Aristotle
384-322 B.C.E. - Wrote in Greek
On the Soul
Written 350 B.C.E
Translated by J. A. Smith
On the Soul
By Aristotle
Book I
Part 1
Holding as we do that, while knowledge of any kind is a thing to be honoured
and prized, one kind of it may, either by reason of its greater exactness
or of a higher dignity and greater wonderfulness in its objects, be more
honourable and precious than another, on both accounts we should naturally
be led to place in the front rank the study of the soul. The knowledge
of the soul admittedly contributes greatly to the advance of truth in general,
and, above all, to our understanding of Nature, for the soul is in some
sense the principle of animal life. Our aim is to grasp and understand,
first its essential nature, and secondly its properties; of these some
are taught to be affections proper to the soul itself, while others are
considered to attach to the animal owing to the presence within it of
soul.
To attain any assured knowledge about the soul is one of the most
difficult things in the world. As the form of question which here presents
itself, viz. the question 'What is it?', recurs in other fields, it might
be supposed that there was some single method of inquiry applicable to
all objects whose essential nature (as we are endeavouring to ascertain
there is for derived properties the single method of demonstration); in
that case what we should have to seek for would be this unique method.
But if there is no such single and general method for solving the question
of essence, our task becomes still more difficult; in the case of each
different subject we shall have to determine the appropriate process of
investigation. If to this there be a clear answer, e.g. that the process
is demonstration or division, or some known method, difficulties and hesitations
still beset us-with what facts shall we begin the inquiry? For the facts
which form the starting-points in different subjects must be different,
as e.g. in the case of numbers and surfaces.
First, no doubt, it is necessary to determine in which of the summa
genera soul lies, what it is; is it 'a this-somewhat, 'a substance, or
is it a quale or a quantum, or some other of the remaining kinds of predicates
which we have distinguished? Further, does soul belong to the class of
potential existents, or is it not rather an actuality? Our answer to this
question is of the greatest importance.
We must consider also whether soul is divisible or is without parts,
and whether it is everywhere homogeneous or not; and if not homogeneous,
whether its various forms are different specifically or generically: up
to the present time those who have discussed and investigated soul seem
to have confined themselves to the human soul. We must be careful not to
ignore the question whether soul can be defined in a single unambiguous
formula, as is the case with animal, or whether we must not give a separate
formula for each of it, as we do for horse, dog, man, god (in the latter
case the 'universal' animal-and so too every other 'common predicate'-being
treated either as nothing at all or as a later product). Further, if what
exists is not a plurality of souls, but a plurality of parts of one soul,
which ought we to investigate first, the whole soul or its parts? (It is
also a difficult problem to decide which of these parts are in nature distinct
from one another.) Again, which ought we to investigate first, these parts
or their functions, mind or thinking, the faculty or the act of sensation,
and so on? If the investigation of the functions precedes that of the parts,
the further question suggests itself: ought we not before either to consider
the correlative objects, e.g. of sense or thought? It seems not only useful
for the discovery of the causes of the derived properties of substances
to be acquainted with the essential nature of those substances (as in mathematics
it is useful for the understanding of the property of the equality of the
interior angles of a triangle to two right angles to know the essential
nature of the straight and the curved or of the line and the plane) but
also conversely, for the knowledge of the essential nature of a substance
is largely promoted by an acquaintance with its properties: for, when we
are able to give an account conformable to experience of all or most of
the properties of a substance, we shall be in the most favourable position
to say something worth saying about the essential nature of that subject;
in all demonstration a definition of the essence is required as a starting-point,
so that definitions which do not enable us to discover the derived properties,
or which fail to facilitate even a conjecture about them, must obviously,
one and all, be dialectical and futile.
A further problem presented by the affections of soul is this:
are they all affections of the complex of body and soul, or is there any
one among them peculiar to the soul by itself? To determine this is indispensable
but difficult. If we consider the majority of them, there seems to be no
case in which the soul can act or be acted upon without involving the body;
e.g. anger, courage, appetite, and sensation generally. Thinking seems
the most probable exception; but if this too proves to be a form of imagination
or to be impossible without imagination, it too requires a body as a condition
of its existence. If there is any way of acting or being acted upon proper
to soul, soul will be capable of separate existence; if there is none,
its separate existence is impossible. In the latter case, it will be like
what is straight, which has many properties arising from the straightness
in it, e.g. that of touching a bronze sphere at a point, though straightness
divorced from the other constituents of the straight thing cannot touch
it in this way; it cannot be so divorced at all, since it is always found
in a body. It therefore seems that all the affections of soul involve a
body-passion, gentleness, fear, pity, courage, joy, loving, and hating;
in all these there is a concurrent affection of the body. In support of
this we may point to the fact that, while sometimes on the occasion of
violent and striking occurrences there is no excitement or fear felt, on
others faint and feeble stimulations produce these emotions, viz. when
the body is already in a state of tension resembling its condition when
we are angry. Here is a still clearer case: in the absence of any external
cause of terror we find ourselves experiencing the feelings of a man in
terror. From all this it is obvious that the affections of soul are enmattered
formulable essences.
Consequently their definitions ought to correspond, e.g. anger
should be defined as a certain mode of movement of such and such a body
(or part or faculty of a body) by this or that cause and for this or that
end. That is precisely why the study of the soul must fall within the science
of Nature, at least so far as in its affections it manifests this double
character. Hence a physicist would define an affection of soul differently
from a dialectician; the latter would define e.g. anger as the appetite
for returning pain for pain, or something like that, while the former would
define it as a boiling of the blood or warm substance surround the heart.
The latter assigns the material conditions, the former the form or formulable
essence; for what he states is the formulable essence of the fact, though
for its actual existence there must be embodiment of it in a material such
as is described by the other. Thus the essence of a house is assigned in
such a formula as 'a shelter against destruction by wind, rain, and heat';
the physicist would describe it as 'stones, bricks, and timbers'; but there
is a third possible description which would say that it was that form in
that material with that purpose or end. Which, then, among these is entitled
to be regarded as the genuine physicist? The one who confines himself to
the material, or the one who restricts himself to the formulable essence
alone? Is it not rather the one who combines both in a single formula?
If this is so, how are we to characterize the other two? Must we not say
that there is no type of thinker who concerns himself with those qualities
or attributes of the material which are in fact inseparable from the material,
and without attempting even in thought to separate them? The physicist
is he who concerns himself with all the properties active and passive of
bodies or materials thus or thus defined; attributes not considered as
being of this character he leaves to others, in certain cases it may be
to a specialist, e.g. a carpenter or a physician, in others (a) where they
are inseparable in fact, but are separable from any particular kind of
body by an effort of abstraction, to the mathematician, (b) where they
are separate both in fact and in thought from body altogether, to the First
Philosopher or metaphysician. But we must return from this digression,
and repeat that the affections of soul are inseparable from the material
substratum of animal life, to which we have seen that such affections,
e.g. passion and fear, attach, and have not the same mode of being as a
line or a plane.
Part 2
For our study of soul it is necessary, while formulating the problems
of which in our further advance we are to find the solutions, to call into
council the views of those of our predecessors who have declared any opinion
on this subject, in order that we may profit by whatever is sound in their
suggestions and avoid their errors.
