Lecture 4 — Different kinds of soul

We now ask whether each of these powers is a soul or a part of a soul: and if a part, whether it is separable only in account or has also a distinct place.

Concerning some of these powers it is not difficult to see the answers to our questions; others, however, give rise to doubts. For, as in the case of plants, some, on being divided, seem to go on living in separation from one another, as if there were in each plant one soul in act, but several in potency; so we find it happens in the case of other differentiations of soul, for instance, in segmented animals when cut up, each division has sensation and local motion; and if sensation, also imagination and appetite, for where there is sensation, there is sorrow and joy, and where these are, there must necessarily be desire.

But as regards the intellect and the theoretical power, nothing is yet manifest; but it seems to be a different kind of soul, and alone seems capable of being separated, as the eternal from the perishable. It is evident, however, from the foregoing that the other parts of the soul are not separable, as some have said.

In account, however, they are obviously distinct. For if sensing is also different than forming an opinion, being for the sensitive power is different from being for the opining power. Likewise with each of the other powers mentioned.

Further, all these powers are in some animals; in others, some only; in yet others, only one. This makes the varieties of animal. The cause for this being so will be considered later. The same obtains even with regard to the senses: certain species of animal have all; certain others, some; yet others have only the one most necessary, touch.

Since we can speak of that whereby we live and sense in two ways—like “that by which we know,” for we name one thing knowledge and another the soul, though we are said to know by both of these; and likewise as “that by which we are healthy,” for health is one thing, while a part of the body (or the whole of it) is another;

and in these cases, knowledge, or health, is the form and certain species and account as the act of something that receives it, the one what is able to know, the other what is able to be healthy (for the acts of agents seem to be in the thing acted upon and disposed)—and soul being that by which primarily we live and sense and move and understand, it follows that the soul will be a certain account and species; but not as the matter and subject.

For substance is spoken of in three ways, as we have said: in one way as the species; in another as the matter; and in another as what is from both. Of these, however, matter is in potency, the species is act, and what results from both is the ensouled being; the body is not the act of the soul, but the soul is the act of a certain body.

And on this account, they thought well who held that the soul is neither apart from the body nor the same as the body; for it is not, indeed, the body, yet it is something of the body.

And therefore, it is in a body and a body of a certain sort, and not as some earlier thinkers made out, who related it to a body without defining at all in which one and of what sort. And truly, it does not seem that just anything can receive anything. And that such is the case is confirmed by reason: for an act is of that which is in potency to it, and it is naturally apt to occur in its proper matter. That the soul, then, is a certain act and account of a thing that has the potency to exist in this way is evident from these considerations.

262. We now ask whether each of these (413b13). After showing that the soul is the one principle of living common to the several genera of life, the Philosopher now inquires into the various principles of the diverse genera, asking how they are related both to the soul and to each other. (Lect. 3, nn. 253–61.) And he does two things here.

First, he puts two questions.

The first is this. Since the soul, the principle of living, is determined by the vegetative, sensitive, locomotive, and intellectual powers, is each of these soul by itself, or is each a part of the soul? And obviously where things only grow and take nourishment, as in plants, the vegetative part is the soul. But in things that vegetate and also sense, the vegetative is only a part of the soul. And the same reasoning applies to other cases.

The second question is this. If each of these is a part of the soul, as in the human soul, which contains all of them, are they parts in the sense that they are separated from each other only in account, that is, such that they are diverse parts, or are they also separated in place, inasmuch as the sense-power is in one part of the body, appetite in another, locomotion in another, and so on, as some indeed have thought?

263. Second, when he says, concerning some of these (413b15), he answers the above questions.

First, he answers the second question;

and second, at further, all these powers (413b32; [270]), he answers the first.

The second question is answered in two parts:

first, he shows whether the parts of the soul are separable according to place;

second, at in account (413b29; [269]), he shows whether they are separable in account.

First, he says that it is not difficult to see how some parts of the soul would be separable in place, that is, separable in subject, but there is doubt about other parts.

264. And he illustrates with an example in which it is easy to see this, with a comparison with plants (413b15). Certain parts, he says, of plants can be cut off and yet seem to go on living (and this is shown by the fact that the cuttings, grafted or replanted, become healthy, which would only have happened if the life in them had remained, and consequently, if the soul that is the principle of living had remained). In these cases, the soul appears to be one in act but many in potency, although one in each plant.

