[
1045b]
[27]
We have now dealt with Being in the
primary sense, to which all the other categories of being are related;
i.e. substance. For it is from the concept of substance that all the
other modes of being take their meaning; both quantity and quality and
all other such terms; for they will all involve the concept of
substance, as we stated it in the beginning of our discussion.
1And since the senses of being are
analyzable
2 not only into
substance or quality or quantity, but also in accordance with
potentiality and actuality and function, let us also gain a clear
understanding about potentiality and actuality; and first about
potentiality in the sense which is most proper to the word, but not
most useful for our present purpose—
[
1046a]
[1]
for
potentiality and actuality extend beyond the sphere of terms which
only refer to motion.When
we have discussed this sense of potentiality we will, in the course of
our definitions of actuality,
3 explain the others also.
We have made it plain elsewhere
4 that "potentiality" and
"can" have several senses.All senses which are merely equivocal may be dismissed; for some are
used by analogy, as in geometry,
5 and we
call things possible or impossible because they "are" or "are not" in
some particular way. But the potentialities which conform to the same
type are all principles, and derive their meaning from one primary
sense of potency, which is the source of change in some other thing,
or in the same thing qua other.
One kind of potentiality is the power of being affected; the
principle in the patient itself which initiates a passive change in it
by the action of some other thing, or of itself qua other. Another is a positive state of impassivity in respect
of deterioration or destruction by something else or by itself qua something else; i.e. by a transformatory
principle—for all these definitions contain the formula of
the primary sense of potentiality.Again, all these potentialities are so called
either because they merely act or are acted upon in a particular way,
or because they do so
well . Hence in their formulae also
the formulae of potentiality in the senses previously described are
present in some degree.
Clearly, then,
in one sense the potentiality for acting and being acted upon is
one
[20]
(for a thing is
"capable" both because it itself possesses the power of being acted
upon, and also because something else has the power of being acted
upon by it);and in another
sense it is not; for it is partly in the patient (for it is because it
contains a certain principle, and because even the matter is a kind of
principle, that the patient is acted upon; i.e., one thing is acted
upon by another: oily stuff is inflammable, and stuff which yields in
a certain way is breakable, and similarly in other
cases)—and
partly in the agent; e.g. heat and the art of building: the former in
that which produces heat, and the latter in that which builds. Hence
in so far as it is a natural unity, nothing is acted upon by itself;
because it is one, and not a separate thing.
"Incapacity" and "the incapable" is the privation
contrary to "capacity" in this sense; so that every "capacity" has a
contrary incapacity for producing the same result in respect of the
same subject.
Privation has several senses
6—it is applied (1.) to anything which
does not possess a certain attribute; (2.) to that which would
naturally possess it, but does not; either (a) in general, or (b) when
it would naturally possess it; and either (1) in a particular way,
e.g. entirely, or (2) in any way at all. And in some cases if things
which would naturally possess some attribute lack it as the result of
constraint, we say that they are "deprived."
Since
some of these principles are inherent in inanimate things, and others
in animate things and in the soul and in the rational part of the
soul,
[
1046b]
[1]
it is clear that some of the potencies
also will be irrational and some rational. Hence all arts, i.e. the
productive sciences, are potencies; because they are principles of
change in another thing, or in the artist himself qua other.
Every rational potency admits
equally of contrary results, but irrational potencies admit of one
result only. E.g., heat can only produce heat, but medical science can
produce disease and health. The reason of this is that science is a
rational account, and the same account explains both the thing and its
privation, though not in the same way; and in one sense it applies to
both, and in another sense rather to the actual fact.Therefore such sciences must
treat of contraries—essentially of the one, and
non-essentially of the other; for the rational account also applies
essentially to the one, but to the other in a kind of accidental way,
since it is by negation and removal that it throws light on the
contrary. For the contrary is the primary privation,
7 and this is the removal of that to
which it is contrary.
