The same objection lies against the view expressed in the ‘Orphic’ poems: there it is said that the soul comes in from the whole when breathing takes place, being borne in upon the winds. Now this cannot take place in the case of plants, nor indeed [411a1] in the case of certain animals, for not all breathe. This fact has escaped the notice of the holders of this view.
If we must construct the soul out of the elements, there is no necessity to suppose that all the elements enter into its construction; one element in each pair of contraries will suffice to enable it to discern both that element itself and its [5] contrary. By means of the straight line we know both itself and the curved—the carpenter’s rule enables us to test both—but what is curved does not enable us to distinguish either itself or the straight.
Certain thinkers say that soul is intermingled in the whole universe, and it is perhaps for that reason that Thales came to the opinion that all things are full of gods. This presents some difficulties: why does the soul when it resides in air or fire [10] not form an animal, while it does so when it resides in mixtures of the elements, and that although it is held to be of higher quality when contained in the former? (One might add the question, why the soul in air is maintained to be higher and more immortal than that in animals.) Both possible ways of replying to the former question lead to absurdity or paradox; for it is beyond paradox to say that fire or air [15] is an animal, and it is absurd to refuse the name of animal to what has soul in it. The opinion that the elements have soul in them seems to have arisen from the doctrine that a whole must be homogeneous with its parts. If it is true that animals become animate by drawing into themselves a portion of what surrounds them, the partisans of this view are bound to say that the soul too is homogeneous with its parts. If the [20] air sucked in is homogeneous, but soul heterogeneous, clearly while some part of soul will exist in the inbreathed air, some other part will not. The soul must either be homogeneous, or such that there are some parts of the whole in which it is not to be found.
From what has been said it is now clear that knowing as an attribute of soul cannot be explained by soul’s being composed of the elements, and that it is neither [25] sound nor true to speak of soul as moved. But since knowing, perceiving, opining, and further desiring, wishing, and generally all other modes of appetition, belong to soul, and the local movements of animals, and growth, maturity, and decay are produced by the soul, we must ask whether each of these is an attribute of the soul as a whole, i.e. whether it is with the whole soul we think, perceive, move ourselves, [411b1] act or are acted upon, or whether each of them requires a different part of the soul? So too with regard to life. Does it depend on one of the parts of soul? Or is it dependent on more than one? Or on all? Or has it some quite other cause?
Some hold that the soul is divisible, and that we think with one part and desire [5] with another. If, then, its nature admits of its being divided, what can it be that holds the parts together? Surely not the body; on the contrary it seems rather to be the soul that holds the body together; at any rate when the soul departs the body disintegrates and decays. If, then, there is something else which makes the soul one, this would have the best right to the name of soul, and we shall have to repeat for it [10] the question: Is it one or multipartite? If it is one, why not at once admit that the soul is one? If it has parts, once more the question must be put: What holds its parts together, and so ad infinitum?
The question might also be raised about the parts of the soul: What is the separate rôle of each in relation to the body? For, if the whole soul holds together [15] the whole body, we should expect each part of the soul to hold together a part of the body. But this seems an impossibility; it is difficult even to imagine what sort of bodily part thought will hold together, or how it will do this.
It is a fact of observation that plants and certain insects go on living when [20] divided into segments; this means that each of the segments has a soul in it identical in species, though not numerically; for both of the segments for a time possess the power of sensation and local movement. That this does not last is not surprising, for they no longer possess the organs necessary for self-maintenance. But, all the same, [25] in each of the parts there are present all the parts of soul, and the souls so present are homogeneous with one another and with the whole—the several parts of the soul being inseparable from one another, although the whole soul is10 divisible. It seems that the principle found in plants is also a kind of soul; for this is the only principle which is common to both animals and plants; and this exists in isolation from the [30] principle of sensation, though there is nothing which has the latter without the former.
BOOK II
[412a1] 1 · Let the foregoing suffice as our account of the views concerning the soul which have been handed on by our predecessors; let us now make as it were a completely fresh start, endeavouring to answer the question, What is soul? i.e. to [5] formulate the most general possible account of it.
We say that substance is one kind of what is, and that in several senses: in the sense of matter or that which in itself is not a this, and in the sense of form or essence, which is that precisely in virtue of which a thing is called a this, and thirdly in the sense of that which is compounded of both. Now matter is potentiality, form [10] actuality; and actuality is of two kinds, one as e.g. knowledge, the other as e.g. reflecting.
Among substances are by general consent reckoned bodies and especially natural bodies; for they are the principles of all other bodies. Of natural bodies some have life in them, others not; by life we mean self-nutrition and growth and decay. It [15] follows that every natural body which has life in it is a substance in the sense of a composite.
Now given that there are bodies of such and such a kind, viz. having life, the soul cannot be a body; for the body is the subject or matter, not what is attributed to [20] it. Hence the soul must be a substance in the sense of the form of a natural body having life potentially within it. But substance is actuality, and thus soul is the actuality of a body as above characterized. Now there are two kinds of actuality corresponding to knowledge and to reflecting. It is obvious that the soul is an actuality like knowledge; for both sleeping and waking presuppose the existence of [25] soul, and of these waking corresponds to reflecting, sleeping to knowledge possessed but not employed, and knowledge of something is temporally prior.
