole give
corresponding segments of the earth. These sections alone are habitable. Beyond the tropics no one can live:
for there the shade would not fall to the north, whereas the earth is known to be uninhabitable before the sun
is in the zenith or the shade is thrown to the south: and the regions below the Bear are uninhabitable because
of the cold.

(The Crown, too, moves over this region: for it is in the zenith when it is on our meridian.)

So we see that the way in which they now describe the geography of the earth is ridiculous. They depict the
inhabited earth as round, but both ascertained facts and general considerations show this to be impossible. If
we reflect we see that the inhabited region is limited in breadth, while the climate admits of its extending all

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round the earth. For we meet with no excessive heat or cold in the direction of its length but only in that of its
breadth; so that there is nothing to prevent our travelling round the earth unless the extent of the sea presents
an obstacle anywhere. The records of journeys by sea and land bear this out. They make the length far greater
than the breadth. If we compute these voyages and journeys the distance from the Pillars of Heracles to India
exceeds that from Aethiopia to Maeotis and the northernmost Scythians by a ratio of more than 5 to 3, as far
as such matters admit of accurate statement. Yet we know the whole breadth of the region we dwell in up to
the uninhabited parts: in one direction no one lives because of the cold, in the other because of the heat.

But it is the sea which divides as it seems the parts beyond India from those beyond the Pillars of Heracles
and prevents the earth from being inhabited all round.

Now since there must be a region bearing the same relation to the southern pole as the place we live in bears
to our pole, it will clearly correspond in the ordering of its winds as well as in other things. So just as we have
a north wind here, they must have a corresponding wind from the antarctic. This wind cannot reach us since
our own north wind is like a land breeze and does not even reach the limits of the region we live in. The
prevalence of north winds here is due to our lying near the north. Yet even here they give out and fail to
penetrate far: in the southern sea beyond Libya east and west winds are always blowing alternately, like north
and south winds with us. So it is clear that the south wind is not the wind that blows from the south pole. It is
neither that nor the wind from the winter tropic. For symmetry would require another wind blowing from the
summer tropic, which there is not, since we know that only one wind blows from that quarter. So the south
wind clearly blows from the torrid region. Now the sun is so near to that region that it has no water, or snow
which might melt and cause Etesiae. But because that place is far more extensive and open the south wind is
greater and stronger and warmer than the north and penetrates farther to the north than the north wind does to
the south.

The origin of these winds and their relation to one another has now been explained.

Let us now explain the position of the winds, their oppositions, which can blow simultaneously with which,
and which cannot, their names and number, and any other of their affections that have not been treated in the
'particular questions'. What we say about their position must be followed with the help of the figure. For
clearness' sake we have drawn the circle of the horizon, which is round, but it represents the zone in which
we live; for that can be divided in the same way. Let us also begin by laying down that those things are
locally contrary which are locally most distant from one another, just as things specifically most remote from
one another are specific contraries. Now things that face one another from opposite ends of a diameter are
locally most distant from one another. (See diagram.)

Let A be the point where the sun sets at the equinox and B, the point opposite, the place where it rises at the
equinox. Let there be another diameter cutting this at right angles, and let the point H on it be the north and
its diametrical opposite O the south. Let Z be the rising of the sun at the summer solstice and E its setting at
the summer solstice; D its rising at the winter solstice, and G its setting at the winter solstice. Draw a
diameter from Z to G from D to E. Then since those things are locally contrary which are most distant from
one another in space, and points diametrically opposite are most distant from one another, those winds must
necessarily be contrary to one another that blow from opposite ends of a diameter.

The names of the winds according to their position are these. Zephyrus is the wind that blows from A, this
being the point where the sun sets at the equinox. Its contrary is Apeliotes blowing from B the point where
the sun rises at the equinox. The wind blowing from H, the north, is the true north wind, called Aparctias:
while Notus blowing from O is its contrary; for this point is the south and O is contrary to H, being

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diametrically opposite to it. Caecias blows from Z, where the sun rises at the summer solstice. Its contrary is
not the wind blowing from E but Lips blowing from G. For Lips blows from the point where the sun sets at
the winter solstice and is diametrically opposite to Caecias: so it is its contrary. Eurus blows from D, coming
from the point where the sun rises at the winter solstice. It borders on Notus, and so we often find that people
speak of 'Euro-Noti'. Its contrary is not Lips blowing from G but the wind that blows from E which some call
Argestes, some Olympias, and some Sciron. This blows from the point where the sun sets at the summer
solstice, and is the only wind that is diametrically opposite to Eurus. These are the winds that are
diametrically opposite to one another and their contraries.

There are other winds which have no contraries. The wind they call Thrascias, which lies between Argestes
and Aparctias, blows from I; and the wind called Meses, which lies between Caecias and Aparctias, from K.
(The line IK nearly coincides with the ever visible circle, but not quite.) These winds have no contraries.
Meses has not, or else there would be a wind blowing from the point M which is diametrically opposite.
Thrascias corresponding to the point I has not, for then there would be a wind blowing from N, the point
which is diametrically opposite. (But perhaps a local wind which the inhabitants of those parts call
Phoenicias blows from that point.)

These are the most important and definite winds and these their places.

There are more winds from the north than from the south. The reason for this is that the region in which we
live lies nearer to the north. Also, much more water and snow is pushed aside into this quarter because the
other lies under the sun and its course. When this thaws and soaks into the earth and is exposed to the heat of
the sun and the earth it necessarily causes evaporation to rise in greater quantities and over a greater space.

Of the winds we have described Aparctias is the north wind in the strict sense. Thrascias and Meses are north
winds too. (Caecias is half north and half east.) South are that which blows from due south and Lips. East, the
wind from the rising of the sun at the equinox and Eurus. Phoenicias is half south and half east. West, the
wind from the true west and that called Argestes. More generally these winds are classified as northerly or
southerly. The west winds are counted as northerly, for they blow from the place of sunset and are therefore
colder; the east winds as southerly, for they are warmer because they blow from the place of sunrise. So the
distinction of cold and hot or warm is the basis for the division of the winds into northerly and southerly. East
winds are warmer than west winds because the sun shines on the east longer, whereas it leaves the west
sooner and reaches it later.

Since this is the distribution of the winds it is clear that contrary winds cannot blow simultaneously. They are
diametrically opposite to one another and one of the two must be overpowered and cease. Winds that are not
diametrically opposite to one another may blow simultaneously: for instance the winds from Z and from D.
Hence it sometimes happens that both of them, though different winds and blowing from different quarters,
are favourable to sailors making for the same point.

Contrary winds commonly blow at opposite seasons. Thus Caecias and in general the winds north of the
summer solstice blow about the time of the spring equinox, but about the autumn equinox Lips; and Zephyrus
about the summer solstice, but about the winter solstice Eurus.

Aparctias, Thrascias, and Argestes are the winds that fall on others most and stop them. Their source is so
close to us that they are greater and stronger than other winds. They bring fair weather most of all winds for
the same reason, for, blowing as they do, from close at hand, they overpower the other winds and stop them;
they also blow away the clouds that are forming and leave a clear sky-unless they happen to be very cold.
Then they do not bring fair weather, but being colder than they are strong they condense the clouds before
driving them away.

METEOROLOGY

Caecias does not bring fair weather because it returns upon itself. Hence the saying: 'Bringing it on himself as
Caecias does clouds.'

When they cease, winds are succeeded by their neighbours in the direction of the movement of the sun. For
an effect is most apt to be produced in the neighbourhood of its cause, and the cause of winds moves with the
sun.

Contrary winds have either the same or contrary effects. Thus Lips and Caecias, sometimes called
Hellespontias, are both rainy gestes and Eurus are dry: the latter being dry at first and rainy afterwards. Meses
and Aparctias are coldest and bring most snow. Aparctias, Thrascias, and Argestes bring hail. Notus,
Zephyrus, and Eurus are hot. Caecias covers the sky with heavy clouds, Lips with lighter ones. Caecias does
this because it returns upon itself and combines the qualities of Boreas and Eurus. By being cold it condenses
and gathers the vaporous air, and because it is easterly it carries with it and drives before it a great quantity of
such matter. Aparctias, Thrascias, and Argestes bring fair weather for the reason we have explained before.
These winds and Meses are most commonly accompanied by lightning. They are cold because they blow
from the north, and lightning is due to cold, being ejected when the clouds contract. Some of these same
bring hail with them for the same reason; namely, that they cause a sudden condensation.

Hurricanes are commonest in autumn, and next in spring: Aparctias, Thrascias, and Argestes give rise to them
most. This is because hurricanes are generally formed when some winds are blowing and others fall on them;
and these are the winds which are most apt to fall on others that are blowing; the reason for which, too, we
have explained before.

The Etesiae veer round: they begin from the north, and become for dwellers in the west Thrasciae, Argestae,
and Zephyrus (for Zephyrus belongs to the north). For dwellers in the east they veer round as far as Apeliotes.

So much for the winds, their origin and nature and the properties common to them all or peculiar to each.

We must go on to discuss earthquakes next, for their cause is akin to our last subject.

The theories that have been put forward up to the present date are three, and their authors three men,
Anaxagoras of Clazomenae, and before him Anaximenes of Miletus, and later Democritus of Abdera.

Anaxagoras says that the ether, which naturally moves upwards, is caught in hollows below the earth and so
shakes it, for though the earth is really all of it equally porous, its surface is clogged up by rain. This implies
that part of the whole sphere is 'above' and part 'below': 'above' being the part on which we live, 'below' the
other.

This theory is perhaps too primitive to require refutation. It is absurd to think of up and down otherwise than
as meaning that heavy bodies move to the earth from every quarter, and light ones, such as fire, away from it;
especially as we see that, as far as our knowledge of the earth goes, the horizon always changes with a change
in our position, which proves that the earth is convex and spherical. It is absurd, too, to maintain that the earth
rests on the air because of its size, and then to say that impact upwards from below shakes it right through.
Besides he gives no account of the circumstances attendant on earthquakes: for not every country or every
season is subject to them.

Democritus says that the earth is full of water and that when a quantity of rain-water is added to this an
earthquake is the result. The hollows in the earth being unable to admit the excess of water it forces its way in

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and so causes an earthquake. Or again, the earth as it dries draws the water from the fuller to the emptier
parts, and the inrush of the water as it changes its place causes the earthquake.

Anaximenes says that the earth breaks up when it grows wet or dry, and earthquakes are due to the fall of
these masses as they break away. Hence earthquakes take place in times of drought and again of heavy rain,
since, as we have explained, the earth grows dry in time of drought and breaks up, whereas the rain makes it
sodden and destroys its cohesion.

But if this were the case the earth ought to be found to be sinking in many places. Again, why do earthquakes
frequently occur in places which are not excessively subject to drought or rain, as they ought to be on the
theory? Besides, on this view, earthquakes ought always to be getting fewer, and should come to an end
entirely some day: the notion of contraction by packing together implies this. So this is impossible the theory
must be impossible too.

We have already shown that wet and dry must both give rise to an evaporation: earthquakes are a necessary
consequence of this fact. The earth is essentially dry, but rain fills it with moisture. Then the sun and its own
fire warm it and give rise to a quantity of wind both outside and inside it. This wind sometimes flows
outwards in a single body, sometimes inwards, and sometimes it is divided. All these are necessary laws.
Next we must find out what body has the greatest motive force. This will certainly be the body that naturally
moves farthest and is most violent. Now that which has the most rapid motion is necessarily the most violent;
for its swiftness gives its impact the greatest force. Again, the rarest body, that which can most readily pass
through every other body, is that which naturally moves farthest. Wind satisfies these conditions in the
highest degree (fire only becomes flame and moves rapidly when wind accompanies it): so that not water nor
earth is the cause of earthquakes but wind-that is, the inrush of the external evaporation into the earth.

Hence, since the evaporation generally follows in a continuous body in the direction in which it first started,
and either all of it flows inwards or all outwards, most earthquakes and the greatest are accompanied by calm.
It is true that some take place when a wind is blowing, but this presents no difficulty. We sometimes find
several winds blowing simultaneously. If one of these enters the earth we get an earthquake attended by wind.
Only these earthquakes are less severe because their source and cause is divided.

Again, most earthquakes and the severest occur at night or, if by day, about noon, that being generally the
calmest part of the day. For when the sun exerts its full power (as it does about noon) it shuts the evaporation
into the earth. Night, too, is calmer than day. The absence of the sun makes the evaporation return into the
earth like a sort of ebb tide, corresponding to the outward flow; especially towards dawn, for the winds, as a
rule, begin to blow then, and if their source changes about like the Euripus and flows inwards the quantity of
wind in the earth is greater and a more violent earthquake results.

The severest earthquakes take place where the sea is full of currents or the earth spongy and cavernous: so
they occur near the Hellespont and in Achaea and Sicily, and those parts of Euboea which correspond to our
description-where the sea is supposed to flow in channels below the earth. The hot springs, too, near
Aedepsus are due to a cause of this kind. It is the confined character of these places that makes them so liable
to earthquakes. A great and therefore violent wind is developed, which would naturally blow away from the
earth: but the onrush of the sea in a great mass thrusts it back into the earth. The countries that are spongy
below the surface are exposed to earthquakes because they have room for so much wind.

For the same reason earthquakes usually take place in spring and autumn and in times of wet and of
drought-because these are the windiest seasons. Summer with its heat and winter with its frost cause calm:

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winter is too cold, summer too dry for winds to form. In time of drought the air is full of wind; drought is just
the predominance of the dry over the moist evaporation. Again, excessive rain causes more of the evaporation
to form in the earth. Then this secretion is shut up in a narrow compass and forced into a smaller space by the
water that fills the cavities. Thus a great wind is compressed into a smaller space and so gets the upper hand,
and then breaks out and beats against the earth and shakes it violently.

We must suppose the action of the wind in the earth to be analogous to the tremors and throbbings caused in
us by the force of the wind contained in our bodies. Thus some earthquakes are a sort of tremor, others a sort
of throbbing. Again, we must think of an earthquake as something like the tremor that often runs through the
body after passing water as the wind returns inwards from without in one volume.

The force wind can have may be gathered not only from what happens in the air (where one might suppose
that it owed its power to produce such effects to its volume), but also from what is observed in animal bodies.
Tetanus and spasms are motions of wind, and their force is such that the united efforts of many men do not
succeed in overcoming the movements of the patients. We must suppose, then (to compare great things with
small), that what happens in the earth is just like that. Our theory has been verified by actual observation in
many places. It has been known to happen that an earthquake has continued until the wind that caused it burst
through the earth into the air and appeared visibly like a hurricane. This happened lately near Heracleia in
Pontus and some time past at the island Hiera, one of the group called the Aeolian islands. Here a portion of
the earth swelled up and a lump like a mound rose with a noise: finally it burst, and a great wind came out of
it and threw up live cinders and ashes which buried the neighbouring town of Lipara and reached some of the
towns in Italy. The spot where this eruption occurred is still to be seen.

Indeed, this must be recognized as the cause of the fire that is generated in the earth: the air is first broken up
in small particles and then the wind is beaten about and so catches fire.

A phenomenon in these islands affords further evidence of the fact that winds move below the surface of the
earth. When a south wind is going to blow there is a premonitory indication: a sound is heard in the places
from which the eruptions issue. This is because the sea is being pushed on from a distance and its advance
thrusts back into the earth the wind that was issuing from it. The reason why there is a noise and no
earthquake is that the underground spaces are so extensive in proportion to the quantity of the air that is being
driven on that the wind slips away into the void beyond.

Again, our theory is supported by the facts that the sun appears hazy and is darkened in the absence of clouds,
and that there is sometimes calm and sharp frost before earthquakes at sunrise. The sun is necessarily
obscured and darkened when the evaporation which dissolves and rarefies the air begins to withdraw into the
earth. The calm, too, and the cold towards sunrise and dawn follow from the theory. The calm we have
already explained. There must as a rule be calm because the wind flows back into the earth: again, it must be
most marked before the more violent earthquakes, for when the wind is not part outside earth, part inside, but
moves in a single body, its strength must be greater. The cold comes because the evaporation which is
naturally and essentially hot enters the earth. (Wind is not recognized to be hot, because it sets the air in
motion, and that is full of a quantity of cold vapour. It is the same with the breath we blow from our mouth:
close by it is warm, as it is when we breathe out through the mouth, but there is so little of it that it is scarcely
noticed, whereas at a distance it is cold for the same reason as wind.) Well, when this evaporation disappears
into the earth the vaporous exhalation concentrates and causes cold in any place in which this disappearance
occurs.

A sign which sometimes precedes earthquakes can be explained in the same way. Either by day or a little
after sunset, in fine weather, a little, light, long-drawn cloud is seen, like a long very straight line. This is
because the wind is leaving the air and dying down. Something analogous to this happens on the sea-shore.
When the sea breaks in great waves the marks left on the sand are very thick and crooked, but when the sea is

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calm they are slight and straight (because the secretion is small). As the sea is to the shore so the wind is to
the cloudy air; so, when the wind drops, this very straight and thin cloud is left, a sort of wave-mark in the
air.

An earthquake sometimes coincides with an eclipse of the moon for the same reason. When the earth is on
the point of being interposed, but the light and heat of the sun has not quite vanished from the air but is dying
away, the wind which causes the earthquake before the eclipse, turns off into the earth, and calm ensues. For
there often are winds before eclipses: at nightfall if the eclipse is at midnight, and at midnight if the eclipse is
at dawn. They are caused by the lessening of the warmth from the moon when its sphere approaches the point
at which the eclipse is going to take place. So the influence which restrained and quieted the air weakens and
the air moves again and a wind rises, and does so later, the later the eclipse.

A severe earthquake does not stop at once or after a single shock, but first the shocks go on, often for about
forty days; after that, for one or even two years it gives premonitory indications in the same place. The
severity of the earthquake is determined by the quantity of wind and the shape of the passages through which
it flows. Where it is beaten back and cannot easily find its way out the shocks are most violent, and there it
must remain in a cramped space like water that cannot escape. Any throbbing in the body does not cease
suddenly or quickly, but by degrees according as the affection passes off. So here the agency which created
the evaporation and gave it an impulse to motion clearly does not at once exhaust the whole of the material
from which it forms the wind which we call an earthquake. So until the rest of this is exhausted the shocks
must continue, though more gently, and they must go on until there is too little of the evaporation left to have
any perceptible effect on the earth at all.

Subterranean noises, too, are due to the wind; sometimes they portend earthquakes but sometimes they have
been heard without any earthquake following. Just as the air gives off various sounds when it is struck, so it
does when it strikes other things; for striking involves being struck and so the two cases are the same. The
sound precedes the shock because sound is thinner and passes through things more readily than wind. But
when the wind is too weak by reason of thinness to cause an earthquake the absence of a shock is due to its
filtering through readily, though by striking hard and hollow masses of different shapes it makes various
noises, so that the earth sometimes seems to 'bellow' as the portentmongers say.

Water has been known to burst out during an earthquake. But that does not make water the cause of the
earthquake. The wind is the efficient cause whether it drives the water along the surface or up from below:
just as winds are the causes of waves and not waves of winds. Else we might as well say that earth was the
cause; for it is upset in an earthquake, just like water (for effusion is a form of upsetting). No, earth and water
are material causes (being patients, not agents): the true cause is the wind.

The combination of a tidal wave with an earthquake is due to the presence of contrary winds. It occurs when
the wind which is shaking the earth does not entirely succeed in driving off the sea which another wind is
bringing on, but pushes it back and heaps it up in a great mass in one place. Given this situation it follows
that when this wind gives way the whole body of the sea, driven on by the other wind, will burst out and
overwhelm the land. This is what happened in Achaea. There a south wind was blowing, but outside a north
wind; then there was a calm and the wind entered the earth, and then the tidal wave came on and
simultaneously there was an earthquake. This was the more violent as the sea allowed no exit to the wind that
had entered the earth, but shut it in. So in their struggle with one another the wind caused the earthquake, and
the wave by its settling down the inundation.

Earthquakes are local and often affect a small district only; whereas winds are not local. Such phenomena are
local when the evaporations at a given place are joined by those from the next and unite; this, as we
explained, is what happens when there is drought or excessive rain locally. Now earthquakes do come about
in this way but winds do not. For earthquakes, rains, and droughts have their source and origin inside the

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earth, so that the sun is not equally able to direct all the evaporations in one direction. But on the evaporations
in the air the sun has more influence so that, when once they have been given an impulse by its motion, which
is determined by its various positions, they flow in one direction.

When the wind is present in sufficient quantity there is an earthquake. The shocks are horizontal like a
tremor; except occasionally, in a few places, where they act vertically, upwards from below, like a throbbing.
It is the vertical direction which makes this kind of earthquake so rare. The motive force does not easily
accumulate in great quantity in the position required, since the surface of the earth secretes far more of the
evaporation than its depths. Wherever an earthquake of this kind does occur a quantity of stones comes to the
surface of the earth (as when you throw up things in a winnowing fan), as we see from Sipylus and the
Phlegraean plain and the district in Liguria, which were devastated by this kind of earthquake.

Islands in the middle of the sea are less exposed to earthquakes than those near land. First, the volume of the
sea cools the evaporations and overpowers them by its weight and so crushes them. Then, currents and not
shocks are produced in the sea by the action of the winds. Again, it is so extensive that evaporations do not
collect in it but issue from it, and these draw the evaporations from the earth after them. Islands near the
continent really form part of it: the intervening sea is not enough to make any difference; but those in the
open sea can only be shaken if the whole of the sea that surrounds them is shaken too.

We have now explained earthquakes, their nature and cause, and the most important of the circumstances
attendant on their appearance.

Let us go on to explain lightning and thunder, and further whirlwind, fire-wind, and thunderbolts: for the
cause of them all is the same.

As we have said, there are two kinds of exhalation, moist and dry, and the atmosphere contains them both
potentially. It, as we have said before, condenses into cloud, and the density of the clouds is highest at their
upper limit. (For they must be denser and colder on the side where the heat escapes to the upper region and
leaves them. This explains why hurricanes and thunderbolts and all analogous phenomena move downwards
in spite of the fact that everything hot has a natural tendency upwards. Just as the pips that we squeeze
between our fingers are heavy but often jump upwards: so these things are necessarily squeezed out away
from the densest part of the cloud.) Now the heat that escapes disperses to the up region. But if any of the dry
exhalation is caught in the process as the air cools, it is squeezed out as the clouds contract, and collides in its
rapid course with the neighbouring clouds, and the sound of this collision is what we call thunder. This
collision is analogous, to compare small with great, to the sound we hear in a flame which men call the
laughter or the threat of Hephaestus or of Hestia. This occurs when the wood dries and cracks and the
exhalation rushes on the flame in a body. So in the clouds, the exhalation is projected and its impact on dense
clouds causes thunder: the variety of the sound is due to the irregularity of the clouds and the hollows that
intervene where their density is interrupted. This then, is thunder, and this its cause.

It usually happens that the exhalation that is ejected is inflamed and burns with a thin and faint fire: this is
what we call lightning, where we see as it were the exhalation coloured in the act of its ejection. It comes into
existence after the collision and the thunder, though we see it earlier because sight is quicker than hearing.
The rowing of triremes illustrates this: the oars are going back again before the sound of their striking the
water reaches us.

However, there are some who maintain that there is actually fire in the clouds. Empedocles says that it
consists of some of the sun's rays which are intercepted: Anaxagoras that it is part of the upper ether (which

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he calls fire) which has descended from above. Lightning, then, is the gleam of this fire, and thunder the
hissing noise of its extinction in the cloud.

But this involves the view that lightning actually is prior to thunder and does not merely appear to be so.
Again, this intercepting of the fire is impossible on either theory, but especially it is said to be drawn down
from the upper ether. Some reason ought to be given why that which naturally ascends should descend, and
why it should not always do so, but only when it is cloudy. When the sky is clear there is no lightning: to say
that there is, is altogether wanton.

The view that the heat of the sun's rays intercepted in the clouds is the cause of these phenomena is equally
unattractive: this, too, is a most careless explanation. Thunder, lightning, and the rest must have a separate
and determinate cause assigned to them on which they ensue. But this theory does nothing of the sort. It is
like supposing that water, snow, and hail existed all along and were produced when the time came and not
generated at all, as if the atmosphere brought each to hand out of its stock from time to time. They are
concretions in the same way as thunder and lightning are discretions, so that if it is true of either that they are
not generated but pre-exist, the same must be true of the other. Again, how can any distinction be made
about the intercepting between this case and that of interception in denser substances such as water? Water,
too, is heated by the sun and by fire: yet when it contracts again and grows cold and freezes no such ejection
as they describe occurs, though it ought on their the. to take place on a proportionate scale. Boiling is due to
the exhalation generated by fire: but it is impossible for it to exist in the water beforehand; and besides they
call the noise 'hissing', not 'boiling'. But hissing is really boiling on a small scale: for when that which is
brought into contact with moisture and is in process of being extinguished gets the better of it, then it boils
and makes the noise in question. Some-Cleidemus is one of them-say that lightning is nothing objective but
merely an appearance. They compare it to what happens when you strike the sea with a rod by night and the
water is seen to shine. They say that the moisture in the cloud is beaten about in the same way, and that
lightning is the appearance of brightness that ensues.

This theory is due to ignorance of the theory of reflection, which is the real cause of that phenomenon. The
water appears to shine when struck because our sight is reflected from it to some bright object: hence the
phenomenon occurs mainly by night: the appearance is not seen by day because the daylight is too in, tense
and obscures it.

These are the theories of others about thunder and lightning: some maintaining that lightning is a reflection,
the others that lightning is fire shining through the cloud and thunder its extinction, the fire not being
generated in each case but existing beforehand. We say that the same stuff is wind on the earth, and
earthquake under it, and in the clouds thunder. The essential constituent of all these phenomena is the same:
namely, the dry exhalation. If it flows in one direction it is wind, in another it causes earthquakes; in the
clouds, when they are in a process of change and contract and condense into water, it is ejected and causes
thunder and lightning and the other phenomena of the same nature.

So much for thunder and lightning.

Book III

LET us explain the remaining operations of this secretion in the same way as we have treated the rest. When
this exhalation is secreted in small and scattered quantities and frequently, and is transitory, and its
constitution rare, it gives rise to thunder and lightning. But if it is secreted in a body and is denser, that is, less
rare, we get a hurricane. The fact that it issues in body explains its violence: it is due to the rapidity of the

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secretion. Now when this secretion issues in a great and continuous current the result corresponds to what we
get when the opposite development takes place and rain and a quantity of water are produced. As far as the
matter from which they are developed goes both sets of phenomena are the same. As soon as a stimulus to the
development of either potentiality appears, that of which there is the greater quantity present in the cloud is at
once secreted from it, and there results either rain, or, if the other exhalation prevails, a hurricane.

Sometimes the exhalation in the cloud, when it is being secreted, collides with another under circumstances
like those found when a wind is forced from an open into a narrow space in a gateway or a road. It often
happens in such cases that the first part of the moving body is deflected because of the resistance due either to
the narrowness or to a contrary current, and so the wind forms a circle and eddy. It is prevented from
advancing in a straight line: at the same time it is pushed on from behind; so it is compelled to move
sideways in the direction of least resistance. The same thing happens to the next part, and the next, and so on,
till the series becomes one, that is, till a circle is formed: for if a figure is described by a single motion that
figure must itself be one. This is how eddies are generated on the earth, and the case is the same in the clouds
as far as the beginning of them goes. Only here (as in the case of the hurricane which shakes off the cloud
without cessation and becomes a continuous wind) the cloud follows the exhalation unbroken, and the
exhalation, failing to break away from the cloud because of its density, first moves in a circle for the reason
given and then descends, because clouds are always densest on the side where the heat escapes. This
phenomenon is called a whirlwind when it is colourless; and it is a sort of undigested hurricane. There is
never a whirlwind when the weather is northerly, nor a hurricane when there is snow. The reason is that all
these phenomena are 'wind', and wind is a dry and warm evaporation. Now frost and cold prevail over this
principle and quench it at its birth: that they do prevail is clear or there could be no snow or northerly rain,
since these occur when the cold does prevail.

So the whirlwind originates in the failure of an incipient hurricane to escape from its cloud: it is due to the
resistance which generates the eddy, and it consists in the spiral which descends to the earth and drags with it
the cloud which it cannot shake off. It moves things by its wind in the direction in which it is blowing in a
straight line, and whirls round by its circular motion and forcibly snatches up whatever it meets.

When the cloud burns as it is drawn downwards, that is, when the exhalation becomes rarer, it is called a
fire-wind, for its fire colours the neighbouring air and inflames it.

When there is a great quantity of exhalation and it is rare and is squeezed out in the cloud itself we get a
thunderbolt. If the exhalation is exceedingly rare this rareness prevents the thunderbolt from scorching and
the poets call it 'bright': if the rareness is less it does scorch and they call it 'smoky'. The former moves
rapidly because of its rareness, and because of its rapidity passes through an object before setting fire to it or
dwelling on it so as to blacken it: the slower one does blacken the object, but passes through it before it can
actually burn it. Further, resisting substances are affected, unresisting ones are not. For instance, it has
happened that the bronze of a shield has been melted while the woodwork remained intact because its texture
was so loose that the exhalation filtered through without affecting it. So it has passed through clothes, too,
without burning them, and has merely reduced them to shreds.

Such evidence is enough by itself to show that the exhalation is at work in all these cases, but we sometimes
get direct evidence as well, as in the case of the conflagration of the temple at Ephesus which we lately
witnessed. There independent sheets of flame left the main fire and were carried bodily in many directions.
Now that smoke is exhalation and that smoke burns is certain, and has been stated in another place before;
but when the flame moves bodily, then we have ocular proof that smoke is exhalation. On this occasion what
is seen in small fires appeared on a much larger scale because of the quantity of matter that was burning. The
beams which were the source of the exhalation split, and a quantity of it rushed in a body from the place from
which it issued forth and went up in a blaze: so that the flame was actually seen moving through the air away
and falling on the houses. For we must recognize that exhalation accompanies and precedes thunderbolts

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though it is colourless and so invisible. Hence, where the thunderbolt is going to strike, the object moves
before it is struck, showing that the exhalation leads the way and falls on the object first. Thunder, too, splits
things not by its noise but because the exhalation that strikes the object and that which makes the noise are
ejected simultaneously. This exhalation splits the thing it strikes but does not scorch it at all.

We have now explained thunder and lightning and hurricane, and further firewinds, whirlwinds, and
thunderbolts, and shown that they are all of them forms of the same thing and wherein they all differ.

Let us now explain the nature and cause of halo, rainbow, mock suns, and rods, since the same account
applies to them all.

We must first describe the phenomena and the circumstances in which each of them occurs. The halo often
appears as a complete circle: it is seen round the sun and the moon and bright stars, by night as well as by
day, and at midday or in the afternoon, more rarely about sunrise or sunset.

The rainbow never forms a full circle, nor any segment greater than a semicircle. At sunset and sunrise the
circle is smallest and the segment largest: as the sun rises higher the circle is larger and the segment smaller.
After the autumn equinox in the shorter days it is seen at every hour of the day, in the summer not about
midday. There are never more than two rainbows at one time. Each of them is three-coloured; the colours are
the same in both and their number is the same, but in the outer rainbow they are fainter and their position is
reversed. In the inner rainbow the first and largest band is red; in the outer rainbow the band that is nearest to
this one and smallest is of the same colour: the other bands correspond on the same principle. These are
almost the only colours which painters cannot manufacture: for there are colours which they create by
mixing, but no mixing will give red, green, or purple. These are the colours of the rainbow, though between
the red and the green an orange colour is often seen.