The starting-point of our inquiry is an exposition of those characteristics
which have chiefly been held to belong to soul in its very nature. Two
characteristic marks have above all others been recognized as distinguishing
that which has soul in it from that which has not-movement and sensation.
It may be said that these two are what our predecessors have fixed upon
as characteristic of soul.
Some say that what originates movement is both pre-eminently and
primarily soul; believing that what is not itself moved cannot originate
movement in another, they arrived at the view that soul belongs to the
class of things in movement. This is what led Democritus to say that soul
is a sort of fire or hot substance; his 'forms' or atoms are infinite in
number; those which are spherical he calls fire and soul, and compares
them to the motes in the air which we see in shafts of light coming through
windows; the mixture of seeds of all sorts he calls the elements of the
whole of Nature (Leucippus gives a similar account); the spherical atoms
are identified with soul because atoms of that shape are most adapted to
permeate everywhere, and to set all the others moving by being themselves
in movement. This implies the view that soul is identical with what produces
movement in animals. That is why, further, they regard respiration as the
characteristic mark of life; as the environment compresses the bodies of
animals, and tends to extrude those atoms which impart movement to them,
because they themselves are never at rest, there must be a reinforcement
of these by similar atoms coming in from without in the act of respiration;
for they prevent the extrusion of those which are already within by counteracting
the compressing and consolidating force of the environment; and animals
continue to live only so long as they are able to maintain this
resistance.
The doctrine of the Pythagoreans seems to rest upon the same ideas;
some of them declared the motes in air, others what moved them, to be soul.
These motes were referred to because they are seen always in movement,
even in a complete calm.
The same tendency is shown by those who define soul as that which
moves itself; all seem to hold the view that movement is what is closest
to the nature of soul, and that while all else is moved by soul, it alone
moves itself. This belief arises from their never seeing anything originating
movement which is not first itself moved.
Similarly also Anaxagoras (and whoever agrees with him in saying
that mind set the whole in movement) declares the moving cause of things
to be soul. His position must, however, be distinguished from that of Democritus.
Democritus roundly identifies soul and mind, for he identifies what appears
with what is true-that is why he commends Homer for the phrase 'Hector
lay with thought distraught'; he does not employ mind as a special faculty
dealing with truth, but identifies soul and mind. What Anaxagoras says
about them is more obscure; in many places he tells us that the cause of
beauty and order is mind, elsewhere that it is soul; it is found, he says,
in all animals, great and small, high and low, but mind (in the sense of
intelligence) appears not to belong alike to all animals, and indeed not
even to all human beings.
All those, then, who had special regard to the fact that what has
soul in it is moved, adopted the view that soul is to be identified with
what is eminently originative of movement. All, on the other hand, who
looked to the fact that what has soul in it knows or perceives what is,
identify soul with the principle or principles of Nature, according as
they admit several such principles or one only. Thus Empedocles declares
that it is formed out of all his elements, each of them also being soul;
his words are:
For 'tis by Earth we see Earth, by Water Water,
By Ether Ether divine, by Fire destructive Fire,
By Love Love, and Hate by cruel Hate.
In the same way Plato in the Timaeus fashions soul out of his elements;
for like, he holds, is known by like, and things are formed out of the
principles or elements, so that soul must be so too. Similarly also in
his lectures 'On Philosophy' it was set forth that the Animal-itself is
compounded of the Idea itself of the One together with the primary length,
breadth, and depth, everything else, the objects of its perception, being
similarly constituted. Again he puts his view in yet other terms: Mind
is the monad, science or knowledge the dyad (because it goes undeviatingly
from one point to another), opinion the number of the plane, sensation
the number of the solid; the numbers are by him expressly identified with
the Forms themselves or principles, and are formed out of the elements;
now things are apprehended either by mind or science or opinion or sensation,
and these same numbers are the Forms of things.
Some thinkers, accepting both premisses, viz. that the soul is
both originative of movement and cognitive, have compounded it of both
and declared the soul to be a self-moving number.
As to the nature and number of the first principles opinions differ.
The difference is greatest between those who regard them as corporeal and
those who regard them as incorporeal, and from both dissent those who make
a blend and draw their principles from both sources. The number of principles
is also in dispute; some admit one only, others assert several. There is
a consequent diversity in their several accounts of soul; they assume,
naturally enough, that what is in its own nature originative of movement
must be among what is primordial. That has led some to regard it as fire,
for fire is the subtlest of the elements and nearest to incorporeality;
further, in the most primary sense, fire both is moved and originates movement
in all the others.
Democritus has expressed himself more ingeniously than the rest
on the grounds for ascribing each of these two characters to soul; soul
and mind are, he says, one and the same thing, and this thing must be one
of the primary and indivisible bodies, and its power of originating movement
must be due to its fineness of grain and the shape of its atoms; he says
that of all the shapes the spherical is the most mobile, and that this
is the shape of the particles of fire and mind.
Anaxagoras, as we said above, seems to distinguish between soul
and mind, but in practice he treats them as a single substance, except
that it is mind that he specially posits as the principle of all things;
at any rate what he says is that mind alone of all that is simple, unmixed,
and pure. He assigns both characteristics, knowing and origination of movement,
to the same principle, when he says that it was mind that set the whole
in movement.
Thales, too, to judge from what is recorded about him, seems to
have held soul to be a motive force, since he said that the magnet has
a soul in it because it moves the iron.
Diogenes (and others) held the soul to be air because he believed
air to be finest in grain and a first principle; therein lay the grounds
of the soul's powers of knowing and originating movement. As the primordial
principle from which all other things are derived, it is cognitive; as
finest in grain, it has the power to originate movement.
Heraclitus too says that the first principle-the 'warm exhalation'
of which, according to him, everything else is composed-is soul; further,
that this exhalation is most incorporeal and in ceaseless flux; that what
is in movement requires that what knows it should be in movement; and that
all that is has its being essentially in movement (herein agreeing with
the majority).
Alcmaeon also seems to have held a similar view about soul; he
says that it is immortal because it resembles 'the immortals,' and that
this immortality belongs to it in virtue of its ceaseless movement; for
all the 'things divine,' moon, sun, the planets, and the whole heavens,
are in perpetual movement.
of More superficial writers, some, e.g. Hippo, have pronounced
it to be water; they seem to have argued from the fact that the seed of
all animals is fluid, for Hippo tries to refute those who say that the
soul is blood, on the ground that the seed, which is the primordial soul,
is not blood.
Another group (Critias, for example) did hold it to be blood; they
take perception to be the most characteristic attribute of soul, and hold
that perceptiveness is due to the nature of blood.
Each of the elements has thus found its partisan, except earth-earth
has found no supporter unless we count as such those who have declared
soul to be, or to be compounded of, all the elements. All, then, it may
be said, characterize the soul by three marks, Movement, Sensation, Incorporeality,
and each of these is traced back to the first principles. That is why (with
one exception) all those who define the soul by its power of knowing make
it either an element or constructed out of the elements. The language they
all use is similar; like, they say, is known by like; as the soul knows
everything, they construct it out of all the principles. Hence all those
who admit but one cause or element, make the soul also one (e.g. fire or
air), while those who admit a multiplicity of principles make the soul
also multiple. The exception is Anaxagoras; he alone says that mind is
impassible and has nothing in common with anything else. But, if this is
so, how or in virtue of what cause can it know? That Anaxagoras has not
explained, nor can any answer be inferred from his words. All who acknowledge
pairs of opposites among their principles, construct the soul also out
of these contraries, while those who admit as principles only one contrary
of each pair, e.g. either hot or cold, likewise make the soul some one
of these. That is why, also, they allow themselves to be guided by the
names; those who identify soul with the hot argue that sen (to live) is
derived from sein (to boil), while those who identify it with the cold
say that soul (psuche) is so called from the process of respiration and
(katapsuxis). Such are the traditional opinions concerning soul, together
with the grounds on which they are maintained.