8And since contrary attributes cannot be
induced in the same subject, and science is a potency which depends
upon the possession of a rational formula, and the soul contains a
principle of motion, it follows that whereas "the salutary" can only
produce health, and "the calefactory" only heat, and "the frigorific"
only cold,
[20]
the scientific
man can produce both contrary results.For the rational account includes both, though
not in the same way; and it is in the soul, which contains a principle
of motion, and will therefore, by means of the same principle, set
both processes in motion, by linking them with the same rational
account. Hence things which have a rational potency produce results
contrary to those of things whose potency is irrational
9; for
the results of the former are included under one principle, the
rational account.It is
evident also that whereas the power of merely producing (or suffering)
a given effect is implied in the power of producing that effect
well , the contrary is not always true; for that
which produces an effect well must also produce it, but that which
merely produces a given effect does not necessarily produce it
well.
There are some, e.g. the Megaric school,
10 who say that a
thing only has potency when it functions, and that when it is not
functioning it has no potency. E.g., they say that a man who is not
building cannot build, but only the man who is building, and at the
moment when he is building; and similarly in the other
cases.It is not
difficult to see the absurd consequences of this theory. Obviously a
man will not be a builder unless he is building, because "to be a
builder" is "to be capable of building"; and the same will be true of
the other arts.If,
therefore, it is impossible to possess these arts without learning
them at some time and having grasped them,
[
1047a]
[1]
and
impossible not to possess them without having lost them at some time
(through forgetfulness or some affection or the lapse of time; not, of
course, through the destruction of the object of the art,
11 because it exists always), when the artist ceases to
practice his art, he will not possess it;and if he immediately starts building again,
how will he have re-acquired the art?
The same is true of inanimate things. Neither the cold nor the hot
nor the sweet nor in general any sensible thing will exist unless we
are perceiving it (and so the result will be that they are affirming
Protagoras' theory
12). Indeed, nothing will have the faculty of sensation
unless it is perceiving, i.e. actually employing the
faculty.If, then,
that is blind which has not sight, though it would naturally have it,
and when it would naturally have it, and while it still exists, the
same people will be blind many times a day; and deaf too.
Further, if that which is deprived of its
potency is incapable, that which is not happening will be incapable of
happening; and he who says that that which is incapable of happening
is or
will be, will be in error, for
this is what "incapable" meant.
13Thus these theories do away with both motion and generation; for
that which is standing will always stand, and that which is sitting
will always sit; because if it is sitting it will not get up, since it
is impossible that anything which is incapable of getting up should
get up.Since, then, we
cannot maintain this, obviously potentiality and actuality are
different. But these theories make potentiality and actuality
identical;
[20]
hence it is
no small thing that they are trying to abolish.
Thus it is possible that a thing may be capable of
being and yet not be, and capable of not being and yet be; and
similarly in the other categories that which is capable of walking may
not walk, and that which is capable of not walking may walk.A thing is capable of doing
something if there is nothing impossible in its having the actuality
of that of which it is said to have the potentiality. I mean, e.g.,
that if a thing is capable of sitting and is not prevented from
sitting, there is nothing impossible in its actually sitting; and
similarly if it is capable of being moved or moving or standing or
making to stand or being or becoming or not being or not
becoming.
The term "actuality," with its
implication of "complete reality," has been extended from motions, to
which it properly belongs, to other things; for it is agreed that
actuality is properly motion.Hence people do not invest non-existent things
with motion, although they do invest them with certain other
predicates. E.g., they say that non-existent things are conceivable
and desirable, but not that they are in motion. This is because,
although these things do not exist actually, they will exist actually;
[
1047b]
[1]
for some non-existent things exist
potentially; yet they do not exist, because they do not exist in
complete reality.
Now if, as we have said, that is
possible which does not involve an impossibility, obviously it cannot
be true to say that so-and-so is possible, but will not be, this view
entirely loses sight of the instances of impossibility.
14 I mean, suppose that
someone—i.e. the sort of man who does not take the
impossible into account—were to say that it is possible to
measure the diagonal of a square, but that it will not be measured,
because there is nothing to prevent a thing which is capable of being
or coming to be from neither being nor being likely ever to
be.But from our
premisses this necessarily follows: that if we are to assume that
which is not, but is possible, to be or to have come to be, nothing
impossible must be involved. But in this case something impossible
will take place; for the measuring of the diagonal is
impossible.
