LECTIO ONE

             § 211. Having reviewed, in Book One, other men's opinions on the soul, Aristotle now begins Book Two of his Treatise, in which he sets out what he himself holds on the matter. First, then, linking up with what has gone before, he states his general aim; and secondly, at 'Now we say that one', he starts to carry it out. He begins by saying that despite all the previous accounts of the soul it is necessary to go into the whole matter again from the beginning. The subject is so difficult that it is wiser to assume that the truth about it has not yet been discovered. And in answer to the question raised in the Introduction to Book One, whether one should first define the soul, and afterwards its parts, he decides now to define the essence of the soul before coming to conclusions about its parts. As though explaining this decision, he adds that we shall thus have acquired the most comprehensive idea of soul. For the definition of the soul itself comprises what is most common or general, whereas that of each of its parts or potencies comprises only some special aspect of it. And as he explains at the beginning of the Physics, the right way to teach is to begin with what is most general and end with precisions in detail.

             § 212. Beginning then at 'Now we say', his treatment divides into two parts, in the first of which he shows what soul in general is, and in the second, starting at 'Of the soul's powers', what are its parts or powers. The first part subdivides into (a) a definition that concludes, and (b) one that introduces, a demonstrative argument;--this latter part comes at 'Since it is from the less clear'. Note in passing that any definition, as he says in Book I of the Posterior Analytics, is either the conclusion of a demonstration, e.g. 'Thunder is a continuous noise in the clouds', or it is the demonstration's starting point, e.g. 'Thunder is the extinction of fire in the clouds', or it is the demonstration itself, but thrown into a different order, e.g. 'Thunder is a continuous noise etc., caused by the extinction of fire etc.' in which the conclusion and the starting point both appear, though not in syllogistic order.

             As to (a), it includes first a definition of the soul, and then, at 'It has been stated then', an explanation of the definition. And to clear the ground before the defining proper begins (at 'Therefore every natural body') he makes some preliminary distinctions.

             § 213. It should be noted here that, according to the teaching of Book VII of the Metaphysics, there is this difference between defining substance and defining accidents that in the former case nothing extrinsic is included: every substance is defined in terms merely of its material and formal principles; but in the latter case something extrinsic to the thing defined is referred to, i.e. the subject of the accidents in question--as when one defines snubness as 'curvature of the nose'. The reason is that a definition must express what a thing is, and while substance is something complete in its being and kind, accidents have being only in relation to a substance. In the same way no form as such is complete in kind; completeness in this sense belongs only to the substance composed of form and matter; so that the latter's definition is complete without reference to anything else, whilst that of the form has to include a reference to its proper subject which is matter. Hence, if the soul is a form its definition will not be complete without reference to its subject or matter.

             § 214. So, in the first part of this section, he makes certain distinctions, first in view of the work of defining the soul's essence, and then, at 'Bodies especially seem to be substances . . .' in view of defining its subject. As regards the former point he alludes to three distinctions, of which the first is that of being into the ten categories; this he hints at when he says that substance is reckoned to be 'one of the kinds of things that are'.

             § 215. The second distinction alluded to is that of substance into matter, form and the compound of both. Matter is that which is not as such a 'particular thing', but is in mere potency to become a 'particular thing'. Form is that by which a 'particular thing' actually exists. And the compound is 'the particular thing' itself; for that is said to be a 'particular thing' (i.e. something you can point to) which is complete in being and in kind; and among material things only the compound is such. For although immaterial substances are not compounds of matter and form, still they are particular things, having actual existence in themselves, and being complete in their own nature. Not so the rational soul; for though it has the existence in itself which belongs to a 'particular thing', it is not a complete nature by itself; it is rather a part of a specific nature. Hence it is not in all respects a 'particular thing'.

             Matter, then, differs from form in this, that it is potential being, form is the 'entelechy' or actuality that renders matter actual; and the compound is the resulting actual being.

             § 216. Thirdly, he distinguishes two senses of the term 'act'. In one sense knowledge is an act, in the other thinking is an act; and the difference can be understood by relating these acts to their potencies. Before one acquires the grammatical habit and becomes a grammarian, whether self-taught or led by another, one is only potentially so; and this potency is actualised by the habit. But once the habit is acquired one is still in potency to the use of it, so long as one is not actually thinking about grammar; and this thinking is a further actualisation. In this sense, then, knowledge is one act and thinking another.

             § 217. Then at 'Bodies especially' he alludes to three distinctions which are presupposed by his enquiry into the meaning of the definition of the soul, so far as the subject endowed with soul is concerned. The first is the distinction between corporeal and incorporeal substances. Now the former are the most evident to us: for, whatever the latter may be in themselves, they do not impinge on our senses, but are only discoverable by an exercise of the reason. Hence he says that 'bodies especially seem to be substances'.

             § 218. The next distinction is between physical or natural bodies and artificial bodies. Man and wood and stone are natural bodies, but a house or a saw is artificial. And of these the natural bodies seem to be the more properly called substances, since artificial bodies are made out of them. Art works upon materials furnished by nature, giving these, moreover, a merely accidental form, such as a new shape and so forth; so that it is only in virtue of their matter, not their form, that artificial bodies are substances at all; they are substances because natural bodies are such. Natural bodies therefore are the more properly called substances, being such through their form as well as through their matter.