The same sort of thing is observable in the forms of non-souled natural bodies, which because of their imperfection do not require diversity in parts; for in any one whole form, it is one in act and many in potency, as also each such body is one in act and many in potency. For these bodies can be divided into parts that are alike in species (for example, air, water, minerals), and hence, if the parts are alike in species both to each other and to the whole, after division there must be the same specific form in each of the parts. And by the same reasoning, the soul of a plant, because it is imperfect in the order of ensouled beings, requires very little differentiation in its parts, so the soul of the whole plant survives in some of its parts.

265. So also we see in the other differences of soul, as in segmented animals when cut up, that is, in those animals that remain alive after being cut up. For each division still has sensation: this is clear since it will shrink back if you prick it, and it even has local motion, as is apparent to sensation. So in one and the same part there is, evidently, the principle of sensation and of movement. And if there is sensation, then it must also have imagination, for imagination is nothing more than a certain motion made by an actual sensation, as will be said below. (Lect. 28, n. 632; lect. 30, nn. 659, 666; bk. 3, lect. 7, n. 792.)

Again, if the divided part has sense, it must also have appetite, since sensation necessarily involves joy and sorrow, that is, pleasure and pain. For it is necessary that, if the perceived sensible is agreeable, it is pleasant, or if harmful, it is painful. But where there is pleasure and pain there must be desire and appetite. So if divided parts of such animals are able to sense, then they also have appetite.

266. In this way, then, it is manifest that one such divided part contains the vegetative, sensitive, appetitive and locomotive principles all together, and from that it is clear that these principles are not to be distinguished by place in the animal’s body. Yet certain powers are obviously distinguished by place: seeing is only in the eye, hearing in the ear, smelling in the nostrils, taste on the tongue and palate. But the primary and most necessary sense, that of touch, is found in the whole body.

267. But a doubt may arise about imagination in the severed part, for some assign to it a determinate organ of the body. But note that imagination in the imperfect animals is indeterminate, as will be shown below in book 3; it is determined only in the perfect animals. (Bk. 3, ch. 10, 433b31–434a5; bk. 2, lect. 29, n. 643; bk. 3, lect. 10, n. 839.) Hence, if we assign a determinate organ to imagination, this is because of the greater perfection and determination of its activities, without which the act of imagination cannot occur, just as the act of seeing cannot occur without an eye. Thereby he has manifested, then, that it is not difficult to see whether, for certain powers of the soul, they are separable in place.

268. Then, at but as regards the intellect (413b24), he points to one part of the soul over which doubts may arise. As regards the intellect, and whatever we call the theoretical or speculative power, nothing is yet manifest. For based on what has been said it is not yet apparent whether it has any organ in the body or is distinct in place from the other organs or is not so distinct. But, even at first sight, it seems to be a different kind of soul than the other parts of the soul, that is, it seems to be of a different nature and to carry itself in a different way; and it seems that it alone is separable from the other parts of the soul (or even seems to exist separate from a bodily organ) as the eternal from the perishable. That the other parts of the soul are not separable from each other in place is evident from the foregoing.

269. Then, at in account (413b29), he shows that the parts are separable in account. For the account of every power is according to the order to its act; if the acts are specifically distinct, then, the powers must have a diverse account of species. Hence, he says here that the sensitive and the opining, that is, intellectual, powers are diverse, that is, have different accounts, for sensing is other than forming opinions; and the same is true of the other powers already mentioned.

270. Then, at further, all these powers (413b32), he answers the first of the two questions proposed above. And he says that this makes a variety of animals because in some animals are all these powers, the powers mentioned above; in others, only some of them; and in some, only one. And where only one of these principles is found, it is the soul itself; but where several are found together, each is a part of the soul and the soul itself is named after the more principal part, whether sensitive or intellectual, as the case may be (the reason why animals differ in this way will be shown later). (Lect. 5, nn. 288–94.) And as with the powers of the soul, so with regard to the senses; for some (that is, the perfect animals) have all the senses; some (for example, moles) have some, but not all; yet others (that is, the imperfect animals) have only the most necessary one, touch.