The false is of course
not the same as the impossible; for although it is false that you are
now standing, it is not impossible.At the same time it is also clear that if B
must be real if A is, then if it is possible for A to be real, it must
also be possible for B to be real; for even if B is not necessarily
possible, there is nothing to prevent its being possible. Let A, then,
be possible. Then when A was possible, if A was assumed to be real,
nothing impossible was involved; but B was necessarily real
too.
[20]
But ex hypothesi
B was impossible. Let B be impossible.Then if B is impossible, A must also be
impossible. But A was by definition possible. Therefore so is
B.
If, therefore, A is possible, B
will also be possible; that is if their relation was such that if A is
real, B must be real.Then
if, A and B being thus related, B is not possible on this condition, A
and B will not be related as we assumed; and if when A is possible B
is necessarily possible, then if A is real B must be real too. For to
say that B must be possible if A is possible means that if A is real
at the time when and in the way in which it was assumed that it was
possible for it to be real, then B must be real at that time and in
that way.
Since all potencies are either innate, like
the senses, or acquired by practice, like flute-playing, or by study,
as in the arts, some—such as are acquired by practice or a
rational formula—we can only possess when we have first
exercised them
15; in the case of
others which are not of this kind and which imply passivity, this is
not necessary.
[
1048a]
[1]
Since anything
which is possible is something possible at some time and in some way,
and with any other qualifications which are necessarily included in
the definition; and since some things can set up processes rationally
and have rational potencies, while others are irrational and have
irrational potencies; and since the former class can only belong to a
living thing, whereas the latter can belong both to living and to
inanimate things: it follows that as for potencies of the latter kind,
when the agent and the patient meet in accordance with the potency in
question, the one must act and the other be acted upon; but in the
former kind of potency this is not necessary, for whereas each single
potency of the latter kind is productive of a single effect, those of
the former kind are productive of contrary effects,
16 so that one potency will produce
at the same time contrary effects.
17But this is impossible. Therefore there must
be some other deciding factor, by which I mean
desire or
conscious choice. For whichever of two things an
animal desires decisively it will do, when it is in circumstances
appropriate to the potency and meets with that which admits of being
acted upon. Therefore everything which is rationally capable, when it
desires something of which it has the capability, and in the
circumstances in which it has the capability, must do that
thing.Now it has the
capability when that which admits of being acted upon is present and
is in a certain state; otherwise it will not be able to act. (To add
the qualification "if nothing external prevents it" is no longer
necessary; because the agent has the capability in so far as it is a
capability of acting; and this is not in all, but in certain
circumstances, in which external hindrances will be
excluded;
[20]
for they are
precluded by some of the positive qualifications in the
definition.)Hence
even if it wishes or desires to do two things or contrary things
simultaneously, it will not do them, for it has not the capability to
do them under these conditions, nor has it the capability of doing
things simultaneously, since it will only do the things to which the
capability applies and under the appropriate conditions.
Since we have now dealt with the kind of potency which is related to
motion, let us now discuss actuality; what it is, and what its
qualities are. For as we continue our analysis it will also become
clear with regard to the potential that we apply the name not only to
that whose nature it is to move or be moved by something else, either
without qualification or in some definite way, but also in other
senses; and it is on this account that in the course of our inquiry we
have discussed these as well.
"Actuality" means the presence
of the thing, not in the sense which we mean by "potentially." We say
that a thing is present potentially as Hermes is present in the wood,
or the half-line in the whole, because it can be separated from it;
and as we call even a man who is not studying "a scholar" if he is
capable of studying. That which is present in the opposite sense to
this is present actually.What we mean can be plainly seen in the particular cases by
induction; we need not seek a definition for every term, but must
comprehend the analogy: that as that which is actually building is to
that which is capable of building,
[
1048b]
[1]
so is that which is
awake to that which is asleep; and that which is seeing to that which
has the eyes shut, but has the power of sight; and that which is
differentiated out of matter to the matter; and the finished article
to the raw material.Let
actuality be defined by one member of this antithesis, and the
potential by the other.
