Various Works

by Aristotle

  Book II

  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 dismiss

  them and make as it were a completely fresh start, endeavouring to

  give a precise answer to the question, What is soul? i.e. to formulate

  the most general possible definition of it.

  We are in the habit of recognizing, as one determinate kind of

  what is, substance, and that in several senses, (a) in the sense of

  matter or that which in itself is not 'a this', and (b) in the sense

  of form or essence, which is that precisely in virtue of which a thing

  is called 'a this', and thirdly (c) in the sense of that which is

  compounded of both (a) and (b). Now matter is potentiality, form

  actuality; of the latter there are two grades related to one another

  as e.g. knowledge to the exercise of knowledge.

  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 (with its correlative decay).

  It follows that every natural body which has life in it is a substance

  in the sense of a composite.

  But since it is also a body of such and such a kind, viz. having

  life, the body cannot be soul; the body is the subject or matter,

  not what is attributed to 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 the word actuality has two senses

  corresponding respectively to the possession of knowledge and the

  actual exercise of knowledge. It is obvious that the soul is actuality

  in the first sense, viz. that of knowledge as possessed, for both

  sleeping and waking presuppose the existence of soul, and of these

  waking corresponds to actual knowing, sleeping to knowledge

  possessed but not employed, and, in the history of the individual,

  knowledge comes before its employment or exercise.

  That is why the soul is the first grade of actuality 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 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 the first grade of actuality

  of a natural organized body. That is why we can wholly dismiss as

  unnecessary the question whether the soul and the body are one: it

  is as meaningless as to ask whether the wax and the shape given to

  it by the stamp 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 most proper and fundamental sense of both is the

  relation of an actuality to that of which it is the actuality. We have

  now given an answer to the question, What is soul?-an answer which

  applies to it in its full extent. It is substance in the sense which

  corresponds to the definitive formula of a thing's essence. That means

  that it is 'the essential whatness' of a body of the character just

  assigned. Suppose that what is literally an 'organ', like an axe, were

  a natural body, its 'essential whatness', 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 just an axe; it wants

  the character which is required to make its whatness or formulable

  essence a soul; for that, it would have had to be 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 or essence of the eye which corresponds to the formula,

  the eye being merely the matter of seeing; when seeing is removed

  the eye is no longer an eye, except in name-it is no more a real eye

  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 departmental sense is to the bodily part which is its

  organ, 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 lost the soul it had, but only what still retains it;

  but seeds and fruits are bodies which possess the qualification.

  Consequently, while waking is actuality in a sense corresponding to

  the cutting and the seeing, the soul is actuality in the sense

  corresponding to the power of sight and the power in the tool; the

  body corresponds to what exists in potentiality; as the pupil plus the

  power of sight constitutes the eye, so the soul plus the body

  constitutes the animal.

  From this it indubitably follows that the soul is inseparable from

  its body, or at any rate that certain parts of it are (if it has

  parts) for the actuality of some of them is nothing but the

  actualities of their bodily parts. 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.

  This must suffice as our sketch or outline determination of the

  nature of soul.

  2

  Since what is clear or logically more evident 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 definitive

  formula to express as most now do the mere fact; it must include and

  exhibit the ground also. At present definitions are given in a form

  analogous to the conclusion of a syllogism; 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 line which is

  a mean proportional between the two unequal sides of the given

  rectangle discloses the ground of 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. Living, that is, may mean thinking or

  perception or local 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 t
hey increase or decrease in all

  spatial directions; they grow up and down, and everything that grows

  increases its bulk alike in both directions or indeed in all, and

  continues to live so long as it can absorb nutriment.

  This power of self-nutrition can be isolated 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.

  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 power of self-nutrition can be isolated from touch and

  sensation generally, so touch can be isolated from all other forms

  of sense. (By the power of self-nutrition we mean that departmental

  power 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 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 motivity.

  Is each of these a soul or a part of a soul? And if a part, a part

  in what sense? A part merely 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 removed to a

  distance from one another (thus showing that in their case the soul of

  each individual plant before division was actually one, potentially

  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.

  We have no evidence as yet about mind or the power to think; it

  seems to be a widely different kind of soul, differing as what is

  eternal from what is perishable; it alone is capable of existence in

  isolation from all other psychic powers. 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

  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 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 (a) knowledge or (b) the soul, for we can speak of knowing

  by or with either, and similarly that whereby we are in health may

  be either (a) health or (b) the body or some part of the body; and

  since of the two terms thus contrasted knowledge or health is the name

  of a form, essence, or ratio, or if we so express it an actuality of a

  recipient matter-knowledge of what is capable of knowing, health of

  what is capable of being made healthy (for the operation of that which

  is capable of originating change terminates and has its seat in what

  is changed or altered); further, since it is the soul by or with which

  primarily we live, perceive, and think:-it follows that the soul

  must be a ratio or formulable essence, not a matter or subject. For,

  as we said, word substance has three meanings form, matter, and the

  complex of both and of these three what is called matter is

  potentiality, what is called 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 csnnot he a body; it is not a body but something

  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. Reflection

  confirms the observed fact; 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 follows that

  soul is an actuality or formulable essence of something that possesses

  a potentiality of being besouled.

  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 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

  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 desire, for desire is just 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 consists 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, 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 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 another order of animate beings, i.e. man and

  possibly another order like man or superior
to him, the power of

  thinking, i.e. mind. It is now 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 distinguishable and apart from

  triangle, c., so here there is no soul apart from the forms of soul

  just enumerated. It is true that a highly general definition can be

  given for figure which will fit all figures without expressing the

  peculiar nature of any figure. So here in the case of soul and its

  specific forms. Hence it is absurd in this and similar cases to demand

  an absolutely general definition which will fail to express the

  peculiar nature of anything that is, or again, omitting this, to

  look for separate definitions corresponding to each infima species.

  The cases of figure and soul are exactly parallel; for the particulars

  subsumed under the common name in both cases-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, animal, man? Why the terms are related in this serial way

  must form the subject of later examination. But the facts are that 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 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 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. The mind

  that knows with immediate intuition presents a different problem.

  It is evident that the way to give the most adequate definition of