But this phrase might also be brought back to the other sense, so that it would be said that, because the Philosopher had shown earlier that the parts of the soul in an animal are not separable from each other in place or subject, on account of this they are not separated even in the diverse animals; rather, in whatever animal one part is found, so too are all found. So, in this phrase, he is removing this view.

271. Next, at since (414a4), he concludes, from the fact that the soul is the first principle of living, to the definition of it already given. And for this he does two things:

first, he proves the definition;

second, at and on this account (414a19; [276]), he draws some further conclusions from the truth of that demonstration.

For the first, he demonstrates thus. By each of two things something is said to be and to act, one is as form (which is the first) the other as matter. But the soul is the first thing whereby we live, even though we live by both the soul and the body. The soul, then, is the form of the living body. And this agrees with the definition already given: the soul is the first act of a natural body potentially having life. (Lect. 1, n. 233.) Clearly, the middle term of this demonstration is a certain definition of the soul as the first thing by which we live.

272. He sets out the argument in four parts.

First, explaining the major premise, he observes that we can speak of that whereby we live and sense in two ways (414a4), as by a form and as by matter, like we speak of that by which we know as proceeding either from knowledge or from the soul, or as we speak of that by which we are healthy as both the health and another thing that is some part of the body or even to the whole of it. In both these cases, one of them is as form and the other as matter. For knowledge or health are forms as the act of something that receives it: knowledge is a form of what is able to know, that is, of the part of the soul in which there is knowledge, and health is the form of a body that is able to be healthy. Thus, he says able to know and able to be healthy in order to indicate the particular subject’s aptitude to its particular form. For the acts of agents, that is, the forms induced into matter by agents, always appear to exist in the thing acted upon and disposed, that is, the form is in that which is naturally apt to suffer the actions of an agent from this sort of agent, and which is disposed to attain the end of the suffering, namely, the form to which it is led in being acted upon.

273. Second, at and soul being that by which (414a12), he states the minor premise, saying that the soul is that by which primarily we live and sense and move and understand—these being the four chief genera of life already mentioned (to live here refers to the vegetative principle which, as has been said, is common to all living things (413a31)). (Lect. 3, nn. 255, 260; nn. 257, 261.) Now, although we are said to be healthy by both health and the body, still health is that by which we are called healthy primarily. For only insofar as the body has health are we said to be healthy. So, too, knowledge is that by which we are primarily said to be knowers, since we are not said to be knowers by the soul except insofar as the soul has knowledge. Likewise, we are not said to be alive by the body except insofar as the body has a soul. Therefore, he says that the soul is that by which primarily we live and sense and move and understand.

274. Third, he provides the conclusion, at it follows that the soul (414a13), linking this premise with the one at since we can speak (414a4). Thus, he concludes that the soul stands as an account and species, and not as the matter and subject.

275. Fourth, at substance is spoken of (414a14), he shows how this conclusion follows from the premises. For it might have seemed to follow that the body no less than the soul was a form, since we are said to live by both. So, to complete the demonstration, he adds that since, as we have said, the term “substance” can refer to three things, to matter, to form, and to the complex of both (the matter is the in potency; the form or species, the act; and the composite, the thing that is ensouled), then the body is clearly not the act of the soul, but rather, the soul is the act of a certain body, whereas the body is in potency with respect to the soul. (Lect. 1, n. 220.) And since the foregoing demonstration has led us to the alternative that the species is either the soul or the body, we can now conclude that the species is the soul; for it is now clear that the body is not the species of the soul.

276. Then, at and on this account (414a19), he deduces certain conclusions from the foregoing.

First, that they were right who thought that the soul was not apart from the body nor the same as the body. It is not the body, for it is not matter, but it is essentially involved with the body, because it is its actuality; from which too it follows, as he says here, that it exists in a body (414a21) whose actuality it is.

277. Second, being then in the body, and in a certain sort of body, namely, a natural and organized one, it is not, however, in it as the earlier (414a22) philosophers said, when they spoke of the soul and its union with the body. For they did not determine in which body it was and of what sort.

And truly, as we now say, the soul is in a determinate body, since it does not seem possible that the soul can receive just any body, but a determinate one. And this we should reasonably expect because each act is naturally apt to occur in its proper and determinate matter. So also, then, the soul is received in a determinate body.

278. Summarizing, he concludes that the soul is a certain act and account of a thing that has the potency to exist in this way, that is, of what is potentially alive (414a27).