Mock suns and rods are always seen by the side of the sun, not above or below it nor in the opposite quarter
of the sky. They are not seen at night but always in the neighbourhood of the sun, either as it is rising or
setting but more commonly towards sunset. They have scarcely ever appeared when the sun was on the
meridian, though this once happened in Bosporus where two mock suns rose with the sun and followed it all
through the day till sunset.

These are the facts about each of these phenomena: the cause of them all is the same, for they are all
reflections. But they are different varieties, and are distinguished by the surface from which and the way in
which the reflection to the sun or some other bright object takes place.

The rainbow is seen by day, and it was formerly thought that it never appeared by night as a moon rainbow.
This opinion was due to the rarity of the occurrence: it was not observed, for though it does happen it does so
rarely. The reason is that the colours are not so easy to see in the dark and that many other conditions must
coincide, and all that in a single day in the month. For if there is to be one it must be at full moon, and then as
the moon is either rising or setting. So we have only met with two instances of a moon rainbow in more than
fifty years.

We must accept from the theory of optics the fact that sight is reflected from air and any object with a smooth
surface just as it is from water; also that in some mirrors the forms of things are reflected, in others only their
colours. Of the latter kind are those mirrors which are so small as to be indivisible for sense. It is impossible
that the figure of a thing should be reflected in them, for if it is the mirror will be sensibly divisible since
divisibility is involved in the notion of figure. But since something must be reflected in them and figure

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cannot be, it remains that colour alone should be reflected. The colour of a bright object sometimes appears
bright in the reflection, but it sometimes, either owing to the admixture of the colour of the mirror or to
weakness of sight, gives rise to the appearance of another colour.

However, we must accept the account we have given of these things in the theory of sensation, and take some
things for granted while we explain others.

Let us begin by explaining the shape of the halo; why it is a circle and why it appears round the sun or the
moon or one of the other stars: the explanation being in all these cases the same.

Sight is reflected in this way when air and vapour are condensed into a cloud and the condensed matter is
uniform and consists of small parts. Hence in itself it is a sign of rain, but if it fades away, of fine weather, if
it is broken up, of wind. For if it does not fade away and is not broken up but is allowed to attain its normal
state, it is naturally a sign of rain since it shows that a process of condensation is proceeding which must,
when it is carried to an end, result in rain. For the same reason these haloes are the darkest. It is a sign of
wind when it is broken up because its breaking up is due to a wind which exists there but has not reached us.
This view finds support in the fact that the wind blows from the quarter in which the main division appears in
the halo. Its fading away is a sign of fine weather because if the air is not yet in a state to get the better of the
heat it contains and proceed to condense into water, this shows that the moist vapour has not yet separated
from the dry and firelike exhalation: and this is the cause of fine weather.

So much for the atmospheric conditions under which the reflection takes place. The reflection is from the
mist that forms round the sun or the moon, and that is why the halo is not seen opposite the sun like the
rainbow.

Since the reflection takes place in the same way from every point the result is necessarily a circle or a
segment of a circle: for if the lines start from the same point and end at the same point and are equal, the
points where they form an angle will always lie on a circle.

Let AGB and AZB and ADB be lines each of which goes from the point A to the point B and forms an angle.
Let the lines AG, AZ, AD be equal and those at B, GB, ZB, DB equal too. (See diagram.)

Draw the line AEB. Then the triangles are equal; for their base AEB is equal. Draw perpendiculars to AEB
from the angles; GE from G, ZE from Z, DE from D. Then these perpendiculars are equal, being in equal
triangles. And they are all in one plane, being all at right angles to AEB and meeting at a single point E. So if
you draw the line it will be a circle and E its centre. Now B is the sun, A the eye, and the circumference
passing through the points GZD the cloud from which the line of sight is reflected to the sun.

The mirrors must be thought of as contiguous: each of them is too small to be visible, but their contiguity
makes the whole made up of them all to seem one. The bright band is the sun, which is seen as a circle,
appearing successively in each of the mirrors as a point indivisible to sense. The band of cloud next to it is
black, its colour being intensified by contrast with the brightness of the halo. The halo is formed rather near
the earth because that is calmer: for where there is wind it is clear that no halo can maintain its position.

Haloes are commoner round the moon because the greater heat of the sun dissolves the condensations of the
air more rapidly.

Haloes are formed round stars for the same reasons, but they are not prognostic in the same way because the
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condensation they imply is so insignificant as to be barren.

We have already stated that the rainbow is a reflection: we have now to explain what sort of reflection it is, to
describe its various concomitants, and to assign their causes.

Sight is reflected from all smooth surfaces, such as are air and water among others. Air must be condensed if
it is to act as a mirror, though it often gives a reflection even uncondensed when the sight is weak. Such was
the case of a man whose sight was faint and indistinct. He always saw an image in front of him and facing
him as he walked. This was because his sight was reflected back to him. Its morbid condition made it so weak
and delicate that the air close by acted as a mirror, just as distant and condensed air normally does, and his
sight could not push it back. So promontories in the sea 'loom' when there is a south-east wind, and
everything seems bigger, and in a mist, too, things seem bigger: so, too, the sun and the stars seem bigger
when rising and setting than on the meridian. But things are best reflected from water, and even in process of
formation it is a better mirror than air, for each of the particles, the union of which constitutes a raindrop, is
necessarily a better mirror than mist. Now it is obvious and has already been stated that a mirror of this kind
renders the colour of an object only, but not its shape. Hence it follows that when it is on the point of raining
and the air in the clouds is in process of forming into raindrops but the rain is not yet actually there, if the sun
is opposite, or any other object bright enough to make the cloud a mirror and cause the sight to be reflected to
the object then the reflection must render the colour of the object without its shape. Since each of the mirrors
is so small as to be invisible and what we see is the continuous magnitude made up of them all, the reflection
necessarily gives us a continuous magnitude made up of one colour; each of the mirrors contributing the same
colour to the whole. We may deduce that since these conditions are realizable there will be an appearance due
to reflection whenever the sun and the cloud are related in the way described and we are between them. But
these are just the conditions under which the rainbow appears. So it is clear that the rainbow is a reflection of
sight to the sun.

So the rainbow always appears opposite the sun whereas the halo is round it. They are both reflections, but
the rainbow is distinguished by the variety of its colours. The reflection in the one case is from water which is
dark and from a distance; in the other from air which is nearer and lighter in colour. White light through a
dark medium or on a dark surface (it makes no difference) looks red. We know how red the flame of green
wood is: this is because so much smoke is mixed with the bright white firelight: so, too, the sun appears red
through smoke and mist. That is why in the rainbow reflection the outer circumference is red (the reflection
being from small particles of water), but not in the case of the halo. The other colours shall be explained later.
Again, a condensation of this kind cannot persist in the neighbourhood of the sun: it must either turn to rain
or be dissolved, but opposite to the sun there is an interval during which the water is formed. If there were not
this distinction haloes would be coloured like the rainbow. Actually no complete or circular halo presents this
colour, only small and fragmentary appearances called 'rods'. But if a haze due to water or any other dark
substance formed there we should have had, as we maintain, a complete rainbow like that which we do find
lamps. A rainbow appears round these in winter, generally with southerly winds. Persons whose eyes are
moist see it most clearly because their sight is weak and easily reflected. It is due to the moistness of the air
and the soot which the flame gives off and which mixes with the air and makes it a mirror, and to the
blackness which that mirror derives from the smoky nature of the soot. The light of the lamp appears as a
circle which is not white but purple. It shows the colours of the rainbow; but because the sight that is
reflected is too weak and the mirror too dark, red is absent. The rainbow that is seen when oars are raised out
of the sea involves the same relative positions as that in the sky, but its colour is more like that round the
lamps, being purple rather than red. The reflection is from very small particles continuous with one another,
and in this case the particles are fully formed water. We get a rainbow, too, if a man sprinkles fine drops in a
room turned to the sun so that the sun is shining in part of the room and throwing a shadow in the rest. Then

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if one man sprinkles in the room, another, standing outside, sees a rainbow where the sun's rays cease and
make the shadow. Its nature and colour is like that from the oars and its cause is the same, for the sprinkling
hand corresponds to the oar.

That the colours of the rainbow are those we described and how the other colours come to appear in it will be
clear from the following considerations. We must recognize, as we have said, and lay down: first, that white
colour on a black surface or seen through a black medium gives red; second, that sight when strained to a
distance becomes weaker and less; third, that black is in a sort the negation of sight: an object is black
because sight fails; so everything at a distance looks blacker, because sight does not reach it. The theory of
these matters belongs to the account of the senses, which are the proper subjects of such an inquiry; we need
only state about them what is necessary for us. At all events, that is the reason why distant objects and objects
seen in a mirror look darker and smaller and smoother, why the reflection of clouds in water is darker than
the clouds themselves. This latter is clearly the case: the reflection diminishes the sight that reaches them. It
makes no difference whether the change is in the object seen or. in the sight, the result being in either case the
same. The following fact further is worth noticing. When there is a cloud near the sun and we look at it does
not look coloured at all but white, but when we look at the same cloud in water it shows a trace of rainbow
colouring. Clearly, then, when sight is reflected it is weakened and, as it makes dark look darker, so it makes
white look less white, changing it and bringing it nearer to black. When the sight is relatively strong the
change is to red; the next stage is green, and a further degree of weakness gives violet. No further change is
visible, but three completes the series of colours (as we find three does in most other things), and the change
into the rest is imperceptible to sense. Hence also the rainbow appears with three colours; this is true of each
of the two, but in a contrary way. The outer band of the primary rainbow is red: for the largest band reflects
most sight to the sun, and the outer band is largest. The middle band and the third go on the same principle.
So if the principles we laid down about the appearance of colours are true the rainbow necessarily has three
colours, and these three and no others. The appearance of yellow is due to contrast, for the red is whitened by
its juxtaposition with green. We can see this from the fact that the rainbow is purest when the cloud is
blackest; and then the red shows most yellow. (Yellow in the rainbow comes between red and green.) So the
whole of the red shows white by contrast with the blackness of the cloud around: for it is white compared to
the cloud and the green. Again, when the rainbow is fading away and the red is dissolving, the white cloud is
brought into contact with the green and becomes yellow. But the moon rainbow affords the best instance of
this colour contrast. It looks quite white: this is because it appears on the dark cloud and at night. So, just as
fire is intensified by added fire, black beside black makes that which is in some degree white look quite
white. Bright dyes too show the effect of contrast. In woven and embroidered stuffs the appearance of colours
is profoundly affected by their juxtaposition with one another (purple, for instance, appears different on white
and on black wool), and also by differences of illumination. Thus embroiderers say that they often make
mistakes in their colours when they work by lamplight, and use the wrong ones.

We have now shown why the rainbow has three colours and that these are its only colours. The same cause
explains the double rainbow and the faintness of the colours in the outer one and their inverted order. When
sight is strained to a great distance the appearance of the distant object is affected in a certain way: and the
same thing holds good here. So the reflection from the outer rainbow is weaker because it takes place from a
greater distance and less of it reaches the sun, and so the colours seen are fainter. Their order is reversed
because more reflection reaches the sun from the smaller, inner band. For that reflection is nearer to our sight
which is reflected from the band which is nearest to the primary rainbow. Now the smallest band in the outer
rainbow is that which is nearest, and so it will be red; and the second and the third will follow the same
principle. Let B be the outer rainbow, A the inner one; let R stand for the red colour, G for green, V for
violet; yellow appears at the point Y. Three rainbows or more are not found because even the second is
fainter, so that the third reflection can have no strength whatever and cannot reach the sun at all. (See
diagram.)

METEOROLOGY

The rainbow can never be a circle nor a segment of a circle greater than a semicircle. The consideration of the
diagram will prove this and the other properties of the rainbow. (See diagram.)

Let A be a hemisphere resting on the circle of the horizon, let its centre be K and let H be another point
appearing on the horizon. Then, if the lines that fall in a cone from K have HK as their axis, and, K and M
being joined, the lines KM are reflected from the hemisphere to H over the greater angle, the lines from K
will fall on the circumference of a circle. If the reflection takes place when the luminous body is rising or
setting the segment of the circle above the earth which is cut off by the horizon will be a semi-circle; if the
luminous body is above the horizon it will always be less than a semicircle, and it will be smallest when the
luminous body culminates. First let the luminous body be appearing on the horizon at the point H, and let
KM be reflected to H, and let the plane in which A is, determined by the triangle HKM, be produced. Then
the section of the sphere will be a great circle. Let it be A (for it makes no difference which of the planes
passing through the line HK and determined by the triangle KMH is produced). Now the lines drawn from H
and K to a point on the semicircle A are in a certain ratio to one another, and no lines drawn from the same
points to another point on that semicircle can have the same ratio. For since both the points H and K and the
line KH are given, the line MH will be given too; consequently the ratio of the line MH to the line MK will
be given too. So M will touch a given circumference. Let this be NM. Then the intersection of the
circumferences is given, and the same ratio cannot hold between lines in the same plane drawn from the same
points to any other circumference but MN.

Draw a line DB outside of the figure and divide it so that D:B=MH:MK. But MH is greater than MK since
the reflection of the cone is over the greater angle (for it subtends the greater angle of the triangle KMH).
Therefore D is greater than B. Then add to B a line Z such that B+Z:D=D:B. Then make another line having
the same ratio to B as KH has to Z, and join MI.

Then I is the pole of the circle on which the lines from K fall. For the ratio of D to IM is the same as that of Z
to KH and of B to KI. If not, let D be in the same ratio to a line indifferently lesser or greater than IM, and let
this line be IP. Then HK and KI and IP will have the same ratios to one another as Z, B, and D. But the ratios
between Z, B, and D were such that Z+B:D=D: B. Therefore IH:IP=IP:IK. Now, if the points K, H be joined
with the point P by the lines HP, KP, these lines will be to one another as IH is to IP, for the sides of the
triangles HIP, KPI about the angle I are homologous. Therefore, HP too will be to KP as HI is to IP. But this
is also the ratio of MH to MK, for the ratio both of HI to IP and of MH to MK is the same as that of D to B.
Therefore, from the points H, K there will have been drawn lines with the same ratio to one another, not only
to the circumference MN but to another point as well, which is impossible. Since then D cannot bear that
ratio to any line either lesser or greater than IM (the proof being in either case the same), it follows that it
must stand in that ratio to MI itself. Therefore as MI is to IK so IH will be to MI and finally MH to MK.

If, then, a circle be described with I as pole at the distance MI it will touch all the angles which the lines from
H and K make by their reflection. If not, it can be shown, as before, that lines drawn to different points in the
semicircle will have the same ratio to one another, which was impossible. If, then, the semicircle A be
revolved about the diameter HKI, the lines reflected from the points H, K at the point M will have the same
ratio, and will make the angle KMH equal, in every plane. Further, the angle which HM and MI make with
HI will always be the same. So there are a number of triangles on HI and KI equal to the triangles HMI and
KMI. Their perpendiculars will fall on HI at the same point and will be equal. Let O be the point on which
they fall. Then O is the centre of the circle, half of which, MN, is cut off by the horizon. (See diagram.)

Next let the horizon be ABG but let H have risen above the horizon. Let the axis now be HI. The proof will
be the same for the rest as before, but the pole I of the circle will be below the horizon AG since the point H

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has risen above the horizon. But the pole, and the centre of the circle, and the centre of that circle (namely
HI) which now determines the position of the sun are on the same line. But since KH lies above the diameter
AG, the centre will be at O on the line KI below the plane of the circle AG determined the position of the sun
before. So the segment YX which is above the horizon will be less than a semicircle. For YXM was a
semicircle and it has now been cut off by the horizon AG. So part of it, YM, will be invisible when the sun
has risen above the horizon, and the segment visible will be smallest when the sun is on the meridian; for the
higher H is the lower the pole and the centre of the circle will be.

In the shorter days after the autumn equinox there may be a rainbow at any time of the day, but in the longer
days from the spring to the autumn equinox there cannot be a rainbow about midday. The reason for this is
that when the sun is north of the equator the visible arcs of its course are all greater than a semicircle, and go
on increasing, while the invisible arc is small, but when the sun is south of the equator the visible arc is small
and the invisible arc great, and the farther the sun moves south of the equator the greater is the invisible arc.
Consequently, in the days near the summer solstice, the size of the visible arc is such that before the point H
reaches the middle of that arc, that is its point of culmination, the point is well below the horizon; the reason
for this being the great size of the visible arc, and the consequent distance of the point of culmination from
the earth. But in the days near the winter solstice the visible arcs are small, and the contrary is necessarily the
case: for the sun is on the meridian before the point H has risen far.

Mock suns, and rods too, are due to the causes we have described. A mock sun is caused by the reflection of
sight to the sun. Rods are seen when sight reaches the sun under circumstances like those which we
described, when there are clouds near the sun and sight is reflected from some liquid surface to the cloud.
Here the clouds themselves are colourless when you look at them directly, but in the water they are full of
rods. The only difference is that in this latter case the colour of the cloud seems to reside in the water, but in
the case of rods on the cloud itself. Rods appear when the composition of the cloud is uneven, dense in part
and in part rare, and more and less watery in different parts. Then the sight is reflected to the sun: the mirrors
are too small for the shape of the sun to appear, but, the bright white light of the sun, to which the sight is
reflected, being seen on the uneven mirror, its colour appears partly red, partly green or yellow. It makes no
difference whether sight passes through or is reflected from a medium of that kind; the colour is the same in
both cases; if it is red in the first case it must be the same in the other.

Rods then are occasioned by the unevenness of the mirror-as regards colour, not form. The mock sun, on the
contrary, appears when the air is very uniform, and of the same density throughout. This is why it is white:
the uniform character of the mirror gives the reflection in it a single colour, while the fact that the sight is
reflected in a body and is thrown on the sun all together by the mist, which is dense and watery though not
yet quite water, causes the sun's true colour to appear just as it does when the reflection is from the dense,
smooth surface of copper. So the sun's colour being white, the mock sun is white too. This, too, is the reason
why the mock sun is a surer sign of rain than the rods; it indicates, more than they do, that the air is ripe for
the production of water. Further a mock sun to the south is a surer sign of rain than one to the north, for the
air in the south is readier to turn into water than that in the north.

Mock suns and rods are found, as we stated, about sunset and sunrise, not above the sun nor below it, but
beside it. They are not found very close to the sun, nor very far from it, for the sun dissolves the cloud if it is
near, but if it is far off the reflection cannot take place, since sight weakens when it is reflected from a small
mirror to a very distant object. (This is why a halo is never found opposite to the sun.) If the cloud is above
the sun and close to it the sun will dissolve it; if it is above the sun but at a distance the sight is too weak for
the reflection to take place, and so it will not reach the sun. But at the side of the sun, it is possible for the
mirror to be at such an interval that the sun does not dissolve the cloud, and yet sight reaches it undiminished

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because it moves close to the earth and is not dissipated in the immensity of space. It cannot subsist below the
sun because close to the earth the sun's rays would dissolve it, but if it were high up and the sun in the middle
of the heavens, sight would be dissipated. Indeed, even by the side of the sun, it is not found when the sun is
in the middle of the sky, for then the line of vision is not close to the earth, and so but little sight reaches the
mirror and the reflection from it is altogether feeble.

Some account has now been given of the effects of the secretion above the surface of the earth; we must go
on to describe its operations below, when it is shut up in the parts of the earth.

Just as its twofold nature gives rise to various effects in the upper region, so here it causes two varieties of
bodies. We maintain that there are two exhalations, one vaporous the other smoky, and there correspond two
kinds of bodies that originate in the earth, 'fossiles' and metals. The heat of the dry exhalation is the cause of
all 'fossiles'. Such are the kinds of stones that cannot be melted, and realgar, and ochre, and ruddle, and
sulphur, and the other things of that kind, most 'fossiles' being either coloured lye or, like cinnabar, a stone
compounded of it. The vaporous exhalation is the cause of all metals, those bodies which are either fusible or
malleable such as iron, copper, gold. All these originate from the imprisonment of the vaporous exhalation in
the earth, and especially in stones. Their dryness compresses it, and it congeals just as dew or hoar-frost does
when it has been separated off, though in the present case the metals are generated before that segregation
occurs. Hence, they are water in a sense, and in a sense not. Their matter was that which might have become
water, but it can no longer do so: nor are they, like savours, due to a qualitative change in actual water.
Copper and gold are not formed like that, but in every case the evaporation congealed before water was
formed. Hence, they all (except gold) are affected by fire, and they possess an admixture of earth; for they
still contain the dry exhalation.

This is the general theory of all these bodies, but we must take up each kind of them and discuss it separately.

Book IV

WE have explained that the qualities that constitute the elements are four, and that their combinations
determine the number of the elements to be four.

Two of the qualities, the hot and the cold, are active; two, the dry and the moist, passive. We can satisfy
ourselves of this by looking at instances. In every case heat and cold determine, conjoin, and change things of
the same kind and things of different kinds, moistening, drying, hardening, and softening them. Things dry
and moist, on the other hand, both in isolation and when present together in the same body are the subjects of
that determination and of the other affections enumerated. The account we give of the qualities when we
define their character shows this too. Hot and cold we describe as active, for 'congregating' is essentially a
species of 'being active': moist and dry are passive, for it is in virtue of its being acted upon in a certain way
that a thing is said to be 'easy to determine' or 'difficult to determine'. So it is clear that some of the qualities
are active and some passive.

Next we must describe the operations of the active qualities and the forms taken by the passive. First of all,
true becoming, that is, natural change, is always the work of these powers and so is the corresponding natural
destruction; and this becoming and this destruction are found in plants and animals and their parts. True
natural becoming is a change introduced by these powers into the matter underlying a given thing when they
are in a certain ratio to that matter, which is the passive qualities we have mentioned. When the hot and the
cold are masters of the matter they generate a thing: if they are not, and the failure is partial, the object is
imperfectly boiled or otherwise unconcocted. But the strictest general opposite of true becoming is

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putrefaction. All natural destruction is on the way to it, as are, for instance, growing old or growing dry.
Putrescence is the end of all these things, that is of all natural objects, except such as are destroyed by
violence: you can burn, for instance, flesh, bone, or anything else, but the natural course of their destruction
ends in putrefaction. Hence things that putrefy begin by being moist and end by being dry. For the moist and
the dry were their matter, and the operation of the active qualities caused the dry to be determined by the
moist.

Destruction supervenes when the determined gets the better of the determining by the help of the
environment (though in a special sense the word putrefaction is applied to partial destruction, when a thing's
nature is perverted). Hence everything, except fire, is liable to putrefy; for earth, water, and air putrefy, being
all of them matter relatively to fire. The definition of putrefaction is: the destruction of the peculiar and
natural heat in any moist subject by external heat, that is, by the heat of the environment. So since lack of
heat is the ground of this affection and everything in as far as it lacks heat is cold, both heat and cold will be
the causes of putrefaction, which will be due indifferently to cold in the putrefying subject or to heat in the
environment.

This explains why everything that putrefies grows drier and ends by becoming earth or dung. The subject's
own heat departs and causes the natural moisture to evaporate with it, and then there is nothing left to draw in
moisture, for it is a thing's peculiar heat that attracts moisture and draws it in. Again, putrefaction takes place
less in cold that in hot seasons, for in winter the surrounding air and water contain but little heat and it has no
power, but in summer there is more. Again, what is frozen does not putrefy, for its cold is greater that the heat
of the air and so is not mastered, whereas what affects a thing does master it. Nor does that which is boiling
or hot putrefy, for the heat in the air being less than that in the object does not prevail over it or set up any
change. So too anything that is flowing or in motion is less apt to putrefy than a thing at rest, for the motion
set up by the heat in the air is weaker than that pre-existing in the object, and so it causes no change. For the
same reason a great quantity of a thing putrefies less readily than a little, for the greater quantity contains too
much proper fire and cold for the corresponding qualities in the environment to get the better of. Hence, the
sea putrefies quickly when broken up into parts, but not as a whole; and all other waters likewise. Animals
too are generated in putrefying bodies, because the heat that has been secreted, being natural, organizes the
particles secreted with it.

So much for the nature of becoming and of destruction.

We must now describe the next kinds of processes which the qualities already mentioned set up in actually
existing natural objects as matter.

Of these concoction is due to heat; its species are ripening, boiling, broiling. Inconcoction is due to cold and
its species are rawness, imperfect boiling, imperfect broiling. (We must recognize that the things are not
properly denoted by these words: the various classes of similar objects have no names universally applicable
to them; consequently we must think of the species enumerated as being not what those words denote but
something like it.) Let us say what each of them is. Concoction is a process in which the natural and proper
heat of an object perfects the corresponding passive qualities, which are the proper matter of any given
object. For when concoction has taken place we say that a thing has been perfected and has come to be itself.
It is the proper heat of a thing that sets up this perfecting, though external influences may contribute in some
degrees to its fulfilment. Baths, for instance, and other things of the kind contribute to the digestion of food,
but the primary cause is the proper heat of the body. In some cases of concoction the end of the process is the
nature of the thing-nature, that is, in the sense of the formal cause and essence. In other cases it leads to some
presupposed state which is attained when the moisture has acquired certain properties or a certain magnitude

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in the process of being broiled or boiled or of putrefying, or however else it is being heated. This state is the
end, for when it has been reached the thing has some use and we say that concoction has taken place. Must is
an instance of this, and the matter in boils when it becomes purulent, and tears when they become rheum, and
so with the rest.

Concoction ensues whenever the matter, the moisture, is mastered. For the matter is what is determined by
the heat connatural to the object, and as long as the ratio between them exists in it a thing maintains its
nature. Hence things like the liquid and solid excreta and ejecta in general are signs of health, and concoction
is said to have taken place in them, for they show that the proper heat has got the better of the indeterminate
matter.

Things that undergo a process of concoction necessarily become thicker and hotter, for the action of heat is to
make things more compact, thicker, and drier.

This then is the nature of concoction: but inconcoction is an imperfect state due to lack of proper heat, that is,
to cold. That of which the imperfect state is, is the corresponding passive qualities which are the natural
matter of anything.

So much for the definition of concoction and inconcoction.

Ripening is a sort of concoction; for we call it ripening when there is a concoction of the nutriment in fruit.
And since concoction is a sort of perfecting, the process of ripening is perfect when the seeds in fruit are able
to reproduce the fruit in which they are found; for in all other cases as well this is what we mean by 'perfect'.
This is what 'ripening' means when the word is applied to fruit. However, many other things that have
undergone concoction are said to be 'ripe', the general character of the process being the same, though the
word is applied by an extension of meaning. The reason for this extension is, as we explained before, that the
various modes in which natural heat and cold perfect the matter they determine have not special names
appropriated to them. In the case of boils and phlegm, and the like, the process of ripening is the concoction
of the moisture in them by their natural heat, for only that which gets the better of matter can determine it. So
everything that ripens is condensed from a spirituous into a watery state, and from a watery into an earthy
state, and in general from being rare becomes dense. In this process the nature of the thing that is ripening
incorporates some of the matter in itself, and some it rejects. So much for the definition of ripening.

Rawness is its opposite and is therefore an imperfect concoction of the nutriment in the fruit, namely, of the
undetermined moisture. Consequently a raw thing is either spirituous or watery or contains both spirit and
water. Ripening being a kind of perfecting, rawness will be an imperfect state, and this state is due to a lack
of natural heat and its disproportion to the moisture that is undergoing the process of ripening. (Nothing moist
ripens without the admixture of some dry matter: water alone of liquids does not thicken.) This disproportion
may be due either to defect of heat or to excess of the matter to be determined: hence the juice of raw things
is thin, cold rather than hot, and unfit for food or drink. Rawness, like ripening, is used to denote a variety of
states. Thus the liquid and solid excreta and catarrhs are called raw for the same reason, for in every case the
word is applied to things because their heat has not got the mastery in them and compacted them. If we go
further, brick is called raw and so is milk and many other things too when they are such as to admit of being
changed and compacted by heat but have remained unaffected. Hence, while we speak of 'boiled' water, we
cannot speak of raw water, since it does not thicken. We have now defined ripening and rawness and
assigned their causes.

Boiling is, in general, a concoction by moist heat of the indeterminate matter contained in the moisture of the
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thing boiled, and the word is strictly applicable only to things boiled in the way of cooking. The
indeterminate matter, as we said, will be either spirituous or watery. The cause of the concoction is the fire
contained in the moisture; for what is cooked in a frying-pan is broiled: it is the heat outside that affects it
and, as for the moisture in which it is contained, it dries this up and draws it into itself. But a thing that is
being boiled behaves in the opposite way: the moisture contained in it is drawn out of it by the heat in the
liquid outside. Hence boiled meats are drier than broiled; for, in boiling, things do not draw the moisture into
themselves, since the external heat gets the better of the internal: if the internal heat had got the better it
would have drawn the moisture to itself. Not every body admits of the process of boiling: if there is no
moisture in it, it does not (for instance, stones), nor does it if there is moisture in it but the density of the body
is too great for it-to-be mastered, as in the case of wood. But only those bodies can be boiled that contain
moisture which can be acted on by the heat contained in the liquid outside. It is true that gold and wood and
many other things are said to be 'boiled': but this is a stretch of the meaning of the word, though the kind of
thing intended is the same, the reason for the usage being that the various cases have no names appropriated
to them. Liquids too, like milk and must, are said to undergo a process of 'boiling' when the external fire that
surrounds and heats them changes the savour in the liquid into a given form, the process being thus in a way
like what we have called boiling.

The end of the things that undergo boiling, or indeed any form of concoction, is not always the same: some
are meant to be eaten, some drunk, and some are intended for other uses; for instance dyes, too, are said to be
'boiled'.

All those things then admit of 'boiling' which can grow denser, smaller, or heavier; also those which do that
with a part of themselves and with a part do the opposite, dividing in such a way that one portion thickens
while the other grows thinner, like milk when it divides into whey and curd. Oil by itself is affected in none
of these ways, and therefore cannot be said to admit of 'boiling'. Such then is the pfcies of concoction known
as 'boiling', and the process is the same in an artificial and in a natural instrument, for the cause will be the
same in every case.

Imperfect boiling is the form of inconcoction opposed to boiling. Now the opposite of boiling properly so
called is an inconcoction of the undetermined matter in a body due to lack of heat in the surrounding liquid.
(Lack of heat implies, as we have pointed out, the presence of cold.) The motion which causes imperfect
boiling is different from that which causes boiling, for the heat which operates the concoction is driven out.
The lack of heat is due either to the amount of cold in the liquid or to the quantity of moisture in the object
undergoing the process of boiling. Where either of these conditions is realized the heat in the surrounding
liquid is too great to have no effect at all, but too small to carry out the process of concocting uniformly and
thoroughly. Hence things are harder when they are imperfectly boiled than when they are boiled, and the
moisture in them more distinct from the solid parts. So much for the definition and causes of boiling and
imperfect boiling.

Broiling is concoction by dry foreign heat. Hence if a man were to boil a thing but the change and concoction
in it were due, not to the heat of the liquid but to that of the fire, the thing will have been broiled and not
boiled when the process has been carried to completion: if the process has gone too far we use the word
'scorched' to describe it. If the process leaves the thing drier at the end the agent has been dry heat. Hence the
outside is drier than the inside, the opposite being true of things boiled. Where the process is artificial,
broiling is more difficult than boiling, for it is difficult to heat the inside and the outside uniformly, since the
parts nearer to the fire are the first to get dry and consequently get more intensely dry. In this way the outer
pores contract and the moisture in the thing cannot be secreted but is shut in by the closing of the pores. Now
broiling and boiling are artificial processes, but the same general kind of thing, as we said, is found in nature
too. The affections produced are similar though they lack a name; for art imitates nature. For instance, the
concoction of food in the body is like boiling, for it takes place in a hot and moist medium and the agent is
the heat of the body. So, too, certain forms of indigestion are like imperfect boiling. And it is not true that

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animals are generated in the concoction of food, as some say. Really they are generated in the excretion
which putrefies in the lower belly, and they ascend afterwards. For concoction goes on in the upper belly but
the excretion putrefies in the lower: the reason for this has been explained elsewhere.