But things are
not all said to exist actually in the same sense, but only by
analogy—as A is in B or to B, so is C in or to D; for the
relation is either that of motion to potentiality, or that of
substance to some particular matter.
Infinity and void
and other concepts of this kind are said to "be" potentially or
actually in a different sense from the majority of existing things,
e.g. that which sees, or walks, or is seen.For in these latter cases the predication may
sometimes be truly made without qualification, since "that which is
seen" is so called sometimes because it is seen and sometimes because
it is capable of being seen; but the Infinite does not exist
potentially in the sense that it will ever exist separately in
actuality; it is separable only in knowledge. For the fact that the
process of division never ceases makes this actuality exist
potentially, but not separately.
18Since no action which has a
limit is an end, but only a means to the end, as, e.g., the process of
thinning;
[20]
and since
the parts of the body themselves, when one is thinning them, are in
motion in the sense that they are not already that which it is the
object of the motion to make them, this process is not an action, or
at least not a complete one, since it is not an end; it is the process
which includes the end that is an action.E.g., at the same time we see and have seen,
understand and have understood, think and have thought; but we cannot
at the same time learn and have learnt, or become healthy and be
healthy. We are living well and have lived well, we are happy and have
been happy, at the same time; otherwise the process would have had to
cease at some time, like the thinning-process; but it has not ceased
at the present moment; we both are living and have lived.
Now of these processes we should call the
one type motions, and the other actualizations.Every motion is
incomplete—the processes of thinning, learning, walking,
building—these are motions, and incomplete at that. For it
is not the same thing which at the same time is walking and has
walked, or is building and has built, or is becoming and has become,
or is being moved and has been moved, but two different things; and
that which is causing motion is different from that which has caused
motion.But the same
thing at the same time is seeing and has seen, is thinking and has
thought. The latter kind of process, then, is what I mean by
actualization, and the former what I mean by motion.
What the actual is, then, and what it is like, may
be regarded as demonstrated from these and similar
considerations.
We must, however, distinguish when a
particular thing exists potentially, and when it does not; for it does
not so exist at any and every time.
[
1049a]
[1]
E.g.,
is earth potentially a man? No, but rather when it has already become
semen,
19 and perhaps not even then; just as not
everything can be healed by medicine, or even by
chance, but there is some definite kind of thing which is capable of
it, and this is that which is potentially healthy.
The
definition of that which as a result of thought comes, from existing
potentially, to exist actually, is that, when it has been willed, if
no external influence hinders it, it comes to pass; and the condition
in the case of the patient, i.e. in the person who is being healed, is
that nothing in him should hinder the process. Similarly a house
exists potentially if there is nothing in X, the matter, to prevent it
from becoming a house, i.e., if there is nothing which must be added
or removed or changed; then X is potentially a house;and similarly in all other
cases where the generative principle is external. And in all cases
where the generative principle is contained in the thing itself, one
thing is potentially another when, if nothing external hinders, it
will of itself become the other. E.g., the semen is not yet
potentially a man; for it must further undergo a change in some other
medium.
20 But when, by its own generative principle, it has
already come to have the necessary attributes, in this state it is now
potentially a man, whereas in the former state it has need of another
principle;just as
earth is not yet potentially a statue, because it must undergo a
change before it becomes bronze.
It
seems that what we are describing is not a particular thing, but a
definite material; e.g., a box is not wood, but wooden material,
21
[20]
and wood is not earth, but earthen material; and
earth also is an illustration of our point if it is similarly not some
other thing, but a definite material—it is always the latter
term in this series which is, in the fullest sense, potentially
something else.E.g., a box
is not earth, nor earthen, but wooden; for it is this that is
potentially a box, and this is the matter of the box—that
is, wooden material in general is the matter of "box" in general,
whereas the matter of a particular box is a particular piece of
wood.