Part 3
We must begin our examination with movement; for doubtless, not
only is it false that the essence of soul is correctly described by those
who say that it is what moves (or is capable of moving) itself, but it
is an impossibility that movement should be even an attribute of
it.
We have already pointed out that there is no necessity that what
originates movement should itself be moved. There are two senses in which
anything may be moved-either (a) indirectly, owing to something other than
itself, or (b) directly, owing to itself. Things are 'indirectly moved'
which are moved as being contained in something which is moved, e.g. sailors
in a ship, for they are moved in a different sense from that in which the
ship is moved; the ship is 'directly moved', they are 'indirectly moved',
because they are in a moving vessel. This is clear if we consider their
limbs; the movement proper to the legs (and so to man) is walking, and
in this case the sailors tare not walking. Recognizing the double sense
of 'being moved', what we have to consider now is whether the soul is 'directly
moved' and participates in such direct movement.
There are four species of movement-locomotion, alteration, diminution,
growth; consequently if the soul is moved, it must be moved with one or
several or all of these species of movement. Now if its movement is not
incidental, there must be a movement natural to it, and, if so, as all
the species enumerated involve place, place must be natural to it. But
if the essence of soul be to move itself, its being moved cannot be incidental
to-as it is to what is white or three cubits long; they too can be moved,
but only incidentally-what is moved is that of which 'white' and 'three
cubits long' are the attributes, the body in which they inhere; hence they
have no place: but if the soul naturally partakes in movement, it follows
that it must have a place.
Further, if there be a movement natural to the soul, there must
be a counter-movement unnatural to it, and conversely. The same applies
to rest as well as to movement; for the terminus ad quem of a thing's natural
movement is the place of its natural rest, and similarly the terminus ad
quem of its enforced movement is the place of its enforced rest. But what
meaning can be attached to enforced movements or rests of the soul, it
is difficult even to imagine.
Further, if the natural movement of the soul be upward, the soul
must be fire; if downward, it must be earth; for upward and downward movements
are the definitory characteristics of these bodies. The same reasoning
applies to the intermediate movements, termini, and bodies. Further, since
the soul is observed to originate movement in the body, it is reasonable
to suppose that it transmits to the body the movements by which it itself
is moved, and so, reversing the order, we may infer from the movements
of the body back to similar movements of the soul. Now the body is moved
from place to place with movements of locomotion. Hence it would follow
that the soul too must in accordance with the body change either its place
as a whole or the relative places of its parts. This carries with it the
possibility that the soul might even quit its body and re-enter it, and
with this would be involved the possibility of a resurrection of animals
from the dead. But, it may be contended, the soul can be moved indirectly
by something else; for an animal can be pushed out of its course. Yes,
but that to whose essence belongs the power of being moved by itself, cannot
be moved by something else except incidentally, just as what is good by
or in itself cannot owe its goodness to something external to it or to
some end to which it is a means.
If the soul is moved, the most probable view is that what moves
it is sensible things.
We must note also that, if the soul moves itself, it must be the
mover itself that is moved, so that it follows that if movement is in every
case a displacement of that which is in movement, in that respect in which
it is said to be moved, the movement of the soul must be a departure from
its essential nature, at least if its self-movement is essential to it,
not incidental.
Some go so far as to hold that the movements which the soul imparts
to the body in which it is are the same in kind as those with which it
itself is moved. An example of this is Democritus, who uses language like
that of the comic dramatist Philippus, who accounts for the movements that
Daedalus imparted to his wooden Aphrodite by saying that he poured quicksilver
into it; similarly Democritus says that the spherical atoms which according
to him constitute soul, owing to their own ceaseless movements draw the
whole body after them and so produce its movements. We must urge the question
whether it is these very same atoms which produce rest also-how they could
do so, it is difficult and even impossible to say. And, in general, we
may object that it is not in this way that the soul appears to originate
movement in animals-it is through intention or process of
thinking.
It is in the same fashion that the Timaeus also tries to give a
physical account of how the soul moves its body; the soul, it is there
said, is in movement, and so owing to their mutual implication moves the
body also. After compounding the soul-substance out of the elements and
dividing it in accordance with the harmonic numbers, in order that it may
possess a connate sensibility for 'harmony' and that the whole may move
in movements well attuned, the Demiurge bent the straight line into a circle;
this single circle he divided into two circles united at two common points;
one of these he subdivided into seven circles. All this implies that the
movements of the soul are identified with the local movements of the
heavens.
Now, in the first place, it is a mistake to say that the soul is
a spatial magnitude. It is evident that Plato means the soul of the whole
to be like the sort of soul which is called mind not like the sensitive
or the desiderative soul, for the movements of neither of these are circular.
Now mind is one and continuous in the sense in which the process of thinking
is so, and thinking is identical with the thoughts which are its parts;
these have a serial unity like that of number, not a unity like that of
a spatial magnitude. Hence mind cannot have that kind of unity either;
mind is either without parts or is continuous in some other way than that
which characterizes a spatial magnitude. How, indeed, if it were a spatial
magnitude, could mind possibly think? Will it think with any one indifferently
of its parts? In this case, the 'part' must be understood either in the
sense of a spatial magnitude or in the sense of a point (if a point can
be called a part of a spatial magnitude). If we accept the latter alternative,
the points being infinite in number, obviously the mind can never exhaustively
traverse them; if the former, the mind must think the same thing over and
over again, indeed an infinite number of times (whereas it is manifestly
possible to think a thing once only). If contact of any part whatsoever
of itself with the object is all that is required, why need mind move in
a circle, or indeed possess magnitude at all? On the other hand, if contact
with the whole circle is necessary, what meaning can be given to the contact
of the parts? Further, how could what has no parts think what has parts,
or what has parts think what has none? We must identify the circle referred
to with mind; for it is mind whose movement is thinking, and it is the
circle whose movement is revolution, so that if thinking is a movement
of revolution, the circle which has this characteristic movement must be
mind.
If the circular movement is eternal, there must be something which
mind is always thinking-what can this be? For all practical processes of
thinking have limits-they all go on for the sake of something outside the
process, and all theoretical processes come to a close in the same way
as the phrases in speech which express processes and results of thinking.
Every such linguistic phrase is either definitory or demonstrative. Demonstration
has both a starting-point and may be said to end in a conclusion or inferred
result; even if the process never reaches final completion, at any rate
it never returns upon itself again to its starting-point, it goes on assuming
a fresh middle term or a fresh extreme, and moves straight forward, but
circular movement returns to its starting-point. Definitions, too, are
closed groups of terms.
Further, if the same revolution is repeated, mind must repeatedly
think the same object.
Further, thinking has more resemblance to a coming to rest or arrest
than to a movement; the same may be said of inferring.