We have seen that the opposite of boiling is imperfect boiling: now there is something correspondingly
opposed to the species of concoction called broiling, but it is more difficult to find a name for it. It would be
the kind of thing that would happen if there were imperfect broiling instead of broiling proper through lack of
heat due to deficiency in the external fire or to the quantity of water in the thing undergoing the process. For
then we should get too much heat for no effect to be produced, but too little for concoction to take place.

We have now explained concoction and inconcoction, ripening and rawness, boiling and broiling, and their
opposites.

We must now describe the forms taken by the passive qualities the moist and the dry. The elements of bodies,
that is, the passive ones, are the moist and the dry; the bodies themselves are compounded of them and
whichever predominates determines the nature of the body; thus some bodies partake more of the dry, others
of the moist. All the forms to be described will exist either actually, or potentially and in their opposite: for
instance, there is actual melting and on the other hand that which admits of being melted.

Since the moist is easily determined and the dry determined with difficulty, their relation to one another is
like that of a dish and its condiments. The moist is what makes the dry determinable, and each serves as a sort
of glue to the other-as Empedocles said in his poem on Nature, 'glueing meal together by means of water.'
Thus the determined body involves them both. Of the elements earth is especially representative of the dry,
water of the moist, and therefore all determinate bodies in our world involve earth and water. Every body
shows the quality of that element which predominates in it. It is because earth and water are the material
elements of all bodies that animals live in them alone and not in air or fire.

Of the qualities of bodies hardness and softness are those which must primarily belong to a determined thing,
for anything made up of the dry and the moist is necessarily either hard or soft. Hard is that the surface of
which does not yield into itself; soft that which does yield but not by interchange of place: water, for instance,
is not soft, for its surface does not yield to pressure or sink in but there is an interchange of place. Those
things are absolutely hard and soft which satisfy the definition absolutely, and those things relatively so
which do so compared with another thing. Now relatively to one another hard and soft are indefinable,
because it is a matter of degree, but since all the objects of sense are determined by reference to the faculty of
sense it is clearly the relation to touch which determines that which is hard and soft absolutely, and touch is
that which we use as a standard or mean. So we call that which exceeds it hard and that which falls short of it
soft.

A body determined by its own boundary must be either hard or soft; for it either yields or does not.

It must also be concrete: or it could not be so determined. So since everything that is determined and solid is
either hard or soft and these qualities are due to concretion, all composite and determined bodies must
involve concretion. Concretion therefore must be discussed.

Now there are two causes besides matter, the agent and the quality brought about, the agent being the
efficient cause, the quality the formal cause. Hence concretion and disaggregation, drying and moistening,

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must have these two causes.

But since concretion is a form of drying let us speak of the latter first.

As we have explained, the agent operates by means of two qualities and the patient is acted on in virtue of
two qualities: action takes place by means of heat or cold, and the quality is produced either by the presence
or by the absence of heat or cold; but that which is acted upon is moist or dry or a compound of both. Water
is the element characterized by the moist, earth that characterized by the dry, for these among the elements
that admit the qualities moist and dry are passive. Therefore cold, too, being found in water and earth (both of
which we recognize to be cold), must be reckoned rather as a passive quality. It is active only as contributing
to destruction or incidentally in the manner described before; for cold is sometimes actually said to burn and
to warm, but not in the same way as heat does, but by collecting and concentrating heat.

The subjects of drying are water and the various watery fluids and those bodies which contain water either
foreign or connatural. By foreign I mean like the water in wool, by connatural, like that in milk. The watery
fluids are wine, urine, whey, and in general those fluids which have no sediment or only a little, except where
this absence of sediment is due to viscosity. For in some cases, in oil and pitch for instance, it is the viscosity
which prevents any sediment from appearing.

It is always a process of heating or cooling that dries things, but the agent in both cases is heat, either internal
or external. For even when things are dried by cooling, like a garment, where the moisture exists separately it
is the internal heat that dries them. It carries off the moisture in the shape of vapour (if there is not too much
of it), being itself driven out by the surrounding cold. So everything is dried, as we have said, by a process
either of heating or cooling, but the agent is always heat, either internal or external, carrying off the moisture
in vapour. By external heat I mean as where things are boiled: by internal where the heat breathes out and
takes away and uses up its moisture. So much for drying.

Liquefaction is, first, condensation into water; second, the melting of a solidified body. The first,
condensation, is due to the cooling of vapour: what melting is will appear from the account of solidification.

Whatever solidifies is either water or a mixture of earth and water, and the agent is either dry heat or cold.
Hence those of the bodies solidified by heat or cold which are soluble at all are dissolved by their opposites.
Bodies solidified by the dry-hot are dissolved by water, which is the moist-cold, while bodies solidified by
cold are dissolved by fire, which is hot. Some things seem to be solidified by water, e.g. boiled honey, but
really it is not the water but the cold in the water which effects the solidification. Aqueous bodies are not
solidified by fire: for it is fire that dissolves them, and the same cause in the same relation cannot have
opposite effects upon the same thing. Again, water solidifies owing to the departure of heat; so it will clearly
be dissolved by the entry into it of heat: cold, therefore, must be the agent in solidifying it.

Hence aqueous bodies do not thicken when they solidify; for thickening occurs when the moisture goes off
and the dry matter comes together, but water is the only liquid that does not thicken. Those bodies that are
made up of both earth and water are solidified both by fire and by cold and in either case are thickened. The
operation of the two is in a way the same and in a way different. Heat acts by drawing off the moisture, and
as the moisture goes off in vapour the dry matter thickens and collects. Cold acts by driving out the heat,
which is accompanied by the moisture as this goes off in vapour with it. Bodies that are soft but not liquid do
not thicken but solidify when the moisture leaves them, e.g. potter's clay in process of baking: but those
mixed bodies that are liquid thicken besides solidifying, like milk. Those bodies which have first been
thickened or hardened by cold often begin by becoming moist: thus potter's clay at first in the process of

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baking steams and grows softer, and is liable to distortion in the ovens for that reason.

Now of the bodies solidified by cold which are made up both of earth and water but in which the earth
preponderates, those which solidify by the departure of heat melt by heat when it enters into them again; this
is the case with frozen mud. But those which solidify by refrigeration, where all the moisture has gone off in
vapour with the heat, like iron and horn, cannot be dissolved except by excessive heat, but they can be
softened-though manufactured iron does melt, to the point of becoming fluid and then solidifying again. This
is how steel is made. The dross sinks to the bottom and is purged away: when this has been done often and
the metal is pure we have steel. The process is not repeated often because the purification of the metal
involves great waste and loss of weight. But the iron that has less dross is the better iron. The stone
pyrimachus, too, melts and forms into drops and becomes fluid; after having been in a fluid state it solidifies
and becomes hard again. Millstones, too, melt and become fluid: when the fluid mass begins to solidify it is
black but its consistency comes to be like that of lime, and earth, too

Of the bodies which are solidified by dry heat some are insoluble, others are dissolved by liquid. Pottery and
some kinds of stone that are formed out of earth burnt up by fire, such as millstones, cannot be dissolved.
Natron and salt are soluble by liquid, but not all liquid but only such as is cold. Hence water and any of its
varieties melt them, but oil does not. For the opposite of the dry-hot is the cold-moist and what the one
solidified the other will dissolve, and so opposites will have opposite effects.

If a body contains more water than earth fire only thickens it: if it contains more earth fire solidifies it. Hence
natron and salt and stone and potter's clay must contain more earth.

The nature of oil presents the greatest problem. If water preponderated in it, cold ought to solidify it; if earth
preponderated, then fire ought to do so. Actually neither solidifies, but both thicken it. The reason is that it is
full of air (hence it floats on the top of water, since air tends to rise). Cold thickens it by turning the air in it
into water, for any mixture of oil and water is thicker than either. Fire and the lapse of time thicken and
whiten it. The whitening follows on the evaporation of any water that may have been in it; the is due to the
change of the air into water as the heat in the oil is dissipated. The effect in both cases is the same and the
cause is the same, but the manner of its operation is different. Both heat and cold thicken it, but neither dries
it (neither the sun nor cold dries oil), not only because it is glutinous but because it contains air. Its glutinous
nature prevents it from giving off vapour and so fire does not dry it or boil it off.

Those bodies which are made up of earth and water may be classified according to the preponderance of
either. There is a kind of wine, for instance, which both solidifies and thickens by boiling-I mean, must. All
bodies of this kind lose their water as they That it is their water may be seen from the fact that the vapour
from them condenses into water when collected. So wherever some sediment is left this is of the nature of
earth. Some of these bodies, as we have said, are also thickened and dried by cold. For cold not only
solidifies but also dries water, and thickens things by turning air into water. (Solidifying, as we have said, is a
form of drying.) Now those things that are not thickened by cold, but solidified, belong rather to water, e.g..
wine, urine, vinegar, lye, whey. But those things that are thickened (not by evaporation due to fire) are made
up either of earth or of water and air: honey of earth, while oil contains air. Milk and blood, too, are made up
of both water and earth, though earth generally predominates in them. So, too, are the liquids out of which
natron and salt are formed; and stones are also formed from some mixtures of this kind. Hence, if the whey
has not been separated, it burns away if you boil it over a fire. But the earthy element in milk can also be
coagulated by the help of fig-juice, if you boil it in a certain way as doctors do when they treat it with
fig-juice, and this is how the whey and the cheese are commonly separated. Whey, once separated, does not
thicken, as the milk did, but boils away like water. Sometimes, however, there is little or no cheese in milk,

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and such milk is not nutritive and is more like water. The case of blood is similar: cold dries and so solidifies
it. Those kinds of blood that do not solidify, like that of the stag, belong rather to water and are very cold.
Hence they contain no fibres: for the fibres are of earth and solid, and blood from which they have been
removed does not solidify. This is because it cannot dry; for what remains is water, just as what remains of
milk when cheese has been removed is water. The fact that diseased blood will not solidify is evidence of the
same thing, for such blood is of the nature of serum and that is phlegm and water, the nature of the animal
having failed to get the better of it and digest it.

Some of these bodies are soluble, e.g. natron, some insoluble, e.g. pottery: of the latter, some, like horn, can
be softened by heat, others, like pottery and stone, cannot. The reason is that opposite causes have opposite
effects: consequently, if solidification is due to two causes, the cold and the dry, solution must be due to the
hot and the moist, that is, to fire and to water (these being opposites): water dissolving what was solidified by
fire alone, fire what was solidified by cold alone. Consequently, if any things happen to be solidified by the
action of both, these are least apt to be soluble. Such a case we find where things have been heated and are
then solidified by cold. When the heat in leaving them has caused most of the moisture to evaporate, the cold
so compacts these bodies together again as to leave no entrance even for moisture. Therefore heat does not
dissolve them (for it only dissolves those bodies that are solidified by cold alone), nor does water (for it does
not dissolve what cold solidifies, but only what is solidified by dry heat). But iron is melted by heat and
solidified by cold. Wood consists of earth and air and is therefore combustible but cannot be melted or
softened by heat. (For the same reason it floats in water-all except ebony. This does not, for other kinds of
wood contain a preponderance of air, but in black ebony the air has escaped and so earth preponderates in it.)
Pottery consists of earth alone because it solidified gradually in the process of drying. Water cannot get into
it, for the pores were only large enough to admit of vapour escaping: and seeing that fire solidified it, that
cannot dissolve it either.

So solidification and melting, their causes, and the kinds of subjects in which they occur have been described.

All this makes it clear that bodies are formed by heat and cold and that these agents operate by thickening and
solidifying. It is because these qualities fashion bodies that we find heat in all of them, and in some cold in so
far as heat is absent. These qualities, then, are present as active, and the moist and the dry as passive, and
consequently all four are found in mixed bodies. So water and earth are the constituents of homogeneous
bodies both in plants and in animals and of metals such as gold, silver, and the rest-water and earth and their
respective exhalations shut up in the compound bodies, as we have explained elsewhere.

All these mixed bodies are distinguished from one another, firstly by the qualities special to the various
senses, that is, by their capacities of action. (For a thing is white, fragrant, sonant, sweet, hot, cold in virtue of
a power of acting on sense). Secondly by other more characteristic affections which express their aptitude to
be affected: I mean, for instance, the aptitude to melt or solidify or bend and so forth, all these qualities, like
moist and dry, being passive. These are the qualities that differentiate bone, flesh, sinew, wood, bark, stone
and all other homogeneous natural bodies. Let us begin by enumerating these qualities expressing the
aptitude or inaptitude of a thing to be affected in a certain way. They are as follows: to be apt or inapt to
solidify, melt, be softened by heat, be softened by water, bend, break, be comminuted, impressed, moulded,
squeezed; to be tractile or non-tractile, malleable or non-malleable, to be fissile or non-fissile, apt or inapt to
be cut; to be viscous or friable, compressible or incompressible, combustible or incombustible; to be apt or
inapt to give off fumes. These affections differentiate most bodies from one another. Let us go on to explain
the nature of each of them. We have already given a general account of that which is apt or inapt to solidify
or to melt, but let us return to them again now. Of all the bodies that admit of solidification and hardening,
some are brought into this state by heat, others by cold. Heat does this by drying up their moisture, cold by

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driving out their heat. Consequently some bodies are affected in this way by defect of moisture, some by
defect of heat: watery bodies by defect of heat, earthy bodies of moisture. Now those bodies that are so
affected by defect of moisture are dissolved by water, unless like pottery they have so contracted that their
pores are too small for the particles of water to enter. All those bodies in which this is not the case are
dissolved by water, e.g. natron, salt, dry mud. Those bodies that solidified through defect of heat are melted
by heat, e.g. ice, lead, copper. So much for the bodies that admit of solidification and of melting, and those
that do not admit of melting.

The bodies which do not admit of solidification are those which contain no aqueous moisture and are not
watery, but in which heat and earth preponderate, like honey and must (for these are in a sort of state of
effervescence), and those which do possess some water but have a preponderance of air, like oil and
quicksilver, and all viscous substances such as pitch and birdlime.

Those bodies admit of softening which are not (like ice) made up of water, but in which earth predominates.
All their moisture must not have left them (as in the case of natron and salt), nor must the relation of dry to
moist in them be incongruous (as in the case of pottery). They must be tractile (without admitting water) or
malleable (without consisting of water), and the agent in softening them is fire. Such are iron and horn.

Both of bodies that can melt and of bodies that cannot, some do and some do not admit of softening in water.
Copper, for instance, which can be melted, cannot be softened in water, whereas wool and earth can be
softened in water, for they can be soaked. (It is true that though copper can be melted the agent in its case is
not water, but some of the bodies that can be melted by water too such as natron and salt cannot be softened
in water: for nothing is said to be so affected unless the water soaks into it and makes it softer.) Some things,
on the other hand, such as wool and grain, can be softened by water though they cannot be melted. Any body
that is to be softened by water must be of earth and must have its pores larger than the particles of water, and
the pores themselves must be able to resist the action of water, whereas bodies that can be 'melted' by water
must have pores throughout.

(Why is it that earth is both 'melted' and softened by moisture, while natron is 'melted' but not softened?
Because natron is pervaded throughout by pores so that the parts are immediately divided by the water, but
earth has also pores which do not connect and is therefore differently affected according as the water enters
by one or the other set of pores.)

Some bodies can be bent or straightened, like the reed or the withy, some cannot, like pottery and stone.
Those bodies are apt to be bent and straightened which can change from being curved to being straight and
from being straight to being curved, and bending and straightening consist in the change or motion to the
straight or to a curve, for a thing is said to be in process of being bent whether it is being made to assume a
convex or a concave shape. So bending is defined as motion to the convex or the concave without a change of
length. For if we added 'or to the straight', we should have a thing bent and straight at once, and it is
impossible for that which is straight to be bent. And if all bending is a bending back or a bending down, the
former being a change to the convex, the latter to the concave, a motion that leads to the straight cannot be
called bending, but bending and straightening are two different things. These, then, are the things that can,
and those that cannot be bent, and be straightened.

Some things can be both broken and comminuted, others admit only one or the other. Wood, for instance, can
be broken but not comminuted, ice and stone can be comminuted but not broken, while pottery may either be
comminuted or broken. The distinction is this: breaking is a division and separation into large parts,
comminution into parts of any size, but there must be more of them than two. Now those solids that have

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many pores not communicating with one another are comminuible (for the limit to their subdivision is set by
the pores), but those whose pores stretch continuously for a long way are breakable, while those which have
pores of both kinds are both comminuible and breakable.

Some things, e.g. copper and wax, are impressible, others, e.g. pottery and water, are not. The process of
being impressed is the sinking of a part of the surface of a thing in response to pressure or a blow, in general
to contact. Such bodies are either soft, like wax, where part of the surface is depressed while the rest remains,
or hard, like copper. Non-impressible bodies are either hard, like pottery (its surface does not give way and
sink in), or liquid, like water (for though water does give way it is not in a part of it, for there is a reciprocal
change of place of all its parts). Those impressibles that retain the shape impressed on them and are easily
moulded by the hand are called 'plastic'; those that are not easily moulded, such as stone or wood, or are
easily moulded but do not retain the shape impressed, like wool or a sponge, are not plastic. The last group
are said to be 'squeezable'. Things are 'squeezable' when they can contract into themselves under pressure,
their surface sinking in without being broken and without the parts interchanging position as happens in the
case of water. (We speak of pressure when there is movement and the motor remains in contact with the thing
moved, of impact when the movement is due to the local movement of the motor.) Those bodies are subject
to squeezing which have empty pores-empty, that is, of the stuff of which the body itself consists-and that
can sink upon the void spaces within them, or rather upon their pores. For sometimes the pores upon which a
body sinks in are not empty (a wet sponge, for instance, has its pores full). But the pores, if full, must be full
of something softer than the body itself which is to contract. Examples of things squeezable are the sponge,
wax, flesh. Those things are not squeezable which cannot be made to contract upon their own pores by
pressure, either because they have no pores or because their pores are full of something too hard. Thus iron,
stone, water and all liquids are incapable of being squeezed.

Things are tractile when their surface can be made to elongate, for being drawn out is a movement of the
surface, remaining unbroken, in the direction of the mover. Some things are tractile, e.g. hair, thongs, sinew,
dough, birdlime, and some are not, e.g. water, stone. Some things are both tractile and squeezable, e.g. wool;
in other cases the two qualities do not coincide; phlegm, for instance, is tractile but not squeezable, and a
sponge squeezable but not tractile.

Some things are malleable, like copper. Some are not, like stone and wood. Things are malleable when their
surface can be made to move (but only in part) both downwards and sideways with one and the same blow:
when this is not possible a body is not malleable. All malleable bodies are impressible, but not all impressible
bodies are malleable, e.g. wood, though on the whole the two go together. Of squeezable things some are
malleable and some not: wax and mud are malleable, wool is not. Some things are fissile, e.g. wood, some are
not, e.g. potter's clay. A thing is fissile when it is apt to divide in advance of the instrument dividing it, for a
body is said to split when it divides to a further point than that to which the dividing instrument divides it and
the act of division advances: which is not the case with cutting. Those bodies which cannot behave like this
are non-fissile. Nothing soft is fissile (by soft I mean absolutely soft and not relatively: for iron itself may be
relatively soft); nor are all hard things fissile, but only such as are neither liquid nor impressible nor
comminuible. Such are the bodies that have the pores along which they cohere lengthwise and not crosswise.

Those hard or soft solids are apt to be cut which do not necessarily either split in advance of the instrument or
break into minute fragments when they are being divided. Those that necessarily do so and liquids cannot be
cut. Some things can be both split and cut, like wood, though generally it is lengthwise that a thing can be
split and crosswise that it can be cut. For, a body being divided into many parts fin so far as its unity is made
up of many lengths it is apt to be split, in so far as it is made up of many breadths it is apt to be cut.

A thing is viscous when, being moist or soft, it is tractile. Bodies owe this property to the interlocking of their
parts when they are composed like chains, for then they can be drawn out to a great length and contracted
again. Bodies that are not like this are friable. Bodies are compressible when they are squeezable and retain

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METEOROLOGY

the shape they have been squeezed into; incompressible when they are either inapt to be squeezed at all or do
not retain the shape they have been squeezed into.

Some bodies are combustible and some are not. Wood, wool, bone are combustible; stone, ice are not. Bodies
are combustible when their pores are such as to admit fire and their longitudinal pores contain moisture
weaker than fire. If they have no moisture, or if, as in ice or very green wood, the moisture is stronger than
fire, they are not combustible.

Those bodies give off fumes which contain moisture, but in such a form that it does not go off separately in
vapour when they are exposed to fire. For vapour is a moist secretion tending to the nature of air produced
from a liquid by the agency of burning heat. Bodies that give off fumes give off secretions of the nature of air
by the lapse of time: as they perish away they dry up or become earth. But the kind of secretion we are
concerned with now differs from others in that it is not moist nor does it become wind (which is a continuous
flow of air in a given direction). Fumes are common secretion of dry and moist together caused by the agency
of burning heat. Hence they do not moisten things but rather colour them.

The fumes of a woody body are called smoke. (I mean to include bones and hair and everything of this kind
in the same class. For there is no name common to all the objects that I mean, but, for all that, these things are
all in the same class by analogy. Compare what Empedocles says: They are one and the same, hair and leaves
and the thick wings of birds and scales that grow on stout limbs.) The fumes of fat are a sooty smoke and
those of oily substances a greasy steam. Oil does not boil away or thicken by evaporation because it does not
give off vapour but fumes. Water on the other hand does not give off fumes, but vapour. Sweet wine does
give off fumes, for it contains fat and behaves like oil. It does not solidify under the influence of cold and it is
apt to burn. Really it is not wine at all in spite of its name: for it does not taste like wine and consequently
does not inebriate as ordinary wine does. It contains but little fumigable stuff and consequently is
inflammable.

All bodies are combustible that dissolve into ashes, and all bodies do this that solidify under the influence
either of heat or of both heat and cold; for we find that all these bodies are mastered by fire. Of stones the
precious stone called carbuncle is least amenable to fire.

Of combustible bodies some are inflammable and some are not, and some of the former are reduced to coals.
Those are called 'inflammable' which produce flame and those which do not are called 'non-inflammable'.
Those fumigable bodies that are not liquid are inflammable, but pitch, oil, wax are inflammable in
conjunction with other bodies rather than by themselves. Most inflammable are those bodies that give off
smoke. Of bodies of this kind those that contain more earth than smoke are apt to be reduced to coals. Some
bodies that can be melted are not inflammable, e.g. copper; and some bodies that cannot be melted are
inflammable, e.g. wood; and some bodies can be melted and are also inflammable, e.g. frankincense. The
reason is that wood has its moisture all together and this is continuous throughout and so it burns up: whereas
copper has it in each part but not continuous, and insufficient in quantity to give rise to flame. In frankincense
it is disposed in both of these ways. Fumigable bodies are inflammable when earth predominates in them and
they are consequently such as to be unable to melt. These are inflammable because they are dry like fire.
When this dry comes to be hot there is fire. This is why flame is burning smoke or dry exhalation. The fumes
of wood are smoke, those of wax and frankincense and such-like, and pitch and whatever contains pitch or
such-like are sooty smoke, while the fumes of oil and oily substances are a greasy steam; so are those of all
substances which are not at all combustible by themselves because there is too little of the dry in them (the
dry being the means by which the transition to fire is effected), but burn very readily in conjunction with
something else. (For the fat is just the conjunction of the oily with the dry.) So those bodies that give off
fumes, like oil and pitch, belong rather to the moist, but those that burn to the dry.

METEOROLOGY

Homogeneous bodies differ to touch-by these affections and differences, as we have said. They also differ in
respect of their smell, taste, and colour.

By homogeneous bodies I mean, for instance, 'metals', gold, copper, silver, tin, iron, stone, and everything
else of this kind and the bodies that are extracted from them; also the substances found in animals and plants,
for instance, flesh, bones, sinew, skin, viscera, hair, fibres, veins (these are the elements of which the
non-homogeneous bodies like the face, a hand, a foot, and everything of that kind are made up), and in
plants, wood, bark, leaves, roots, and the rest like them.

The homogeneous bodies, it is true, are constituted by a different cause, but the matter of which they are
composed is the dry and the moist, that is, water and earth (for these bodies exhibit those qualities most
clearly). The agents are the hot and the cold, for they constitute and make concrete the homogeneous bodies
out of earth and water as matter. Let us consider, then, which of the homogeneous bodies are made of earth
and which of water, and which of both.

Of organized bodies some are liquid, some soft, some hard. The soft and the hard are constituted by a process
of solidification, as we have already explained.

Those liquids that go off in vapour are made of water, those that do not are either of the nature of earth, or a
mixture either of earth and water, like milk, or of earth and air, like wood, or of water and air, like oil. Those
liquids which are thickened by heat are a mixture. (Wine is a liquid which raises a difficulty: for it is both
liable to evaporation and it also thickens; for instance new wine does. The reason is that the word 'wine' is
ambiguous and different 'wines' behave in different ways. New wine is more earthy than old, and for this
reason it is more apt to be thickened by heat and less apt to be congealed by cold. For it contains much heat
and a great proportion of earth, as in Arcadia, where it is so dried up in its skins by the smoke that you scrape
it to drink. If all wine has some sediment in it then it will belong to earth or to water according to the quantity
of the sediment it possesses.) The liquids that are thickened by cold are of the nature of earth; those that are
thickened either by heat or by cold consist of more than one element, like oil and honey, and 'sweet wine'.

Of solid bodies those that have been solidified by cold are of water, e.g. ice, snow, hail, hoar-frost. Those
solidified by heat are of earth, e.g. pottery, cheese, natron, salt. Some bodies are solidified by both heat and
cold. Of this kind are those solidified by refrigeration, that is by the privation both of heat and of the moisture
which departs with the heat. For salt and the bodies that are purely of earth solidify by the privation of
moisture only, ice by that of heat only, these bodies by that of both. So both the active qualities and both
kinds of matter were involved in the process. Of these bodies those from which all the moisture has gone are
all of them of earth, like pottery or amber. (For amber, also, and the bodies called 'tears' are formed by
refrigeration, like myrrh, frankincense, gum. Amber, too, appears to belong to this class of things: the animals
enclosed in it show that it is formed by solidification. The heat is driven out of it by the cold of the river and
causes the moisture to evaporate with it, as in the case of honey when it has been heated and is immersed in
water.) Some of these bodies cannot be melted or softened; for instance, amber and certain stones, e.g. the
stalactites in caves. (For these stalactites, too, are formed in the same way: the agent is not fire, but cold
which drives out the heat, which, as it leaves the body, draws out the moisture with it: in the other class of
bodies the agent is external fire.) In those from which the moisture has not wholly gone earth still
preponderates, but they admit of softening by heat, e.g. iron and horn.

Now since we must include among 'meltables' those bodies which are melted by fire, these contain some
water: indeed some of them, like wax, are common to earth and water alike. But those that are melted by
water are of earth. Those that are not melted either by fire or water are of earth, or of earth and water.

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METEOROLOGY

Since, then, all bodies are either liquid or solid, and since the things that display the affections we have
enumerated belong to these two classes and there is nothing intermediate, it follows that we have given a
complete account of the criteria for distinguishing whether a body consists of earth or of water or of more
elements than one, and whether fire was the agent in its formation, or cold, or both.

Gold, then, and silver and copper and tin and lead and glass and many nameless stone are of water: for they
are all melted by heat. Of water, too, are some wines and urine and vinegar and lye and whey and serum: for
they are all congealed by cold. In iron, horn, nails, bones, sinews, wood, hair, leaves, bark, earth
preponderates. So, too, in amber, myrrh, frankincense, and all the substances called 'tears', and stalactites, and
fruits, such as leguminous plants and corn. For things of this kind are, to a greater or less degree, of earth. For
of all these bodies some admit of softening by heat, the rest give off fumes and are formed by refrigeration.
So again in natron, salt, and those kinds of stones that are not formed by refrigeration and cannot be melted.
Blood, on the other hand, and semen, are made up of earth and water and air. If the blood contains fibres,
earth preponderates in it: consequently its solidifies by refrigeration and is melted by liquids; if not, it is of
water and therefore does not solidify. Semen solidifies by refrigeration, its moisture leaving it together with
its heat.

We must investigate in the light of the results we have arrived at what solid or liquid bodies are hot and what
cold.

Bodies consisting of water are commonly cold, unless (like lye, urine, wine) they contain foreign heat. Bodies
consisting of earth, on the other hand, are commonly hot because heat was active in forming them: for
instance lime and ashes.

We must recognize that cold is in a sense the matter of bodies. For the dry and the moist are matter (being
passive) and earth and water are the elements that primarily embody them, and they are characterized by cold.
Consequently cold must predominate in every body that consists of one or other of the elements simply,
unless such a body contains foreign heat as water does when it boils or when it has been strained through
ashes. This latter, too, has acquired heat from the ashes, for everything that has been burnt contains more or
less heat. This explains the generation of animals in putrefying bodies: the putrefying body contains the heat
which destroyed its proper heat.

Bodies made up of earth and water are hot, for most of them derive their existence from concoction and heat,
though some, like the waste products of the body, are products of putrefaction. Thus blood, semen, marrow,
figjuice, and all things of the kinds are hot as long as they are in their natural state, but when they perish and
fall away from that state they are so no longer. For what is left of them is their matter and that is earth and
water. Hence both views are held about them, some people maintaining them to be cold and others to be
warm; for they are observed to be hot when they are in their natural state, but to solidify when they have
fallen away from it. That, then, is the case of mixed bodies. However, the distinction we laid down holds
good: if its matter is predominantly water a body is cold (water being the complete opposite of fire), but if
earth or air it tends to be warm.

It sometimes happens that the coldest bodies can be raised to the highest temperature by foreign heat; for the
most solid and the hardest bodies are coldest when deprived of heat and most burning after exposure to fire:
thus water is more burning than smoke and stone than water.

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METEOROLOGY

Having explained all this we must describe the nature of flesh, bone, and the other homogeneous bodies
severally.

Our account of the formation of the homogeneous bodies has given us the elements out of which they are
compounded and the classes into which they fall, and has made it clear to which class each of those bodies
belongs. The homogeneous bodies are made up of the elements, and all the works of nature in turn of the
homogeneous bodies as matter. All the homogeneous bodies consist of the elements described, as matter, but
their essential nature is determined by their definition. This fact is always clearer in the case of the later
products of those, in fact, that are instruments, as it were, and have an end: it is clearer, for instance, that a
dead man is a man only in name. And so the hand of a dead man, too, will in the same way be a hand in name
only, just as stone flutes might still be called flutes: for these members, too, are instruments of a kind. But in
the case of flesh and bone the fact is not so clear to see, and in that of fire and water even less. For the end is
least obvious there where matter predominates most. If you take the extremes, matter is pure matter and the
essence is pure definition; but the bodies intermediate between the two are matter or definition in proportion
as they are near to either. For each of those elements has an end and is not water or fire in any and every
condition of itself, just as flesh is not flesh nor viscera viscera, and the same is true in a higher degree with
face and hand. What a thing is always determined by its function: a thing really is itself when it can perform
its function; an eye, for instance, when it can see. When a thing cannot do so it is that thing only in name, like
a dead eye or one made of stone, just as a wooden saw is no more a saw than one in a picture. The same, then,
is true of flesh, except that its function is less clear than that of the tongue. So, too, with fire; but its function
is perhaps even harder to specify by physical inquiry than that of flesh. The parts of plants, and inanimate
bodies like copper and silver, are in the same case. They all are what they are in virtue of a certain power of
action or passion-just like flesh and sinew. But we cannot state their form accurately, and so it is not easy to
tell when they are really there and when they are not unless the body is thoroughly corrupted and its shape
only remains. So ancient corpses suddenly become ashes in the grave and very old fruit preserves its shape
only but not its taste: so, too, with the solids that form from milk.

