Book I, Chapter 4

There is yet another opinion about the soul that has been handed down, one which many find no less convincing than any of the views so far mentioned, and which has rendered its accounts, as though before auditors, even to the discussions that are carried on in public. For they say that the soul is a kind of harmony (harmonia); for harmony, they say, is a blending and composition of contraries, and the body is composed of contraries. And yet harmony is a certain ratio of the things blended, or else their composition, and the soul can be neither of these. Again, to originate movement does not belong to a harmony, whereas practically everyone assigns this above all else to the soul. And it is more fitting to speak of harmony in the case of health, and of the bodily excellences generally, than in the case of the soul. This becomes most evident if one tries to render the affections and the functions of the soul in terms of some harmony; for it is hard to make them fit.

Again, if we speak of harmony we do so with two things in view: most properly, in the case of magnitudes which have movement and position, harmony is the composition of these when they are so fitted together that they admit nothing homogeneous between them; and derivatively from this, it is the ratio of things that have been mixed. Neither sense, then, is reasonable. As for the composition of the parts of the body, that is far too easy to refute; for the compositions of the parts are many, and are made in many ways. Of what, then, or in what manner, must we suppose the intellect (nous) to be a composition? Or the faculty of perception, or the faculty of desire?

It is likewise absurd that the soul should be the ratio of the mixture. For the mixture of the elements in virtue of which flesh exists does not have the same ratio as the mixture in virtue of which bone exists. It will follow, then, that a body has many souls, and has them throughout the whole of itself, if indeed all its parts are composed of mixed elements, and the ratio of the mixture is a harmony and a soul. One might demand an answer on this point from Empedocles as well; for he says that each of these things exists in virtue of a certain ratio. Is the soul, then, this ratio? Or is it rather something different that comes to be present in the limbs? Again, is Love the cause of any chance mixture, or of the mixture that accords with the ratio? And is Love itself the ratio, or something else besides the ratio?

These, then, are the difficulties which such views involve. But if the soul is something other than the mixture, why is it destroyed at the very moment at which the being of flesh is destroyed, and the being of the other parts of the animal? And besides this, if each of the parts does not possess a soul — supposing the soul is not the ratio of the mixture — what is it that perishes when the soul departs?

That the soul, then, can neither be a harmony nor be carried round in a circle is clear from what has been said. But that it is moved incidentally, as we said, is possible, and that it moves itself incidentally: that is, that in which it is may be moved, and this may be moved by the soul; in no other way is it possible for the soul to be moved in respect of place.

With more reason might one raise a difficulty about the soul's being moved, if one looks to facts of the following kind. For we say that the soul is pained and is pleased, is confident and is afraid, and further that it is angry and perceives and thinks; and all these seem to be movements. Whence one might suppose that the soul itself is moved. But this is not necessary. For even if being pained or being pleased or thinking are movements in the fullest sense, and each of them is a being-moved, still this being-moved is caused by the soul — as being angry or being afraid is the heart's being moved in such and such a way, while thinking is perhaps a movement of this kind, or perhaps of some other; and of these some come about through the locomotion of certain things, others through alteration. Which they are, and how, is another account.

To say that the soul is angry is like saying that the soul weaves or builds. For it is surely better not to say that the soul pities or learns or thinks, but that the man does so with his soul; and this not in the sense that the movement is in the soul, but in the sense that the movement sometimes reaches as far as the soul, and sometimes starts from it — as perception starts from these particular external things, whereas recollection starts from the soul and proceeds to the movements, or the persisting traces of them, in the sense organs.

But the intellect seems to come to be present as a kind of substance, and not to be destroyed. For it would be destroyed above all by the dimming that comes in old age; but as things are, what happens is doubtless just what happens in the case of the sense organs. For if an old man could obtain an eye of the right sort, he would see just as a young man sees. So that old age is not due to the soul's having been affected in any way, but to that in which the soul is, as happens in drunkenness and disease. And thus thinking and contemplating decay because something else within is being destroyed, while the intellect itself is unaffected. But thinking, and loving or hating, are not affections of the intellect, but of that which possesses the intellect, in so far as it possesses it. Hence, when this perishes, a man neither remembers nor loves; for these did not belong to the intellect, but to the compound, which has perished. The intellect, however, is doubtless something more divine and unaffected.

That the soul, then, cannot be moved is evident from these considerations; and if it is not moved at all, plainly it is not moved by itself either.

By far the most unreasonable of the views mentioned is the one which says that the soul is a number that moves itself. For those who hold it are involved in impossibilities: first, those that follow from its being moved, and then, peculiar to them, those that follow from calling the soul a number. For how are we to conceive of a unit being moved, and by what, and how, seeing that it is without parts and without differentiation? For if it is both able to move and able to be moved, it must be differentiated. Again, since they say that a line in motion makes a surface, and a point a line, the movements of units will also be lines; for a point is a unit having position, and the number of the soul is already somewhere and has position. Again, if from a number one takes away a number or a unit, another number remains; but plants and many animals go on living when divided, and are thought to have a soul that is the same in kind.

It would seem to make no difference whether we speak of units or of small bodies. For even if Democritus' small spheres were to become points, and only their quantity remained, there would still be in it something that moves and something that is moved, as there is in the continuous; for what has been said comes about not through a difference of largeness or smallness, but because there is quantity. Hence there must necessarily be something to set the units in motion. But if in an animal it is the soul that moves, so too in the number; so that the soul is not both mover and moved, but mover only.

But in what way is it possible for this to be a unit? For it must possess some difference marking it off from the others; and what difference could a unitary point have except position? If, then, the units in the body and the points are different, the units will be in the same place as the points; for each will occupy the room of a point. And yet, if two can be in the same place, what prevents an infinite number from being there? For things whose place is indivisible are themselves indivisible. But if the points in the body are the number of the soul, or if the soul is the number composed of the points in the body, why do not all bodies possess a soul? For points seem to be present in all of them, and to be infinite in number. Again, how is it possible for souls to be separated and released from their bodies, if lines are not divisible into points?