It might also be urged that what is difficult and enforced is incompatible
with blessedness; if the movement of the soul is not of its essence, movement
of the soul must be contrary to its nature. It must also be painful for
the soul to be inextricably bound up with the body; nay more, if, as is
frequently said and widely accepted, it is better for mind not to be embodied,
the union must be for it undesirable.
Further, the cause of the revolution of the heavens is left obscure.
It is not the essence of soul which is the cause of this circular movement-that
movement is only incidental to soul-nor is, a fortiori, the body its cause.
Again, it is not even asserted that it is better that soul should be so
moved; and yet the reason for which God caused the soul to move in a circle
can only have been that movement was better for it than rest, and movement
of this kind better than any other. But since this sort of consideration
is more appropriate to another field of speculation, let us dismiss it
for the present.
The view we have just been examining, in company with most theories
about the soul, involves the following absurdity: they all join the soul
to a body, or place it in a body, without adding any specification of the
reason of their union, or of the bodily conditions required for it. Yet
such explanation can scarcely be omitted; for some community of nature
is presupposed by the fact that the one acts and the other is acted upon,
the one moves and the other is moved; interaction always implies a special
nature in the two interagents. All, however, that these thinkers do is
to describe the specific characteristics of the soul; they do not try to
determine anything about the body which is to contain it, as if it were
possible, as in the Pythagorean myths, that any soul could be clothed upon
with any body-an absurd view, for each body seems to have a form and shape
of its own. It is as absurd as to say that the art of carpentry could embody
itself in flutes; each art must use its tools, each soul its
body.
Part 4
There is yet another theory about soul, which has commended itself
to many as no less probable than any of those we have hitherto mentioned,
and has rendered public account of itself in the court of popular discussion.
Its supporters say that the soul is a kind of harmony, for (a) harmony
is a blend or composition of contraries, and (b) the body is compounded
out of contraries. Harmony, however, is a certain proportion or composition
of the constituents blended, and soul can be neither the one nor the other
of these. Further, the power of originating movement cannot belong to a
harmony, while almost all concur in regarding this as a principal attribute
of soul. It is more appropriate to call health (or generally one of the
good states of the body) a harmony than to predicate it of the soul. The
absurdity becomes most apparent when we try to attribute the active and
passive affections of the soul to a harmony; the necessary readjustment
of their conceptions is difficult. Further, in using the word 'harmony'
we have one or other of two cases in our mind; the most proper sense is
in relation to spatial magnitudes which have motion and position, where
harmony means the disposition and cohesion of their parts in such a manner
as to prevent the introduction into the whole of anything homogeneous with
it, and the secondary sense, derived from the former, is that in which
it means the ratio between the constituents so blended; in neither of these
senses is it plausible to predicate it of soul. That soul is a harmony
in the sense of the mode of composition of the parts of the body is a view
easily refutable; for there are many composite parts and those variously
compounded; of what bodily part is mind or the sensitive or the appetitive
faculty the mode of composition? And what is the mode of composition which
constitutes each of them? It is equally absurd to identify the soul with
the ratio of the mixture; for the mixture which makes flesh has a different
ratio between the elements from that which makes bone. The consequence
of this view will therefore be that distributed throughout the whole body
there will be many souls, since every one of the bodily parts is a different
mixture of the elements, and the ratio of mixture is in each case a harmony,
i.e. a soul.
From Empedocles at any rate we might demand an answer to the following
question for he says that each of the parts of the body is what it is in
virtue of a ratio between the elements: is the soul identical with this
ratio, or is it not rather something over and above this which is formed
in the parts? Is love the cause of any and every mixture, or only of those
that are in the right ratio? Is love this ratio itself, or is love something
over and above this? Such are the problems raised by this account. But,
on the other hand, if the soul is different from the mixture, why does
it disappear at one and the same moment with that relation between the
elements which constitutes flesh or the other parts of the animal body?
Further, if the soul is not identical with the ratio of mixture, and it
is consequently not the case that each of the parts has a soul, what is
that which perishes when the soul quits the body?
That the soul cannot either be a harmony, or be moved in a circle,
is clear from what we have said. Yet that it can be moved incidentally
is, as we said above, possible, and even that in a sense it can move itself,
i.e. in the sense that the vehicle in which it is can be moved, and moved
by it; in no other sense can the soul be moved in space.
More legitimate doubts might remain as to its movement in view
of the following facts. We speak of the soul as being pained or pleased,
being bold or fearful, being angry, perceiving, thinking. All these are
regarded as modes of movement, and hence it might be inferred that the
soul is moved. This, however, does not necessarily follow. We may admit
to the full that being pained or pleased, or thinking, are movements (each
of them a 'being moved'), and that the movement is originated by the soul.
For example we may regard anger or fear as such and such movements of the
heart, and thinking as such and such another movement of that organ, or
of some other; these modifications may arise either from changes of place
in certain parts or from qualitative alterations (the special nature of
the parts and the special modes of their changes being for our present
purpose irrelevant). Yet to say that it is the soul which is angry is as
inexact as it would be to say that it is the soul that weaves webs or builds
houses. It is doubtless better to avoid saying that the soul pities or
learns or thinks and rather to say that it is the man who does this with
his soul. What we mean is not that the movement is in the soul, but that
sometimes it terminates in the soul and sometimes starts from it, sensation
e.g. coming from without inwards, and reminiscence starting from the soul
and terminating with the movements, actual or residual, in the sense
organs.
The case of mind is different; it seems to be an independent substance
implanted within the soul and to be incapable of being destroyed. If it
could be destroyed at all, it would be under the blunting influence of
old age. What really happens in respect of mind in old age is, however,
exactly parallel to what happens in the case of the sense organs; if the
old man could recover the proper kind of eye, he would see just as well
as the young man. The incapacity of old age is due to an affection not
of the soul but of its vehicle, as occurs in drunkenness or disease. Thus
it is that in old age the activity of mind or intellectual apprehension
declines only through the decay of some other inward part; mind itself
is impassible. Thinking, loving, and hating are affections not of mind,
but of that which has mind, so far as it has it. That is why, when this
vehicle decays, memory and love cease; they were activities not of mind,
but of the composite which has perished; mind is, no doubt, something more
divine and impassible. That the soul cannot be moved is therefore clear
from what we have said, and if it cannot be moved at all, manifestly it
cannot be moved by itself.
Of all the opinions we have enumerated, by far the most unreasonable
is that which declares the soul to be a self-moving number; it involves
in the first place all the impossibilities which follow from regarding
the soul as moved, and in the second special absurdities which follow from
calling it a number. How we to imagine a unit being moved? By what agency?
What sort of movement can be attributed to what is without parts or internal
differences? If the unit is both originative of movement and itself capable
of being moved, it must contain difference.
Further, since they say a moving line generates a surface and a
moving point a line, the movements of the psychic units must be lines (for
a point is a unit having position, and the number of the soul is, of course,
somewhere and has position).
Again, if from a number a number or a unit is subtracted, the remainder
is another number; but plants and many animals when divided continue to
live, and each segment is thought to retain the same kind of
soul.