Now heat and cold and the motions they set up as the bodies are solidified by the hot and the cold are
sufficient to form all such parts as are the homogeneous bodies, flesh, bone, hair, sinew, and the rest. For they
are all of them differentiated by the various qualities enumerated above, tension, tractility, comminuibility,
hardness, softness, and the rest of them: all of which are derived from the hot and the cold and the mixture of
their motions. But no one would go as far as to consider them sufficient in the case of the non-homogeneous
parts (like the head, the hand, or the foot) which these homogeneous parts go to make up. Cold and heat and
their motion would be admitted to account for the formation of copper or silver, but not for that of a saw, a
bowl, or a box. So here, save that in the examples given the cause is art, but in the nonhomogeneous bodies
nature or some other cause.

Since, then, we know to what element each of the homogeneous bodies belongs, we must now find the
definition of each of them, the answer, that is, to the question, 'what is' flesh, semen, and the rest? For we
know the cause of a thing and its definition when we know the material or the formal or, better, both the
material and the formal conditions of its generation and destruction, and the efficient cause of it.

After the homogeneous bodies have been explained we must consider the non-homogeneous too, and lastly
the bodies made up of these, such as man, plants, and the rest.

-THE END-

12 55

ON THE MOTION OF ANIMALS

by Aristotle

ON THE MOTION OF ANIMALS

Table of Contents

ON THE MOTION OF ANIMALS 1

by Aristotle 1

_1 1

2 2

3. 2

A 3

_5 4

6 4

1_ 4

1 5

_9 6

JO 7

11 7

ON THE MOTION OF ANIMALS

by Aristotle

translated by A. S. L. Farquharson

•1
•2
•3
•4
•5
•6

• 7
•8
•9

• 10

• 11

ELSEWHERE we have investigated in detail the movement of animals after their various kinds, the
differences between them, and the reasons for their particular characters (for some animals fly, some swim,
some walk, others move in various other ways); there remains an investigation of the common ground of any
sort of animal movement whatsoever.

Now we have already determined (when we were discussing whether eternal motion exists or not, and its
definition, if it does exist) that the origin of all other motions is that which moves itself, and that the origin of
this is the immovable, and that the prime mover must of necessity be immovable. And we must grasp this not
only generally in theory, but also by reference to individuals in the world of sense, for with these in view we
seek general theories, and with these we believe that general theories ought to harmonize. Now in the world
of sense too it is plainly impossible for movement to be initiated if there is nothing at rest, and before all else
in our present subject- animal life. For if one of the parts of an animal be moved, another must be at rest, and
this is the purpose of their joints; animals use joints like a centre, and the whole member, in which the joint
is, becomes both one and two, both straight and bent, changing potentially and actually by reason of the joint.
And when it is bending and being moved one of the points in the joint is moved and one is at rest, just as if
the points A and D of a diameter were at rest, and B were moved, and DAC were generated. However, in the
geometrical illustration, the centre is held to be altogether indivisible (for in mathematics motion is a fiction,
as the phrase goes, no mathematical entity being really moved), whereas in the case of joints the centres
become now one potentially and divided actually, and now one actually and divided potentially. But still the
origin of movement, qua origin, always remains at rest when the lower part of a limb is moved; for example,
the elbow joint, when the forearm is moved, and the shoulder, when the whole arm; the knee when the tibia is
moved, and the hip when the whole leg. Accordingly it is plain that each animal as a whole must have within

ON THE MOTION OF ANIMALS 1

ON THE MOTION OF ANIMALS

itself a point at rest, whence will be the origin of that which is moved, and supporting itself upon which it
will be moved both as a complete whole and in its members.

But the point of rest in the animal is still quite ineffectual unless there be something without which is
absolutely at rest and immovable. Now it is worth while to pause and consider what has been said, for it
involves a speculation which extends beyond animals even to the motion and march of the universe. For just
as there must be something immovable within the animal, if it is to be moved, so even more must there be
without it something immovable, by supporting itself upon which that which is moved moves. For were that
something always to give way (as it does for mice walking in grain or persons walking in sand) advance
would be impossible, and neither would there be any walking unless the ground were to remain still, nor any
flying or swimming were not the air and the sea to resist. And this which resists must needs be different from
what is moved, the whole of it from the whole of that, and what is thus immovable must be no part of what is
moved; otherwise there will be no movement. Evidence of this lies in the problem why it is that a man easily
moves a boat from outside, if he push with a pole, putting it against the mast or some other part, but if he
tried to do this when in the boat itself he would never move it, no not giant Tityus himself nor Boreas
blowing from inside the ship, if he really were blowing in the way painters represent him; for they paint him
sending the breath out from the boat. For whether one blew gently or so stoutly as to make a very great wind,
and whether what were thrown or pushed were wind or something else, it is necessary in the first place to be
supported upon one of one's own members which is at rest and so to push, and in the second place for this
member, either itself, or that of which it is a part, to remain at rest, fixing itself against something external to
itself. Now the man who is himself in the boat, if he pushes, fixing himself against the boat, very naturally
does not move the boat, because what he pushes against should properly remain at rest. Now what he is trying
to move, and what he is fixing himself against is in his case the same. If, however, he pushes or pulls from
outside he does move it, for the ground is no part of the boat.

Here we may ask the difficult question whether if something moves the whole heavens this mover must be
immovable, and moreover be no part of the heavens, nor in the heavens. For either it is moved itself and
moves the heavens, in which case it must touch something immovable in order to create movement, and then
this is no part of that which creates movement; or if the mover is from the first immovable it will equally be
no part of that which is moved. In this point at least they argue correctly who say that as the Sphere is carried
round in a circle no single part remains still, for then either the whole would necessarily stand still or its
continuity be torn asunder; but they argue less well in supposing that the poles have a certain force, though
conceived as having no magnitude, but as merely termini or points. For besides the fact that no such things
have any substantial existence it is impossible for a single movement to be initiated by what is twofold; and
yet they make the poles two. From a review of these difficulties we may conclude that there is something so
related to the whole of Nature, as the earth is to animals and things moved by them.

And the mythologists with their fable of Atlas setting his feet upon the earth appear to have based the fable
upon intelligent grounds. They make Atlas a kind of diameter twirling the heavens about the poles. Now as
the earth remains still this would be reasonable enough, but their theory involves them in the position that the
earth is no part of the universe. And further the force of that which initiates movement must be made equal to
the force of that which remains at rest. For there is a definite quantity of force or power by dint of which that
which remains at rest does so, just as there is of force by dint of which that which initiates movement does so;
and as there is a necessary proportion between opposite motions, so there is between absences of motion.
Now equal forces are unaffected by one another, but are overcome by a superiority of force. And so in their
theory Atlas, or whatever similar power initiates movement from within, must exert no more force than will

ON THE MOTION OF ANIMALS

exactly balance the stability of the earth- otherwise the earth will be moved out of her place in the centre of
things. For as the pusher pushes so is the pushed pushed, and with equal force. But the prime mover moves
that which is to begin with at rest, so that the power it exerts is greater, rather than equal and like to the power
which produces absence of motion in that which is moved. And similarly also the power of what is moved
and so moves must be greater than the power of that which is moved but does not initiate movement.
Therefore the force of the earth in its immobility will have to be as great as the force of the whole heavens,
and of that which moves the heavens. But if that is impossible, it follows that the heavens cannot possibly be
moved by any force of this kind inside them.

There is a further difficulty about the motions of the parts of the heavens which, as akin to what has gone
before, may be considered next. For if one could overcome by force of motion the immobility of the earth he
would clearly move it away from the centre. And it is plain that the power from which this force would
originate will not be infinite, for the earth is not infinite and therefore its weight is not. Now there are more
senses than one of the word 'impossible'. When we say it is impossible to see a sound, and when we say it is
impossible to see the men in the moon, we use two senses of the word; the former is of necessity, the latter,
though their nature is to be seen, cannot as a fact be seen by us. Now we suppose that the heavens are of
necessity impossible to destroy and to dissolve, whereas the result of the present argument would be to do
away with this necessity. For it is natural and possible for a motion to exist greater than the force by dint of
which the earth is at rest, or than that by dint of which Fire and Aether are moved. If then there are superior
motions, these will be dissolved in succession by one another: and if there actually are not, but might possibly
be (for the earth cannot be infinite because no body can possibly be infinite), there is a possibility of the
heavens being dissolved. For what is to prevent this coming to pass, unless it be impossible? And it is not
impossible unless the opposite is necessary. This difficulty, however, we will discuss elsewhere.

To resume, must there be something immovable and at rest outside of what is moved, and no part of it, or
not? And must this necessarily be so also in the case of the universe? Perhaps it would be thought strange
were the origin of movement inside. And to those who so conceive it the word of Homer would appear to
have been well spoken:

'Nay, ye would not pull Zeus, highest of all from heaven to the plain, no not even if ye toiled right hard;
come, all ye gods and goddesses! Set hands to the chain'; for that which is entirely immovable cannot
possibly be moved by anything. And herein lies the solution of the difficulty stated some time back, the
possibility or impossibility of dissolving the system of the heavens, in that it depends from an original which
is immovable.

Now in the animal world there must be not only an immovable without, but also within those things which
move in place, and initiate their own movement. For one part of an animal must be moved, and another be at
rest, and against this the part which is moved will support itself and be moved; for example, if it move one of
its parts; for one part, as it were, supports itself against another part at rest.

But about things without life which are moved one might ask the question whether all contain in themselves
both that which is at rest and that which initiates movement, and whether they also, for instance fire, earth, or
any other inanimate thing, must support themselves against something outside which is at rest. Or is this
impossible and must it not be looked for rather in those primary causes by which they are set in motion? For
all things without life are moved by something other, and the origin of all things so moved are things which
move themselves. And out of these we have spoken about animals (for they must all have in themselves that
which is at rest, and without them that against which they are supported); but whether there is some higher
and prime mover is not clear, and an origin of that kind involves a different discussion. Animals at any rate

ON THE MOTION OF ANIMALS

which move themselves are all moved supporting themselves on what is outside them, even when they
inspire and expire; for there is no essential difference between casting a great and a small weight, and this is
what men do when they spit and cough and when they breathe in and breathe out.

But is it only in that which moves itself in place that there must be a point at rest, or does this hold also of
that which causes its own qualitative changes, and its own growth? Now the question of original generation
and decay is different; for if there is, as we hold, a primary movement, this would be the cause of generation
and decay, and probably of all the secondary movements too. And as in the universe, so in the animal world
this is the primary movement, when the creature attains maturity; and therefore it is the cause of growth,
when the creature becomes the cause of its own growth, and the cause too of alteration. But if this is not the
primary movement then the point at rest is not necessary. However, the earliest growth and alteration in the
living creature arise through another and by other channels, nor can anything possibly be the cause of its own
generation and decay, for the mover must exist before the moved, the begetter before the begotten, and
nothing is prior to itself.

Now whether the soul is moved or not, and how it is moved if it be moved, has been stated before in our
treatise concerning it. And since all inorganic things are moved by some other thing- and the manner of the
movement of the first and eternally moved, and how the first mover moves it, has been determined before in
our Metaphysics, it remains to inquire how the soul moves the body, and what is the origin of movement in a
living creature. For, if we except the movement of the universe, things with life are the causes of the
movement of all else, that is of all that are not moved by one another by mutual impact. And so all their
motions have a term or limit, inasmuch as the movements of things with life have such. For all living things
both move and are moved with some object, so that this is the term of all their movement, the end, that is, in
view. Now we see that the living creature is moved by intellect, imagination, purpose, wish, and appetite.
And all these are reducible to mind and desire. For both imagination and sensation are on common ground
with mind, since all three are faculties of judgement though differing according to distinctions stated
elsewhere. Will, however, impulse, and appetite, are all three forms of desire, while purpose belongs both to
intellect and to desire. Therefore the object of desire or of intellect first initiates movement, not, that is, every
object of intellect, only the end in the domain of conduct. Accordingly among goods that which moves is a
practical end, not the good in its whole extent. For it initiates movement only so far as something else is for
its sake, or so far as it is the object of that which is for the sake of something else. And we must suppose that
a seeming good may take the room of actual good, and so may the pleasant, which is itself a seeming good.
From these considerations it is clear that in one regard that which is eternally moved by the eternal mover is
moved in the same way as every living creature, in another regard differently, and so while it is moved
eternally, the movement of living creatures has a term. Now the eternal beautiful, and the truly and primarily
good (which is not at one time good, at another time not good), is too divine and precious to be relative to
anything else. The prime mover then moves, itself being unmoved, whereas desire and its faculty are moved
and so move. But it is not necessary for the last in the chain of things moved to move something else;
wherefore it is plainly reasonable that motion in place should be the last of what happens in the region of
things happening, since the living creature is moved and goes forward by reason of desire or purpose, when
some alteration has been set going on the occasion of sensation or imagination.

But how is it that thought (viz. sense, imagination, and thought proper) is sometimes followed by action,
sometimes not; sometimes by movement, sometimes not? What happens seems parallel to the case of

ON THE MOTION OF ANIMALS

thinking and inferring about the immovable objects of science. There the end is the truth seen (for, when one
conceives the two premisses, one at once conceives and comprehends the conclusion), but here the two
premisses result in a conclusion which is an action- for example, one conceives that every man ought to
walk, one is a man oneself: straightway one walks; or that, in this case, no man should walk, one is a man:
straightway one remains at rest. And one so acts in the two cases provided that there is nothing in the one
case to compel or in the other to prevent. Again, I ought to create a good, a house is good: straightway I make
a house. I need a covering, a coat is a covering: I need a coat. What I need I ought to make, I need a coat: I
make a coat. And the conclusion I must make a coat is an action. And the action goes back to the beginning
or first step. If there is to be a coat, one must first have B, and if B then A, so one gets A to begin with. Now
that the action is the conclusion is clear. But the premisses of action are of two kinds, of the good and of the
possible.

And as in some cases of speculative inquiry we suppress one premise so here the mind does not stop to
consider at all an obvious minor premise; for example if walking is good for man, one does not dwell upon
the minor 'I am a man'. And so what we do without reflection, we do quickly. For when a man actualizes
himself in relation to his object either by perceiving, or imagining or conceiving it, what he desires he does at
once. For the actualizing of desire is a substitute for inquiry or reflection. I want to drink, says appetite; this is
drink, says sense or imagination or mind: straightway I drink. In this way living creatures are impelled to
move and to act, and desire is the last or immediate cause of movement, and desire arises after perception or
after imagination and conception. And things that desire to act now create and now act under the influence of
appetite or impulse or of desire or wish.

The movements of animals may be compared with those of automatic puppets, which are set going on the
occasion of a tiny movement; the levers are released, and strike the twisted strings against one another; or
with the toy wagon. For the child mounts on it and moves it straight forward, and then again it is moved in a
circle owing to its wheels being of unequal diameter (the smaller acts like a centre on the same principle as
the cylinders). Animals have parts of a similar kind, their organs, the sinewy tendons to wit and the bones; the
bones are like the wooden levers in the automaton, and the iron; the tendons are like the strings, for when
these are tightened or leased movement begins. However, in the automata and the toy wagon there is no
change of quality, though if the inner wheels became smaller and greater by turns there would be the same
circular movement set up. In an animal the same part has the power of becoming now larger and now smaller,
and changing its form, as the parts increase by warmth and again contract by cold and change their quality.
This change of quality is caused by imaginations and sensations and by ideas. Sensations are obviously a
form of change of quality, and imagination and conception have the same effect as the objects so imagined
and conceived For in a measure the form conceived be it of hot or cold or pleasant or fearful is like what the
actual objects would be, and so we shudder and are frightened at a mere idea. Now all these affections
involve changes of quality, and with those changes some parts of the body enlarge, others grow smaller. And
it is not hard to see that a small change occurring at the centre makes great and numerous changes at the
circumference, just as by shifting the rudder a hair's breadth you get a wide deviation at the prow. And
further, when by reason of heat or cold or some kindred affection a change is set up in the region of the heart,
even in an imperceptibly small part of the heart, it produces a vast difference in the periphery of the body,-
blushing, let us say, or turning white, goose-skin and shivers and their opposites.

But to return, the object we pursue or avoid in the field of action is, as has been explained, the original of
movement, and upon the conception and imagination of this there necessarily follows a change in the
temperature of the body. For what is painful we avoid, what is pleasing we pursue. We are, however,
unconscious of what happens in the minute parts; still anything painful or pleasing is generally speaking
accompanied by a definite change of temperature in the body. One may see this by considering the affections.

ON THE MOTION OF ANIMALS

Blind courage and panic fears, erotic motions, and the rest of the corporeal affections, pleasant and painful,
are all accompanied by a change of temperature, some in a particular member, others in the body generally.
So, memories and anticipations, using as it were the reflected images of these pleasures and pains, are now
more and now less causes of the same changes of temperature. And so we see the reason of nature's
handiwork in the inward parts, and in the centres of movement of the organic members; they change from
solid to moist, and from moist to solid, from soft to hard and vice versa. And so when these are affected in
this way, and when besides the passive and active have the constitution we have many times described, as
often as it comes to pass that one is active and the other passive, and neither of them falls short of the
elements of its essence, straightway one acts and the other responds. And on this account thinking that one
ought to go and going are virtually simultaneous, unless there be something else to hinder action. The organic
parts are suitably prepared by the affections, these again by desire, and desire by imagination. Imagination in
its turn depends either upon conception or sense-perception. And the simultaneity and speed are due to the
natural correspondence of the active and passive.

However, that which first moves the animal organism must be situate in a definite original. Now we have said
that a joint is the beginning of one part of a limb, the end of another. And so nature employs it sometimes as
one, sometimes as two. When movement arises from a joint, one of the extreme points must remain at rest,
and the other be moved (for as we explained above the mover must support itself against a point at rest);
accordingly, in the case of the elbow-joint, the last point of the forearm is moved but does not move
anything, while, in the flexion, one point of the elbow, which lies in the whole forearm that is being moved,
is moved, but there must also be a point which is unmoved, and this is our meaning when we speak of a point
which is in potency one, but which becomes two in actual exercise. Now if the arm were the living animal,
somewhere in its elbow-joint would be situate the original seat of the moving soul. Since, however, it is
possible for a lifeless thing to be so related to the hand as the forearm is to the upper (for example, when a
man moves a stick in his hand), it is evident that the soul, the original of movement, could not lie in either of
the two extreme points, neither, that is, in the last point of the stick which is moved, nor in the original point
which causes movement. For the stick too has an end point and an originative point by reference to the hand.
Accordingly, this example shows that the moving original which derives from the soul is not in the stick and
if not, then not in the hand; for a precisely similar relation obtains between the hand and the wrist, as between
the wrist and the elbow. In this matter it makes no difference whether the part is a continuous part of the body
or not; the stick may be looked at as a detached part of the whole. It follows then of necessity that the original
cannot lie in any individual origin which is the end of another member, even though there may lie another
part outside the one in question. For example, relatively to the end point of the stick the hand is the original,
but the original of the hand's movement is in the wrist. And so if the true original is not in the hand, be-there
is still something higher up, neither is the true original in the wrist, for once more if the elbow is at rest the
whole part below it can be moved as a continuous whole.

Now since the left and the right sides are symmetrical, and these opposites are moved simultaneously, it
cannot be that the left is moved by the right remaining stationary, nor vice versa; the original must always be
in what lies above both. Therefore, the original seat of the moving soul must be in that which lies in the
middle, for of both extremes the middle is the limiting point; and this is similarly related to the movements
from above [and below,] those that is from the head, and to the bones which spring from the spinal column, in
creatures that have a spinal column.

And this is a reasonable arrangement. For the sensorium is in our opinion in the centre too; and so, if the
region of the original of movement is altered in structure through sense-perception and thus changes, it
carries with it the parts that depend upon it and they too are extended or contracted, and in this way the
movement of the creature necessarily follows. And the middle of the body must needs be in potency one but

ON THE MOTION OF ANIMALS

in action more than one; for the limbs are moved simultaneously from the original seat of movement, and
when one is at rest the other is moved. For example, in the line BAC, B is moved, and A is the mover. There
must, however, be a point at rest if one is to move, the other to be moved. A (AE) then being one in potency
must be two in action, and so be a definite spatial magnitude not a mathematical point. Again, C may be
moved simultaneously with B. Both the originals then in A must move and be, and so there must be
something other than them which moves but is not moved. For otherwise, when the movement begins, the
extremes, i.e. the originals, in A would rest upon one another, like two men putting themselves back to back
and so moving their legs. There must then be some one thing which moves both. This something is the soul,
distinct from the spatial magnitude just described and yet located therein.

Although from the point of view of the definition of movement- a definition which gives the cause- desire is
the middle term or cause, and desire moves being moved, still in the material animated body there must be
some material which itself moves being moved. Now that which is moved, but whose nature is not to initiate
movement, is capable of being passive to an external force, while that which initiates movement must needs
possess a kind of force and power. Now experience shows us that animals do both possess connatural spirit
and derive power from this. (How this connatural spirit is maintained in the body is explained in other
passages of our works.) And this spirit appears to stand to the soul-centre or original in a relation analogous
to that between the point in a joint which moves being moved and the unmoved. Now since this centre is for
some animals in the heart, in the rest in a part analogous with the heart, we further see the reason for the
connatural spirit being situate where it actually is found. The question whether the spirit remains always the
same or constantly changes and is renewed, like the cognate question about the rest of the parts of the body,
is better postponed. At all events we see that it is well disposed to excite movement and to exert power; and
the functions of movement are thrusting and pulling. Accordingly, the organ of movement must be capable of
expanding and contracting; and this is precisely the characteristic of spirit. It contracts and expands naturally,
and so is able to pull and to thrust from one and the same cause, exhibiting gravity compared with the fiery
element, and levity by comparison with the opposites of fire. Now that which is to initiate movement without
change of structure must be of the kind described, for the elementary bodies prevail over one another in a
compound body by dint of disproportion; the light is overcome and kept down by the heavier, and the heavy
kept up by the lighter.

We have now explained what the part is which is moved when the soul originates movement in the body, and
what is the reason for this. And the animal organism must be conceived after the similitude of a
well-governed commonwealth. When order is once established in it there is no more need of a separate
monarch to preside over each several task. The individuals each play their assigned part as it is ordered, and
one thing follows another in its accustomed order. So in animals there is the same orderliness- nature taking
the place of custom- and each part naturally doing his own work as nature has composed them. There is no
need then of a soul in each part, but she resides in a kind of central governing place of the body, and the
remaining parts live by continuity of natural structure, and play the parts Nature would have them play.

So much then for the voluntary movements of animal bodies, and the reasons for them. These bodies,
however, display in certain members involuntary movements too, but most often non-voluntary movements.
By involuntary I mean motions of the heart and of the privy member; for often upon an image arising and
without express mandate of the reason these parts are moved. By non-voluntary I mean sleep and waking and
respiration, and other similar organic movements. For neither imagination nor desire is properly mistress of
any of these; but since the animal body must undergo natural changes of quality, and when the parts are so
altered some must increase and other decrease, the body must straightway be moved and change with the

10 7

ON THE MOTION OF ANIMALS

changes that nature makes dependent upon one another. Now the causes of the movements are natural
changes of temperature, both those coming from outside the body, and those taking place within it. So the
involuntary movements which occur in spite of reason in the aforesaid parts occur when a change of quality
supervenes. For conception and imagination, as we said above, produce the conditions necessary to
affections, since they bring to bear the images or forms which tend to create these states. And the two parts
aforesaid display this motion more conspicuously than the rest, because each is in a sense a separate vital
organism, the reason being that each contains vital moisture. In the case of the heart the cause is plain, for the
heart is the seat of the senses, while an indication that the generative organ too is vital is that there flows from
it the seminal potency, itself a kind of organism. Again, it is a reasonable arrangement that the movements
arise in the centre upon movements in the parts, and in the parts upon movements in the centre, and so reach
one another. Conceive A to be the centre or starting point. The movements then arrive at the centre from each
letter in the diagram we have drawn, and flow back again from the centre which is moved and changes, (for
the centre is potentially multiple) the movement of B goes to B, that of C to C, the movement of both to both;
but from B to C the movements flow by dint of going from B to A as to a centre, and then from A to C as
from a centre.

Moreover a movement contrary to reason sometimes does and sometimes does not arise in the organs on the
occasion of the same thoughts; the reason is that sometimes the matter which is passive to the impressions is
there in sufficient quantity and of the right quality and sometimes not.

And so we have finished our account of the reasons for the parts of each kind of animal, of the soul, and
furthere of sense-perception, of sleep, of memory, and of movement in general; it remains to speak of animal
generation.

-THE END-

Nicomachean Ethics

Aristotle

Nicomachean Ethics

Table of Contents

Nicomachean Ethics 1

Aristotle 1

Nicomachean Ethics

Aristotle

translated by W. D. Ross

• Book I

• Book II

• Book III

• Book IV

• Book V

• Book VI

• Book VII

• Book VIII

• Book IX

• Book X

BOOK I

EVERY art and every inquiry, and similarly every action and pursuit, is thought to aim at some good; and for
this reason the good has rightly been declared to be that at which all things aim. But a certain difference is
found among ends; some are activities, others are products apart from the activities that produce them. Where
there are ends apart from the actions, it is the nature of the products to be better than the activities. Now, as
there are many actions, arts, and sciences, their ends also are many; the end of the medical art is health, that
of shipbuilding a vessel, that of strategy victory, that of economics wealth. But where such arts fall under a
single capacity- as bridle-making and the other arts concerned with the equipment of horses fall under the
art of riding, and this and every military action under strategy, in the same way other arts fall under yet
others- in all of these the ends of the master arts are to be preferred to all the subordinate ends; for it is for
the sake of the former that the latter are pursued. It makes no difference whether the activities themselves are
the ends of the actions, or something else apart from the activities, as in the case of the sciences just
mentioned.

If, then, there is some end of the things we do, which we desire for its own sake (everything else being
desired for the sake of this), and if we do not choose everything for the sake of something else (for at that rate
the process would go on to infinity, so that our desire would be empty and vain), clearly this must be the
good and the chief good. Will not the knowledge of it, then, have a great influence on life? Shall we not, like
archers who have a mark to aim at, be more likely to hit upon what is right? If so, we must try, in outline at
least, to determine what it is, and of which of the sciences or capacities it is the object. It would seem to
belong to the most authoritative art and that which is most truly the master art. And politics appears to be of
this nature; for it is this that ordains which of the sciences should be studied in a state, and which each class
of citizens should learn and up to what point they should learn them; and we see even the most highly
esteemed of capacities to fall under this, e.g. strategy, economics, rhetoric; now, since politics uses the rest of
the sciences, and since, again, it legislates as to what we are to do and what we are to abstain from, the end of
this science must include those of the others, so that this end must be the good for man. For even if the end is
the same for a single man and for a state, that of the state seems at all events something greater and more
complete whether to attain or to preserve; though it is worth while to attain the end merely for one man, it is
finer and more godlike to attain it for a nation or for city-states. These, then, are the ends at which our
inquiry aims, since it is political science, in one sense of that term.

Nicomachean Ethics

Our discussion will be adequate if it has as much clearness as the subject-matter admits of, for precision is
not to be sought for alike in all discussions, any more than in all the products of the crafts. Now fine and just
actions, which political science investigates, admit of much variety and fluctuation of opinion, so that they
may be thought to exist only by convention, and not by nature. And goods also give rise to a similar
fluctuation because they bring harm to many people; for before now men have been undone by reason of their
wealth, and others by reason of their courage. We must be content, then, in speaking of such subjects and
with such premisses to indicate the truth roughly and in outline, and in speaking about things which are only
for the most part true and with premisses of the same kind to reach conclusions that are no better. In the same
spirit, therefore, should each type of statement be received; for it is the mark of an educated man to look for
precision in each class of things just so far as the nature of the subject admits; it is evidently equally foolish
to accept probable reasoning from a mathematician and to demand from a rhetorician scientific proofs.

Now each man judges well the things he knows, and of these he is a good judge. And so the man who has
been educated in a subject is a good judge of that subject, and the man who has received an all-round
education is a good judge in general. Hence a young man is not a proper hearer of lectures on political
science; for he is inexperienced in the actions that occur in life, but its discussions start from these and are
about these; and, further, since he tends to follow his passions, his study will be vain and unprofitable,
because the end aimed at is not knowledge but action. And it makes no difference whether he is young in
years or youthful in character; the defect does not depend on time, but on his living, and pursuing each
successive object, as passion directs. For to such persons, as to the incontinent, knowledge brings no profit;
but to those who desire and act in accordance with a rational principle knowledge about such matters will be
of great benefit.

These remarks about the student, the sort of treatment to be expected, and the purpose of the inquiry, may be
taken as our preface.

Let us resume our inquiry and state, in view of the fact that all knowledge and every pursuit aims at some
good, what it is that we say political science aims at and what is the highest of all goods achievable by action.
Verbally there is very general agreement; for both the general run of men and people of superior refinement
say that it is happiness, and identify living well and doing well with being happy; but with regard to what
happiness is they differ, and the many do not give the same account as the wise. For the former think it is
some plain and obvious thing, like pleasure, wealth, or honour; they differ, however, from one another- and
often even the same man identifies it with different things, with health when he is ill, with wealth when he is
poor; but, conscious of their ignorance, they admire those who proclaim some great ideal that is above their
comprehension. Now some thought that apart from these many goods there is another which is
self-subsistent and causes the goodness of all these as well. To examine all the opinions that have been held
were perhaps somewhat fruitless; enough to examine those that are most prevalent or that seem to be
arguable.

Let us not fail to notice, however, that there is a difference between arguments from and those to the first
principles. For Plato, too, was right in raising this question and asking, as he used to do, 'are we on the way
from or to the first principles?' There is a difference, as there is in a race-course between the course from the
judges to the turning-point and the way back. For, while we must begin with what is known, things are
objects of knowledge in two senses- some to us, some without qualification. Presumably, then, we must
begin with things known to us. Hence any one who is to listen intelligently to lectures about what is noble
and just, and generally, about the subjects of political science must have been brought up in good habits. For
the fact is the starting-point, and if this is sufficiently plain to him, he will not at the start need the reason as
well; and the man who has been well brought up has or can easily get startingpoints. And as for him who
neither has nor can get them, let him hear the words of Hesiod:

Far best is he who knows all things himself;
Nicomachean Ethics 2

Nicomachean Ethics

Good, he that hearkens when men counsel right;
But he who neither knows, nor lays to heart
Another's wisdom, is a useless wight.

