LECTIO TWO

             § 235. The Philosopher now begins to explain the definition of the soul given in Lectio 1; after which, at 'Therefore it is evident', he draws a conclusion from it. The explanation has two parts, in the first of which he is concerned directly with the soul itself, while in the second, where he says 'Not that which has cast off', he explains that part of the definition which refers to the subject which has a soul. With regard to the soul itself, he begins by illustrating the definition by a comparison with artificial things; and then goes on, at 'Now what has . . .', to explain it by considering the parts of the soul separately.

             In artificial things, made by human skill, the forms imposed on the material are accidental forms; and since these are easier for us to perceive than is substantial form, as being more accessible to the senses, it is obviously reasonable to approach the soul, which is a substantial form, through a comparison with accidental forms. And again, the soul's parts or potencies are more readily perceptible to us than its essence; for all our enquiry into the soul has to start from the objective terms of its activities and then proceed from these activities to their potencies, and thence to an understanding of the soul in its essence; that is why a study of the soul's parts can throw light on the definition of it.

             § 236. First, then, he observes that the definition given above is 'general', i.e. it applies to any soul. It posits the soul as a substance which is a form; and this means that it presents to us the idea of the essence of something. For there is this difference between a form that is substance and one that is not, that the latter sort are not strictly of the essence or 'whatness' of a thing: whiteness is not of the essence of a white body; whereas substantial form is essential and quidditative. To call the soul a substantial form, therefore, is to imply that it is of the essence and 'whatness' of the body it animates. Hence he says 'this', i.e. this quidditative substance, 'is the essence of this body', i.e. of the body that is what it is precisely through having this particular form. For this form is essential to the thing, and is denoted by the definition of what the thing is.

             § 237. And because substantial forms, including the forms of natural bodies, are not evident to us, Aristotle makes his meaning clear with an example taken from the forms (accidental) of artificial things. 'If', he says, 'some utensil (i.e. an artificial instrument) for example an axe, were a physical (i.e. a natural) body,' it would possess a form in the manner already explained. So he continues: 'Then being-an-axe would be its substance,' i.e. would be the substantial form of the axe, which is that to which we refer our idea of axe as such. This idea of axe as such he identifies with the essence of the axe, with what causes it to be an axe; and this essential form he identifies with the substance of the axe. He says 'substance' because the forms of natural bodies are substantial forms. Furthermore, if the axe were not merely a natural, but also an animate, body, its form would be a soul; and if it lost this soul it would no longer be an axe, except in name; just as when the soul leaves the body there is no longer an eye or flesh, except in name. Of course the axe, not being in fact a natural body, has no axe-form which is of the essence of the body that it is; so that if it lost the form of axe, the axe would still exist substantially, because the substance of artificial things is their matter which remains when the artificial form and, with this artificial form, the actuality of the artificial body as such, is removed.

             § 238. Then he explains why he has distinguished between the axe as it actually is and as it would be were it a physical, (that is, a natural) living body: for the soul is not the essence and idea, i.e. the form, of an artificial body like an axe, but 'of such a physical body', i.e. of a body that is alive. To make this clearer he adds 'as has in itself the principle of movement and rest'--which is characteristic of natural things. For Nature is this sort of principle, as he says in the Physics, Book II.

             § 239. Then at 'Now what has been said', he applies what has been concluded about the soul as a whole, and the animate body as a whole, to the parts of each. If, he says, the eye were a whole animal, its soul would be sight; for sight is the essential form of the eye; which in itself is the material condition of sight; in the same way as an organic body is the material condition of a soul. Once sight is lost, the eye is no longer an eye, except in the sense that a stone or painted eye may be called an eye equivocally (this term is used when the same name is given to essentially different things). Remove, then, what makes an eye really an eye, and there is left only the name. And the same argument applies to the animate body as a whole: what makes it an animate body is its form, the soul. This removed, you have a living body only equivocally. For as one part of the sensitive soul is to one part of the sensitive body, so the faculty of sense as a whole is to the whole sensitive body as such.

             § 240. Next, at 'Not that which has cast off', he explains what was meant by defining the soul as the 'act of a potentially animate body'. Now 'potentially' may be said about a thing in either of two senses: (a) as lacking the power to act; (b) as possessed of this power but not acting by it. And the body, whose act is the soul, is potentially animate in the second sense only. So, when he calls the body a thing potentially alive he does not mean that it has lost the soul it had and now lacks a life-principle altogether; he is speaking of what still has such a principle. On the other hand, seeds and the fruits that contain them are only potentially living bodies with souls; for a seed as yet lacks a soul. It is 'potential' therefore like that which has lost its soul.

             § 241. And to show just how the body is potential to the actuality that comes from its soul he adds that being awake is the actuality of the sensitive soul in the same way as cutting is the actuality of a knife and seeing is that of an eye; for each of these acts is the activity and use of a principle already there. But the soul is the first and underlying actuality; like the faculty of sight itself or the capacity of any tool; for each of these is the operative principle itself So the body, complete with its soul, is potentially animate in the sense that, though it has its first actuality, it may lack the second. And as the eye is a thing composed of a pupil as its matter and the faculty of sight as its form, so an animal is a thing composed of soul as its form and body as its matter.

             § 242. Then, at 'Therefore it is evident', he deduces a truth from the foregoing. Having shown that the soul is the whole body's actuality, its 'parts' being the actualities of the body's parts, and granted that an actuality or form cannot be separated from that which is actual and has form, we can certainly conclude that no soul can be separated from its body,--at least certain parts of the soul cannot be separated, if the soul can be said to have parts. For obviously some 'parts' of the soul are nothing but actualities of parts of the body; as we have seen in the case of sight, that it is the eye's actuality. On the other hand, certain parts of the soul may well be separable from the body, since they are not the actuality of any corporeal part, as will be proved when we come to treat of the intellect.

             § 243. As to Plato's opinion that the soul is the act of the body not as its form but as its mover, he adds that it is not yet clear whether the soul is the act of the body as a sailor of a ship, i.e. as its mover only.

             § 244. Finally, recapitulating, he says that the foregoing is an 'outline' description of the soul, meaning that it is extrinsic, as it were, and superficial and incomplete. It will be completed when he comes to define the innermost nature of the soul and the nature of each of its parts.

413a 11-413b 13