That is why the soul is an actuality of the first kind of a natural body having life potentially in it. The body so described is a body which is organized. The parts of plants in spite of their extreme simplicity are organs; e.g. the leaf serves to shelter [412b1] the pericarp, the pericarp to shelter the fruit, while the roots of plants are analogous to the mouth of animals, both serving for the absorption of food. If, then, we have to give a general formula applicable to all kinds of soul, we must describe it as an actuality of the first kind of a natural organized body. That is why we can dismiss as [5] unnecessary the question whether the soul and the body are one: it is as though we were to ask whether the wax and its shape are one, or generally the matter of a thing and that of which it is the matter. Unity has many senses (as many as ‘is’ has), but the proper one is that of actuality.
We have now given a general answer to the question, What is soul? It is [10] substance in the sense which corresponds to the account of a thing. That means that it is what it is to be for a body of the character just assigned. Suppose that a tool, e.g. an axe, were a natural body, then being an axe would have been its essence, and so its soul; if this disappeared from it, it would have ceased to be an axe, except in name. As it is, it is an axe; for it is not of a body of that sort that what it is to be, i.e. [15] its account, is a soul, but of a natural body of a particular kind, viz. one having in itself the power of setting itself in movement and arresting itself. Next, apply this doctrine in the case of the parts of the living body. Suppose that the eye were an animal—sight would have been its soul, for sight is the substance of the eye which corresponds to the account
, the eye being merely the matter of seeing; when seeing [20] is removed the eye is no longer an eye, except in name—no more than the eye of a statue or of a painted figure. We must now extend our consideration from the parts to the whole living body; for what the part is to the part, that the whole faculty of sense is to the whole sensitive body as such.
We must not understand by that which is potentially capable of living what has [25] lost the soul it had, but only what still retains it; but seeds and fruits are bodies which are potentially of that sort. Consequently, while waking is actuality in a sense corresponding to the cutting and the seeing, the soul is actuality in the sense corresponding to sight and the power in the tool; the body corresponds to what is in [413a1] potentiality; as the pupil plus the power of sight constitutes the eye, so the soul plus the body constitutes the animal.
From this it is clear that the soul is inseparable from its body, or at any rate that certain parts of it are (if it has parts)—for the [5] actuality of some of them is the actuality of the parts themselves. Yet some may be separable because they are not the actualities of any body at all. Further, we have no light on the problem whether the soul may not be the actuality of its body in the sense in which the sailor is the actuality of the ship.11
This must suffice as our sketch or outline of the nature of soul. [10]
2 · Since what is clear and more familiar in account emerges from what in itself is confused but more observable by us, we must reconsider our results from this point of view. For it is not enough for a definitional account to express as most [15] now do the mere fact; it must include and exhibit the cause also. At present definitions are given in a form analogous to the conclusion of an argument; e.g. What is squaring? The construction of an equilateral rectangle equal to a given oblong rectangle. Such a definition is in form equivalent to a conclusion. One that tells us that squaring is the discovery of a mean proportional discloses the cause of [20] what is defined.
We resume our inquiry from a fresh starting-point by calling attention to the fact that what has soul in it differs from what has not in that the former displays life. Now this word has more than one sense, and provided any one alone of these is found in a thing we say that thing is living—viz. thinking or perception or local [25] movement and rest, or movement in the sense of nutrition, decay and growth. Hence we think of plants also as living, for they are observed to possess in themselves an originative power through which they increase or decrease in all spatial directions; they do not grow up but not down—they grow alike in both, indeed in all, directions; [30] and that holds for everything which is constantly nourished and continues to live, so long as it can absorb nutriment.
This power of self-nutrition can be separated from the other powers mentioned, but not they from it—in mortal beings at least. The fact is obvious in plants; for it is the only psychic power they possess.
[413b1] This is the originative power the possession of which leads us to speak of things as living at all, but it is the possession of sensation that leads us for the first time to speak of living things as animals; for even those beings which possess no power of local movement but do possess the power of sensation we call animals and not merely living things.
The primary form of sense is touch, which belongs to all animals. Just as the [5] power of self-nutrition can be separated from touch and sensation generally, so touch can be separated from all other forms of sense. (By the power of self-nutrition we mean that part of the soul which is common to plants and animals: all animals whatsoever are observed to have the sense of touch.) What the explanation of these [10] two facts is, we must discuss later. At present we must confine ourselves to saying that soul is the source of these phenomena and is characterized by them, viz. by the powers of self-nutrition, sensation, thinking, and movement.
Is each of these a soul or a part of a soul? And if a part, a part merely [15] distinguishable by definition or a part distinct in local situation as well? In the case of certain of these powers, the answers to these questions are easy, in the case of others we are puzzled what to say. Just as in the case of plants which when divided are observed to continue to live though separated from one another (thus showing that in their case the soul of each individual plant was actually one, potentially [20] many), so we notice a similar result in other varieties of soul, i.e. in insects which have been cut in two; each of the segments possesses both sensation and local movement; and if sensation, necessarily also imagination and appetition; for, where there is sensation, there is also pleasure and pain, and, where these, necessarily also desire.