Let us, however, resume our discussion from the point at which we digressed. To judge from the lives that
men lead, most men, and men of the most vulgar type, seem (not without some ground) to identify the good,
or happiness, with pleasure; which is the reason why they love the life of enjoyment. For there are, we may
say, three prominent types of life- that just mentioned, the political, and thirdly the contemplative life. Now
the mass of mankind are evidently quite slavish in their tastes, preferring a life suitable to beasts, but they get
some ground for their view from the fact that many of those in high places share the tastes of Sardanapallus.
A consideration of the prominent types of life shows that people of superior refinement and of active
disposition identify happiness with honour; for this is, roughly speaking, the end of the political life. But it
seems too superficial to be what we are looking for, since it is thought to depend on those who bestow honour
rather than on him who receives it, but the good we divine to be something proper to a man and not easily
taken from him. Further, men seem to pursue honour in order that they may be assured of their goodness; at
least it is by men of practical wisdom that they seek to be honoured, and among those who know them, and
on the ground of their virtue; clearly, then, according to them, at any rate, virtue is better. And perhaps one
might even suppose this to be, rather than honour, the end of the political life. But even this appears
somewhat incomplete; for possession of virtue seems actually compatible with being asleep, or with lifelong
inactivity, and, further, with the greatest sufferings and misfortunes; but a man who was living so no one
would call happy, unless he were maintaining a thesis at all costs. But enough of this; for the subject has been
sufficiently treated even in the current discussions. Third comes the contemplative life, which we shall
consider later.

The life of money-making is one undertaken under compulsion, and wealth is evidently not the good we are
seeking; for it is merely useful and for the sake of something else. And so one might rather take the
aforenamed objects to be ends; for they are loved for themselves. But it is evident that not even these are
ends; yet many arguments have been thrown away in support of them. Let us leave this subject, then.

We had perhaps better consider the universal good and discuss thoroughly what is meant by it, although such
an inquiry is made an uphill one by the fact that the Forms have been introduced by friends of our own. Yet it
would perhaps be thought to be better, indeed to be our duty, for the sake of maintaining the truth even to
destroy what touches us closely, especially as we are philosophers or lovers of wisdom; for, while both are
dear, piety requires us to honour truth above our friends.

The men who introduced this doctrine did not posit Ideas of classes within which they recognized priority and
posteriority (which is the reason why they did not maintain the existence of an Idea embracing all numbers);
but the term 'good' is used both in the category of substance and in that of quality and in that of relation, and
that which is per se, i.e. substance, is prior in nature to the relative (for the latter is like an off shoot and
accident of being); so that there could not be a common Idea set over all these goods. Further, since 'good' has
as many senses as 'being' (for it is predicated both in the category of substance, as of God and of reason, and
in quality, i.e. of the virtues, and in quantity, i.e. of that which is moderate, and in relation, i.e. of the useful,
and in time, i.e. of the right opportunity, and in place, i.e. of the right locality and the like), clearly it cannot
be something universally present in all cases and single; for then it could not have been predicated in all the
categories but in one only. Further, since of the things answering to one Idea there is one science, there would
have been one science of all the goods; but as it is there are many sciences even of the things that fall under
one category, e.g. of opportunity, for opportunity in war is studied by strategics and in disease by medicine,
and the moderate in food is studied by medicine and in exercise by the science of gymnastics. And one might
ask the question, what in the world they mean by 'a thing itself, is (as is the case) in 'man himself and in a
particular man the account of man is one and the same. For in so far as they are man, they will in no respect
differ; and if this is so, neither will 'good itself and particular goods, in so far as they are good. But again it

Nicomachean Ethics 3

Nicomachean Ethics

will not be good any the more for being eternal, since that which lasts long is no whiter than that which
perishes in a day. The Pythagoreans seem to give a more plausible account of the good, when they place the
one in the column of goods; and it is they that Speusippus seems to have followed.

But let us discuss these matters elsewhere; an objection to what we have said, however, may be discerned in
the fact that the Platonists have not been speaking about all goods, and that the goods that are pursued and
loved for themselves are called good by reference to a single Form, while those which tend to produce or to
preserve these somehow or to prevent their contraries are called so by reference to these, and in a secondary
sense. Clearly, then, goods must be spoken of in two ways, and some must be good in themselves, the others
by reason of these. Let us separate, then, things good in themselves from things useful, and consider whether
the former are called good by reference to a single Idea. What sort of goods would one call good in
themselves? Is it those that are pursued even when isolated from others, such as intelligence, sight, and
certain pleasures and honours? Certainly, if we pursue these also for the sake of something else, yet one
would place them among things good in themselves. Or is nothing other than the Idea of good good in itself?
In that case the Form will be empty. But if the things we have named are also things good in themselves, the
account of the good will have to appear as something identical in them all, as that of whiteness is identical in
snow and in white lead. But of honour, wisdom, and pleasure, just in respect of their goodness, the accounts
are distinct and diverse. The good, therefore, is not some common element answering to one Idea.

But what then do we mean by the good? It is surely not like the things that only chance to have the same
name. Are goods one, then, by being derived from one good or by all contributing to one good, or are they
rather one by analogy? Certainly as sight is in the body, so is reason in the soul, and so on in other cases. But
perhaps these subjects had better be dismissed for the present; for perfect precision about them would be
more appropriate to another branch of philosophy. And similarly with regard to the Idea; even if there is some
one good which is universally predicable of goods or is capable of separate and independent existence,
clearly it could not be achieved or attained by man; but we are now seeking something attainable. Perhaps,
however, some one might think it worth while to recognize this with a view to the goods that are attainable
and achievable; for having this as a sort of pattern we shall know better the goods that are good for us, and if
we know them shall attain them. This argument has some plausibility, but seems to clash with the procedure
of the sciences; for all of these, though they aim at some good and seek to supply the deficiency of it, leave
on one side the knowledge of the good. Yet that all the exponents of the arts should be ignorant of, and
should not even seek, so great an aid is not probable. It is hard, too, to see how a weaver or a carpenter will
be benefited in regard to his own craft by knowing this 'good itself, or how the man who has viewed the Idea
itself will be a better doctor or general thereby. For a doctor seems not even to study health in this way, but
the health of man, or perhaps rather the health of a particular man; it is individuals that he is healing. But
enough of these topics.

Let us again return to the good we are seeking, and ask what it can be. It seems different in different actions
and arts; it is different in medicine, in strategy, and in the other arts likewise. What then is the good of each?
Surely that for whose sake everything else is done. In medicine this is health, in strategy victory, in
architecture a house, in any other sphere something else, and in every action and pursuit the end; for it is for
the sake of this that all men do whatever else they do. Therefore, if there is an end for all that we do, this will
be the good achievable by action, and if there are more than one, these will be the goods achievable by action.

So the argument has by a different course reached the same point; but we must try to state this even more
clearly. Since there are evidently more than one end, and we choose some of these (e.g. wealth, flutes, and in
general instruments) for the sake of something else, clearly not all ends are final ends; but the chief good is
evidently something final. Therefore, if there is only one final end, this will be what we are seeking, and if
there are more than one, the most final of these will be what we are seeking. Now we call that which is in
itself worthy of pursuit more final than that which is worthy of pursuit for the sake of something else, and
that which is never desirable for the sake of something else more final than the things that are desirable both

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in themselves and for the sake of that other thing, and therefore we call final without qualification that which
is always desirable in itself and never for the sake of something else.

Now such a thing happiness, above all else, is held to be; for this we choose always for self and never for the
sake of something else, but honour, pleasure, reason, and every virtue we choose indeed for themselves (for if
nothing resulted from them we should still choose each of them), but we choose them also for the sake of
happiness, judging that by means of them we shall be happy. Happiness, on the other hand, no one chooses
for the sake of these, nor, in general, for anything other than itself.

From the point of view of self-sufficiency the same result seems to follow; for the final good is thought to be
self-sufficient. Now by self-sufficient we do not mean that which is sufficient for a man by himself, for one
who lives a solitary life, but also for parents, children, wife, and in general for his friends and fellow citizens,
since man is born for citizenship. But some limit must be set to this; for if we extend our requirement to
ancestors and descendants and friends' friends we are in for an infinite series. Let us examine this question,
however, on another occasion; the self-sufficient we now define as that which when isolated makes life
desirable and lacking in nothing; and such we think happiness to be; and further we think it most desirable of
all things, without being counted as one good thing among others- if it were so counted it would clearly be
made more desirable by the addition of even the least of goods; for that which is added becomes an excess of
goods, and of goods the greater is always more desirable. Happiness, then, is something final and
self-sufficient, and is the end of action.

Presumably, however, to say that happiness is the chief good seems a platitude, and a clearer account of what
it is still desired. This might perhaps be given, if we could first ascertain the function of man. For just as for a
flute-player, a sculptor, or an artist, and, in general, for all things that have a function or activity, the good
and the 'well' is thought to reside in the function, so would it seem to be for man, if he has a function. Have
the carpenter, then, and the tanner certain functions or activities, and has man none? Is he born without a
function? Or as eye, hand, foot, and in general each of the parts evidently has a function, may one lay it down
that man similarly has a function apart from all these? What then can this be? Life seems to be common even
to plants, but we are seeking what is peculiar to man. Let us exclude, therefore, the life of nutrition and
growth. Next there would be a life of perception, but it also seems to be common even to the horse, the ox,
and every animal. There remains, then, an active life of the element that has a rational principle; of this, one
part has such a principle in the sense of being obedient to one, the other in the sense of possessing one and
exercising thought. And, as 'life of the rational element' also has two meanings, we must state that life in the
sense of activity is what we mean; for this seems to be the more proper sense of the term. Now if the function
of man is an activity of soul which follows or implies a rational principle, and if we say 'so-and-so-and 'a
good so-and-so' have a function which is the same in kind, e.g. a lyre, and a good lyre-player, and so
without qualification in all cases, eminence in respect of goodness being idded to the name of the function
(for the function of a lyre-player is to play the lyre, and that of a good lyre-player is to do so well): if this is
the case, and we state the function of man to be a certain kind of life, and this to be an activity or actions of
the soul implying a rational principle, and the function of a good man to be the good and noble performance
of these, and if any action is well performed when it is performed in accordance with the appropriate
excellence: if this is the case, human good turns out to be activity of soul in accordance with virtue, and if
there are more than one virtue, in accordance with the best and most complete.

But we must add 'in a complete life.' For one swallow does not make a summer, nor does one day; and so too
one day, or a short time, does not make a man blessed and happy.

Let this serve as an outline of the good; for we must presumably first sketch it roughly, and then later fill in
the details. But it would seem that any one is capable of carrying on and articulating what has once been well
outlined, and that time is a good discoverer or partner in such a work; to which facts the advances of the arts
are due; for any one can add what is lacking. And we must also remember what has been said before, and not

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look for precision in all things alike, but in each class of things such precision as accords with the
subject-matter, and so much as is appropriate to the inquiry. For a carpenter and a geometer investigate the
right angle in different ways; the former does so in so far as the right angle is useful for his work, while the
latter inquires what it is or what sort of thing it is; for he is a spectator of the truth. We must act in the same
way, then, in all other matters as well, that our main task may not be subordinated to minor questions. Nor
must we demand the cause in all matters alike; it is enough in some cases that the fact be well established, as
in the case of the first principles; the fact is the primary thing or first principle. Now of first principles we see
some by induction, some by perception, some by a certain habituation, and others too in other ways. But each
set of principles we must try to investigate in the natural way, and we must take pains to state them definitely,
since they have a great influence on what follows. For the beginning is thought to be more than half of the
whole, and many of the questions we ask are cleared up by it.

We must consider it, however, in the light not only of our conclusion and our premisses, but also of what is
commonly said about it; for with a true view all the data harmonize, but with a false one the facts soon clash.
Now goods have been divided into three classes, and some are described as external, others as relating to soul
or to body; we call those that relate to soul most properly and truly goods, and psychical actions and activities
we class as relating to soul. Therefore our account must be sound, at least according to this view, which is an
old one and agreed on by philosophers. It is correct also in that we identify the end with certain actions and
activities; for thus it falls among goods of the soul and not among external goods. Another belief which
harmonizes with our account is that the happy man lives well and does well; for we have practically defined
happiness as a sort of good life and good action. The characteristics that are looked for in happiness seem
also, all of them, to belong to what we have defined happiness as being. For some identify happiness with
virtue, some with practical wisdom, others with a kind of philosophic wisdom, others with these, or one of
these, accompanied by pleasure or not without pleasure; while others include also external prosperity. Now
some of these views have been held by many men and men of old, others by a few eminent persons; and it is
not probable that either of these should be entirely mistaken, but rather that they should be right in at least
some one respect or even in most respects.

With those who identify happiness with virtue or some one virtue our account is in harmony; for to virtue
belongs virtuous activity. But it makes, perhaps, no small difference whether we place the chief good in
possession or in use, in state of mind or in activity. For the state of mind may exist without producing any
good result, as in a man who is asleep or in some other way quite inactive, but the activity cannot; for one
who has the activity will of necessity be acting, and acting well. And as in the Olympic Games it is not the
most beautiful and the strongest that are crowned but those who compete (for it is some of these that are
victorious), so those who act win, and rightly win, the noble and good things in life.

Their life is also in itself pleasant. For pleasure is a state of soul, and to each man that which he is said to be a
lover of is pleasant; e.g. not only is a horse pleasant to the lover of horses, and a spectacle to the lover of
sights, but also in the same way just acts are pleasant to the lover of justice and in general virtuous acts to the
lover of virtue. Now for most men their pleasures are in conflict with one another because these are not by
nature pleasant, but the lovers of what is noble find pleasant the things that are by nature pleasant; and
virtuous actions are such, so that these are pleasant for such men as well as in their own nature. Their life,
therefore, has no further need of pleasure as a sort of adventitious charm, but has its pleasure in itself. For,
besides what we have said, the man who does not rejoice in noble actions is not even good; since no one
would call a man just who did not enjoy acting justly, nor any man liberal who did not enjoy liberal actions;
and similarly in all other cases. If this is so, virtuous actions must be in themselves pleasant. But they are also
good and noble, and have each of these attributes in the highest degree, since the good man judges well about
these attributes; his judgement is such as we have described. Happiness then is the best, noblest, and most
pleasant thing in the world, and these attributes are not severed as in the inscription at Delos-

Most noble is that which is justest, and best is health;
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But pleasantest is it to win what we love.

For all these properties belong to the best activities; and these, or one- the best- of these, we identify with
happiness.

Yet evidently, as we said, it needs the external goods as well; for it is impossible, or not easy, to do noble acts
without the proper equipment. In many actions we use friends and riches and political power as instruments;
and there are some things the lack of which takes the lustre from happiness, as good birth, goodly children,
beauty; for the man who is very ugly in appearance or ill-born or solitary and childless is not very likely to
be happy, and perhaps a man would be still less likely if he had thoroughly bad children or friends or had lost
good children or friends by death. As we said, then, happiness seems to need this sort of prosperity in
addition; for which reason some identify happiness with good fortune, though others identify it with virtue.

For this reason also the question is asked, whether happiness is to be acquired by learning or by habituation
or some other sort of training, or comes in virtue of some divine providence or again by chance. Now if there
is any gift of the gods to men, it is reasonable that happiness should be god-given, and most surely
god-given of all human things inasmuch as it is the best. But this question would perhaps be more
appropriate to another inquiry; happiness seems, however, even if it is not god-sent but comes as a result of
virtue and some process of learning or training, to be among the most godlike things; for that which is the
prize and end of virtue seems to be the best thing in the world, and something godlike and blessed.

It will also on this view be very generally shared; for all who are not maimed as regards their potentiality for
virtue may win it by a certain kind of study and care. But if it is better to be happy thus than by chance, it is
reasonable that the facts should be so, since everything that depends on the action of nature is by nature as
good as it can be, and similarly everything that depends on art or any rational cause, and especially if it
depends on the best of all causes. To entrust to chance what is greatest and most noble would be a very
defective arrangement.

The answer to the question we are asking is plain also from the definition of happiness; for it has been said to
be a virtuous activity of soul, of a certain kind. Of the remaining goods, some must necessarily pre-exist as
conditions of happiness, and others are naturally co-operative and useful as instruments. And this will be
found to agree with what we said at the outset; for we stated the end of political science to be the best end,
and political science spends most of its pains on making the citizens to be of a certain character, viz. good
and capable of noble acts.

It is natural, then, that we call neither ox nor horse nor any other of the animals happy; for none of them is
capable of sharing in such activity. For this reason also a boy is not happy; for he is not yet capable of such
acts, owing to his age; and boys who are called happy are being congratulated by reason of the hopes we have
for them. For there is required, as we said, not only complete virtue but also a complete life, since many
changes occur in life, and all manner of chances, and the most prosperous may fall into great misfortunes in
old age, as is told of Priam in the Trojan Cycle; and one who has experienced such chances and has ended
wretchedly no one calls happy.

Must no one at all, then, be called happy while he lives; must we, as Solon says, see the end? Even if we are
to lay down this doctrine, is it also the case that a man is happy when he is dead? Or is not this quite absurd,
especially for us who say that happiness is an activity? But if we do not call the dead man happy, and if Solon
does not mean this, but that one can then safely call a man blessed as being at last beyond evils and
misfortunes, this also affords matter for discussion; for both evil and good are thought to exist for a dead
man, as much as for one who is alive but not aware of them; e.g. honours and dishonours and the good or bad
fortunes of children and in general of descendants. And this also presents a problem; for though a man has
lived happily up to old age and has had a death worthy of his life, many reverses may befall his descendants-

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some of them may be good and attain the life they deserve, while with others the opposite may be the case;
and clearly too the degrees of relationship between them and their ancestors may vary indefinitely. It would
be odd, then, if the dead man were to share in these changes and become at one time happy, at another
wretched; while it would also be odd if the fortunes of the descendants did not for some time have some
effect on the happiness of their ancestors.

But we must return to our first difficulty; for perhaps by a consideration of it our present problem might be
solved. Now if we must see the end and only then call a man happy, not as being happy but as having been so
before, surely this is a paradox, that when he is happy the attribute that belongs to him is not to be truly
predicated of him because we do not wish to call living men happy, on account of the changes that may befall
them, and because we have assumed happiness to be something permanent and by no means easily changed,
while a single man may suffer many turns of fortune's wheel. For clearly if we were to keep pace with his
fortunes, we should often call the same man happy and again wretched, making the happy man out to be
chameleon and insecurely based. Or is this keeping pace with his fortunes quite wrong? Success or failure in
life does not depend on these, but human life, as we said, needs these as mere additions, while virtuous
activities or their opposites are what constitute happiness or the reverse.

The question we have now discussed confirms our definition. For no function of man has so much
permanence as virtuous activities (these are thought to be more durable even than knowledge of the sciences),
and of these themselves the most valuable are more durable because those who are happy spend their life
most readily and most continuously in these; for this seems to be the reason why we do not forget them. The
attribute in question, then, will belong to the happy man, and he will be happy throughout his life; for always,
or by preference to everything else, he will be engaged in virtuous action and contemplation, and he will bear
the chances of life most nobly and altogether decorously, if he is 'truly good' and 'foursquare beyond
reproach'.

Now many events happen by chance, and events differing in importance; small pieces of good fortune or of
its opposite clearly do not weigh down the scales of life one way or the other, but a multitude of great events
if they turn out well will make life happier (for not only are they themselves such as to add beauty to life, but
the way a man deals with them may be noble and good), while if they turn out ill they crush and maim
happiness; for they both bring pain with them and hinder many activities. Yet even in these nobility shines
through, when a man bears with resignation many great misfortunes, not through insensibility to pain but
through nobility and greatness of soul.

If activities are, as we said, what gives life its character, no happy man can become miserable; for he will
never do the acts that are hateful and mean. For the man who is truly good and wise, we think, bears all the
chances life becomingly and always makes the best of circumstances, as a good general makes the best
military use of the army at his command and a good shoemaker makes the best shoes out of the hides that are
given him; and so with all other craftsmen. And if this is the case, the happy man can never become
miserable; though he will not reach blessedness, if he meet with fortunes like those of Priam.

Nor, again, is he many-coloured and changeable; for neither will he be moved from his happy state easily or
by any ordinary misadventures, but only by many great ones, nor, if he has had many great misadventures,
will he recover his happiness in a short time, but if at all, only in a long and complete one in which he has
attained many splendid successes.

When then should we not say that he is happy who is active in accordance with complete virtue and is
sufficiently equipped with external goods, not for some chance period but throughout a complete life? Or
must we add 'and who is destined to live thus and die as befits his life'? Certainly the future is obscure to us,
while happiness, we claim, is an end and something in every way final. If so, we shall call happy those
among living men in whom these conditions are, and are to be, fulfilled- but happy men. So much for these

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questions.

That the fortunes of descendants and of all a man's friends should not affect his happiness at all seems a very
unfriendly doctrine, and one opposed to the opinions men hold; but since the events that happen are
numerous and admit of all sorts of difference, and some come more near to us and others less so, it seems a
long- nay, an infinite- task to discuss each in detail; a general outline will perhaps suffice. If, then, as some
of a man's own misadventures have a certain weight and influence on life while others are, as it were, lighter,
so too there are differences among the misadventures of our friends taken as a whole, and it makes a
difference whether the various suffering befall the living or the dead (much more even than whether lawless
and terrible deeds are presupposed in a tragedy or done on the stage), this difference also must be taken into
account; or rather, perhaps, the fact that doubt is felt whether the dead share in any good or evil. For it seems,
from these considerations, that even if anything whether good or evil penetrates to them, it must be
something weak and negligible, either in itself or for them, or if not, at least it must be such in degree and
kind as not to make happy those who are not happy nor to take away their blessedness from those who are.
The good or bad fortunes of friends, then, seem to have some effects on the dead, but effects of such a kind
and degree as neither to make the happy unhappy nor to produce any other change of the kind.

These questions having been definitely answered, let us consider whether happiness is among the things that
are praised or rather among the things that are prized; for clearly it is not to be placed among potentialities.
Everything that is praised seems to be praised because it is of a certain kind and is related somehow to
something else; for we praise the just or brave man and in general both the good man and virtue itself because
of the actions and functions involved, and we praise the strong man, the good runner, and so on, because he is
of a certain kind and is related in a certain way to something good and important. This is clear also from the
praises of the gods; for it seems absurd that the gods should be referred to our standard, but this is done
because praise involves a reference, to something else. But if if praise is for things such as we have described,
clearly what applies to the best things is not praise, but something greater and better, as is indeed obvious; for
what we do to the gods and the most godlike of men is to call them blessed and happy. And so too with good
things; no one praises happiness as he does justice, but rather calls it blessed, as being something more divine
and better.

Eudoxus also seems to have been right in his method of advocating the supremacy of pleasure; he thought
that the fact that, though a good, it is not praised indicated it to be better than the things that are praised, and
that this is what God and the good are; for by reference to these all other things are judged. Praise is
appropriate to virtue, for as a result of virtue men tend to do noble deeds, but encomia are bestowed on acts,
whether of the body or of the soul. But perhaps nicety in these matters is more proper to those who have
made a study of encomia; to us it is clear from what has been said that happiness is among the things that are
prized and perfect. It seems to be so also from the fact that it is a first principle; for it is for the sake of this
that we all do all that we do, and the first principle and cause of goods is, we claim, something prized and
divine.

Since happiness is an activity of soul in accordance with perfect virtue, we must consider the nature of virtue;
for perhaps we shall thus see better the nature of happiness. The true student of politics, too, is thought to
have studied virtue above all things; for he wishes to make his fellow citizens good and obedient to the laws.
As an example of this we have the lawgivers of the Cretans and the Spartans, and any others of the kind that
there may have been. And if this inquiry belongs to political science, clearly the pursuit of it will be in
accordance with our original plan. But clearly the virtue we must study is human virtue; for the good we were
seeking was human good and the happiness human happiness. By human virtue we mean not that of the body
but that of the soul; and happiness also we call an activity of soul. But if this is so, clearly the student of
politics must know somehow the facts about soul, as the man who is to heal the eyes or the body as a whole
must know about the eyes or the body; and all the more since politics is more prized and better than
medicine; but even among doctors the best educated spend much labour on acquiring knowledge of the body.

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The student of politics, then, must study the soul, and must study it with these objects in view, and do so just
to the extent which is sufficient for the questions we are discussing; for further precision is perhaps
something more laborious than our purposes require.

Some things are said about it, adequately enough, even in the discussions outside our school, and we must
use these; e.g. that one element in the soul is irrational and one has a rational principle. Whether these are
separated as the parts of the body or of anything divisible are, or are distinct by definition but by nature
inseparable, like convex and concave in the circumference of a circle, does not affect the present question.

Of the irrational element one division seems to be widely distributed, and vegetative in its nature, I mean that
which causes nutrition and growth; for it is this kind of power of the soul that one must assign to all nurslings
and to embryos, and this same power to fullgrown creatures; this is more reasonable than to assign some
different power to them. Now the excellence of this seems to be common to all species and not specifically
human; for this part or faculty seems to function most in sleep, while goodness and badness are least manifest
in sleep (whence comes the saying that the happy are not better off than the wretched for half their lives; and
this happens naturally enough, since sleep is an inactivity of the soul in that respect in which it is called good
or bad), unless perhaps to a small extent some of the movements actually penetrate to the soul, and in this
respect the dreams of good men are better than those of ordinary people. Enough of this subject, however; let
us leave the nutritive faculty alone, since it has by its nature no share in human excellence.

There seems to be also another irrational element in the soul-one which in a sense, however, shares in a
rational principle. For we praise the rational principle of the continent man and of the incontinent, and the
part of their soul that has such a principle, since it urges them aright and towards the best objects; but there is
found in them also another element naturally opposed to the rational principle, which fights against and
resists that principle. For exactly as paralysed limbs when we intend to move them to the right turn on the
contrary to the left, so is it with the soul; the impulses of incontinent people move in contrary directions. But
while in the body we see that which moves astray, in the soul we do not. No doubt, however, we must none
the less suppose that in the soul too there is something contrary to the rational principle, resisting and
opposing it. In what sense it is distinct from the other elements does not concern us. Now even this seems to
have a share in a rational principle, as we said; at any rate in the continent man it obeys the rational principle
and presumably in the temperate and brave man it is still more obedient; for in him it speaks, on all matters,
with the same voice as the rational principle.

Therefore the irrational element also appears to be two-fold. For the vegetative element in no way shares in a
rational principle, but the appetitive and in general the desiring element in a sense shares in it, in so far as it
listens to and obeys it; this is the sense in which we speak of 'taking account' of one's father or one's friends,
not that in which we speak of 'accounting for a mathematical property. That the irrational element is in some
sense persuaded by a rational principle is indicated also by the giving of advice and by all reproof and
exhortation. And if this element also must be said to have a rational principle, that which has a rational
principle (as well as that which has not) will be twofold, one subdivision having it in the strict sense and in
itself, and the other having a tendency to obey as one does one's father.

Virtue too is distinguished into kinds in accordance with this difference; for we say that some of the virtues
are intellectual and others moral, philosophic wisdom and understanding and practical wisdom being
intellectual, liberality and temperance moral. For in speaking about a man's character we do not say that he is
wise or has understanding but that he is good-tempered or temperate; yet we praise the wise man also with
respect to his state of mind; and of states of mind we call those which merit praise virtues.

BOOK II

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VIRTUE, then, being of two kinds, intellectual and moral, intellectual virtue in the main owes both its birth
and its growth to teaching (for which reason it requires experience and time), while moral virtue comes about
as a result of habit, whence also its name (ethike) is one that is formed by a slight variation from the word
ethos (habit). From this it is also plain that none of the moral virtues arises in us by nature; for nothing that
exists by nature can form a habit contrary to its nature. For instance the stone which by nature moves
downwards cannot be habituated to move upwards, not even if one tries to train it by throwing it up ten
thousand times; nor can fire be habituated to move downwards, nor can anything else that by nature behaves
in one way be trained to behave in another. Neither by nature, then, nor contrary to nature do the virtues arise
in us; rather we are adapted by nature to receive them, and are made perfect by habit.

Again, of all the things that come to us by nature we first acquire the potentiality and later exhibit the activity
(this is plain in the case of the senses; for it was not by often seeing or often hearing that we got these senses,
but on the contrary we had them before we used them, and did not come to have them by using them); but the
virtues we get by first exercising them, as also happens in the case of the arts as well. For the things we have
to learn before we can do them, we learn by doing them, e.g. men become builders by building and
lyreplayers by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts,
brave by doing brave acts.

This is confirmed by what happens in states; for legislators make the citizens good by forming habits in them,
and this is the wish of every legislator, and those who do not effect it miss their mark, and it is in this that a
good constitution differs from a bad one.

Again, it is from the same causes and by the same means that every virtue is both produced and destroyed,
and similarly every art; for it is from playing the lyre that both good and bad lyre-players are produced. And
the corresponding statement is true of builders and of all the rest; men will be good or bad builders as a result
of building well or badly. For if this were not so, there would have been no need of a teacher, but all men
would have been born good or bad at their craft. This, then, is the case with the virtues also; by doing the acts
that we do in our transactions with other men we become just or unjust, and by doing the acts that we do in
the presence of danger, and being habituated to feel fear or confidence, we become brave or cowardly. The
same is true of appetites and feelings of anger; some men become temperate and good-tempered, others
self-indulgent and irascible, by behaving in one way or the other in the appropriate circumstances. Thus, in
one word, states of character arise out of like activities. This is why the activities we exhibit must be of a
certain kind; it is because the states of character correspond to the differences between these. It makes no
small difference, then, whether we form habits of one kind or of another from our very youth; it makes a very
great difference, or rather all the difference.

Since, then, the present inquiry does not aim at theoretical knowledge like the others (for we are inquiring not
in order to know what virtue is, but in order to become good, since otherwise our inquiry would have been of
no use), we must examine the nature of actions, namely how we ought to do them; for these determine also
the nature of the states of character that are produced, as we have said. Now, that we must act according to
the right rule is a common principle and must be assumed-it will be discussed later, i.e. both what the right
rule is, and how it is related to the other virtues. But this must be agreed upon beforehand, that the whole
account of matters of conduct must be given in outline and not precisely, as we said at the very beginning that
the accounts we demand must be in accordance with the subject-matter; matters concerned with conduct and
questions of what is good for us have no fixity, any more than matters of health. The general account being of
this nature, the account of particular cases is yet more lacking in exactness; for they do not fall under any art
or precept but the agents themselves must in each case consider what is appropriate to the occasion, as
happens also in the art of medicine or of navigation.

But though our present account is of this nature we must give what help we can. First, then, let us consider
this, that it is the nature of such things to be destroyed by defect and excess, as we see in the case of strength

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and of health (for to gain light on things imperceptible we must use the evidence of sensible things); both
excessive and defective exercise destroys the strength, and similarly drink or food which is above or below a
certain amount destroys the health, while that which is proportionate both produces and increases and
preserves it. So too is it, then, in the case of temperance and courage and the other virtues. For the man who
flies from and fears everything and does not stand his ground against anything becomes a coward, and the
man who fears nothing at all but goes to meet every danger becomes rash; and similarly the man who
indulges in every pleasure and abstains from none becomes self-indulgent, while the man who shuns every
pleasure, as boors do, becomes in a way insensible; temperance and courage, then, are destroyed by excess
and defect, and preserved by the mean.

But not only are the sources and causes of their origination and growth the same as those of their destruction,
but also the sphere of their actualization will be the same; for this is also true of the things which are more
evident to sense, e.g. of strength; it is produced by taking much food and undergoing much exertion, and it is
the strong man that will be most able to do these things. So too is it with the virtues; by abstaining from
pleasures we become temperate, and it is when we have become so that we are most able to abstain from
them; and similarly too in the case of courage; for by being habituated to despise things that are terrible and
to stand our ground against them we become brave, and it is when we have become so that we shall be most
able to stand our ground against them.

We must take as a sign of states of character the pleasure or pain that ensues on acts; for the man who
abstains from bodily pleasures and delights in this very fact is temperate, while the man who is annoyed at it
is self-indulgent, and he who stands his ground against things that are terrible and delights in this or at least
is not pained is brave, while the man who is pained is a coward. For moral excellence is concerned with
pleasures and pains; it is on account of the pleasure that we do bad things, and on account of the pain that we
abstain from noble ones. Hence we ought to have been brought up in a particular way from our very youth, as
Plato says, so as both to delight in and to be pained by the things that we ought; for this is the right education.