It must be all the same whether we speak of units or corpuscles;
for if the spherical atoms of Democritus became points, nothing being retained
but their being a quantum, there must remain in each a moving and a moved
part, just as there is in what is continuous; what happens has nothing
to do with the size of the atoms, it depends solely upon their being a
quantum. That is why there must be something to originate movement in the
units. If in the animal what originates movement is the soul, so also must
it be in the case of the number, so that not the mover and the moved together,
but the mover only, will be the soul. But how is it possible for one of
the units to fulfil this function of originating movement? There must be
some difference between such a unit and all the other units, and what difference
can there be between one placed unit and another except a difference of
position? If then, on the other hand, these psychic units within the body
are different from the points of the body, there will be two sets of units
both occupying the same place; for each unit will occupy a point. And yet,
if there can be two, why cannot there be an infinite number? For if things
can occupy an indivisible lace, they must themselves be indivisible. If,
on the other hand, the points of the body are identical with the units
whose number is the soul, or if the number of the points in the body is
the soul, why have not all bodies souls? For all bodies contain points
or an infinity of points.
Further, how is it possible for these points to be isolated or
separated from their bodies, seeing that lines cannot be resolved into
points?
Part 5
The result is, as we have said, that this view, while on the one
side identical with that of those who maintain that soul is a subtle kind
of body, is on the other entangled in the absurdity peculiar to Democritus'
way of describing the manner in which movement is originated by soul. For
if the soul is present throughout the whole percipient body, there must,
if the soul be a kind of body, be two bodies in the same place; and for
those who call it a number, there must be many points at one point, or
every body must have a soul, unless the soul be a different sort of number-other,
that is, than the sum of the points existing in a body. Another consequence
that follows is that the animal must be moved by its number precisely in
the way that Democritus explained its being moved by his spherical psychic
atoms. What difference does it make whether we speak of small spheres or
of large units, or, quite simply, of units in movement? One way or another,
the movements of the animal must be due to their movements. Hence those
who combine movement and number in the same subject lay themselves open
to these and many other similar absurdities. It is impossible not only
that these characters should give the definition of soul-it is impossible
that they should even be attributes of it. The point is clear if the attempt
be made to start from this as the account of soul and explain from it the
affections and actions of the soul, e.g. reasoning, sensation, pleasure,
pain, &c. For, to repeat what we have said earlier, movement and number
do not facilitate even conjecture about the derivative properties of
soul.
Such are the three ways in which soul has traditionally been defined;
one group of thinkers declared it to be that which is most originative
of movement because it moves itself, another group to be the subtlest and
most nearly incorporeal of all kinds of body. We have now sufficiently
set forth the difficulties and inconsistencies to which these theories
are exposed. It remains now to examine the doctrine that soul is composed
of the elements.
The reason assigned for this doctrine is that thus the soul may
perceive or come to know everything that is, but the theory necessarily
involves itself in many impossibilities. Its upholders assume that like
is known only by like, and imagine that by declaring the soul to be composed
of the elements they succeed in identifying the soul with all the things
it is capable of apprehending. But the elements are not the only things
it knows; there are many others, or, more exactly, an infinite number of
others, formed out of the elements. Let us admit that the soul knows or
perceives the elements out of which each of these composites is made up;
but by what means will it know or perceive the composite whole, e.g. what
God, man, flesh, bone (or any other compound) is? For each is, not merely
the elements of which it is composed, but those elements combined in a
determinate mode or ratio, as Empedocles himself says of
bone,
The kindly Earth in its broad-bosomed moulds
Won of clear Water two parts out of eight, And four of
Fire; and so white bones were formed.
Nothing, therefore, will be gained by the presence of the elements
in the soul, unless there be also present there the various formulae of
proportion and the various compositions in accordance with them. Each element
will indeed know its fellow outside, but there will be no knowledge of
bone or man, unless they too are present in the constitution of the soul.
The impossibility of this needs no pointing out; for who would suggest
that stone or man could enter into the constitution of the soul? The same
applies to 'the good' and 'the not-good', and so on.
Further, the word 'is' has many meanings: it may be used of a 'this'
or substance, or of a quantum, or of a quale, or of any other of the kinds
of predicates we have distinguished. Does the soul consist of all of these
or not? It does not appear that all have common elements. Is the soul formed
out of those elements alone which enter into substances? so how will it
be able to know each of the other kinds of thing? Will it be said that
each kind of thing has elements or principles of its own, and that the
soul is formed out of the whole of these? In that case, the soul must be
a quantum and a quale and a substance. But all that can be made out of
the elements of a quantum is a quantum, not a substance. These (and others
like them) are the consequences of the view that the soul is composed of
all the elements.
It is absurd, also, to say both (a) that like is not capable of
being affected by like, and (b) that like is perceived or known by like,
for perceiving, and also both thinking and knowing, are, on their own assumption,
ways of being affected or moved.
There are many puzzles and difficulties raised by saying, as Empedocles
does, that each set of things is known by means of its corporeal elements
and by reference to something in soul which is like them, and additional
testimony is furnished by this new consideration; for all the parts of
the animal body which consist wholly of earth such as bones, sinews, and
hair seem to be wholly insensitive and consequently not perceptive even
of objects earthy like themselves, as they ought to have
been.
Further, each of the principles will have far more ignorance than
knowledge, for though each of them will know one thing, there will be many
of which it will be ignorant. Empedocles at any rate must conclude that
his God is the least intelligent of all beings, for of him alone is it
true that there is one thing, Strife, which he does not know, while there
is nothing which mortal beings do not know, for ere is nothing which does
not enter into their composition.
In general, we may ask, Why has not everything a soul, since everything
either is an element, or is formed out of one or several or all of the
elements? Each must certainly know one or several or
all.
The problem might also be raised, What is that which unifies the
elements into a soul? The elements correspond, it would appear, to the
matter; what unites them, whatever it is, is the supremely important factor.
But it is impossible that there should be something superior to, and dominant
over, the soul (and a fortiori over the mind); it is reasonable to hold
that mind is by nature most primordial and dominant, while their statement
that it is the elements which are first of all that
is.
All, both those who assert that the soul, because of its knowledge
or perception of what is compounded out of the elements, and is those who
assert that it is of all things the most originative of movement, fail
to take into consideration all kinds of soul. In fact (1) not all beings
that perceive can originate movement; there appear to be certain animals
which stationary, and yet local movement is the only one, so it seems,
which the soul originates in animals. And (2) the same object-on holds
against all those who construct mind and the perceptive faculty out of
the elements; for it appears that plants live, and yet are not endowed
with locomotion or perception, while a large number of animals are without
discourse of reason. Even if these points were waived and mind admitted
to be a part of the soul (and so too the perceptive faculty), still, even
so, there would be kinds and parts of soul of which they had failed to
give any account.
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 in the case of certain classes of animal,
for not all classes of animal 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 know
both that element itself and its 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 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 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 of the Whole too is homogeneous with all
its parts. If the 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 sound nor true to speak of soul as moved. But since
(a) knowing, perceiving, opining, and further (b) desiring, wishing, and
generally all other modes of appetition, belong to soul, and (c) the local
movements of animals, and (d) 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, 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 one part thinks,
another desires. 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 unifying agency would
have the best right to the name of soul, and we shall have to repeat for
it 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 role of each in relation to the body? For, if the
whole soul holds together 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 mind will hold
together, or how it will do this.