If there is some primary
stuff, which is not further called the material of some other thing,
this is primary matter. E.g., if earth is "made of air," and air is
not fire, but "made of fire," then fire is primary matter, not being
an individual thing.For
the subject or substrate is distinguishable into two kinds by either
being or not being an individual thing. Take for example as the
subject of the attributes "man," or "body" or "soul," and as an
attribute "cultured" or "white." Now the subject, when culture is
induced in it, is called not "culture" but "cultured," and the man is
called not whiteness but white; nor is he called "ambulation" or
"motion," but "walking" or "moving"; just as we said that things are
of a definite material.Thus where "subject" has this sense, the ultimate substrate is
substance; but where it has not this sense, and the predicate is a
form or individuality, the ultimate substrate is matter or material
substance. It is quite proper that both matter and attributes should
be described by a derivative predicate,
[
1049b]
[1]
since
they are both indefinite.
Thus it has
now been stated when a thing should be said to exist potentially, and
when it should not.
Now since we have distinguished
22 the several senses of priority, it is
obvious that actuality is prior to potentiality. By potentiality I
mean not that which we have defined as "a principle of change which is
in something other than the thing changed, or in that same thing qua other," but in general any principle of
motion or of rest; for nature also is in the same genus as
potentiality, because it is a principle of motion, although not in
some other thing, but in the thing itself qua
itself.
23To every potentiality of this kind
actuality is prior, both in formula and in substance; in time it is
sometimes prior and sometimes not.
That
actuality is prior in formula is evident; for it is because it can be
actualized that the potential, in the primary sense, is potential, I
mean, e.g., that the potentially constructive is that which can
construct, the potentially seeing that which can see, and the
potentially visible that which can be seen.The same principle holds in all other cases
too, so that the formula and knowledge of the actual must precede the
knowledge of the potential.
In time it
is prior in this sense: the actual is prior to the potential with
which it is formally identical, but not to that with which it is
identical numerically.What
I mean is this:
[20]
that the
matter and the seed and the thing which is capable of seeing, which
are potentially a man and corn and seeing, but are not yet so
actually, are prior in time to the individual man and corn and seeing
subject which already exist in actuality.But prior in time to these potential entities
are other actual entities from which the former are generated; for the
actually existent is always generated from the potentially existent by
something which is actually existent—e.g., man by man,
cultured by cultured—there is always some prime mover; and
that which initiates motion exists already in actuality.
We have said
24
in our discussion of substance that everything which is generated is
generated from something and by something; and by something formally
identical with itself.Hence it seems impossible that a man can be a builder if he has
never built, or a harpist if he has never played a harp; because he
who learns to play the harp learns by playing it, and similarly in all
other cases.This was the
origin of the sophists' quibble that a man who does not know a given
science will be doing that which is the object of that science,
because the learner does not know the science. But since something of
that which is being generated is already generated, and something of
that which is being moved as a whole is already moved (this is
demonstrated in our discussion on Motion
25),
[
1050a]
[1]
presumably the learner too must
possess something of the science.At any rate from this argument it is clear
that actuality is prior to potentiality in this sense too, i.e. in
respect of generation and time.
But it
is also prior in substantiality; (a) because things which are
posterior in generation are prior in form and substantiality; e.g.,
adult is prior to child, and man to semen, because the one already
possesses the form, but the other does not;and (b) because everything which is generated
moves towards a principle, i.e. its
end . For the object
of a thing is its principle; and generation has as its object the
end . And the actuality is the end, and it is for
the sake of this that the potentiality is acquired; for animals do not
see in order that they may have sight, but have sight in order that
they may see.Similarly
men possess the art of building in order that they may build, and the
power of speculation that they may speculate; they do not speculate in
order that they may have the power of speculation—except
those who are learning by practice; and they do not really speculate,
but only in a limited sense, or about a subject about which they have
no desire to speculate.
Further, matter
exists potentially, because it may attain to the form; but when it
exists actually, it is then
in the form. The same applies
in all other cases, including those where the end is motion.Hence, just as teachers think
that they have achieved their end when they have exhibited their pupil
performing, so it is with nature. For if this is not so,
[20]
it will be another case of
"Pauson's Hermes"
26; it will be impossible to
say whether the knowledge is
in the pupil or outside him,
as in the case of the Hermes. For the activity is the end, and the
actuality is the activity; hence the term "actuality" is derived from
"activity," and tends to have the meaning of "complete
reality."
