LECTIO FOURTEEN

             § 199. Having reviewed and criticised earlier opinions on the soul the Philosopher proceeds now to put certain questions of his own; which at 'Some say' he begins to answer. But first we have to realise that the activities of the soul, such as sensation, understanding, desire, movement in space, and growth, can be considered in two distinct ways.

             We can consider the mode of these activities; and from this point of view we can distinguish, underlying these activities, three powers of the soul: the vegetative, the sensitive and the intellectual.

             § 200. And these powers differ. For whilst the vegetative or nutritive power acts through active and passive qualities of matter, such as heat and cold and the like, the sensitive power requires no such sensible qualities for its sentient activity, though it does depend on corporeal organs; while the intellectual power acts through neither sensible qualities nor a corporeal organ, for it functions in an entirely incorporeal way.

             § 201. But if we consider the kinds of activities within the soul's range, then we distinguish five powers with five corresponding activities: the nutritive, sensitive, locomotive, appetitive and intellectual powers.

             § 202. Having then discussed and criticised earlier opinions on the soul in general, Aristotle begins now an enquiry into the parts and particular activities of the soul. And he proposes two problems. The first is whether activities like sensing, rational judgement, desiring, deliberating, and also appetition (which he related to special parts of the soul in a more general way than these, placing the irascible urge in both the sensitive and the rational parts), together with local motion and rest, growth and decline, whether all these pertain to the whole soul in such a way that each one occurs in every part of the soul, so that with each part we both understand and sense and move and desire and assimilate food; or whether the truth is not rather that each activity has its own special part, that is to say, that with one part we understand, with another we sense, and so on.

             § 203. The second problem is this. Granted that each activity has its special part of the soul, is this true of the activity of simply being alive? Is this activity proper to any one of these parts? Or to many? Or to all at once? Or does it perhaps belong to some other part?

             § 204. Then at 'Some say' he answers these questions in order. As to the first one, he states and then rejects a view of certain philosophers that the activities in question spring severally from the soul's parts, not from the soul in general; that the soul is so divided into parts that it understands with one and desires with another, just as some people hold that the sensitive power is in the brain and the vital power in the heart, and so on.

             § 205. Now this is partly true and partly false. If you take it to mean that the soul has different parts potentially, it is quite true that its parts and powers are distinct and that one of them understands and another senses. The soul is a whole in the sense that it has a total capacity with partial capacities subordinate to the whole. But if you take it quantitatively, as though the soul were of a certain size with parts of certain sizes, then this opinion is false. And this was how the philosophers in question thought of the soul--even to the extent that they made out the soul's different powers to be different souls.

             § 206. Next, at 'If then the soul' Aristotle attacks this last hypothesis, with three arguments. The first is this. Different things cannot be unified except by something else that unites them. If the one body contained several souls, these would have to be joined together and contained by something else. But there is nothing else that can do this; therefore the hypothesis is groundless. That there is no other unifying principle is shown thus. Whatever contains and unifies the soul will be either the body or some other thing. Now it is not the body. Rather, the body is contained and unified by its soul and falls to pieces when the soul leaves it. Then it is something else; but this must be a soul if it pertains especially to soul to unify and control. Is then this unifying soul itself intrinsically one, or made of several parts? If of several parts, then what unites them? And so on ad infinitum. But if this unifying soul is intrinsically one, then 'why not call it the soul straightway', i.e. why not concede at the beginning that the soul is intrinsically one? The soul, then, is not, as they thought, quantitatively divisible.

             § 207. The second argument comes at 'A further query'. If the different parts of the soul are in different parts of the body, then each soul-activity has its own corporeal part or organ. But the intellect has no special corporeal organ. Hence their conception of the soul's parts is false.

             § 208. The third argument starts at 'It is also held'. If each of the various activities of soul is proper to a special part of the body, then no one part is the organ of several distinct activities, nor are there several parts in an animal's body the same in kind. But experience proves that certain living things have parts with several activities each, and a soul that is identical in kind in the whole and in all the parts; e.g. in plants and in certain (segmented) animals which go on living after being cut up, the cut off parts retaining their feelings and movement for some time. It does not matter if these parts live for only a short time through lack of the organs of self-preservation. The point is that several soul-activities exist in several distinct corporeal parts at once, and the latter are specifically similar to each other and to the whole. Therefore the soul is not divided according to the different parts of the body.

             The reason why such animals go on living after being divided is that the number and diversity of activities complete in themselves varies in direct proportion to the perfection of the soul in living things. The higher the soul the wider is the range of its activities; and the wider its active range the more, and the more distinctly diversified, organs or bodily instruments are required by it. So the relatively greater nobility of the rational soul calls for a greater diversity of its bodily organs, whilst the far lower soul of a segmented animal or a plant has only a narrow field of activity and therefore needs a body that is more uniform and less articulated, and in any part of which, taken separately, it can maintain its being.

             § 209. Then, at 'It would seem', he answers the second question; concerning which we must realise that life belongs, properly speaking, to things that move and act of themselves and are not caused to do so by others. So 'to live' has two meanings. It can mean the being of a living thing, and in this sense Aristotle says that living is the being of living things. And also it can mean activity.

             § 210. Now the soul of plants, the vegetative soul, seems to be a sort of primary manifestation of life among things here on earth; for nothing lives without it and all living things share in it, though in other ways their modes of life differ. Animals and plants have only this in common. It can exist without sense or intelligence, but not sense or intelligence without it; no animal has sense or reason except it first have vegetative life. Thus it bears the same relation to life as touch to sensation. Not that living things only live by this principle, but it is the point where life first appears.