It is a fact of observation that plants and certain insects go
on living when divided into segments; this means that each of the segments
has a soul in it identical in species, though not numerically identical
in the different segments, 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, in each of the bodily parts there are present all the
parts of soul, and the souls so present are homogeneous with one another
and with the whole; this means that the several parts of the soul are indisseverable
from one another, although the whole soul is divisible. It seems also 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 principle of sensation, though there nothing which has
the latter without the former.
On the Soul
By Aristotle
Book II
Part 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.
Part 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 they 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.
Part 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 soul is to seek in the case of each of its forms for the most appropriate
definition.
Part 4
It is necessary for the student of these forms of soul first to
find a definition of each, expressive of what it is, and then to investigate
its derivative properties, &c. But if we are to express what each is, viz.
what the thinking power is, or the perceptive, or the nutritive, we must
go farther back and first give an account of thinking or perceiving, for
in the order of investigation the question of what an agent does precedes
the question, what enables it to do what it does. If this is correct, we
must on the same ground go yet another step farther back and have some
clear view of the objects of each; thus we must start with these objects,
e.g. with food, with what is perceptible, or with what is
intelligible.
It follows that first of all we must treat of nutrition and reproduction,
for the nutritive soul is found along with all the others and is the most
primitive and widely distributed power of soul, being indeed that one in
virtue of which all are said to have life. The acts in which it manifests
itself are reproduction and the use of food-reproduction, I say, because
for any living thing that has reached its normal development and which
is unmutilated, and whose mode of generation is not spontaneous, the most
natural act is the production of another like itself, an animal producing
an animal, a plant a plant, in order that, as far as its nature allows,
it may partake in the eternal and divine. That is the goal towards which
all things strive, that for the sake of which they do whatsoever their
nature renders possible. The phrase 'for the sake of which' is ambiguous;
it may mean either (a) the end to achieve which, or (b) the being in whose
interest, the act is done. Since then no living thing is able to partake
in what is eternal and divine by uninterrupted continuance (for nothing
perishable can for ever remain one and the same), it tries to achieve that
end in the only way possible to it, and success is possible in varying
degrees; so it remains not indeed as the self-same individual but continues
its existence in something like itself-not numerically but specifically
one.
The soul is the cause or source of the living body. The terms cause
and source have many senses. But the soul is the cause of its body alike
in all three senses which we explicitly recognize. It is (a) the source
or origin of movement, it is (b) the end, it is (c) the essence of the
whole living body.
That it is the last, is clear; for in everything the essence is
identical with the ground of its being, and here, in the case of living
things, their being is to live, and of their being and their living the
soul in them is the cause or source. Further, the actuality of whatever
is potential is identical with its formulable essence.
It is manifest that the soul is also the final cause of its body.
For Nature, like mind, always does whatever it does for the sake of something,
which something is its end. To that something corresponds in the case of
animals the soul and in this it follows the order of nature; all natural
bodies are organs of the soul. This is true of those that enter into the
constitution of plants as well as of those which enter into that of animals.
This shows that that the sake of which they are is soul. We must here recall
the two senses of 'that for the sake of which', viz. (a) the end to achieve
which, and (b) the being in whose interest, anything is or is
done.
We must maintain, further, that the soul is also the cause of the
living body as the original source of local movement. The power of locomotion
is not found, however, in all living things. But change of quality and
change of quantity are also due to the soul. Sensation is held to be a
qualitative alteration, and nothing except what has soul in it is capable
of sensation. The same holds of the quantitative changes which constitute
growth and decay; nothing grows or decays naturally except what feeds itself,
and nothing feeds itself except what has a share of soul in
it.
Empedocles is wrong in adding that growth in plants is to be explained,
the downward rooting by the natural tendency of earth to travel downwards,
and the upward branching by the similar natural tendency of fire to travel
upwards. For he misinterprets up and down; up and down are not for all
things what they are for the whole Cosmos: if we are to distinguish and
identify organs according to their functions, the roots of plants are analogous
to the head in animals. Further, we must ask what is the force that holds
together the earth and the fire which tend to travel in contrary directions;
if there is no counteracting force, they will be torn asunder; if there
is, this must be the soul and the cause of nutrition and growth. By some
the element of fire is held to be the cause of nutrition and growth, for
it alone of the primary bodies or elements is observed to feed and increase
itself. Hence the suggestion that in both plants and animals it is it which
is the operative force. A concurrent cause in a sense it certainly is,
but not the principal cause, that is rather the soul; for while the growth
of fire goes on without limit so long as there is a supply of fuel, in
the case of all complex wholes formed in the course of nature there is
a limit or ratio which determines their size and increase, and limit and
ratio are marks of soul but not of fire, and belong to the side of formulable
essence rather than that of matter.
Nutrition and reproduction are due to one and the same psychic
power. It is necessary first to give precision to our account of food,
for it is by this function of absorbing food that this psychic power is
distinguished from all the others. The current view is that what serves
as food to a living thing is what is contrary to it-not that in every pair
of contraries each is food to the other: to be food a contrary must not
only be transformable into the other and vice versa, it must also in so
doing increase the bulk of the other. Many a contrary is transformed into
its other and vice versa, where neither is even a quantum and so cannot
increase in bulk, e.g. an invalid into a healthy subject. It is clear that
not even those contraries which satisfy both the conditions mentioned above
are food to one another in precisely the same sense; water may be said
to feed fire, but not fire water. Where the members of the pair are elementary
bodies only one of the contraries, it would appear, can be said to feed
the other. But there is a difficulty here. One set of thinkers assert that
like fed, as well as increased in amount, by like. Another set, as we have
said, maintain the very reverse, viz. that what feeds and what is fed are
contrary to one another; like, they argue, is incapable of being affected
by like; but food is changed in the process of digestion, and change is
always to what is opposite or to what is intermediate. Further, food is
acted upon by what is nourished by it, not the other way round, as timber
is worked by a carpenter and not conversely; there is a change in the carpenter
but it is merely a change from not-working to working. In answering this
problem it makes all the difference whether we mean by 'the food' the 'finished'
or the 'raw' product. If we use the word food of both, viz. of the completely
undigested and the completely digested matter, we can justify both the
rival accounts of it; taking food in the sense of undigested matter, it
is the contrary of what is fed by it, taking it as digested it is like
what is fed by it. Consequently it is clear that in a certain sense we
may say that both parties are right, both wrong.
Since nothing except what is alive can be fed, what is fed is the
besouled body and just because it has soul in it. Hence food is essentially
related to what has soul in it. Food has a power which is other than the
power to increase the bulk of what is fed by it; so far forth as what has
soul in it is a quantum, food may increase its quantity, but it is only
so far as what has soul in it is a 'this-somewhat' or substance that food
acts as food; in that case it maintains the being of what is fed, and that
continues to be what it is so long as the process of nutrition continues.
Further, it is the agent in generation, i.e. not the generation of the
individual fed but the reproduction of another like it; the substance of
the individual fed is already in existence; the existence of no substance
is a self-generation but only a self-maintenance.
Hence the psychic power which we are now studying may be described
as that which tends to maintain whatever has this power in it of continuing
such as it was, and food helps it to do its work. That is why, if deprived
of food, it must cease to be.