Again, if the virtues are concerned with actions and passions, and every passion and every action is
accompanied by pleasure and pain, for this reason also virtue will be concerned with pleasures and pains.
This is indicated also by the fact that punishment is inflicted by these means; for it is a kind of cure, and it is
the nature of cures to be effected by contraries.

Again, as we said but lately, every state of soul has a nature relative to and concerned with the kind of things
by which it tends to be made worse or better; but it is by reason of pleasures and pains that men become bad,
by pursuing and avoiding these- either the pleasures and pains they ought not or when they ought not or as
they ought not, or by going wrong in one of the other similar ways that may be distinguished. Hence men
even define the virtues as certain states of impassivity and rest; not well, however, because they speak
absolutely, and do not say 'as one ought' and 'as one ought not' and 'when one ought or ought not', and the
other things that may be added. We assume, then, that this kind of excellence tends to do what is best with
regard to pleasures and pains, and vice does the contrary.

The following facts also may show us that virtue and vice are concerned with these same things. There being
three objects of choice and three of avoidance, the noble, the advantageous, the pleasant, and their contraries,
the base, the injurious, the painful, about all of these the good man tends to go right and the bad man to go
wrong, and especially about pleasure; for this is common to the animals, and also it accompanies all objects
of choice; for even the noble and the advantageous appear pleasant.

Again, it has grown up with us all from our infancy; this is why it is difficult to rub off this passion,
engrained as it is in our life. And we measure even our actions, some of us more and others less, by the rule
of pleasure and pain. For this reason, then, our whole inquiry must be about these; for to feel delight and pain
rightly or wrongly has no small effect on our actions.

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Again, it is harder to fight with pleasure than with anger, to use Heraclitus' phrase', but both art and virtue are
always concerned with what is harder; for even the good is better when it is harder. Therefore for this reason
also the whole concern both of virtue and of political science is with pleasures and pains; for the man who
uses these well will be good, he who uses them badly bad.

That virtue, then, is concerned with pleasures and pains, and that by the acts from which it arises it is both
increased and, if they are done differently, destroyed, and that the acts from which it arose are those in which
it actualizes itself- let this be taken as said.

The question might be asked,; what we mean by saying that we must become just by doing just acts, and
temperate by doing temperate acts; for if men do just and temperate acts, they are already just and temperate,
exactly as, if they do what is in accordance with the laws of grammar and of music, they are grammarians and
musicians.

Or is this not true even of the arts? It is possible to do something that is in accordance with the laws of
grammar, either by chance or at the suggestion of another. A man will be a grammarian, then, only when he
has both done something grammatical and done it grammatically; and this means doing it in accordance with
the grammatical knowledge in himself.

Again, the case of the arts and that of the virtues are not similar; for the products of the arts have their
goodness in themselves, so that it is enough that they should have a certain character, but if the acts that are in
accordance with the virtues have themselves a certain character it does not follow that they are done justly or
temperately. The agent also must be in a certain condition when he does them; in the first place he must have
knowledge, secondly he must choose the acts, and choose them for their own sakes, and thirdly his action
must proceed from a firm and unchangeable character. These are not reckoned in as conditions of the
possession of the arts, except the bare knowledge; but as a condition of the possession of the virtues
knowledge has little or no weight, while the other conditions count not for a little but for everything, i.e. the
very conditions which result from often doing just and temperate acts.

Actions, then, are called just and temperate when they are such as the just or the temperate man would do; but
it is not the man who does these that is just and temperate, but the man who also does them as just and
temperate men do them. It is well said, then, that it is by doing just acts that the just man is produced, and by
doing temperate acts the temperate man; without doing these no one would have even a prospect of becoming
good.

But most people do not do these, but take refuge in theory and think they are being philosophers and will
become good in this way, behaving somewhat like patients who listen attentively to their doctors, but do none
of the things they are ordered to do. As the latter will not be made well in body by such a course of treatment,
the former will not be made well in soul by such a course of philosophy.

Next we must consider what virtue is. Since things that are found in the soul are of three kinds- passions,
faculties, states of character, virtue must be one of these. By passions I mean appetite, anger, fear,
confidence, envy, joy, friendly feeling, hatred, longing, emulation, pity, and in general the feelings that are
accompanied by pleasure or pain; by faculties the things in virtue of which we are said to be capable of
feeling these, e.g. of becoming angry or being pained or feeling pity; by states of character the things in virtue
of which we stand well or badly with reference to the passions, e.g. with reference to anger we stand badly if
we feel it violently or too weakly, and well if we feel it moderately; and similarly with reference to the other
passions.

Now neither the virtues nor the vices are passions, because we are not called good or bad on the ground of
our passions, but are so called on the ground of our virtues and our vices, and because we are neither praised

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nor blamed for our passions (for the man who feels fear or anger is not praised, nor is the man who simply
feels anger blamed, but the man who feels it in a certain way), but for our virtues and our vices we are praised
or blamed.

Again, we feel anger and fear without choice, but the virtues are modes of choice or involve choice. Further,
in respect of the passions we are said to be moved, but in respect of the virtues and the vices we are said not
to be moved but to be disposed in a particular way.

For these reasons also they are not faculties; for we are neither called good nor bad, nor praised nor blamed,
for the simple capacity of feeling the passions; again, we have the faculties by nature, but we are not made
good or bad by nature; we have spoken of this before. If, then, the virtues are neither passions nor faculties,
all that remains is that they should be states of character.

Thus we have stated what virtue is in respect of its genus.

We must, however, not only describe virtue as a state of character, but also say what sort of state it is. We
may remark, then, that every virtue or excellence both brings into good condition the thing of which it is the
excellence and makes the work of that thing be done well; e.g. the excellence of the eye makes both the eye
and its work good; for it is by the excellence of the eye that we see well. Similarly the excellence of the horse
makes a horse both good in itself and good at running and at carrying its rider and at awaiting the attack of
the enemy. Therefore, if this is true in every case, the virtue of man also will be the state of character which
makes a man good and which makes him do his own work well.

How this is to happen we have stated already, but it will be made plain also by the following consideration of
the specific nature of virtue. In everything that is continuous and divisible it is possible to take more, less, or
an equal amount, and that either in terms of the thing itself or relatively to us; and the equal is an intermediate
between excess and defect. By the intermediate in the object I mean that which is equidistant from each of the
extremes, which is one and the same for all men; by the intermediate relatively to us that which is neither too
much nor too little- and this is not one, nor the same for all. For instance, if ten is many and two is few, six is
the intermediate, taken in terms of the object; for it exceeds and is exceeded by an equal amount; this is
intermediate according to arithmetical proportion. But the intermediate relatively to us is not to be taken so; if
ten pounds are too much for a particular person to eat and two too little, it does not follow that the trainer will
order six pounds; for this also is perhaps too much for the person who is to take it, or too little- too little for
Milo, too much for the beginner in athletic exercises. The same is true of running and wrestling. Thus a
master of any art avoids excess and defect, but seeks the intermediate and chooses this- the intermediate not
in the object but relatively to us.

If it is thus, then, that every art does its work well- by looking to the intermediate and judgling its works by
this standard (so that we often say of good works of art that it is not possible either to take away or to add
anything, implying that excess and defect destroy the goodness of works of art, while the mean preserves it;
and good artists, as we say, look to this in their work), and if, further, virtue is more exact and better than any
art, as nature also is, then virtue must have the quality of aiming at the intermediate. I mean moral virtue; for
it is this that is concerned with passions and actions, and in these there is excess, defect, and the intermediate.
For instance, both fear and confidence and appetite and anger and pity and in general pleasure and pain may
be felt both too much and too little, and in both cases not well; but to feel them at the right times, with
reference to the right objects, towards the right people, with the right motive, and in the right way, is what is
both intermediate and best, and this is characteristic of virtue. Similarly with regard to actions also there is
excess, defect, and the intermediate. Now virtue is concerned with passions and actions, in which excess is a
form of failure, and so is defect, while the intermediate is praised and is a form of success; and being praised
and being successful are both characteristics of virtue. Therefore virtue is a kind of mean, since, as we have
seen, it aims at what is intermediate.

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Again, it is possible to fail in many ways (for evil belongs to the class of the unlimited, as the Pythagoreans
conjectured, and good to that of the limited), while to succeed is possible only in one way (for which reason
also one is easy and the other difficult- to miss the mark easy, to hit it difficult); for these reasons also, then,
excess and defect are characteristic of vice, and the mean of virtue;

For men are good in but one way, but bad in many.

Virtue, then, is a state of character concerned with choice, lying in a mean, i.e. the mean relative to us, this
being determined by a rational principle, and by that principle by which the man of practical wisdom would
determine it. Now it is a mean between two vices, that which depends on excess and that which depends on
defect; and again it is a mean because the vices respectively fall short of or exceed what is right in both
passions and actions, while virtue both finds and chooses that which is intermediate. Hence in respect of its
substance and the definition which states its essence virtue is a mean, with regard to what is best and right an
extreme.

But not every action nor every passion admits of a mean; for some have names that already imply badness,
e.g. spite, shamelessness, envy, and in the case of actions adultery, theft, murder; for all of these and suchlike
things imply by their names that they are themselves bad, and not the excesses or deficiencies of them. It is
not possible, then, ever to be right with regard to them; one must always be wrong. Nor does goodness or
badness with regard to such things depend on committing adultery with the right woman, at the right time,
and in the right way, but simply to do any of them is to go wrong. It would be equally absurd, then, to expect
that in unjust, cowardly, and voluptuous action there should be a mean, an excess, and a deficiency; for at that
rate there would be a mean of excess and of deficiency, an excess of excess, and a deficiency of deficiency.
But as there is no excess and deficiency of temperance and courage because what is intermediate is in a sense
an extreme, so too of the actions we have mentioned there is no mean nor any excess and deficiency, but
however they are done they are wrong; for in general there is neither a mean of excess and deficiency, nor
excess and deficiency of a mean.

We must, however, not only make this general statement, but also apply it to the individual facts. For among
statements about conduct those which are general apply more widely, but those which are particular are more
genuine, since conduct has to do with individual cases, and our statements must harmonize with the facts in
these cases. We may take these cases from our table. With regard to feelings of fear and confidence courage
is the mean; of the people who exceed, he who exceeds in fearlessness has no name (many of the states have
no name), while the man who exceeds in confidence is rash, and he who exceeds in fear and falls short in
confidence is a coward. With regard to pleasures and pains- not all of them, and not so much with regard to
the pains- the mean is temperance, the excess self-indulgence. Persons deficient with regard to the pleasures
are not often found; hence such persons also have received no name. But let us call them 'insensible'.

With regard to giving and taking of money the mean is liberality, the excess and the defect prodigality and
meanness. In these actions people exceed and fall short in contrary ways; the prodigal exceeds in spending
and falls short in taking, while the mean man exceeds in taking and falls short in spending. (At present we are
giving a mere outline or summary, and are satisfied with this; later these states will be more exactly
determined.) With regard to money there are also other dispositions- a mean, magnificence (for the
magnificent man differs from the liberal man; the former deals with large sums, the latter with small ones), an
excess, tastelessness and vulgarity, and a deficiency, niggardliness; these differ from the states opposed to
liberality, and the mode of their difference will be stated later. With regard to honour and dishonour the mean
is proper pride, the excess is known as a sort of 'empty vanity', and the deficiency is undue humility; and as
we said liberality was related to magnificence, differing from it by dealing with small sums, so there is a state
similarly related to proper pride, being concerned with small honours while that is concerned with great. For
it is possible to desire honour as one ought, and more than one ought, and less, and the man who exceeds in
his desires is called ambitious, the man who falls short unambitious, while the intermediate person has no

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name. The dispositions also are nameless, except that that of the ambitious man is called ambition. Hence the
people who are at the extremes lay claim to the middle place; and we ourselves sometimes call the
intermediate person ambitious and sometimes unambitious, and sometimes praise the ambitious man and
sometimes the unambitious. The reason of our doing this will be stated in what follows; but now let us speak
of the remaining states according to the method which has been indicated.

With regard to anger also there is an excess, a deficiency, and a mean. Although they can scarcely be said to
have names, yet since we call the intermediate person good-tempered let us call the mean good temper; of
the persons at the extremes let the one who exceeds be called irascible, and his vice irascibility, and the man
who falls short an inirascible sort of person, and the deficiency inirascibility.

There are also three other means, which have a certain likeness to one another, but differ from one another:
for they are all concerned with intercourse in words and actions, but differ in that one is concerned with truth
in this sphere, the other two with pleasantness; and of this one kind is exhibited in giving amusement, the
other in all the circumstances of life. We must therefore speak of these too, that we may the better see that in
all things the mean is praise-worthy, and the extremes neither praiseworthy nor right, but worthy of blame.
Now most of these states also have no names, but we must try, as in the other cases, to invent names
ourselves so that we may be clear and easy to follow. With regard to truth, then, the intermediate is a truthful
sort of person and the mean may be called truthfulness, while the pretence which exaggerates is boastfulness
and the person characterized by it a boaster, and that which understates is mock modesty and the person
characterized by it mock-modest. With regard to pleasantness in the giving of amusement the intermediate
person is ready-witted and the disposition ready wit, the excess is buffoonery and the person characterized
by it a buffoon, while the man who falls short is a sort of boor and his state is boorishness. With regard to the
remaining kind of pleasantness, that which is exhibited in life in general, the man who is pleasant in the right
way is friendly and the mean is friendliness, while the man who exceeds is an obsequious person if he has no
end in view, a flatterer if he is aiming at his own advantage, and the man who falls short and is unpleasant in
all circumstances is a quarrelsome and surly sort of person.

There are also means in the passions and concerned with the passions; since shame is not a virtue, and yet
praise is extended to the modest man. For even in these matters one man is said to be intermediate, and
another to exceed, as for instance the bashful man who is ashamed of everything; while he who falls short or
is not ashamed of anything at all is shameless, and the intermediate person is modest. Righteous indignation
is a mean between envy and spite, and these states are concerned with the pain and pleasure that are felt at the
fortunes of our neighbours; the man who is characterized by righteous indignation is pained at undeserved
good fortune, the envious man, going beyond him, is pained at all good fortune, and the spiteful man falls so
far short of being pained that he even rejoices. But these states there will be an opportunity of describing
elsewhere; with regard to justice, since it has not one simple meaning, we shall, after describing the other
states, distinguish its two kinds and say how each of them is a mean; and similarly we shall treat also of the
rational virtues.

There are three kinds of disposition, then, two of them vices, involving excess and deficiency respectively,
and one a virtue, viz. the mean, and all are in a sense opposed to all; for the extreme states are contrary both
to the intermediate state and to each other, and the intermediate to the extremes; as the equal is greater
relatively to the less, less relatively to the greater, so the middle states are excessive relatively to the
deficiencies, deficient relatively to the excesses, both in passions and in actions. For the brave man appears
rash relatively to the coward, and cowardly relatively to the rash man; and similarly the temperate man
appears self-indulgent relatively to the insensible man, insensible relatively to the self-indulgent, and the
liberal man prodigal relatively to the mean man, mean relatively to the prodigal. Hence also the people at the
extremes push the intermediate man each over to the other, and the brave man is called rash by the coward,
cowardly by the rash man, and correspondingly in the other cases.

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These states being thus opposed to one another, the greatest contrariety is that of the extremes to each other,
rather than to the intermediate; for these are further from each other than from the intermediate, as the great is
further from the small and the small from the great than both are from the equal. Again, to the intermediate
some extremes show a certain likeness, as that of rashness to courage and that of prodigality to liberality; but
the extremes show the greatest unlikeness to each other; now contraries are defined as the things that are
furthest from each other, so that things that are further apart are more contrary.

To the mean in some cases the deficiency, in some the excess is more opposed; e.g. it is not rashness, which
is an excess, but cowardice, which is a deficiency, that is more opposed to courage, and not insensibility,
which is a deficiency, but self-indulgence, which is an excess, that is more opposed to temperance. This
happens from two reasons, one being drawn from the thing itself; for because one extreme is nearer and liker
to the intermediate, we oppose not this but rather its contrary to the intermediate. E.g. since rashness is
thought liker and nearer to courage, and cowardice more unlike, we oppose rather the latter to courage; for
things that are further from the intermediate are thought more contrary to it. This, then, is one cause, drawn
from the thing itself; another is drawn from ourselves; for the things to which we ourselves more naturally
tend seem more contrary to the intermediate. For instance, we ourselves tend more naturally to pleasures, and
hence are more easily carried away towards self-indulgence than towards propriety. We describe as contrary
to the mean, then, rather the directions in which we more often go to great lengths; and therefore
self-indulgence, which is an excess, is the more contrary to temperance.

That moral virtue is a mean, then, and in what sense it is so, and that it is a mean between two vices, the one
involving excess, the other deficiency, and that it is such because its character is to aim at what is
intermediate in passions and in actions, has been sufficiently stated. Hence also it is no easy task to be good.
For in everything it is no easy task to find the middle, e.g. to find the middle of a circle is not for every one
but for him who knows; so, too, any one can get angry- that is easy- or give or spend money; but to do this
to the right person, to the right extent, at the right time, with the right motive, and in the right way, that is not
for every one, nor is it easy; wherefore goodness is both rare and laudable and noble.

Hence he who aims at the intermediate must first depart from what is the more contrary to it, as Calypso
advises-

Hold the ship out beyond that surf and spray.

For of the extremes one is more erroneous, one less so; therefore, since to hit the mean is hard in the extreme,
we must as a second best, as people say, take the least of the evils; and this will be done best in the way we
describe. But we must consider the things towards which we ourselves also are easily carried away; for some
of us tend to one thing, some to another; and this will be recognizable from the pleasure and the pain we feel.
We must drag ourselves away to the contrary extreme; for we shall get into the intermediate state by drawing
well away from error, as people do in straightening sticks that are bent.

Now in everything the pleasant or pleasure is most to be guarded against; for we do not judge it impartially.
We ought, then, to feel towards pleasure as the elders of the people felt towards Helen, and in all
circumstances repeat their saying; for if we dismiss pleasure thus we are less likely to go astray. It is by doing
this, then, (to sum the matter up) that we shall best be able to hit the mean.

But this is no doubt difficult, and especially in individual cases; for or is not easy to determine both how and
with whom and on what provocation and how long one should be angry; for we too sometimes praise those
who fall short and call them good-tempered, but sometimes we praise those who get angry and call them
manly. The man, however, who deviates little from goodness is not blamed, whether he do so in the direction
of the more or of the less, but only the man who deviates more widely; for he does not fail to be noticed. But
up to what point and to what extent a man must deviate before he becomes blameworthy it is not easy to

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determine by reasoning, any more than anything else that is perceived by the senses; such things depend on
particular facts, and the decision rests with perception. So much, then, is plain, that the intermediate state is in
all things to be praised, but that we must incline sometimes towards the excess, sometimes towards the
deficiency; for so shall we most easily hit the mean and what is right.

BOOK III

SINCE virtue is concerned with passions and actions, and on voluntary passions and actions praise and blame
are bestowed, on those that are involuntary pardon, and sometimes also pity, to distinguish the voluntary and
the involuntary is presumably necessary for those who are studying the nature of virtue, and useful also for
legislators with a view to the assigning both of honours and of punishments. Those things, then, are
thought-involuntary, which take place under compulsion or owing to ignorance; and that is compulsory of
which the moving principle is outside, being a principle in which nothing is contributed by the person who is
acting or is feeling the passion, e.g. if he were to be carried somewhere by a wind, or by men who had him in
their power.

But with regard to the things that are done from fear of greater evils or for some noble object (e.g. if a tyrant
were to order one to do something base, having one's parents and children in his power, and if one did the
action they were to be saved, but otherwise would be put to death), it may be debated whether such actions
are involuntary or voluntary. Something of the sort happens also with regard to the throwing of goods
overboard in a storm; for in the abstract no one throws goods away voluntarily, but on condition of its
securing the safety of himself and his crew any sensible man does so. Such actions, then, are mixed, but are
more like voluntary actions; for they are worthy of choice at the time when they are done, and the end of an
action is relative to the occasion. Both the terms, then, 'voluntary' and 'involuntary', must be used with
reference to the moment of action. Now the man acts voluntarily; for the principle that moves the
instrumental parts of the body in such actions is in him, and the things of which the moving principle is in a
man himself are in his power to do or not to do. Such actions, therefore, are voluntary, but in the abstract
perhaps involuntary; for no one would choose any such act in itself.

For such actions men are sometimes even praised, when they endure something base or painful in return for
great and noble objects gained; in the opposite case they are blamed, since to endure the greatest indignities
for no noble end or for a trifling end is the mark of an inferior person. On some actions praise indeed is not
bestowed, but pardon is, when one does what he ought not under pressure which overstrains human nature
and which no one could withstand. But some acts, perhaps, we cannot be forced to do, but ought rather to
face death after the most fearful sufferings; for the things that 'forced' Euripides Alcmaeon to slay his mother
seem absurd. It is difficult sometimes to determine what should be chosen at what cost, and what should be
endured in return for what gain, and yet more difficult to abide by our decisions; for as a rule what is
expected is painful, and what we are forced to do is base, whence praise and blame are bestowed on those
who have been compelled or have not.

What sort of acts, then, should be called compulsory? We answer that without qualification actions are so
when the cause is in the external circumstances and the agent contributes nothing. But the things that in
themselves are involuntary, but now and in return for these gains are worthy of choice, and whose moving
principle is in the agent, are in themselves involuntary, but now and in return for these gains voluntary. They
are more like voluntary acts; for actions are in the class of particulars, and the particular acts here are
voluntary. What sort of things are to be chosen, and in return for what, it is not easy to state; for there are
many differences in the particular cases.

But if some one were to say that pleasant and noble objects have a compelling power, forcing us from
without, all acts would be for him compulsory; for it is for these objects that all men do everything they do.
And those who act under compulsion and unwillingly act with pain, but those who do acts for their

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pleasantness and nobility do them with pleasure; it is absurd to make external circumstances responsible, and
not oneself, as being easily caught by such attractions, and to make oneself responsible for noble acts but the
pleasant objects responsible for base acts. The compulsory, then, seems to be that whose moving principle is
outside, the person compelled contributing nothing.

Everything that is done by reason of ignorance is not voluntary; it is only what produces pain and repentance
that is involuntary. For the man who has done something owing to ignorance, and feels not the least vexation
at his action, has not acted voluntarily, since he did not know what he was doing, nor yet involuntarily, since
he is not pained. Of people, then, who act by reason of ignorance he who repents is thought an involuntary
agent, and the man who does not repent may, since he is different, be called a not voluntary agent; for, since
he differs from the other, it is better that he should have a name of his own.

Acting by reason of ignorance seems also to be different from acting in ignorance; for the man who is drunk
or in a rage is thought to act as a result not of ignorance but of one of the causes mentioned, yet not
knowingly but in ignorance.

Now every wicked man is ignorant of what he ought to do and what he ought to abstain from, and it is by
reason of error of this kind that men become unjust and in general bad; but the term 'involuntary' tends to be
used not if a man is ignorant of what is to his advantage- for it is not mistaken purpose that causes
involuntary action (it leads rather to wickedness), nor ignorance of the universal (for that men are blamed),
but ignorance of particulars, i.e. of the circumstances of the action and the objects with which it is concerned.
For it is on these that both pity and pardon depend, since the person who is ignorant of any of these acts
involuntarily.

Perhaps it is just as well, therefore, to determine their nature and number. A man may be ignorant, then, of
who he is, what he is doing, what or whom he is acting on, and sometimes also what (e.g. what instrument)
he is doing it with, and to what end (e.g. he may think his act will conduce to some one's safety), and how he
is doing it (e.g. whether gently or violently). Now of all of these no one could be ignorant unless he were
mad, and evidently also he could not be ignorant of the agent; for how could he not know himself? But of
what he is doing a man might be ignorant, as for instance people say 'it slipped out of their mouths as they
were speaking', or 'they did not know it was a secret', as Aeschylus said of the mysteries, or a man might say
he 'let it go off when he merely wanted to show its working', as the man did with the catapult. Again, one
might think one's son was an enemy, as Merope did, or that a pointed spear had a button on it, or that a stone
was pumicestone; or one might give a man a draught to save him, and really kill him; or one might want to
touch a man, as people do in sparring, and really wound him. The ignorance may relate, then, to any of these
things, i.e. of the circumstances of the action, and the man who was ignorant of any of these is thought to
have acted involuntarily, and especially if he was ignorant on the most important points; and these are
thought to be the circumstances of the action and its end. Further, the doing of an act that is called
involuntary in virtue of ignorance of this sort must be painful and involve repentance.

Since that which is done under compulsion or by reason of ignorance is involuntary, the voluntary would
seem to be that of which the moving principle is in the agent himself, he being aware of the particular
circumstances of the action. Presumably acts done by reason of anger or appetite are not rightly called
involuntary. For in the first place, on that showing none of the other animals will act voluntarily, nor will
children; and secondly, is it meant that we do not do voluntarily any of the acts that are due to appetite or
anger, or that we do the noble acts voluntarily and the base acts involuntarily? Is not this absurd, when one
and the same thing is the cause? But it would surely be odd to describe as involuntary the things one ought to
desire; and we ought both to be angry at certain things and to have an appetite for certain things, e.g. for
health and for learning. Also what is involuntary is thought to be painful, but what is in accordance with
appetite is thought to be pleasant. Again, what is the difference in respect of involuntariness between errors
committed upon calculation and those committed in anger? Both are to be avoided, but the irrational passions

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are thought not less human than reason is, and therefore also the actions which proceed from anger or appetite
are the man's actions. It would be odd, then, to treat them as involuntary.

Both the voluntary and the involuntary having been delimited, we must next discuss choice; for it is thought
to be most closely bound up with virtue and to discriminate characters better than actions do.

Choice, then, seems to be voluntary, but not the same thing as the voluntary; the latter extends more widely.
For both children and the lower animals share in voluntary action, but not in choice, and acts done on the spur
of the moment we describe as voluntary, but not as chosen.

Those who say it is appetite or anger or wish or a kind of opinion do not seem to be right. For choice is not
common to irrational creatures as well, but appetite and anger are. Again, the incontinent man acts with
appetite, but not with choice; while the continent man on the contrary acts with choice, but not with appetite.
Again, appetite is contrary to choice, but not appetite to appetite. Again, appetite relates to the pleasant and
the painful, choice neither to the painful nor to the pleasant.

Still less is it anger; for acts due to anger are thought to be less than any others objects of choice.

But neither is it wish, though it seems near to it; for choice cannot relate to impossibles, and if any one said
he chose them he would be thought silly; but there may be a wish even for impossibles, e.g. for immortality.
And wish may relate to things that could in no way be brought about by one's own efforts, e.g. that a
particular actor or athlete should win in a competition; but no one chooses such things, but only the things
that he thinks could be brought about by his own efforts. Again, wish relates rather to the end, choice to the
means; for instance, we wish to be healthy, but we choose the acts which will make us healthy, and we wish
to be happy and say we do, but we cannot well say we choose to be so; for, in general, choice seems to relate
to the things that are in our own power.

For this reason, too, it cannot be opinion; for opinion is thought to relate to all kinds of things, no less to
eternal things and impossible things than to things in our own power; and it is distinguished by its falsity or
truth, not by its badness or goodness, while choice is distinguished rather by these.

Now with opinion in general perhaps no one even says it is identical. But it is not identical even with any
kind of opinion; for by choosing what is good or bad we are men of a certain character, which we are not by
holding certain opinions. And we choose to get or avoid something good or bad, but we have opinions about
what a thing is or whom it is good for or how it is good for him; we can hardly be said to opine to get or
avoid anything. And choice is praised for being related to the right object rather than for being rightly related
to it, opinion for being truly related to its object. And we choose what we best know to be good, but we opine
what we do not quite know; and it is not the same people that are thought to make the best choices and to
have the best opinions, but some are thought to have fairly good opinions, but by reason of vice to choose
what they should not. If opinion precedes choice or accompanies it, that makes no difference; for it is not this
that we are considering, but whether it is identical with some kind of opinion.

What, then, or what kind of thing is it, since it is none of the things we have mentioned? It seems to be
voluntary, but not all that is voluntary to be an object of choice. Is it, then, what has been decided on by
previous deliberation? At any rate choice involves a rational principle and thought. Even the name seems to
suggest that it is what is chosen before other things.

Do we deliberate about everything, and is everything a possible subject of deliberation, or is deliberation
impossible about some things? We ought presumably to call not what a fool or a madman would deliberate
about, but what a sensible man would deliberate about, a subject of deliberation. Now about eternal things no
one deliberates, e.g. about the material universe or the incommensurability of the diagonal and the side of a

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square. But no more do we deliberate about the things that involve movement but always happen in the same
way, whether of necessity or by nature or from any other cause, e.g. the solstices and the risings of the stars;
nor about things that happen now in one way, now in another, e.g. droughts and rains; nor about chance
events, like the finding of treasure. But we do not deliberate even about all human affairs; for instance, no
Spartan deliberates about the best constitution for the Scythians. For none of these things can be brought
about by our own efforts.

We deliberate about things that are in our power and can be done; and these are in fact what is left. For
nature, necessity, and chance are thought to be causes, and also reason and everything that depends on man.
Now every class of men deliberates about the things that can be done by their own efforts. And in the case of
exact and self-contained sciences there is no deliberation, e.g. about the letters of the alphabet (for we have
no doubt how they should be written); but the things that are brought about by our own efforts, but not
always in the same way, are the things about which we deliberate, e.g. questions of medical treatment or of
money-making. And we do so more in the case of the art of navigation than in that of gymnastics, inasmuch
as it has been less exactly worked out, and again about other things in the same ratio, and more also in the
case of the arts than in that of the sciences; for we have more doubt about the former. Deliberation is
concerned with things that happen in a certain way for the most part, but in which the event is obscure, and
with things in which it is indeterminate. We call in others to aid us in deliberation on important questions,
distrusting ourselves as not being equal to deciding.

We deliberate not about ends but about means. For a doctor does not deliberate whether he shall heal, nor an
orator whether he shall persuade, nor a statesman whether he shall produce law and order, nor does any one
else deliberate about his end. They assume the end and consider how and by what means it is to be attained;
and if it seems to be produced by several means they consider by which it is most easily and best produced,
while if it is achieved by one only they consider how it will be achieved by this and by what means this will
be achieved, till they come to the first cause, which in the order of discovery is last. For the person who
deliberates seems to investigate and analyse in the way described as though he were analysing a geometrical
construction (not all investigation appears to be deliberation- for instance mathematical investigations- but
all deliberation is investigation), and what is last in the order of analysis seems to be first in the order of
becoming. And if we come on an impossibility, we give up the search, e.g. if we need money and this cannot
be got; but if a thing appears possible we try to do it. By 'possible' things I mean things that might be brought
about by our own efforts; and these in a sense include things that can be brought about by the efforts of our
friends, since the moving principle is in ourselves. The subject of investigation is sometimes the instruments,
sometimes the use of them; and similarly in the other cases- sometimes the means, sometimes the mode of
using it or the means of bringing it about. It seems, then, as has been said, that man is a moving principle of
actions; now deliberation is about the things to be done by the agent himself, and actions are for the sake of
things other than themselves. For the end cannot be a subject of deliberation, but only the means; nor indeed
can the particular facts be a subject of it, as whether this is bread or has been baked as it should; for these are
matters of perception. If we are to be always deliberating, we shall have to go on to infinity.

