LECTIO FOUR

             § 262. After showing that 'soul' is the one principle common to the several types of vitality, the Philosopher now enquires into the various principles of the latter, asking how they are related both to the soul and to each other. And he does two things here. First, he puts two questions (a) If the soul, the life-principle, is realised actually as a vegetative, sensitive, locomotive or intellectual principle, is each of these principles to be identified with the soul proper, or is each no more than a part of the soul? Now obviously, where the thing's vitality consists entirely in growing and taking nourishment (as in plants) the vegetative principle is simply the soul or life-principle itself. But where the thing also has sensation, this vegetative principle is only a part of the soul. And the same reasoning applies to other cases. (b) If each of these principles is a part of the life-principle, as in the human soul which contains all of them, are they parts in the sense that they are merely diverse powers of the one soul, existing in one thing though they can be thought of apart from one another, or are they distinct beings having each its distinct locality, so that the sense-power is in one part of the body, appetition in another, locomotion in another, and so on; as some indeed have thought.

             § 263. Secondly, when he says 'Concerning some of these', he answers the above questions: first the second one; then, at 'Further, all these powers', the first. The second question is answered in two parts: (a) with respect to the local separability of the parts of the soul, and (b) at 'By definition', concerning their separability in the mind. As to (a) he says that some parts of the soul raise no difficulties, but that others do.

             § 264. And he illustrates this by a comparison with plant-life. Certain parts, he says, of plants can be cut off and yet seem to go on living; for the cuttings, grafted or replanted, unite with a new stem or with the soil. In these cases the life-principle appears to be actually single but potentially many. The same sort of thing is observable in the forms of inanimate physical bodies; as each such body is actually one and potentially many, so in the lower animate bodies whose parts are still undifferentiated, the soul exists as one whole actually, but as many potentially. For inanimate bodies can be divided into parts which each retain the same specific nature (e.g. air, water, minerals) and this nature was also the nature of the whole body; and it is somewhat the same with plants, the lowest order of animate beings; they require very little differentiation in their parts, and the life-principle of the whole survives, as such, in some of the separated parts.

             § 265. So also with those animals which remain alive after being cut up. Each division still has a sensitive soul: it will shrink back if you prick it. And obviously it can move about. So the same part retains, evidently, the principle of sensation and local movement. And if sensation, then it must also have imagination which is simply a certain motion derived from actual sensation, as we shall see later. Again, it must also have appetition, since sensation necessarily involves satisfaction or dissatisfaction, i.e. pleasure or pain, because it involves a contact with the congenial or the uncongenial. And pleasure and pain involve desire and appetition. So the divided parts of such animals are able to desire.

             § 266. Now if each such divided part contains the vegetative, sensitive, appetitive and locomotive principles all together, it is clear that these principles are not to be located in any special parts of the animal's body. Yet certain powers are obviously so located: seeing is only in the eye, hearing in the ear, smelling in the nostrils, taste on the tongue and palate. But the fundamental and most necessary sense of touch is found over the whole body.

             § 267. A doubt may occur about imagination; for some assign to it a special organ of the body. But note that imagination (as will be shown later) in the lower animals is indefinite; it is definite only in the higher animals. Hence if we assign a special organ to imagination, this is because the special completeness and definiteness of its activities call for a special organ of the body, just as seeing requires an eye. But as to some powers of the soul it is not difficult to decide whether they are located in distinct parts of the body.

             § 268. Then, at 'But as regards intellect', he points to one part of the soul over which doubts may arise. About the intellect, or whatever we call the percipient or speculative faculty, we are still, he says, uncertain. No proof has yet been given of its location in any special or particular organ of the body. Yet even at first sight it would seem to be of a different nature from the other parts of the soul, and to exist in a different way; and that it alone is separarable from the rest of the soul (and may even exist apart from any organ of the body) as what is immortal from what is mortal. That the other parts of the soul are not locally separated is now clear.

             § 269. Then at 'By definition', he shows that they are mentally separable from one another. For we distinguish potencies by their relation to acts; if the acts are specifically distinct, then so are the potencies. Hence he says here that the sensitive and opining, i.e. intellectual, principles are diverse; meaning that, as sensing is other than forming opinions, the faculties implied have distinct definitions. And the same is true of the other principles already mentioned.