Now whereas in some cases the ultimate
thing is the use of the faculty, as, e.g., in the case of sight seeing
is the ultimate thing, and sight produces nothing else besides this;
but in other cases something is produced, e.g. the art of building
produces not only the act of building but a house; nevertheless in the
one case the use of the faculty is the end, and in the other it is
more truly the end than is the potentiality. For the act of building
resides in the thing built; i.e., it comes to be and exists
simultaneously with the house.
Thus in all cases
where the result is something other than the exercise of the faculty,
the actuality resides in the thing produced; e.g. the act of building
in the thing built, the act of weaving in the thing woven, and so on;
and in general the motion resides in the thing moved. But where there
is no other result besides the actualization, the actualization
resides in the subject; e.g. seeing in the seer, and speculation in
the speculator, and life in the soul
[
1050b]
[1]
(and hence also
happiness, since happiness is a particular kind of life). Evidently,
therefore, substance or form is actuality. Thus it is obvious by this
argument that actuality is prior in substantiality to potentiality;
and that in point of time, as we have said, one actuality presupposes
another right back to that of the prime mover in each case.
It is also prior in a deeper sense; because that which is eternal is
prior in substantiality to that which is perishable, and nothing
eternal is potential. The argument is as follows. Every potentiality
is at the same time a potentiality for the opposite.
27 For whereas that
which is incapable of happening cannot happen to anything, everything
which is capable may fail to be actualized.Therefore that which is capable of being may
both be and not be. Therefore the same thing is capable both of being
and of not being. But that which is capable of not being may possibly
not be; and that which may possibly not be is perishable; either
absolutely, or in the particular sense in which it is said that it may
possibly not be; that is, in respect either of place or of quantity or
of quality. "Absolutely" means in respect of substance.Hence nothing which is
absolutely imperishable is absolutely potential (although there is no
reason why it should not be potential in some particular respect; e.g.
of quality or place); therefore all imperishable things are actual.
Nor can anything which is of necessity be potential; and yet these
things are primary, for if they did not exist, nothing would
exist.
[20]
Nor can motion
be potential, if there is any eternal motion. Nor, if there is
anything eternally in motion, is it potentially in motion (except in
respect of some starting-point or destination), and there is no reason
why the matter of such a thing should not exist.Hence the sun and stars and the whole
visible heaven are always active, and there is no fear that they will
ever stop—a fear which the writers
28 on physics entertain. Nor do the
heavenly bodies tire in their activity; for motion does not imply for
them, as it does for perishable things, the potentiality for the
opposite, which makes the continuity of the motion distressing; this
results when the substance is matter and potentiality, not
actuality.
Imperishable things are resembled in
this respect by things which are always undergoing transformation,
such as earth and fire; for the latter too are always active, since
they have their motion independently and in themselves.
29 Other potentialities, according to the
distinctions already made,
30 all admit of the
opposite result; for that which is capable of causing motion in a
certain way can also cause it not in that way; that is if it acts
rationally.The same
irrational potentialities can only produce opposite results by their
presence or absence.
Thus if there are
any entities or substances such as the dialecticians
31
describe the Ideas to be, there must be something which has much more
knowledge than absolute knowledge, and much more mobility than motion;
[
1051a]
[1]
for they will be in a truer sense
actualities, whereas knowledge and motion will be their
potentialities.
32 Thus it is obvious that actuality is prior
both to potentiality and to every principle of change.
That a good actuality is both better and more estimable than a good
potentiality will be obvious from the following arguments. Everything
of which we speak as capable is alike capable of contrary results;
e.g., that which we call capable of being well is alike capable of
being ill, and has both potentialities at once; for the same
potentiality admits of health and disease, or of rest and motion, or
of building and of pulling down, or of being built and of falling
down.Thus the
capacity for two contraries can belong to a thing at the same time,
but the contraries cannot belong at the same time; i.e., the
actualities, e.g. health and disease, cannot belong to a thing at the
same time. Therefore one of them must be the good; but the
potentiality may equally well be both or neither. Therefore the
actuality is better.
Also in the case of evils the end or
actuality must be worse than the potentiality; for that which is
capable is capable alike of both contraries.