The process of nutrition involves three factors, (a) what is fed,
(b) that wherewith it is fed, (c) what does the feeding; of these (c) is
the first soul, (a) the body which has that soul in it, (b) the food. But
since it is right to call things after the ends they realize, and the end
of this soul is to generate another being like that in which it is, the
first soul ought to be named the reproductive soul. The expression (b)
'wherewith it is fed' is ambiguous just as is the expression 'wherewith
the ship is steered'; that may mean either (i) the hand or (ii) the rudder,
i.e. either (i) what is moved and sets in movement, or (ii) what is merely
moved. We can apply this analogy here if we recall that all food must be
capable of being digested, and that what produces digestion is warmth;
that is why everything that has soul in it possesses
warmth.
We have now given an outline account of the nature of food; further
details must be given in the appropriate place.
Part 5
Having made these distinctions let us now speak of sensation in
the widest sense. Sensation depends, as we have said, on a process of movement
or affection from without, for it is held to be some sort of change of
quality. Now some thinkers assert that like is affected only by like; in
what sense this is possible and in what sense impossible, we have explained
in our general discussion of acting and being acted
upon.
Here arises a problem: why do we not perceive the senses themselves
as well as the external objects of sense, or why without the stimulation
of external objects do they not produce sensation, seeing that they contain
in themselves fire, earth, and all the other elements, which are the direct
or indirect objects is so of sense? It is clear that what is sensitive
is only potentially, not actually. The power of sense is parallel to what
is combustible, for that never ignites itself spontaneously, but requires
an agent which has the power of starting ignition; otherwise it could have
set itself on fire, and would not have needed actual fire to set it
ablaze.
In reply we must recall that we use the word 'perceive' in two
ways, for we say (a) that what has the power to hear or see, 'sees' or
'hears', even though it is at the moment asleep, and also (b) that what
is actually seeing or hearing, 'sees' or 'hears'. Hence 'sense' too must
have two meanings, sense potential, and sense actual. Similarly 'to be
a sentient' means either (a) to have a certain power or (b) to manifest
a certain activity. To begin with, for a time, let us speak as if there
were no difference between (i) being moved or affected, and (ii) being
active, for movement is a kind of activity-an imperfect kind, as has elsewhere
been explained. Everything that is acted upon or moved is acted upon by
an agent which is actually at work. Hence it is that in one sense, as has
already been stated, what acts and what is acted upon are like, in another
unlike, i.e. prior to and during the change the two factors are unlike,
after it like.
But we must now distinguish not only between what is potential
and what is actual but also different senses in which things can be said
to be potential or actual; up to now we have been speaking as if each of
these phrases had only one sense. We can speak of something as 'a knower'
either (a) as when we say that man is a knower, meaning that man falls
within the class of beings that know or have knowledge, or (b) as when
we are speaking of a man who possesses a knowledge of grammar; each of
these is so called as having in him a certain potentiality, but there is
a difference between their respective potentialities, the one (a) being
a potential knower, because his kind or matter is such and such, the other
(b), because he can in the absence of any external counteracting cause
realize his knowledge in actual knowing at will. This implies a third meaning
of 'a knower' (c), one who is already realizing his knowledge-he is a knower
in actuality and in the most proper sense is knowing, e.g. this A. Both
the former are potential knowers, who realize their respective potentialities,
the one (a) by change of quality, i.e. repeated transitions from one state
to its opposite under instruction, the other (b) by the transition from
the inactive possession of sense or grammar to their active exercise. The
two kinds of transition are distinct.
Also the expression 'to be acted upon' has more than one meaning;
it may mean either (a) the extinction of one of two contraries by the other,
or (b) the maintenance of what is potential by the agency of what is actual
and already like what is acted upon, with such likeness as is compatible
with one's being actual and the other potential. For what possesses knowledge
becomes an actual knower by a transition which is either not an alteration
of it at all (being in reality a development into its true self or actuality)
or at least an alteration in a quite different sense from the usual
meaning.
Hence it is wrong to speak of a wise man as being 'altered' when
he uses his wisdom, just as it would be absurd to speak of a builder as
being altered when he is using his skill in building a
house.
What in the case of knowing or understanding leads from potentiality
to actuality ought not to be called teaching but something else. That which
starting with the power to know learns or acquires knowledge through the
agency of one who actually knows and has the power of teaching either (a)
ought not to be said 'to be acted upon' at all or (b) we must recognize
two senses of alteration, viz. (i) the substitution of one quality for
another, the first being the contrary of the second, or (ii) the development
of an existent quality from potentiality in the direction of fixity or
nature.
In the case of what is to possess sense, the first transition is
due to the action of the male parent and takes place before birth so that
at birth the living thing is, in respect of sensation, at the stage which
corresponds to the possession of knowledge. Actual sensation corresponds
to the stage of the exercise of knowledge. But between the two cases compared
there is a difference; the objects that excite the sensory powers to activity,
the seen, the heard, &c., are outside. The ground of this difference is
that what actual sensation apprehends is individuals, while what knowledge
apprehends is universals, and these are in a sense within the soul. That
is why a man can exercise his knowledge when he wishes, but his sensation
does not depend upon himself a sensible object must be there. A similar
statement must be made about our knowledge of what is sensible-on the same
ground, viz. that the sensible objects are individual and
external.
A later more appropriate occasion may be found thoroughly to clear
up all this. At present it must be enough to recognize the distinctions
already drawn; a thing may be said to be potential in either of two senses,
(a) in the sense in which we might say of a boy that he may become a general
or (b) in the sense in which we might say the same of an adult, and there
are two corresponding senses of the term 'a potential sentient'. There
are no separate names for the two stages of potentiality; we have pointed
out that they are different and how they are different. We cannot help
using the incorrect terms 'being acted upon or altered' of the two transitions
involved. As we have said, has the power of sensation is potentially like
what the perceived object is actually; that is, while at the beginning
of the process of its being acted upon the two interacting factors are
dissimilar, at the end the one acted upon is assimilated to the other and
is identical in quality with it.
Part 6
In dealing with each of the senses we shall have first to speak
of the objects which are perceptible by each. The term 'object of sense'
covers three kinds of objects, two kinds of which are, in our language,
directly perceptible, while the remaining one is only incidentally perceptible.
Of the first two kinds one (a) consists of what is perceptible by a single
sense, the other (b) of what is perceptible by any and all of the senses.
I call by the name of special object of this or that sense that which cannot
be perceived by any other sense than that one and in respect of which no
error is possible; in this sense colour is the special object of sight,
sound of hearing, flavour of taste. Touch, indeed, discriminates more than
one set of different qualities. Each sense has one kind of object which
it discerns, and never errs in reporting that what is before it is colour
or sound (though it may err as to what it is that is coloured or where
that is, or what it is that is sounding or where that is.) Such objects
are what we propose to call the special objects of this or that
sense.
'Common sensibles' are movement, rest, number, figure, magnitude;
these are not peculiar to any one sense, but are common to all. There are
at any rate certain kinds of movement which are perceptible both by touch
and by sight.
We speak of an incidental object of sense where e.g. the white
object which we see is the son of Diares; here because 'being the son of
Diares' is incidental to the directly visible white patch we speak of the
son of Diares as being (incidentally) perceived or seen by us. Because
this is only incidentally an object of sense, it in no way as such affects
the senses. Of the two former kinds, both of which are in their own nature
perceptible by sense, the first kind-that of special objects of the several
senses-constitute the objects of sense in the strictest sense of the term
and it is to them that in the nature of things the structure of each several
sense is adapted.
