Book III, Chapter 5

Since in the whole of nature there is, on the one hand, something that is matter to each kind of thing (and this is what is potentially all of them), and, on the other hand, something else which is the cause and the productive factor, in that it makes them all — the way art stands to its material — these differences must necessarily be present in the soul as well.

And there is an intellect of the one sort by becoming all things, and an intellect of the other sort by making all things, as a kind of positive state, like light; for in a way light too makes colours that are potentially colours into colours in actuality. And this intellect is separable and unaffected and unmixed, being in its substance an actuality. For that which acts is always more honourable than that which is acted upon, and the first principle than the matter.

Now actual knowledge is identical with its object; but potential knowledge is prior in time in the individual, though taken as a whole it is not prior even in time. But it is not the case that this intellect at one time thinks and at another does not think. When it has been separated it is just that alone which it is, and this alone is immortal and eternal. But we do not remember, because this is unaffected, whereas the passive intellect is perishable, and without this it thinks nothing.

Book III, Chapter 6

The thinking of indivisible objects, then, occurs among those things about which there is no falsity. But among those things where there is both falsity and truth, there is already a kind of combining of thoughts as though they made a unity, just as Empedocles said that they were afterwards put together by Love. So too these separate items are combined, as for instance "incommensurable" and "the diagonal." And if the objects are things past or things to come, one combines them while also thinking of the time. For falsity always lies in a combination; for even if one says that the white is not-white, one has combined "not-white." It is possible also to call all these cases division. At any rate, it is not only true or false that Cleon is white, but also that he was or will be white. And that which makes each of them one is the intellect.

Now since "indivisible" has two senses — either potentially or actually — nothing prevents one from thinking an indivisible when one thinks a length; for it is indivisible in actuality, and one thinks it in an indivisible time; for the time is divisible and indivisible in the same way as the length. So it is not possible to say what one is thinking in each of the two halves; for the halves do not exist, unless the whole has been divided, except potentially. But in thinking each of the halves separately one divides the time as well, at the same time; and then the halves are, as it were, lengths. But if one thinks the length as composed of both halves, one thinks it also in the time that answers to both.

But that which is indivisible not in quantity but in form one thinks in an indivisible time and by an indivisible part of the soul. This holds only incidentally: it is not qua divisible that that by which it thinks and the time in which it thinks are divisible, but qua indivisible. For there is present in these too something indivisible, though perhaps not separable, which makes the time one and the length one. And this is likewise present in everything continuous, both time and length.

But the point, and every division, and what is indivisible in this way, is exhibited in the manner of a privation. And the account is similar in the other cases: for instance, how one comes to know the bad or the black; for one knows them in a way by the contrary. And that which knows must be potentially the contrary, and the contrary must be present within it. But if among the causes there is any to which nothing is contrary, then it knows itself, and is in actuality, and is separable.

Now assertion is the saying of something about something, as is affirmation, and every such saying is either true or false. But not every act of intellect is of this kind: the thinking of what a thing is, in respect of its essence, is true, and is not the saying of something about something. But just as the seeing of its proper object is true, while whether the white thing is a man or not is not always true, so it stands with everything that is without matter.

Book III, Chapter 7

Actual knowledge is identical with its object. But potential knowledge is prior in time in the individual, though taken as a whole it is not prior even in time; for everything that comes to be comes to be from something that exists in full actuality. And it is evident that the perceptible object makes the perceptive faculty, which was potential, actual; for the perceptive faculty is not affected nor altered. Hence this is a different kind of change; for change was the actuality of what is incomplete, whereas actuality without qualification, that of what has been completed, is something different.

Perceiving, then, is like bare asserting and thinking; but when the object is pleasant or painful, the soul, as though affirming or denying, pursues or avoids it. And to feel pleasure and to feel pain are the activity of the perceptive mean directed towards the good or the bad as such. And avoidance and desire, taken in their actuality, are this same thing; and the faculty of desire and the faculty of avoidance are not different, either from one another or from the perceptive faculty — but their being is different.

To the thinking soul the images serve as sense-impressions. And when it affirms or denies that something is good or bad, it avoids or pursues it. Hence the soul never thinks without an image. And just as the air makes the pupil of the eye of such and such a kind, and the pupil in turn acts upon something else, and it is the same with hearing — but the last term is one, and there is a single mean, though its being is manifold.

By what the soul discerns how sweet differs from hot has been stated before as well, but it must be stated in this way also. For it is some one thing, but one in the way that a boundary is. And these, being one by analogy and in number, stand to each of the two objects as those objects stand to one another. For what difference does it make whether we raise the puzzle about how it discriminates things of the same kind, or contraries, such as white and black? Let A, the white, then, stand to B, the black, as C stands to D; so that they may also be taken alternately. If, then, C and D belong to one and the same subject, they will stand in the same relation as A and B do: they are the same and one, yet their being is not the same; and it will be likewise with that other pair. And the same account holds if A were the sweet and B the white.

The faculty of thought, then, thinks the forms in the images; and just as in those images what is to be pursued and what avoided is marked out for it, so too, apart from sense-perception, when it is occupied with the images it is moved. For instance, perceiving that the beacon is fire, one recognises by the common sense, seeing it moving, that it signals an enemy. But at other times, by means of the images or thoughts in the soul, one reasons, as though seeing them, and deliberates about what is to come in the light of what is present; and when one says, as there in perception, that the thing is pleasant or painful, here in thought one avoids or pursues it — and so generally in action. And what is apart from action too, the true and the false, belongs to the same genus as the good and the bad; but they differ in that the one pair is without qualification, the other relative to some particular person.

The things spoken of by abstraction it thinks in the way one would think the snub: qua snub, one would not think it separately, but qua concave, if anyone thought it in actuality, he would think it without the flesh in which the concavity is. So too, when it thinks the objects of mathematics, it thinks as separate things that are not separate. And in general, the intellect in actuality is the things which it thinks. Whether it is possible for the intellect, while itself not separate from magnitude, to think any of the things that are separate, must be considered later.