[25] We have no evidence as yet about thought or the power of reflexion; it seems to be a different kind of soul, differing as what is eternal from what is perishable; it alone is capable of being separated. All the other parts of soul, it is evident from what we have said, are, in spite of certain statements to the contrary, incapable of separate existence though, of course, distinguishable by definition. If opining is distinct from perceiving, to be capable of opining and to be capable of perceiving [30] must be distinct, and so with all the other forms of living above enumerated. Further, some animals possess all these parts of soul, some certain of them only, others one only (this is what enables us to classify animals); the cause must be [414a1] considered later. A similar arrangement is found also within the field of the senses; some classes of animals have all the senses, some only certain of them, others only one, the most indispensable, touch.
Since the expression ‘that whereby we live and perceive’ has two meanings, just like the expression ‘that whereby we know’—that may mean either knowledge [5] or the soul, for we can speak of knowing by either, and similarly that whereby we are in health may be either health or the body or some part of the body; and since of these knowledge or health is a form, essence, or account, or if we so express it an activity of a recipient matter—knowledge of what is capable of knowing, health of [10] what is capable of being made healthy (for the activity of that which is capable of originating change seems to take place in what is changed or altered); further, since it is the soul by which primarily we live, perceive, and think:—it follows that the soul must be an account and essence, not matter or a subject. For, as we said, the word substance has three meanings—form, matter, and the complex of both—and [15] of these matter is potentiality, form actuality. Since then the complex here is the living thing, the body cannot be the actuality of the soul; it is the soul which is the actuality of a certain kind of body. Hence the rightness of the view that the soul cannot be without a body, while it cannot be a body; it is not a body but something [20] relative to a body. That is why it is in a body, and a body of a definite kind. It was a mistake, therefore, to do as former thinkers did, merely to fit it into a body without adding a definite specification of the. kind or character of that body, although evidently one chance thing will not receive another. It comes about as reason [25] requires: the actuality of any given thing can only be realized in what is already potentially that thing, i.e. in a matter of its own appropriate to it. From all this it is plain that soul is an actuality or account of something that possesses a potentiality of being such.
3 · Of the psychic powers above enumerated some kinds of living things, as we have said, possess all, some less than all, others one only. Those we have [30] mentioned are the nutritive, the appetitive, the sensory, the locomotive, and the power of thinking. Plants have none but the first, the nutritive, while another order of living things has this plus the sensory. If any order of living things has the [414b1] sensory, it must also have the appetitive; for appetite is the genus of which desire, passion, and wish are the species; now all animals have one sense at least, viz. touch, and whatever has a sense has the capacity for pleasure and pain and therefore has pleasant and painful objects present to it, and wherever these are present, there is [5] desire, for desire is appetition of what is pleasant. Further, all animals have the sense for food (for touch is the sense for food; the food of all living things consist
s of what is dry, moist, hot, cold, and these are the qualities apprehended by touch) all other sensible qualities are apprehended by touch only indirectly. Sounds, colours, [10] and odours contribute nothing to nutriment; flavours fall within the field of tangible qualities. Hunger and thirst are forms of desire, hunger a desire for what is dry and hot, thirst a desire for what is cold and moist; flavour is a sort of seasoning added to both. We must later clear up these points, but at present it may be enough to say [15] that all animals that possess the sense of touch have also appetition. The case of imagination is obscure; we must examine it later. Certain kinds of animals possess in addition the power of locomotion, and still others, i.e. man and possibly another order like man or superior to him, the power of thinking and thought. It is now [20] evident that a single definition can be given of soul only in the same sense as one can be given of figure. For, as in that case there is no figure apart from triangle and those that follow in order, so here there is no soul apart from the forms of soul just enumerated. It is true that a common definition can be given for figure which will fit all figures without expressing the peculiar nature of any figure. So here in the [25] case of soul and its specific forms. Hence it is absurd in this and similar cases to look for a common definition which will not express the peculiar nature of anything that is and will not apply to the appropriate indivisible species, while at the same time omitting to look for an account which will. The cases of figure and soul are exactly parallel; for the particulars subsumed under the common name in both cases—[30] figures and living beings—constitute a series, each successive term of which potentially contains its predecessor, e.g. the square the triangle, the sensory power the self-nutritive. Hence we must ask in the case of each order of living things, What is its soul, i.e. What is the soul of plant, man, beast? Why the terms are [415a1] related in this serial way must form the subject of examination. For the power of perception is never found apart from the power of self-nutrition, while—in plants—the latter is found isolated from the former. Again, no sense is found apart [5] from that of touch, while touch is found by itself; many animals have neither sight, hearing, nor smell. Again, among living things that possess sense some have the power of locomotion, some not. Lastly, certain living beings—a small minority— possess calculation and thought, for (among mortal beings) those which possess [10] calculation have all the other powers above mentioned, while the converse does not hold—indeed some live by imagination alone, while others have not even imagination. Reflective thought presents a different problem.
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