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, (5) 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. (10) 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, (15) 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 when they have exhibited the pupil at work, nature does likewise. For if this is not the case, (20) 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.17 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), (25) 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, (30) 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, (35) 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). [1050b]
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,18 one actuality always precedes another in time right back to the actuality of the eternal prime mover. (5)
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, (10) 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, (15) 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, (20) 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.19 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, (25) 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 things20 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.21 But the other potencies, (30) according to our previous discussion,22 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 dialecticians23 say the Ideas are, (35) 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 these.24 [1051a]
Obviously, then, actuality is prior both to potency and to every principle of change.
9 That the actuality is also better and more valuable than the good potency is evident from the following argument. (5) 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, (10) 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, (15) 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.25 And therefore we may also say that in the things which are from the beginning, (20) i. e. in eternal things, there is nothing bad, nothing defective, nothing perverted (for perversion is something bad).26
It is by 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, (25) 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). (30)
10 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 non-actuality, (35) and thirdly in the sense of true and false. [1051b] This depends, on th
e 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, (5) 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, (10) 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, (15) 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, (20) 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), (25) 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 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. (30) 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, (35) if the object is existent it exists in a particular way, and if it does not exist in this way it does not exist at all.27 [1052a] 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, (5) 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, (10) but whether our judgement be true or false, it is implied that the fact is eternal.
* * *
1 Cf. vii, viii.
2 Cf. vii. 1.
3 Cf. ix. 1048a 27–b 6.
4 Cf. v. 12.
5 i. e. the event would not happen if the passive factor were different. What is oily cannot necessarily be crushed, nor what is yielding burnt.
6 i. e. with the rational formula.
7 The object of knowledge is always a form, which is eternal. The matter which makes things perishable is no object for knowledge.
8 Cf. iv. 5, 6.
9 Cf. 1047a 24–26.
10 sc. so related that if the reality of A implies the reality of B the possibility of A implies the possibility of B.
11 sc. if A is possible.
12 sc. so related that the reality of A implies the reality of B.
13 Cf. ix. 1–5.
14 Cf. v. 11.
15 Cf. vii. 7, 8.
16 Cf. Phys. vi. 6.
17 The reference is apparently to a tricky painting in which the figure was painted so as to stand out in high relief.
18 1049b 17–29.
19 e. g. Empedocles (Cf. De Caelo, 284a 24–6).
20 sc. the heavenly bodies.
21 i. e. they are both movers and moved.
22 Cf. b 8–12.
23 The Platonists are meant; Cf. i. 987b 31.
24 The Idea, being the universal apart from its special manifestations, will be a potentiality, and will therefore be inferior to the corresponding particulars—e. g. the Idea of science will be inferior to particular acts of scientific thought.
25 sc. while the eternal and substantial must be better than the potency.
26 The paragraph seems to be directed against Plato: Cf. Rep. 402 C, 476 A, Theaet. 176 E, Laws 896 E, 898 C.
27 i. e. we have not here A and B, which may or may not be combined, but A, which if it exists at all exists as A.
BOOK I (X)
1 We have said previously, (15) in our distinction of the various meanings of words,1 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 tied together; and of these, that has more unity and is prior, (20) whose movement2 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. (25) 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, (30) 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 one3 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. (35) 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. [1052b] ‘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, (5) 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), (10) 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 h
as 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. (15) For this reason, too, ‘to be one’ means ‘to be indivisible, being essentially a “this” and 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. (20) 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, (25) 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;4 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. (30))
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. (35) 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. [1053a] 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, (5) 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. (10) 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.
The Basic Works of Aristotle (Modern Library Classics) Page 116