The same thing is deliberated upon and is chosen, except that the object of choice is already determinate,
since it is that which has been decided upon as a result of deliberation that is the object of choice. For every
one ceases to inquire how he is to act when he has brought the moving principle back to himself and to the
ruling part of himself; for this is what chooses. This is plain also from the ancient constitutions, which Homer
represented; for the kings announced their choices to the people. The object of choice being one of the things
in our own power which is desired after deliberation, choice will be deliberate desire of things in our own
power; for when we have decided as a result of deliberation, we desire in accordance with our deliberation.

We may take it, then, that we have described choice in outline, and stated the nature of its objects and the fact
that it is concerned with means.

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That wish is for the end has already been stated; some think it is for the good, others for the apparent good.
Now those who say that the good is the object of wish must admit in consequence that that which the man
who does not choose aright wishes for is not an object of wish (for if it is to be so, it must also be good; but it
was, if it so happened, bad); while those who say the apparent good is the object of wish must admit that
there is no natural object of wish, but only what seems good to each man. Now different things appear good
to different people, and, if it so happens, even contrary things.

If these consequences are unpleasing, are we to say that absolutely and in truth the good is the object of wish,
but for each person the apparent good; that that which is in truth an object of wish is an object of wish to the
good man, while any chance thing may be so the bad man, as in the case of bodies also the things that are in
truth wholesome are wholesome for bodies which are in good condition, while for those that are diseased
other things are wholesome- or bitter or sweet or hot or heavy, and so on; since the good man judges each
class of things rightly, and in each the truth appears to him? For each state of character has its own ideas of
the noble and the pleasant, and perhaps the good man differs from others most by seeing the truth in each
class of things, being as it were the norm and measure of them. In most things the error seems to be due to
pleasure; for it appears a good when it is not. We therefore choose the pleasant as a good, and avoid pain as
an evil.

The end, then, being what we wish for, the means what we deliberate about and choose, actions concerning
means must be according to choice and voluntary. Now the exercise of the virtues is concerned with means.
Therefore virtue also is in our own power, and so too vice. For where it is in our power to act it is also in our
power not to act, and vice versa; so that, if to act, where this is noble, is in our power, not to act, which will
be base, will also be in our power, and if not to act, where this is noble, is in our power, to act, which will be
base, will also be in our power. Now if it is in our power to do noble or base acts, and likewise in our power
not to do them, and this was what being good or bad meant, then it is in our power to be virtuous or vicious.

The saying that 'no one is voluntarily wicked nor involuntarily happy' seems to be partly false and partly true;
for no one is involuntarily happy, but wickedness is voluntary. Or else we shall have to dispute what has just
been said, at any rate, and deny that man is a moving principle or begetter of his actions as of children. But if
these facts are evident and we cannot refer actions to moving principles other than those in ourselves, the acts
whose moving principles are in us must themselves also be in our power and voluntary.

Witness seems to be borne to this both by individuals in their private capacity and by legislators themselves;
for these punish and take vengeance on those who do wicked acts (unless they have acted under compulsion
or as a result of ignorance for which they are not themselves responsible), while they honour those who do
noble acts, as though they meant to encourage the latter and deter the former. But no one is encouraged to do
the things that are neither in our power nor voluntary; it is assumed that there is no gain in being persuaded
not to be hot or in pain or hungry or the like, since we shall experience these feelings none the less. Indeed,
we punish a man for his very ignorance, if he is thought responsible for the ignorance, as when penalties are
doubled in the case of drunkenness; for the moving principle is in the man himself, since he had the power of
not getting drunk and his getting drunk was the cause of his ignorance. And we punish those who are ignorant
of anything in the laws that they ought to know and that is not difficult, and so too in the case of anything else
that they are thought to be ignorant of through carelessness; we assume that it is in their power not to be
ignorant, since they have the power of taking care.

But perhaps a man is the kind of man not to take care. Still they are themselves by their slack lives
responsible for becoming men of that kind, and men make themselves responsible for being unjust or
self-indulgent, in the one case by cheating and in the other by spending their time in drinking bouts and the
like; for it is activities exercised on particular objects that make the corresponding character. This is plain
from the case of people training for any contest or action; they practise the activity the whole time. Now not
to know that it is from the exercise of activities on particular objects that states of character are produced is

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the mark of a thoroughly senseless person. Again, it is irrational to suppose that a man who acts unjustly does
not wish to be unjust or a man who acts self-indulgently to be self-indulgent. But if without being ignorant a
man does the things which will make him unjust, he will be unjust voluntarily. Yet it does not follow that if
he wishes he will cease to be unjust and will be just. For neither does the man who is ill become well on those
terms. We may suppose a case in which he is ill voluntarily, through living incontinently and disobeying his
doctors. In that case it was then open to him not to be ill, but not now, when he has thrown away his chance,
just as when you have let a stone go it is too late to recover it; but yet it was in your power to throw it, since
the moving principle was in you. So, too, to the unjust and to the self-indulgent man it was open at the
beginning not to become men of this kind, and so they are unjust and selfindulgent voluntarily; but now that
they have become so it is not possible for them not to be so.

But not only are the vices of the soul voluntary, but those of the body also for some men, whom we
accordingly blame; while no one blames those who are ugly by nature, we blame those who are so owing to
want of exercise and care. So it is, too, with respect to weakness and infirmity; no one would reproach a man
blind from birth or by disease or from a blow, but rather pity him, while every one would blame a man who
was blind from drunkenness or some other form of self-indulgence. Of vices of the body, then, those in our
own power are blamed, those not in our power are not. And if this be so, in the other cases also the vices that
are blamed must be in our own power.

Now some one may say that all men desire the apparent good, but have no control over the appearance, but
the end appears to each man in a form answering to his character. We reply that if each man is somehow
responsible for his state of mind, he will also be himself somehow responsible for the appearance; but if not,
no one is responsible for his own evildoing, but every one does evil acts through ignorance of the end,
thinking that by these he will get what is best, and the aiming at the end is not self-chosen but one must be
born with an eye, as it were, by which to judge rightly and choose what is truly good, and he is well endowed
by nature who is well endowed with this. For it is what is greatest and most noble, and what we cannot get or
learn from another, but must have just such as it was when given us at birth, and to be well and nobly
endowed with this will be perfect and true excellence of natural endowment. If this is true, then, how will
virtue be more voluntary than vice? To both men alike, the good and the bad, the end appears and is fixed by
nature or however it may be, and it is by referring everything else to this that men do whatever they do.

Whether, then, it is not by nature that the end appears to each man such as it does appear, but something also
depends on him, or the end is natural but because the good man adopts the means voluntarily virtue is
voluntary, vice also will be none the less voluntary; for in the case of the bad man there is equally present that
which depends on himself in his actions even if not in his end. If, then, as is asserted, the virtues are voluntary
(for we are ourselves somehow partly responsible for our states of character, and it is by being persons of a
certain kind that we assume the end to be so and so), the vices also will be voluntary; for the same is true of
them.

With regard to the virtues in general we have stated their genus in outline, viz. that they are means and that
they are states of character, and that they tend, and by their own nature, to the doing of the acts by which they
are produced, and that they are in our power and voluntary, and act as the right rule prescribes. But actions
and states of character are not voluntary in the same way; for we are masters of our actions from the
beginning right to the end, if we know the particular facts, but though we control the beginning of our states
of character the gradual progress is not obvious any more than it is in illnesses; because it was in our power,
however, to act in this way or not in this way, therefore the states are voluntary.

Let us take up the several virtues, however, and say which they are and what sort of things they are concerned
with and how they are concerned with them; at the same time it will become plain how many they are. And
first let us speak of courage.

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That it is a mean with regard to feelings of fear and confidence has already been made evident; and plainly
the things we fear are terrible things, and these are, to speak without qualification, evils; for which reason
people even define fear as expectation of evil. Now we fear all evils, e.g. disgrace, poverty, disease,
friendlessness, death, but the brave man is not thought to be concerned with all; for to fear some things is
even right and noble, and it is base not to fear them- e.g. disgrace; he who fears this is good and modest, and
he who does not is shameless. He is, however, by some people called brave, by a transference of the word to
a new meaning; for he has in him something which is like the brave man, since the brave man also is a
fearless person. Poverty and disease we perhaps ought not to fear, nor in general the things that do not
proceed from vice and are not due to a man himself. But not even the man who is fearless of these is brave.
Yet we apply the word to him also in virtue of a similarity; for some who in the dangers of war are cowards
are liberal and are confident in face of the loss of money. Nor is a man a coward if he fears insult to his wife
and children or envy or anything of the kind; nor brave if he is confident when he is about to be flogged. With
what sort of terrible things, then, is the brave man concerned? Surely with the greatest; for no one is more
likely than he to stand his ground against what is awe-inspiring. Now death is the most terrible of all things;
for it is the end, and nothing is thought to be any longer either good or bad for the dead. But the brave man
would not seem to be concerned even with death in all circumstances, e.g. at sea or in disease. In what
circumstances, then? Surely in the noblest. Now such deaths are those in battle; for these take place in the
greatest and noblest danger. And these are correspondingly honoured in city-states and at the courts of
monarchs. Properly, then, he will be called brave who is fearless in face of a noble death, and of all
emergencies that involve death; and the emergencies of war are in the highest degree of this kind. Yet at sea
also, and in disease, the brave man is fearless, but not in the same way as the seaman; for he has given up
hope of safety, and is disliking the thought of death in this shape, while they are hopeful because of their
experience. At the same time, we show courage in situations where there is the opportunity of showing
prowess or where death is noble; but in these forms of death neither of these conditions is fulfilled.

What is terrible is not the same for all men; but we say there are things terrible even beyond human strength.
These, then, are terrible to every one- at least to every sensible man; but the terrible things that are not
beyond human strength differ in magnitude and degree, and so too do the things that inspire confidence. Now
the brave man is as dauntless as man may be. Therefore, while he will fear even the things that are not
beyond human strength, he will face them as he ought and as the rule directs, for honour's sake; for this is the
end of virtue. But it is possible to fear these more, or less, and again to fear things that are not terrible as if
they were. Of the faults that are committed one consists in fearing what one should not, another in fearing as
we should not, another in fearing when we should not, and so on; and so too with respect to the things that
inspire confidence. The man, then, who faces and who fears the right things and from the right motive, in the
right way and from the right time, and who feels confidence under the corresponding conditions, is brave; for
the brave man feels and acts according to the merits of the case and in whatever way the rule directs. Now the
end of every activity is conformity to the corresponding state of character. This is true, therefore, of the brave
man as well as of others. But courage is noble. Therefore the end also is noble; for each thing is defined by its
end. Therefore it is for a noble end that the brave man endures and acts as courage directs.

Of those who go to excess he who exceeds in fearlessness has no name (we have said previously that many
states of character have no names), but he would be a sort of madman or insensible person if he feared
nothing, neither earthquakes nor the waves, as they say the Celts do not; while the man who exceeds in
confidence about what really is terrible is rash. The rash man, however, is also thought to be boastful and
only a pretender to courage; at all events, as the brave man is with regard to what is terrible, so the rash man
wishes to appear; and so he imitates him in situations where he can. Hence also most of them are a mixture of
rashness and cowardice; for, while in these situations they display confidence, they do not hold their ground
against what is really terrible. The man who exceeds in fear is a coward; for he fears both what he ought not
and as he ought not, and all the similar characterizations attach to him. He is lacking also in confidence; but
he is more conspicuous for his excess of fear in painful situations. The coward, then, is a despairing sort of
person; for he fears everything. The brave man, on the other hand, has the opposite disposition; for

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confidence is the mark of a hopeful disposition. The coward, the rash man, and the brave man, then, are
concerned with the same objects but are differently disposed towards them; for the first two exceed and fall
short, while the third holds the middle, which is the right, position; and rash men are precipitate, and wish for
dangers beforehand but draw back when they are in them, while brave men are keen in the moment of action,
but quiet beforehand.

As we have said, then, courage is a mean with respect to things that inspire confidence or fear, in the
circumstances that have been stated; and it chooses or endures things because it is noble to do so, or because
it is base not to do so. But to die to escape from poverty or love or anything painful is not the mark of a brave
man, but rather of a coward; for it is softness to fly from what is troublesome, and such a man endures death
not because it is noble but to fly from evil.

Courage, then, is something of this sort, but the name is also applied to five other kinds.

First comes the courage of the citizen-soldier; for this is most like true courage. Citizen-soldiers seem to
face dangers because of the penalties imposed by the laws and the reproaches they would otherwise incur,
and because of the honours they win by such action; and therefore those peoples seem to be bravest among
whom cowards are held in dishonour and brave men in honour. This is the kind of courage that Homer
depicts, e.g. in Diomede and in Hector:

First will Polydamas be to heap reproach on me then; and

For Hector one day 'mid the Trojans shall utter his vaulting
harangue:
Afraid was Tydeides, and fled from my face.

This kind of courage is most like to that which we described earlier, because it is due to virtue; for it is due to
shame and to desire of a noble object (i.e. honour) and avoidance of disgrace, which is ignoble. One might
rank in the same class even those who are compelled by their rulers; but they are inferior, inasmuch as they
do what they do not from shame but from fear, and to avoid not what is disgraceful but what is painful; for
their masters compel them, as Hector does:

But if I shall spy any dastard that cowers far from the fight,
Vainly will such an one hope to escape from the dogs.

And those who give them their posts, and beat them if they retreat, do the same, and so do those who draw
them up with trenches or something of the sort behind them; all of these apply compulsion. But one ought to
be brave not under compulsion but because it is noble to be so.

(2) Experience with regard to particular facts is also thought to be courage; this is indeed the reason why
Socrates thought courage was knowledge. Other people exhibit this quality in other dangers, and professional
soldiers exhibit it in the dangers of war; for there seem to be many empty alarms in war, of which these have
had the most comprehensive experience; therefore they seem brave, because the others do not know the
nature of the facts. Again, their experience makes them most capable in attack and in defence, since they can
use their arms and have the kind that are likely to be best both for attack and for defence; therefore they fight
like armed men against unarmed or like trained athletes against amateurs; for in such contests too it is not the
bravest men that fight best, but those who are strongest and have their bodies in the best condition.
Professional soldiers turn cowards, however, when the danger puts too great a strain on them and they are
inferior in numbers and equipment; for they are the first to fly, while citizen-forces die at their posts, as in
fact happened at the temple of Hermes. For to the latter flight is disgraceful and death is preferable to safety
on those terms; while the former from the very beginning faced the danger on the assumption that they were
stronger, and when they know the facts they fly, fearing death more than disgrace; but the brave man is not

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that sort of person.

(3) Passion also is sometimes reckoned as courage; those who act from passion, like wild beasts rushing at
those who have wounded them, are thought to be brave, because brave men also are passionate; for passion
above all things is eager to rush on danger, and hence Homer's 'put strength into his passion' and 'aroused
their spirit and passion and 'hard he breathed panting' and 'his blood boiled'. For all such expressions seem to
indicate the stirring and onset of passion. Now brave men act for honour's sake, but passion aids them; while
wild beasts act under the influence of pain; for they attack because they have been wounded or because they
are afraid, since if they are in a forest they do not come near one. Thus they are not brave because, driven by
pain and passion, they rush on danger without foreseeing any of the perils, since at that rate even asses would
be brave when they are hungry; for blows will not drive them from their food; and lust also makes adulterers
do many daring things. (Those creatures are not brave, then, which are driven on to danger by pain or
passion.) The 'courage' that is due to passion seems to be the most natural, and to be courage if choice and
motive be added.

Men, then, as well as beasts, suffer pain when they are angry, and are pleased when they exact their revenge;
those who fight for these reasons, however, are pugnacious but not brave; for they do not act for honour's
sake nor as the rule directs, but from strength of feeling; they have, however, something akin to courage.

(4) Nor are sanguine people brave; for they are confident in danger only because they have conquered often
and against many foes. Yet they closely resemble brave men, because both are confident; but brave men are
confident for the reasons stated earlier, while these are so because they think they are the strongest and can
suffer nothing. (Drunken men also behave in this way; they become sanguine). When their adventures do not
succeed, however, they run away; but it was the mark of a brave man to face things that are, and seem,
terrible for a man, because it is noble to do so and disgraceful not to do so. Hence also it is thought the mark
of a braver man to be fearless and undisturbed in sudden alarms than to be so in those that are foreseen; for it
must have proceeded more from a state of character, because less from preparation; acts that are foreseen
may be chosen by calculation and rule, but sudden actions must be in accordance with one's state of
character.

(5) People who are ignorant of the danger also appear brave, and they are not far removed from those of a
sanguine temper, but are inferior inasmuch as they have no self-reliance while these have. Hence also the
sanguine hold their ground for a time; but those who have been deceived about the facts fly if they know or
suspect that these are different from what they supposed, as happened to the Argives when they fell in with
the Spartans and took them for Sicyonians.

We have, then, described the character both of brave men and of those who are thought to be brave.

Though courage is concerned with feelings of confidence and of fear, it is not concerned with both alike, but
more with the things that inspire fear; for he who is undisturbed in face of these and bears himself as he
should towards these is more truly brave than the man who does so towards the things that inspire confidence.
It is for facing what is painful, then, as has been said, that men are called brave. Hence also courage involves
pain, and is justly praised; for it is harder to face what is painful than to abstain from what is pleasant.

Yet the end which courage sets before it would seem to be pleasant, but to be concealed by the attending
circumstances, as happens also in athletic contests; for the end at which boxers aim is pleasant- the crown
and the honours- but the blows they take are distressing to flesh and blood, and painful, and so is their whole
exertion; and because the blows and the exertions are many the end, which is but small, appears to have
nothing pleasant in it. And so, if the case of courage is similar, death and wounds will be painful to the brave
man and against his will, but he will face them because it is noble to do so or because it is base not to do so.
And the more he is possessed of virtue in its entirety and the happier he is, the more he will be pained at the

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thought of death; for life is best worth living for such a man, and he is knowingly losing the greatest goods,
and this is painful. But he is none the less brave, and perhaps all the more so, because he chooses noble deeds
of war at that cost. It is not the case, then, with all the virtues that the exercise of them is pleasant, except in
so far as it reaches its end. But it is quite possible that the best soldiers may be not men of this sort but those
who are less brave but have no other good; for these are ready to face danger, and they sell their life for
trifling gains.

So much, then, for courage; it is not difficult to grasp its nature in outline, at any rate, from what has been
said.

After courage let us speak of temperance; for these seem to be the virtues of the irrational parts. We have said
that temperance is a mean with regard to pleasures (for it is less, and not in the same way, concerned with
pains); self-indulgence also is manifested in the same sphere. Now, therefore, let us determine with what sort
of pleasures they are concerned. We may assume the distinction between bodily pleasures and those of the
soul, such as love of honour and love of learning; for the lover of each of these delights in that of which he is
a lover, the body being in no way affected, but rather the mind; but men who are concerned with such
pleasures are called neither temperate nor self-indulgent. Nor, again, are those who are concerned with the
other pleasures that are not bodily; for those who are fond of hearing and telling stories and who spend their
days on anything that turns up are called gossips, but not self-indulgent, nor are those who are pained at the
loss of money or of friends.

Temperance must be concerned with bodily pleasures, but not all even of these; for those who delight in
objects of vision, such as colours and shapes and painting, are called neither temperate nor self-indulgent; yet
it would seem possible to delight even in these either as one should or to excess or to a deficient degree.

And so too is it with objects of hearing; no one calls those who delight extravagantly in music or acting
self-indulgent, nor those who do so as they ought temperate.

Nor do we apply these names to those who delight in odour, unless it be incidentally; we do not call those
self-indulgent who delight in the odour of apples or roses or incense, but rather those who delight in the
odour of unguents or of dainty dishes; for self-indulgent people delight in these because these remind them
of the objects of their appetite. And one may see even other people, when they are hungry, delighting in the
smell of food; but to delight in this kind of thing is the mark of the self-indulgent man; for these are objects
of appetite to him.

Nor is there in animals other than man any pleasure connected with these senses, except incidentally. For
dogs do not delight in the scent of hares, but in the eating of them, but the scent told them the hares were
there; nor does the lion delight in the lowing of the ox, but in eating it; but he perceived by the lowing that it
was near, and therefore appears to delight in the lowing; and similarly he does not delight because he sees 'a
stag or a wild goat', but because he is going to make a meal of it. Temperance and self-indulgence, however,
are concerned with the kind of pleasures that the other animals share in, which therefore appear slavish and
brutish; these are touch and taste. But even of taste they appear to make little or no use; for the business of
taste is the discriminating of flavours, which is done by winetasters and people who season dishes; but they
hardly take pleasure in making these discriminations, or at least self-indulgent people do not, but in the
actual enjoyment, which in all cases comes through touch, both in the case of food and in that of drink and in
that of sexual intercourse. This is why a certain gourmand prayed that his throat might become longer than a
crane's, implying that it was the contact that he took pleasure in. Thus the sense with which self-indulgence
is connected is the most widely shared of the senses; and self-indulgence would seem to be justly a matter of
reproach, because it attaches to us not as men but as animals. To delight in such things, then, and to love
them above all others, is brutish. For even of the pleasures of touch the most liberal have been eliminated,
e.g. those produced in the gymnasium by rubbing and by the consequent heat; for the contact characteristic of

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the self-indulgent man does not affect the whole body but only certain parts.

Of the appetites some seem to be common, others to be peculiar to individuals and acquired; e.g. the appetite
for food is natural, since every one who is without it craves for food or drink, and sometimes for both, and for
love also (as Homer says) if he is young and lusty; but not every one craves for this or that kind of
nourishment or love, nor for the same things. Hence such craving appears to be our very own. Yet it has of
course something natural about it; for different things are pleasant to different kinds of people, and some
things are more pleasant to every one than chance objects. Now in the natural appetites few go wrong, and
only in one direction, that of excess; for to eat or drink whatever offers itself till one is surfeited is to exceed
the natural amount, since natural appetite is the replenishment of one's deficiency. Hence these people are
called belly-gods, this implying that they fill their belly beyond what is right. It is people of entirely slavish
character that become like this. But with regard to the pleasures peculiar to individuals many people go
wrong and in many ways. For while the people who are 'fond of so and so' are so called because they delight
either in the wrong things, or more than most people do, or in the wrong way, the self-indulgent exceed in all
three ways; they both delight in some things that they ought not to delight in (since they are hateful), and if
one ought to delight in some of the things they delight in, they do so more than one ought and than most men
do.

Plainly, then, excess with regard to pleasures is self-indulgence and is culpable; with regard to pains one is
not, as in the case of courage, called temperate for facing them or self-indulgent for not doing so, but the
selfindulgent man is so called because he is pained more than he ought at not getting pleasant things (even his
pain being caused by pleasure), and the temperate man is so called because he is not pained at the absence of
what is pleasant and at his abstinence from it.

The self-indulgent man, then, craves for all pleasant things or those that are most pleasant, and is led by his
appetite to choose these at the cost of everything else; hence he is pained both when he fails to get them and
when he is merely craving for them (for appetite involves pain); but it seems absurd to be pained for the sake
of pleasure. People who fall short with regard to pleasures and delight in them less than they should are
hardly found; for such insensibility is not human. Even the other animals distinguish different kinds of food
and enjoy some and not others; and if there is any one who finds nothing pleasant and nothing more attractive
than anything else, he must be something quite different from a man; this sort of person has not received a
name because he hardly occurs. The temperate man occupies a middle position with regard to these objects.
For he neither enjoys the things that the self-indulgent man enjoys most-but rather dislikes them-nor in
general the things that he should not, nor anything of this sort to excess, nor does he feel pain or craving
when they are absent, or does so only to a moderate degree, and not more than he should, nor when he should
not, and so on; but the things that, being pleasant, make for health or for good condition, he will desire
moderately and as he should, and also other pleasant things if they are not hindrances to these ends, or
contrary to what is noble, or beyond his means. For he who neglects these conditions loves such pleasures
more than they are worth, but the temperate man is not that sort of person, but the sort of person that the right
rule prescribes.

Self-indulgence is more like a voluntary state than cowardice. For the former is actuated by pleasure, the
latter by pain, of which the one is to be chosen and the other to be avoided; and pain upsets and destroys the
nature of the person who feels it, while pleasure does nothing of the sort. Therefore self-indulgence is more
voluntary. Hence also it is more a matter of reproach; for it is easier to become accustomed to its objects,
since there are many things of this sort in life, and the process of habituation to them is free from danger,
while with terrible objects the reverse is the case. But cowardice would seem to be voluntary in a different
degree from its particular manifestations; for it is itself painless, but in these we are upset by pain, so that we
even throw down our arms and disgrace ourselves in other ways; hence our acts are even thought to be done
under compulsion. For the self-indulgent man, on the other hand, the particular acts are voluntary (for he
does them with craving and desire), but the whole state is less so; for no one craves to be self-indulgent.

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The name self-indulgence is applied also to childish faults; for they bear a certain resemblance to what we
have been considering. Which is called after which, makes no difference to our present purpose; plainly,
however, the later is called after the earlier. The transference of the name seems not a bad one; for that which
desires what is base and which develops quickly ought to be kept in a chastened condition, and these
characteristics belong above all to appetite and to the child, since children in fact live at the beck and call of
appetite, and it is in them that the desire for what is pleasant is strongest. If, then, it is not going to be
obedient and subject to the ruling principle, it will go to great lengths; for in an irrational being the desire for
pleasure is insatiable even if it tries every source of gratification, and the exercise of appetite increases its
innate force, and if appetites are strong and violent they even expel the power of calculation. Hence they
should be moderate and few, and should in no way oppose the rational principle-and this is what we call an
obedient and chastened state-and as the child should live according to the direction of his tutor, so the
appetitive element should live according to rational principle. Hence the appetitive element in a temperate
man should harmonize with the rational principle; for the noble is the mark at which both aim, and the
temperate man craves for the things be ought, as he ought, as when he ought; and when he ought; and this is
what rational principle directs.

Here we conclude our account of temperance.

BOOK IV

LET us speak next of liberality. It seems to be the mean with regard to wealth; for the liberal man is praised
not in respect of military matters, nor of those in respect of which the temrate man is praised, nor of judicial
decisions, but with regard to the giving and taking of wealth, and especially in respect of giving. Now by
'wealth' we mean all the things whose value is measured by money. Further, prodigality and meanness are
excesses and defects with regard to wealth; and meanness we always impute to those who care more than
they ought for wealth, but we sometimes apply the word 'prodigality' in a complex sense; for we call those
men prodigals who are incontinent and spend money on self-indulgence. Hence also they are thought the
poorest characters; for they combine more vices than one. Therefore the application of the word to them is
not its proper use; for a 'prodigal' means a man who has a single evil quality, that of wasting his substance;
since a prodigal is one who is being ruined by his own fault, and the wasting of substance is thought to be a
sort of ruining of oneself, life being held to depend on possession of substance.

This, then, is the sense in which we take the word 'prodigality'. Now the things that have a use may be used
either well or badly; and riches is a useful thing; and everything is used best by the man who has the virtue
concerned with it; riches, therefore, will be used best by the man who has the virtue concerned with wealth;
and this is the liberal man. Now spending and giving seem to be the using of wealth; taking and keeping
rather the possession of it. Hence it is more the mark of the liberal man to give to the right people than to take
from the right sources and not to take from the wrong. For it is more characteristic of virtue to do good than
to have good done to one, and more characteristic to do what is noble than not to do what is base; and it is not
hard to see that giving implies doing good and doing what is noble, and taking implies having good done to
one or not acting basely. And gratitude is felt towards him who gives, not towards him who does not take,
and praise also is bestowed more on him. It is easier, also, not to take than to give; for men are apter to give
away their own too little than to take what is another's. Givers, too, are called liberal; but those who do not
take are not praised for liberality but rather for justice; while those who take are hardly praised at all. And the
liberal are almost the most loved of all virtuous characters, since they are useful; and this depends on their
giving.

Now virtuous actions are noble and done for the sake of the noble. Therefore the liberal man, like other
virtuous men, will give for the sake of the noble, and rightly; for he will give to the right people, the right
amounts, and at the right time, with all the other qualifications that accompany right giving; and that too with
pleasure or without pain; for that which is virtuous is pleasant or free from pain-least of all will it be painful.

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But he who gives to the wrong people or not for the sake of the noble but for some other cause, will be called
not liberal but by some other name. Nor is he liberal who gives with pain; for he would prefer the wealth to
the noble act, and this is not characteristic of a liberal man. But no more will the liberal man take from wrong
sources; for such taking is not characteristic of the man who sets no store by wealth. Nor will he be a ready
asker; for it is not characteristic of a man who confers benefits to accept them lightly. But he will take from
the right sources, e.g. from his own possessions, not as something noble but as a necessity, that he may have
something to give. Nor will he neglect his own property, since he wishes by means of this to help others. And
he will refrain from giving to anybody and everybody, that he may have something to give to the right
people, at the right time, and where it is noble to do so. It is highly characteristic of a liberal man also to go to
excess in giving, so that he leaves too little for himself; for it is the nature of a liberal man not to look to
himself. The term 'liberality' is used relatively to a man's substance; for liberality resides not in the multitude
of the gifts but in the state of character of the giver, and this is relative to the giver's substance. There is
therefore nothing to prevent the man who gives less from being the more liberal man, if he has less to give
those are thought to be more liberal who have not made their wealth but inherited it; for in the first place they
have no experience of want, and secondly all men are fonder of their own productions, as are parents and
poets. It is not easy for the liberal man to be rich, since he is not apt either at taking or at keeping, but at
giving away, and does not value wealth for its own sake but as a means to giving. Hence comes the charge
that is brought against fortune, that those who deserve riches most get it least. But it is not unreasonable that
it should turn out so; for he cannot have wealth, any more than anything else, if he does not take pains to have
it. Yet he will not give to the wrong people nor at the wrong time, and so on; for he would no longer be acting
in accordance with liberality, and if he spent on these objects he would have nothing to spend on the right
objects. For, as has been said, he is liberal who spends according to his substance and on the right objects;
and he who exceeds is prodigal. Hence we do not call despots prodigal; for it is thought not easy for them to
give and spend beyond the amount of their possessions. Liberality, then, being a mean with regard to giving
and taking of wealth, the liberal man will both give and spend the right amounts and on the right objects,
alike in small things and in great, and that with pleasure; he will also take the right amounts and from the
right sources. For, the virtue being a mean with regard to both, he will do both as he ought; since this sort of
taking accompanies proper giving, and that which is not of this sort is contrary to it, and accordingly the
giving and taking that accompany each other are present together in the same man, while the contrary kinds
evidently are not. But if he happens to spend in a manner contrary to what is right and noble, he will be
pained, but moderately and as he ought; for it is the mark of virtue both to be pleased and to be pained at the
right objects and in the right way. Further, the liberal man is easy to deal with in money matters; for he can be
got the better of, since he sets no store by money, and is more annoyed if he has not spent something that he
ought than pained if he has spent something that he ought not, and does not agree with the saying of
Simonides.

The prodigal errs in these respects also; for he is neither pleased nor pained at the right things or in the right
way; this will be more evident as we go on. We have said that prodigality and meanness are excesses and
deficiencies, and in two things, in giving and in taking; for we include spending under giving. Now
prodigality exceeds in giving and not taking, while meanness falls short in giving, and exceeds in taking,
except in small things.