             § 219. Thirdly, he distinguishes between living and non-living natural bodies; and the living are those which of themselves take nutriment and grow and decay. Note here that this is said by way of example rather than definition. For, besides growth and decay, living things may exhibit sensation and intellectual knowledge and other vital activities. Immaterial substances, as is proved in the Metaphysics, Book XI, have the life of intellect and volition, though they cannot grow and do not take food. But because, in the sphere of things that are born and die, the plant-soul (the principle of nutrition and growth) marks the point where life begins, this soul is here taken as the type of all living things. However, life is essentially that by which anything has power to move itself, taking movement in its wide sense so as to include the 'movement' or activity of the intellect. For we call those things inanimate which are moved only from outside.

             § 220. After this, at 'Therefore every natural body', he begins to define the soul, presupposing the distinctions already made. And his enquiry here has three parts: (a) he enquires into the elements of the definition taken separately; (b) at, 'If, then, there is any one generalisation', he states his definition; and (c) at 'Hence it is unnecessary', he uses it to refute an objection. As to (a) he first deals with the elements that refer to the soul's essence, and then to those that refer to its subject, at 'Such a body will be organic', and in the part that concerns the essence he considers first the statement that the soul is an 'act', and then, at 'Now this can mean one of two things', that it is a 'primary act'.

             Aristotle's first conclusion, then, in line with what has been said already, is that if physical bodies are substances in the fullest sense, all living bodies are substances too, for they are physical bodies. And as each living body is an actual being, it must be a compound substance. But just because to say 'living body' is to imply two things, the body itself and that modification of body by which it is alive, it cannot be said that the element in the composition referred to by the term body is itself the principle of life or the 'soul'. By 'soul' we understand that by which a living thing is alive; it is understood, therefore, as existing in a subject, taking 'subject' in a broad sense to include not only those actual beings which are subjects of their accidental modifications, but also bare matter or potential being. On the other hand the body that receives life is more like a subject and a matter than a modification existing in a subject.

             § 221. Since, then, there are three sorts of substance: the compound; matter; and form; and since the soul is neither the compound--the living body itself; nor its matter--the body as the subject that receives life; we have no choice but to say that the soul is a substance in the manner of a form that determines or characterises a particular sort of body, i.e. a physical body potentially alive.

             § 222. Note that he does not say simply 'alive', but 'potentially alive'. For by a body actually alive is understood a living compound; and no compound as such can enter into the definition of a form. On the other hand the matter of a living body stands to the body's life as a potency to its act; and the soul is precisely the actuality whereby the body has life. It is as though we were to say that shape is an actuality; it is not exactly the actuality of an actually shaped body--i.e. the compound of body and shape--but rather of the body as able to receive a shape, of the body as in potency to an actual shape.

             § 223. But lest it be thought that soul is an actuality in the manner of any merely accidental form, he adds that it is a substantial actuality or form. And since every form has the matter proper to it, the soul must actualise just this special sort of body.

             § 224. The difference between accidental form and substantial form is that whereas the former does not make a thing simply be, but only makes it be in this or that mode--e.g. as quantified, or white--the substantial form gives it simple being. Hence the accidental form presupposes an already existing subject; but the substantial form presupposes only potentiality to existence, i.e. bare matter. That is why there cannot be more than one substantial form in any one thing; the first makes the thing an actual being; and if others are added, they confer only accidental modifications, since they presuppose the subject already in act of being.

             § 225. We can therefore reject the view of Avicebron (in the Book called Fons Vitae) that according to the way in which any given thing can be divided into genera and species so it can be divided into substantial forms. Thus an individual man would have one form that made him a substance, another that gave him a body, another that gave him life, and so on. But what our premisses compel us to say is that it is one and the same substantial form that makes a man a particular thing or substance, and a bodily thing, and a living thing, and so on. For the higher form can give to its matter all that a lower form gives, and more; the soul gives not only substance and body (as a stone's form does) but life also. We must not think, therefore, of the soul and body as though the body had its own form making it a body, to which a soul is super-added, making it a living body; but rather that the body gets both its being and its life from the soul. This is not to deny, however, that bodily being as such is, in its imperfection, material with respect to life.

             § 226. Therefore, when life departs the body is not left specifically the same; the eyes and flesh of a dead man, as is shown in the Metaphysics, Book VII, are only improperly called eyes and flesh. When the soul leaves the body another substantial form takes its place; for a passing-away always involves a concomitant coming-to-be.

             § 227. Then, at 'Now this can mean', he examines the second term in the definition. He observes that there are two kinds of actuality, as we explained above, the kind that is like knowledge and the kind like thinking. And clearly the soul is of the former kind; for it is due to the soul that an animal is able to be both awake and asleep; and while waking is similar to thinking (for it is a use of the exterior senses just as thinking is a use of knowledge already possessed), sleep is more like the knowledge which lies dormant in the mind so long as it is not actually being used; for in sleep an animal's faculties are quiescent.