             § 270. Then, at 'Further, all these powers', he answers the first of the two questions proposed above, observing that animals differ in this, that in some are found all the four vital principles mentioned above, in others only some of them, and in some only one. And where one only 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 principal part, whether sensitive or intellectual as the case may be (the reason why animals differ in this way will be shown later). And as with the powers of the soul, so with the particular senses; for some animals (the higher) have all the senses; some (e.g. moles) have some, but not all; while some (the lowest animals) have only the most necessary one, touch.

             This passage might also be understood as referring to the statement, made a few lines earlier, that the parts of the soul which coexist in any one animal are not distinct beings nor in different places. For from this one might argue that they are not separable as between one animal and another; which error this passage removes.

             § 271. Next, at 'Since etc.', he concludes, from the fact, that the soul is the first principle of life, to the definition of it already given; first proving this definition, and then, at 'And on this account', drawing some further conclusions. The proof runs thus. Granted that there are two principles of our being and activity, one (the form) will be prior to the other (the matter). Now both body and soul are principles of life in us, but the soul comes first in this respect. The soul then is the form of the living body; which agrees with the definition already given: the soul is the primary actuality of a physical body capable of life. Clearly, the middle term of this argument is the definition of the soul as the primary principle of life.

             § 272. The argument itself he sets out in four parts. (1) Explaining the major, he observes that we can speak of the principle of life and sensation from two points of view, formally or materially. Just as we speak of the act of knowing as proceeding either from knowledge itself or from the soul; or as we speak of becoming healthy either with respect to health itself, or with respect to some part of the body, or to the whole of it. In both these cases, one of the principles is formal and the other material. For knowledge and health are forms or actualities of certain subjects: knowledge is a form of the part of the soul that knows, health of the body capable of health. Thus he says 'capable of knowing' and 'capable of health' in order to indicate the particular subject's aptitude to its particular form. For the actuality of an active principle, such as the form transmitted to matter by an agent, always appears to exist in what receives it and is adapted to it, i.e. in the subject, whose nature it is to receive from some one particular active principle, and which is adapted to attain the final term of the receiving-process, namely the form in question.

             § 273. (2) At 'and soul being that by which', he states the minor, saying that the soul is the primary principle of our life and feeling and movement and understanding--these being the four chief manifestations of vitality already mentioned (for by 'life' here is meant the vegetative principle which, as has been said, is common to all living things). Now though it is in the body that we enjoy health, health itself is that by which we are called healthy primarily. Only in so far as the body has health are we said to be healthy. So too our souls are not said to know except in so far as they have knowledge; thus knowledge itself is that by which, primarily, the soul is said to be in the state of knowing. And the same is true of our body and its life; we are not said to live by the body except in so far as the body has a soul. Therefore he calls the 'soul' here the first principle of life and feeling, etc.

             § 274. (3) He concludes at 'it follows that the soul', linking this phrase with the previous one, that the soul is a sort of nature or specific form; not the material for, or mere subject of, anything.

             § 275. (4) Then at 'Substance is predicated', he shows how this conclusion follows from the premisses. For it might have seemed to follow that the body no less than the soul was a form, since we call the body also a principle of life. So, to clinch the argument, he adds that if, as we have said, the term 'substance' can refer to three things, to matter, to form, and to the complex of both (the matter being the potential element; the form the actuality; and the complex the thing that is alive in this way) the body is clearly not the soul's actuality, but rather the soul is the body's; for the body is potential with respect to the soul. And if the foregoing argument has led us to the alternative that the specifying principle is either the soul or the body, we can now conclude that it is the soul; for it is now clear that the body is not the form of the soul.

             § 276. Then at 'And on this account', he deduces from the foregoing: (a) that they were right who thought that the soul required the body and yet was essentially distinct from it. It is not the body, for it is not matter; but it is essentially involved with the body, because it is its actuality; whence too it follows, as he says here, that it exists in that body whose actuality it is.

             § 277. (b) Being then in the body, and in a special kind of body, namely physical and organic, it is not, however, in it as the old natural philosophers fancied when they spoke of it. For they did not specify the kind of body that it has. Yet it does in fact have only one kind of body. And this we should expect a priori, it being natural to any act to be realised in some definite and appropriate material. So also, then, with the soul.

             § 278. Summarising, he concludes that the soul is a certain actuality and formal principle of that which exists accordingly, namely as potentially animate.

414a 28-414b 31