The characteristics of prodigality are not often combined; for it is not easy to give to all if you take from
none; private persons soon exhaust their substance with giving, and it is to these that the name of prodigals is
applied- though a man of this sort would seem to be in no small degree better than a mean man. For he is
easily cured both by age and by poverty, and thus he may move towards the middle state. For he has the
characteristics of the liberal man, since he both gives and refrains from taking, though he does neither of
these in the right manner or well. Therefore if he were brought to do so by habituation or in some other way,
he would be liberal; for he will then give to the right people, and will not take from the wrong sources. This is
why he is thought to have not a bad character; it is not the mark of a wicked or ignoble man to go to excess in
giving and not taking, but only of a foolish one. The man who is prodigal in this way is thought much better

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than the mean man both for the aforesaid reasons and because he benefits many while the other benefits no
one, not even himself.

But most prodigal people, as has been said, also take from the wrong sources, and are in this respect mean.
They become apt to take because they wish to spend and cannot do this easily; for their possessions soon run
short. Thus they are forced to provide means from some other source. At the same time, because they care
nothing for honour, they take recklessly and from any source; for they have an appetite for giving, and they
do not mind how or from what source. Hence also their giving is not liberal; for it is not noble, nor does it
aim at nobility, nor is it done in the right way; sometimes they make rich those who should be poor, and will
give nothing to people of respectable character, and much to flatterers or those who provide them with some
other pleasure. Hence also most of them are self-indulgent; for they spend lightly and waste money on their
indulgences, and incline towards pleasures because they do not live with a view to what is noble.

The prodigal man, then, turns into what we have described if he is left untutored, but if he is treated with care
he will arrive at the intermediate and right state. But meanness is both incurable (for old age and every
disability is thought to make men mean) and more innate in men than prodigality; for most men are fonder of
getting money than of giving. It also extends widely, and is multiform, since there seem to be many kinds of
meanness.

For it consists in two things, deficiency in giving and excess in taking, and is not found complete in all men
but is sometimes divided; some men go to excess in taking, others fall short in giving. Those who are called
by such names as 'miserly', 'close', 'stingy', all fall short in giving, but do not covet the possessions of others
nor wish to get them. In some this is due to a sort of honesty and avoidance of what is disgraceful (for some
seem, or at least profess, to hoard their money for this reason, that they may not some day be forced to do
something disgraceful; to this class belong the cheeseparer and every one of the sort; he is so called from his
excess of unwillingness to give anything); while others again keep their hands off the property of others from
fear, on the ground that it is not easy, if one takes the property of others oneself, to avoid having one's own
taken by them; they are therefore content neither to take nor to give.

Others again exceed in respect of taking by taking anything and from any source, e.g. those who ply sordid
trades, pimps and all such people, and those who lend small sums and at high rates. For all of these take more
than they ought and from wrong sources. What is common to them is evidently sordid love of gain; they all
put up with a bad name for the sake of gain, and little gain at that. For those who make great gains but from
wrong sources, and not the right gains, e.g. despots when they sack cities and spoil temples, we do not call
mean but rather wicked, impious, and unjust. But the gamester and the footpad (and the highwayman) belong
to the class of the mean, since they have a sordid love of gain. For it is for gain that both of them ply their
craft and endure the disgrace of it, and the one faces the greatest dangers for the sake of the booty, while the
other makes gain from his friends, to whom he ought to be giving. Both, then, since they are willing to make
gain from wrong sources, are sordid lovers of gain; therefore all such forms of taking are mean.

And it is natural that meanness is described as the contrary of liberality; for not only is it a greater evil than
prodigality, but men err more often in this direction than in the way of prodigality as we have described it.

So much, then, for liberality and the opposed vices.

It would seem proper to discuss magnificence next. For this also seems to be a virtue concerned with wealth;
but it does not like liberality extend to all the actions that are concerned with wealth, but only to those that
involve expenditure; and in these it surpasses liberality in scale. For, as the name itself suggests, it is a fitting
expenditure involving largeness of scale. But the scale is relative; for the expense of equipping a trireme is
not the same as that of heading a sacred embassy. It is what is fitting, then, in relation to the agent, and to the
circumstances and the object. The man who in small or middling things spends according to the merits of the

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case is not called magnificent (e.g. the man who can say 'many a gift I gave the wanderer'), but only the man
who does so in great things. For the magnificent man is liberal, but the liberal man is not necessarily
magnificent. The deficiency of this state of character is called niggardliness, the excess vulgarity, lack of
taste, and the like, which do not go to excess in the amount spent on right objects, but by showy expenditure
in the wrong circumstances and the wrong manner; we shall speak of these vices later.

The magnificent man is like an artist; for he can see what is fitting and spend large sums tastefully. For, as we
said at the begining, a state of character is determined by its activities and by its objects. Now the expenses of
the magnificent man are large and fitting. Such, therefore, are also his results; for thus there will be a great
expenditure and one that is fitting to its result. Therefore the result should be worthy of the expense, and the
expense should be worthy of the result, or should even exceed it. And the magnificent man will spend such
sums for honour's sake; for this is common to the virtues. And further he will do so gladly and lavishly; for
nice calculation is a niggardly thing. And he will consider how the result can be made most beautiful and
most becoming rather than for how much it can be produced and how it can be produced most cheaply. It is
necessary, then, that the magnificent man be also liberal. For the liberal man also will spend what he ought
and as he ought; and it is in these matters that the greatness implied in the name of the magnificent man-his
bigness, as it were-is manifested, since liberality is concerned with these matters; and at an equal expense he
will produce a more magnificent work of art. For a possession and a work of art have not the same
excellence. The most valuable possession is that which is worth most, e.g. gold, but the most valuable work
of art is that which is great and beautiful (for the contemplation of such a work inspires admiration, and so
does magnificence); and a work has an excellence-viz. magnificence-which involves magnitude.
Magnificence is an attribute of expenditures of the kind which we call honourable, e.g. those connected with
the gods-votive offerings, buildings, and sacrifices-and similarly with any form of religious worship, and all
those that are proper objects of public-spirited ambition, as when people think they ought to equip a chorus
or a trireme, or entertain the city, in a brilliant way. But in all cases, as has been said, we have regard to the
agent as well and ask who he is and what means he has; for the expenditure should be worthy of his means,
and suit not only the result but also the producer. Hence a poor man cannot be magnificent, since he has not
the means with which to spend large sums fittingly; and he who tries is a fool, since he spends beyond what
can be expected of him and what is proper, but it is right expenditure that is virtuous. But great expenditure is
becoming to those who have suitable means to start with, acquired by their own efforts or from ancestors or
connexions, and to people of high birth or reputation, and so on; for all these things bring with them greatness
and prestige. Primarily, then, the magnificent man is of this sort, and magnificence is shown in expenditures
of this sort, as has been said; for these are the greatest and most honourable. Of private occasions of
expenditure the most suitable are those that take place once for all, e.g. a wedding or anything of the kind, or
anything that interests the whole city or the people of position in it, and also the receiving of foreign guests
and the sending of them on their way, and gifts and counter-gifts; for the magnificent man spends not on
himself but on public objects, and gifts bear some resemblance to votive offerings. A magnificent man will
also furnish his house suitably to his wealth (for even a house is a sort of public ornament), and will spend by
preference on those works that are lasting (for these are the most beautiful), and on every class of things he
will spend what is becoming; for the same things are not suitable for gods and for men, nor in a temple and in
a tomb. And since each expenditure may be great of its kind, and what is most magnificent absolutely is great
expenditure on a great object, but what is magnificent here is what is great in these circumstances, and
greatness in the work differs from greatness in the expense (for the most beautiful ball or bottle is
magnificent as a gift to a child, but the price of it is small and mean),-therefore it is characteristic of the
magnificent man, whatever kind of result he is producing, to produce it magnificently (for such a result is not
easily surpassed) and to make it worthy of the expenditure.

Such, then, is the magnificent man; the man who goes to excess and is vulgar exceeds, as has been said, by
spending beyond what is right. For on small objects of expenditure he spends much and displays a tasteless
showiness; e.g. he gives a club dinner on the scale of a wedding banquet, and when he provides the chorus for
a comedy he brings them on to the stage in purple, as they do at Megara. And all such things he will do not

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for honour's sake but to show off his wealth, and because he thinks he is admired for these things, and where
he ought to spend much he spends little and where little, much. The niggardly man on the other hand will fall
short in everything, and after spending the greatest sums will spoil the beauty of the result for a trifle, and
whatever he is doing he will hesitate and consider how he may spend least, and lament even that, and think he
is doing everything on a bigger scale than he ought.

These states of character, then, are vices; yet they do not bring disgrace because they are neither harmful to
one's neighbour nor very unseemly.

Pride seems even from its name to be concerned with great things; what sort of great things, is the first
question we must try to answer. It makes no difference whether we consider the state of character or the man
characterized by it. Now the man is thought to be proud who thinks himself worthy of great things, being
worthy of them; for he who does so beyond his deserts is a fool, but no virtuous man is foolish or silly. The
proud man, then, is the man we have described. For he who is worthy of little and thinks himself worthy of
little is temperate, but not proud; for pride implies greatness, as beauty implies a goodsized body, and little
people may be neat and well-proportioned but cannot be beautiful. On the other hand, he who thinks himself
worthy of great things, being unworthy of them, is vain; though not every one who thinks himself worthy of
more than he really is worthy of in vain. The man who thinks himself worthy of worthy of less than he is
really worthy of is unduly humble, whether his deserts be great or moderate, or his deserts be small but his
claims yet smaller. And the man whose deserts are great would seem most unduly humble; for what would he
have done if they had been less? The proud man, then, is an extreme in respect of the greatness of his claims,
but a mean in respect of the Tightness of them; for he claims what is accordance with his merits, while the
others go to excess or fall short.

If, then, he deserves and claims great things, and above all the great things, he will be concerned with one
thing in particular. Desert is relative to external goods; and the greatest of these, we should say, is that which
we render to the gods, and which people of position most aim at, and which is the prize appointed for the
noblest deeds; and this is honour; that is surely the greatest of external goods. Honours and dishonours,
therefore, are the objects with respect to which the proud man is as he should be. And even apart from
argument it is with honour that proud men appear to be concerned; for it is honour that they chiefly claim, but
in accordance with their deserts. The unduly humble man falls short both in comparison with his own merits
and in comparison with the proud man's claims. The vain man goes to excess in comparison with his own
merits, but does not exceed the proud man's claims.

Now the proud man, since he deserves most, must be good in the highest degree; for the better man always
deserves more, and the best man most. Therefore the truly proud man must be good. And greatness in every
virtue would seem to be characteristic of a proud man. And it would be most unbecoming for a proud man to
fly from danger, swinging his arms by his sides, or to wrong another; for to what end should he do
disgraceful acts, he to whom nothing is great? If we consider him point by point we shall see the utter
absurdity of a proud man who is not good. Nor, again, would he be worthy of honour if he were bad; for
honour is the prize of virtue, and it is to the good that it is rendered. Pride, then, seems to be a sort of crown
of the virtues; for it makes them greater, and it is not found without them. Therefore it is hard to be truly
proud; for it is impossible without nobility and goodness of character. It is chiefly with honours and
dishonours, then, that the proud man is concerned; and at honours that are great and conferred by good men
he will be moderately Pleased, thinking that he is coming by his own or even less than his own; for there can
be no honour that is worthy of perfect virtue, yet he will at any rate accept it since they have nothing greater
to bestow on him; but honour from casual people and on trifling grounds he will utterly despise, since it is not
this that he deserves, and dishonour too, since in his case it cannot be just. In the first place, then, as has been
said, the proud man is concerned with honours; yet he will also bear himself with moderation towards wealth
and power and all good or evil fortune, whatever may befall him, and will be neither over-joyed by good
fortune nor over-pained by evil. For not even towards honour does he bear himself as if it were a very great

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thing. Power and wealth are desirable for the sake of honour (at least those who have them wish to get honour
by means of them); and for him to whom even honour is a little thing the others must be so too. Hence proud
men are thought to be disdainful.

The goods of fortune also are thought to contribute towards pride. For men who are well-born are thought
worthy of honour, and so are those who enjoy power or wealth; for they are in a superior position, and
everything that has a superiority in something good is held in greater honour. Hence even such things make
men prouder; for they are honoured by some for having them; but in truth the good man alone is to be
honoured; he, however, who has both advantages is thought the more worthy of honour. But those who
without virtue have such goods are neither justified in making great claims nor entitled to the name of 'proud';
for these things imply perfect virtue. Disdainful and insolent, however, even those who have such goods
become. For without virtue it is not easy to bear gracefully the goods of fortune; and, being unable to bear
them, and thinking themselves superior to others, they despise others and themselves do what they please.
They imitate the proud man without being like him, and this they do where they can; so they do not act
virtuously, but they do despise others. For the proud man despises justly (since he thinks truly), but the many
do so at random.

He does not run into trifling dangers, nor is he fond of danger, because he honours few things; but he will
face great dangers, and when he is in danger he is unsparing of his life, knowing that there are conditions on
which life is not worth having. And he is the sort of man to confer benefits, but he is ashamed of receiving
them; for the one is the mark of a superior, the other of an inferior. And he is apt to confer greater benefits in
return; for thus the original benefactor besides being paid will incur a debt to him, and will be the gainer by
the transaction. They seem also to remember any service they have done, but not those they have received
(for he who receives a service is inferior to him who has done it, but the proud man wishes to be superior),
and to hear of the former with pleasure, of the latter with displeasure; this, it seems, is why Thetis did not
mention to Zeus the services she had done him, and why the Spartans did not recount their services to the
Athenians, but those they had received. It is a mark of the proud man also to ask for nothing or scarcely
anything, but to give help readily, and to be dignified towards people who enjoy high position and good
fortune, but unassuming towards those of the middle class; for it is a difficult and lofty thing to be superior to
the former, but easy to be so to the latter, and a lofty bearing over the former is no mark of ill-breeding, but
among humble people it is as vulgar as a display of strength against the weak. Again, it is characteristic of the
proud man not to aim at the things commonly held in honour, or the things in which others excel; to be
sluggish and to hold back except where great honour or a great work is at stake, and to be a man of few
deeds, but of great and notable ones. He must also be open in his hate and in his love (for to conceal one's
feelings, i.e. to care less for truth than for what people will think, is a coward's part), and must speak and act
openly; for he is free of speech because he is contemptuous, and he is given to telling the truth, except when
he speaks in irony to the vulgar. He must be unable to make his life revolve round another, unless it be a
friend; for this is slavish, and for this reason all flatterers are servile and people lacking in self-respect are
flatterers. Nor is he given to admiration; for nothing to him is great. Nor is he mindful of wrongs; for it is not
the part of a proud man to have a long memory, especially for wrongs, but rather to overlook them. Nor is he
a gossip; for he will speak neither about himself nor about another, since he cares not to be praised nor for
others to be blamed; nor again is he given to praise; and for the same reason he is not an evil-speaker, even
about his enemies, except from haughtiness. With regard to necessary or small matters he is least of all me
given to lamentation or the asking of favours; for it is the part of one who takes such matters seriously to
behave so with respect to them. He is one who will possess beautiful and profitless things rather than
profitable and useful ones; for this is more proper to a character that suffices to itself.

Further, a slow step is thought proper to the proud man, a deep voice, and a level utterance; for the man who
takes few things seriously is not likely to be hurried, nor the man who thinks nothing great to be excited,
while a shrill voice and a rapid gait are the results of hurry and excitement.

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Such, then, is the proud man; the man who falls short of him is unduly humble, and the man who goes
beyond him is vain. Now even these are not thought to be bad (for they are not malicious), but only mistaken.
For the unduly humble man, being worthy of good things, robs himself of what he deserves, and to have
something bad about him from the fact that he does not think himself worthy of good things, and seems also
not to know himself; else he would have desired the things he was worthy of, since these were good. Yet such
people are not thought to be fools, but rather unduly retiring. Such a reputation, however, seems actually to
make them worse; for each class of people aims at what corresponds to its worth, and these people stand back
even from noble actions and undertakings, deeming themselves unworthy, and from external goods no less.
Vain people, on the other hand, are fools and ignorant of themselves, and that manifestly; for, not being
worthy of them, they attempt honourable undertakings, and then are found out; and tetadorn themselves with
clothing and outward show and such things, and wish their strokes of good fortune to be made public, and
speak about them as if they would be honoured for them. But undue humility is more opposed to pride than
vanity is; for it is both commoner and worse.

Pride, then, is concerned with honour on the grand scale, as has been said.

There seems to be in the sphere of honour also, as was said in our first remarks on the subject, a virtue which
would appear to be related to pride as liberality is to magnificence. For neither of these has anything to do
with the grand scale, but both dispose us as is right with regard to middling and unimportant objects; as in
getting and giving of wealth there is a mean and an excess and defect, so too honour may be desired more
than is right, or less, or from the right sources and in the right way. We blame both the ambitious man as am
at honour more than is right and from wrong sources, and the unambitious man as not willing to be honoured
even for noble reasons. But sometimes we praise the ambitious man as being manly and a lover of what is
noble, and the unambitious man as being moderate and self-controlled, as we said in our first treatment of the
subject. Evidently, since 'fond of such and such an object' has more than one meaning, we do not assign the
term 'ambition' or 'love of honour' always to the same thing, but when we praise the quality we think of the
man who loves honour more than most people, and when we blame it we think of him who loves it more than
is right. The mean being without a name, the extremes seem to dispute for its place as though that were
vacant by default. But where there is excess and defect, there is also an intermediate; now men desire honour
both more than they should and less; therefore it is possible also to do so as one should; at all events this is
the state of character that is praised, being an unnamed mean in respect of honour. Relatively to ambition it
seems to be unambitiousness, and relatively to unambitiousness it seems to be ambition, while relatively to
both severally it seems in a sense to be both together. This appears to be true of the other virtues also. But in
this case the extremes seem to be contradictories because the mean has not received a name.

Good temper is a mean with respect to anger; the middle state being unnamed, and the extremes almost
without a name as well, we place good temper in the middle position, though it inclines towards the
deficiency, which is without a name. The excess might called a sort of 'irascibility'. For the passion is anger,
while its causes are many and diverse.

The man who is angry at the right things and with the right people, and, further, as he ought, when he ought,
and as long as he ought, is praised. This will be the good-tempered man, then, since good temper is praised.
For the good-tempered man tends to be unperturbed and not to be led by passion, but to be angry in the
manner, at the things, and for the length of time, that the rule dictates; but he is thought to err rather in the
direction of deficiency; for the good-tempered man is not revengeful, but rather tends to make allowances.

The deficiency, whether it is a sort of 'inirascibility' or whatever it is, is blamed. For those who are not angry
at the things they should be angry at are thought to be fools, and so are those who are not angry in the right
way, at the right time, or with the right persons; for such a man is thought not to feel things nor to be pained
by them, and, since he does not get angry, he is thought unlikely to defend himself; and to endure being
insulted and put up with insult to one's friends is slavish.

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The excess can be manifested in all the points that have been named (for one can be angry with the wrong
persons, at the wrong things, more than is right, too quickly, or too long); yet all are not found in the same
person. Indeed they could not; for evil destroys even itself, and if it is complete becomes unbearable. Now
hot-tempered people get angry quickly and with the wrong persons and at the wrong things and more than is
right, but their anger ceases quickly-which is the best point about them. This happens to them because they
do not restrain their anger but retaliate openly owing to their quickness of temper, and then their anger ceases.
By reason of excess choleric people are quick-tempered and ready to be angry with everything and on every
occasion; whence their name. Sulky people are hard to appease, and retain their anger long; for they repress
their passion. But it ceases when they retaliate; for revenge relieves them of their anger, producing in them
pleasure instead of pain. If this does not happen they retain their burden; for owing to its not being obvious
no one even reasons with them, and to digest one's anger in oneself takes time. Such people are most
troublesome to themselves and to their dearest friends. We call had-tempered those who are angry at the
wrong things, more than is right, and longer, and cannot be appeased until they inflict vengeance or
punishment.

To good temper we oppose the excess rather than the defect; for not only is it commoner since revenge is the
more human), but bad-tempered people are worse to live with.

What we have said in our earlier treatment of the subject is plain also from what we are now saying; viz. that
it is not easy to define how, with whom, at what, and how long one should be angry, and at what point right
action ceases and wrong begins. For the man who strays a little from the path, either towards the more or
towards the less, is not blamed; since sometimes we praise those who exhibit the deficiency, and call them
good-tempered, and sometimes we call angry people manly, as being capable of ruling. How far, therefore,
and how a man must stray before he becomes blameworthy, it is not easy to state in words; for the decision
depends on the particular facts and on perception. But so much at least is plain, that the middle state is
praiseworthy- that in virtue of which we are angry with the right people, at the right things, in the right way,
and so on, while the excesses and defects are blameworthy- slightly so if they are present in a low degree,
more if in a higher degree, and very much if in a high degree. Evidently, then, we must cling to the middle
state.- Enough of the states relative to anger.

In gatherings of men, in social life and the interchange of words and deeds, some men are thought to be
obsequious, viz. those who to give pleasure praise everything and never oppose, but think it their duty 'to give
no pain to the people they meet'; while those who, on the contrary, oppose everything and care not a whit
about giving pain are called churlish and contentious. That the states we have named are culpable is plain
enough, and that the middle state is laudable- that in virtue of which a man will put up with, and will resent,
the right things and in the right way; but no name has been assigned to it, though it most resembles
friendship. For the man who corresponds to this middle state is very much what, with affection added, we call
a good friend. But the state in question differs from friendship in that it implies no passion or affection for
one's associates; since it is not by reason of loving or hating that such a man takes everything in the right
way, but by being a man of a certain kind. For he will behave so alike towards those he knows and those he
does not know, towards intimates and those who are not so, except that in each of these cases he will behave
as is befitting; for it is not proper to have the same care for intimates and for strangers, nor again is it the
same conditions that make it right to give pain to them. Now we have said generally that he will associate
with people in the right way; but it is by reference to what is honourable and expedient that he will aim at not
giving pain or at contributing pleasure. For he seems to be concerned with the pleasures and pains of social
life; and wherever it is not honourable, or is harmful, for him to contribute pleasure, he will refuse, and will
choose rather to give pain; also if his acquiescence in another's action would bring disgrace, and that in a high
degree, or injury, on that other, while his opposition brings a little pain, he will not acquiesce but will decline.
He will associate differently with people in high station and with ordinary people, with closer and more
distant acquaintances, and so too with regard to all other differences, rendering to each class what is befitting,
and while for its own sake he chooses to contribute pleasure, and avoids the giving of pain, he will be guided

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by the consequences, if these are greater, i.e. honour and expediency. For the sake of a great future pleasure,
too, he will inflict small pains.

The man who attains the mean, then, is such as we have described, but has not received a name; of those who
contribute pleasure, the man who aims at being pleasant with no ulterior object is obsequious, but the man
who does so in order that he may get some advantage in the direction of money or the things that money buys
is a flatterer; while the man who quarrels with everything is, as has been said, churlish and contentious. And
the extremes seem to be contradictory to each other because the mean is without a name.

The mean opposed to boastfulness is found in almost the same sphere; and this also is without a name. It will
be no bad plan to describe these states as well; for we shall both know the facts about character better if we
go through them in detail, and we shall be convinced that the virtues are means if we see this to be so in all
cases. In the field of social life those who make the giving of pleasure or pain their object in associating with
others have been described; let us now describe those who pursue truth or falsehood alike in words and deeds
and in the claims they put forward. The boastful man, then, is thought to be apt to claim the things that bring
glory, when he has not got them, or to claim more of them than he has, and the mock-modest man on the
other hand to disclaim what he has or belittle it, while the man who observes the mean is one who calls a
thing by its own name, being truthful both in life and in word, owning to what he has, and neither more nor
less. Now each of these courses may be adopted either with or without an object. But each man speaks and
acts and lives in accordance with his character, if he is not acting for some ulterior object. And falsehood is in
itself mean and culpable, and truth noble and worthy of praise. Thus the truthful man is another case of a man
who, being in the mean, is worthy of praise, and both forms of untruthful man are culpable, and particularly
the boastful man.

Let us discuss them both, but first of all the truthful man. We are not speaking of the man who keeps faith in
his agreements, i.e. in the things that pertain to justice or injustice (for this would belong to another virtue),
but the man who in the matters in which nothing of this sort is at stake is true both in word and in life because
his character is such. But such a man would seem to be as a matter of fact equitable. For the man who loves
truth, and is truthful where nothing is at stake, will still more be truthful where something is at stake; he will
avoid falsehood as something base, seeing that he avoided it even for its own sake; and such a man is worthy
of praise. He inclines rather to understate the truth; for this seems in better taste because exaggerations are
wearisome.

He who claims more than he has with no ulterior object is a contemptible sort of fellow (otherwise he would
not have delighted in falsehood), but seems futile rather than bad; but if he does it for an object, he who does
it for the sake of reputation or honour is (for a boaster) not very much to be blamed, but he who does it for
money, or the things that lead to money, is an uglier character (it is not the capacity that makes the boaster,
but the purpose; for it is in virtue of his state of character and by being a man of a certain kind that he is
boaster); as one man is a liar because he enjoys the lie itself, and another because he desires reputation or
gain. Now those who boast for the sake of reputation claim such qualities as will praise or congratulation, but
those whose object is gain claim qualities which are of value to one's neighbours and one's lack of which is
not easily detected, e.g. the powers of a seer, a sage, or a physician. For this reason it is such things as these
that most people claim and boast about; for in them the above-mentioned qualities are found.

Mock-modest people, who understate things, seem more attractive in character; for they are thought to speak
not for gain but to avoid parade; and here too it is qualities which bring reputation that they disclaim, as
Socrates used to do. Those who disclaim trifling and obvious qualities are called humbugs and are more
contemptible; and sometimes this seems to be boastfulness, like the Spartan dress; for both excess and great
deficiency are boastful. But those who use understatement with moderation and understate about matters that
do not very much force themselves on our notice seem attractive. And it is the boaster that seems to be
opposed to the truthful man; for he is the worse character.

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Since life includes rest as well as activity, and in this is included leisure and amusement, there seems here
also to be a kind of intercourse which is tasteful; there is such a thing as saying- and again listening to- what
one should and as one should. The kind of people one is speaking or listening to will also make a difference.
Evidently here also there is both an excess and a deficiency as compared with the mean. Those who carry
humour to excess are thought to be vulgar buffoons, striving after humour at all costs, and aiming rather at
raising a laugh than at saying what is becoming and at avoiding pain to the object of their fun; while those
who can neither make a joke themselves nor put up with those who do are thought to be boorish and
unpolished. But those who joke in a tasteful way are called ready-witted, which implies a sort of readiness to
turn this way and that; for such sallies are thought to be movements of the character, and as bodies are
discriminated by their movements, so too are characters. The ridiculous side of things is not far to seek,
however, and most people delight more than they should in amusement and in jestinly. and so even buffoons
are called ready-witted because they are found attractive; but that they differ from the ready-witted man, and
to no small extent, is clear from what has been said.

To the middle state belongs also tact; it is the mark of a tactful man to say and listen to such things as befit a
good and well-bred man; for there are some things that it befits such a man to say and to hear by way of jest,
and the well-bred man's jesting differs from that of a vulgar man, and the joking of an educated man from
that of an uneducated. One may see this even from the old and the new comedies; to the authors of the former
indecency of language was amusing, to those of the latter innuendo is more so; and these differ in no small
degree in respect of propriety. Now should we define the man who jokes well by his saying what is not
unbecoming to a well-bred man, or by his not giving pain, or even giving delight, to the hearer? Or is the
latter definition, at any rate, itself indefinite, since different things are hateful or pleasant to different people?
The kind of jokes he will listen to will be the same; for the kind he can put up with are also the kind he seems
to make. There are, then, jokes he will not make; for the jest is a sort of abuse, and there are things that
lawgivers forbid us to abuse; and they should, perhaps, have forbidden us even to make a jest of such. The
refined and well-bred man, therefore, will be as we have described, being as it were a law to himself.

Such, then, is the man who observes the mean, whether he be called tactful or ready-witted. The buffoon, on
the other hand, is the slave of his sense of humour, and spares neither himself nor others if he can raise a
laugh, and says things none of which a man of refinement would say, and to some of which he would not
even listen. The boor, again, is useless for such social intercourse; for he contributes nothing and finds fault
with everything. But relaxation and amusement are thought to be a necessary element in life.

The means in life that have been described, then, are three in number, and are all concerned with an
interchange of words and deeds of some kind. They differ, however, in that one is concerned with truth; and
the other two with pleasantness. Of those concerned with pleasure, one is displayed in jests, the other in the
general social intercourse of life.

Shame should not be described as a virtue; for it is more like a feeling than a state of character. It is defined,
at any rate, as a kind of fear of dishonour, and produces an effect similar to that produced by fear of danger;
for people who feel disgraced blush, and those who fear death turn pale. Both, therefore, seem to be in a
sense bodily conditions, which is thought to be characteristic of feeling rather than of a state of character.

The feeling is not becoming to every age, but only to youth. For we think young people should be prone to
the feeling of shame because they live by feeling and therefore commit many errors, but are restrained by
shame; and we praise young people who are prone to this feeling, but an older person no one would praise for
being prone to the sense of disgrace, since we think he should not do anything that need cause this sense. For
the sense of disgrace is not even characteristic of a good man, since it is consequent on bad actions (for such
actions should not be done; and if some actions are disgraceful in very truth and others only according to
common opinion, this makes no difference; for neither class of actions should be done, so that no disgrace
should be felt); and it is a mark of a bad man even to be such as to do any disgraceful action. To be so

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constituted as to feel disgraced if one does such an action, and for this reason to think oneself good, is absurd;
for it is for voluntary actions that shame is felt, and the good man will never voluntarily do bad actions. But
shame may be said to be conditionally a good thing; if a good man does such actions, he will feel disgraced;
but the virtues are not subject to such a qualification. And if shamelessness-not to be ashamed of doing base
actions-is bad, that does not make it good to be ashamed of doing such actions. Continence too is not virtue,
but a mixed sort of state; this will be shown later. Now, however, let us discuss justice.

BOOKV

WITH regards to justice and injustice we must (1) consider what kind of actions they are concerned with, (2)
what sort of mean justice is, and (3) between what extremes the just act is intermediate. Our investigation
shall follow the same course as the preceding discussions.

We see that all men mean by justice that kind of state of character which makes people disposed to do what is
just and makes them act justly and wish for what is just; and similarly by injustice that state which makes
them act unjustly and wish for what is unjust. Let us too, then, lay this down as a general basis. For the same
is not true of the sciences and the faculties as of states of character. A faculty or a science which is one and
the same is held to relate to contrary objects, but a state of character which is one of two contraries does not
produce the contrary results; e.g. as a result of health we do not do what is the opposite of healthy, but only
what is healthy; for we say a man walks healthily, when he walks as a healthy man would.

Now often one contrary state is recognized from its contrary, and often states are recognized from the
subjects that exhibit them; for (A) if good condition is known, bad condition also becomes known, and (B)
good condition is known from the things that are in good condition, and they from it. If good condition is
firmness of flesh, it is necessary both that bad condition should be flabbiness of flesh and that the wholesome
should be that which causes firmness in flesh. And it follows for the most part that if one contrary is
ambiguous the other also will be ambiguous; e.g. if 'just' is so, that 'unjust' will be so too.

Now justice' and 'injustice' seem to be ambiguous, but because their different meanings approach near to one
another the ambiguity escapes notice and is not obvious as it is, comparatively, when the meanings are far
apart, e.g. (for here the difference in outward form is great) as the ambiguity in the use of kleis for the
collar-bone of an animal and for that with which we lock a door. Let us take as a starting-point, then, the
various meanings of 'an unjust man'. Both the lawless man and the grasping and unfair man are thought to be
unjust, so that evidently both the law-abiding and the fair man will be just.

The Complete Works of Aristotle - Part 3