             § 228. Now, of these two actualities, knowledge comes first in the order of coming-to-be in the same person; for it stands to thinking as potency to act. But in the order of nature or essence act is prior to potency (see the Metaphysics, Book IX) as the end and complete perfection of potency. And even in the temporal order of coming-to-be, act, in a quite general sense, is prior; for the potential is actualised only by something already in act. But in this or that particular thing considered in itself potentiality may come first; the thing may be actualised by degrees. Hence his remark that 'knowledge . . . is prior (i.e. to thinking) in the order of generation in one and the same thing'.

             § 229. So he concludes that soul is the primary act of a physical body potentially alive, where act means the same sort of actuality as knowledge. He says primary act, not only to distinguish soul from its subsequent activities, but also to distinguish it from the forms of the elements; for these retain their own proper activities, unless impeded.

             § 230. Next, at 'Such a body', he examines that part of the definition which has to do with the soul's subject, observing that the 'physical body' referred to is any organic body, i.e. any body equipped with the various organs required by a living body in consequence of the life-principle's various vital activities. For from this principle (the soul) which is the richest of embodied forms, spring many different activities, so that it requires, in the matter informed by it, a full equipment of different organs. Not so the less perfect forms of inanimate things.

             § 231. Now plants, the least perfect of animate things, exhibit less organic diversity than animals. That is why Aristotle chooses plants to illustrate his assertion that every animate body is organic, saying that even plants have organically diversified parts. But these parts are very simple, i.e. like to one another; they lack the differentiation that we find in animals. Thus the foot of an animal is made up of different parts, flesh, nerves, bones and so forth, but the organs of plants are composed of less diverse sets of parts.

             § 232. The organic character of the parts of plants is displayed in their diverse functions. Thus a leaf functions as a covering for the pericarp or fruit-bearing part, i.e. for the part in which the fruit is born. The pericarp, again, protects the fruit itself. So too the roots have a function in a plant similar to that of the mouth in an animal; they draw in nourishment.

             § 233. Next, at 'If, then,' he gathers all these observations into one definition, saying that if any definition covers all types of 'soul' it will be this: the soul is the primary actuality of a physical bodily organism. He does not need to add 'having life potentially'; for this is implied in 'organism'.

             § 234. Then at 'Hence it is' he applies this definition to solve a difficulty. There had been much uncertainty about the way the soul and body are conjoined. Some had supposed a sort of medium connecting the two together by a sort of bond. But the difficulty can be set aside now that it has been shown that the soul is the form of the body. As he says, there is no more reason to ask whether soul and body together make one thing than to ask the same about wax and the impression sealed on it, or about any other matter and its form. For, as is shown in the Metaphysics, Book VIII, form is directly related to matter as the actuality of matter; once matter actually is it is informed. Moreover, although, as he goes on to say, being and unity are variously predicated (in one way of potential, and in another way of actual, being), that is primarily and properly a being and a unity which has actuality. Just as potential being is only a being under a certain aspect, so it is only a unity under a certain aspect; for unity follows being. Therefore, just as the body gets its being from the soul, as from its form, so too it makes a unity with this soul to which it is immediately related. If, on the other hand, we regard the soul in its function as the mover of the body, then there is no reason why it should not move by means of a medium, moving one part of the body by means of another.

412b 10-413a 10

THE DEFINITION EXPLAINED

SOUL AND BODY

             IT has been stated, then, what the soul in general is. It is 'substance' as definable form; and this means what is the essence of such a kind of body. If some utensil, for example an axe, were a natural body, then 'being-an-axe' [axeishness] would be its substance, and this would be its soul. Apart from this, it would no longer be an axe, save equivocally. As it is, it is really an axe. And the soul is not the essence or 'what-it-is' of such a body as this, but of a natural body, such as has in itself the principle of motion and rest.§§ 235-8

             Now what has been said should be considered with respect to parts. For if the eye were an animal, sight would be its soul. For this is the substance, in the sense of the definable form, of the eye. The eye is the matter of sight, and apart from this it is an eye no longer save equivocally, as with a painted or stone eye. What, therefore, holds of a part, we ought to apply to the whole living body: for the relation of a part [of the soul] to part [of the body] corresponds to that of sensitivity as a whole to the whole sensitive body, considered as such.§ 239

             Not that which has cast off its soul is 'capable of life', but that which possesses it. But seed and fruit are only in potency such a body. As cutting or seeing is act, so is consciousness. The soul is like sight and the capacity of a tool; the body, like the thing in potency. But as an eye is a pupil together with the power of sight, so is there a living thing where there are both body and soul.§§ 240-1

             Therefore it is evident enough that the soul is inseparable from the body--or certain parts of it, if it naturally has parts; for it is of certain bodily parts themselves that it is the act. But with respect to certain of its parts there is nothing to prevent its being separated, because these are acts of nothing bodily. Furthermore, it is not clear that the soul is not the 'act' of the body in the way that a sailor is of his ship. Let these remarks serve to describe and define the soul, in outline.§§ 242-4