Clearly, then, evil does not exist apart from
things ; for evil is by nature posterior to
potentiality.
33
[20]
Nor is there in things which are original and eternal any evil or
error, or anything which has been destroyed—for destruction
is an evil.
Geometrical constructions, too, are discovered
by an actualization, because it is by dividing that we discover them.
If the division were already done, they would be obvious; but as it is
the division is only there potentially. Why is the sum of the interior
angles of a triangle equal to two right angles? Because the angles
about one point <in a straight line> are equal to two
right angles. If the line parallel to the side had been already drawn,
the answer would have been obvious at sight.
34Why is the angle in a semicircle always a right angle? If three
lines are equal, the two forming the base, and the one set upright
from the middle of the base, the answer is obvious to one who knows
the former proposition.
35 Thus it is evident that the
potential constructions are discovered by being actualized. The reason
for this is that the actualization is an act of thinking. Thus
potentiality comes from actuality (and therefore it is by constructive
action that we acquire knowledge). <But this is true only in
the abstract>, for the individual actuality is posterior in
generation to its potentiality.
36The terms "being" and
"not-being" are used not only with reference to the types of
predication, and to the potentiality or actuality, or non-potentiality
and non-actuality, of these types,
[
1051b]
[1]
but also (in the
strictest sense
37) to
denote truth and falsity. This depends, in the case of the objects,
upon their being united or divided; so that he who thinks that what is
divided is divided, or that what is united is united, is right; while
he whose thought is contrary to the real condition of the objects is
in error. Then
when do what we call truth and falsity
exist or not exist? We must consider what we mean by these
terms.
It is not because we are right in thinking
that you are white that you are white; it is because you are white
that we are right in saying so. Now if whereas some things are always
united and cannot be divided, and others are always divided and cannot
be united, others again admit of both contrary states, then "to be" is
to be united, i.e. a unity; and "not to be" is to be not united, but a
plurality.Therefore
as regards the class of things which admit of both contrary states,
the same opinion or the same statement comes to be false and true, and
it is possible at one time to be right and at another wrong; but as
regards things which cannot be otherwise the same opinion is not
sometimes true and sometimes false, but the same opinions are always
true or always false.
But with regard to incomposite
things, what is being or not-being, and truths or falsity? Such a
thing is not composite, so as to be when it is united and not to be
when it is divided,
[20]
like the
proposition that "the wood is white," or "the diagonal is
incommensurable"; nor will truth and falsity apply in the same way to
these cases as to the previous ones.In point of fact, just as truth is not the
same in these cases, so neither is being. Truth and falsity are as
follows: contact
38 and assertion are truth (for
assertion is not the same as affirmation), and ignorance is
non-contact. I say ignorance, because it is impossible to be deceived
with respect to what a thing is, except accidentally
39;and the same applies to incomposite
substances, for it is impossible to be deceived about them. And they
all exist actually, not potentially; otherwise they would be generated
and destroyed; but as it is, Being itself is not generated (nor
destroyed); if it were, it would be generated out of something. With
respect, then, to all things which are essences and actual, there is
no question of being mistaken, but only of thinking or not thinking
them.Inquiry as to
what they are takes the form of inquiring whether
they are of such-and-such a nature or not.
As for being in the sense of truth, and not-being
in the sense of falsity, a unity is true if the terms are combined,
and if they are not combined it is false. Again, if the unity exists,
it exists in a particular way, and if it does not exist in that way,
it does not exist at all.
[
1052a]
[1]
Truth means to think these objects, and
there is no falsity or deception, but only ignorance—not,
however, ignorance such as blindness is; for blindness is like a total
absence of the power of thinking. And it is obvious that with regard
to immovable things also, if one assumes that there are immovable
things, there is no deception in respect of time.E.g., if we suppose that the triangle
is immutable, we shall not suppose that it sometimes contains two
right angles and sometimes does not, for this would imply that it
changes; but we may suppose that one thing has a certain property and
another has not; e.g., that no even number is a prime, or that some
are primes and others are not. But about a single number we cannot be
mistaken even in this way, for we can no longer suppose that one
instance is of such a nature, and another not, but whether we are
right or wrong, the fact is always the same.