Part 7
The object of sight is the visible, and what is visible is (a)
colour and (b) a certain kind of object which can be described in words
but which has no single name; what we mean by (b) will be abundantly clear
as we proceed. Whatever is visible is colour and colour is what lies upon
what is in its own nature visible; 'in its own nature' here means not that
visibility is involved in the definition of what thus underlies colour,
but that that substratum contains in itself the cause of visibility. Every
colour has in it the power to set in movement what is actually transparent;
that power constitutes its very nature. That is why it is not visible except
with the help of light; it is only in light that the colour of a thing
is seen. Hence our first task is to explain what light
is.
Now there clearly is something which is transparent, and by 'transparent'
I mean what is visible, and yet not visible in itself, but rather owing
its visibility to the colour of something else; of this character are air,
water, and many solid bodies. Neither air nor water is transparent because
it is air or water; they are transparent because each of them has contained
in it a certain substance which is the same in both and is also found in
the eternal body which constitutes the uppermost shell of the physical
Cosmos. Of this substance light is the activity-the activity of what is
transparent so far forth as it has in it the determinate power of becoming
transparent; where this power is present, there is also the potentiality
of the contrary, viz. darkness. Light is as it were the proper colour of
what is transparent, and exists whenever the potentially transparent is
excited to actuality by the influence of fire or something resembling 'the
uppermost body'; for fire too contains something which is one and the same
with the substance in question.
We have now explained what the transparent is and what light is;
light is neither fire nor any kind whatsoever of body nor an efflux from
any kind of body (if it were, it would again itself be a kind of body)-it
is the presence of fire or something resembling fire in what is transparent.
It is certainly not a body, for two bodies cannot be present in the same
place. The opposite of light is darkness; darkness is the absence from
what is transparent of the corresponding positive state above characterized;
clearly therefore, light is just the presence of that.
Empedocles (and with him all others who used the same forms of
expression) was wrong in speaking of light as 'travelling' or being at
a given moment between the earth and its envelope, its movement being unobservable
by us; that view is contrary both to the clear evidence of argument and
to the observed facts; if the distance traversed were short, the movement
might have been unobservable, but where the distance is from extreme East
to extreme West, the draught upon our powers of belief is too
great.
What is capable of taking on colour is what in itself is colourless,
as what can take on sound is what is soundless; what is colourless includes
(a) what is transparent and (b) what is invisible or scarcely visible,
i.e. what is 'dark'. The latter (b) is the same as what is transparent,
when it is potentially, not of course when it is actually transparent;
it is the same substance which is now darkness, now
light.
Not everything that is visible depends upon light for its visibility.
This is only true of the 'proper' colour of things. Some objects of sight
which in light are invisible, in darkness stimulate the sense; that is,
things that appear fiery or shining. This class of objects has no simple
common name, but instances of it are fungi, flesh, heads, scales, and eyes
of fish. In none of these is what is seen their own proper' colour. Why
we see these at all is another question. At present what is obvious is
that what is seen in light is always colour. That is why without the help
of light colour remains invisible. Its being colour at all means precisely
its having in it the power to set in movement what is already actually
transparent, and, as we have seen, the actuality of what is transparent
is just light.
The following experiment makes the necessity of a medium clear.
If what has colour is placed in immediate contact with the eye, it cannot
be seen. Colour sets in movement not the sense organ but what is transparent,
e.g. the air, and that, extending continuously from the object to the organ,
sets the latter in movement. Democritus misrepresents the facts when he
expresses the opinion that if the interspace were empty one could distinctly
see an ant on the vault of the sky; that is an impossibility. Seeing is
due to an affection or change of what has the perceptive faculty, and it
cannot be affected by the seen colour itself; it remains that it must be
affected by what comes between. Hence it is indispensable that there be
something in between-if there were nothing, so far from seeing with greater
distinctness, we should see nothing at all.
We have now explained the cause why colour cannot be seen otherwise
than in light. Fire on the other hand is seen both in darkness and in light;
this double possibility follows necessarily from our theory, for it is
just fire that makes what is potentially transparent actually
transparent.
The same account holds also of sound and smell; if the object of
either of these senses is in immediate contact with the organ no sensation
is produced. In both cases the object sets in movement only what lies between,
and this in turn sets the organ in movement: if what sounds or smells is
brought into immediate contact with the organ, no sensation will be produced.
The same, in spite of all appearances, applies also to touch and taste;
why there is this apparent difference will be clear later. What comes between
in the case of sounds is air; the corresponding medium in the case of smell
has no name. But, corresponding to what is transparent in the case of colour,
there is a quality found both in air and water, which serves as a medium
for what has smell-I say 'in water' because animals that live in water
as well as those that live on land seem to possess the sense of smell,
and 'in air' because man and all other land animals that breathe, perceive
smells only when they breathe air in. The explanation of this too will
be given later.
Part 8
Now let us, to begin with, make certain distinctions about sound
and hearing.
Sound may mean either of two things (a) actual, and (b) potential,
sound. There are certain things which, as we say, 'have no sound', e.g.
sponges or wool, others which have, e.g. bronze and in general all things
which are smooth and solid-the latter are said to have a sound because
they can make a sound, i.e. can generate actual sound between themselves
and the organ of hearing.
Actual sound requires for its occurrence (i, ii) two such bodies
and (iii) a space between them; for it is generated by an impact. Hence
it is impossible for one body only to generate a sound-there must be a
body impinging and a body impinged upon; what sounds does so by striking
against something else, and this is impossible without a movement from
place to place.
As we have said, not all bodies can by impact on one another produce
sound; impact on wool makes no sound, while the impact on bronze or any
body which is smooth and hollow does. Bronze gives out a sound when struck
because it is smooth; bodies which are hollow owing to reflection repeat
the original impact over and over again, the body originally set in movement
being unable to escape from the concavity.
Further, we must remark that sound is heard both in air and in
water, though less distinctly in the latter. Yet neither air nor water
is the principal cause of sound. What is required for the production of
sound is an impact of two solids against one another and against the air.
The latter condition is satisfied when the air impinged upon does not retreat
before the blow, i.e. is not dissipated by it.
That is why it must be struck with a sudden sharp blow, if it is
to sound-the movement of the whip must outrun the dispersion of the air,
just as one might get in a stroke at a heap or whirl of sand as it was
traveling rapidly past.
An echo occurs, when, a mass of air having been unified, bounded,
and prevented from dissipation by the containing walls of a vessel, the
air originally struck by the impinging body and set in movement by it rebounds
from this mass of air like a ball from a wall. It is probable that in all
generation of sound echo takes place, though it is frequently only indistinctly
heard. What happens here must be analogous to what happens in the case
of light; light is always reflected-otherwise it would not be diffused
and outside what was directly illuminated by the sun there would be blank
darkness; but this reflected light is not always strong enough, as it is
when it is reflected from water, bronze, and other smooth bodies, to cast
a shadow, which is the distinguishing mark by which we recognize
light.
It is rightly said that an empty space plays the chief part in
the production of hearing, for what people mean by 'the vacuum' is the
air, which is what causes hearing, when that air is set in movement as
one continuous mass; but owing to its friability it emits no sound, being
dissipated by impinging upon any surface which is not smooth. When the
surface on which it impinges is quite smooth, what is produced by the original
impact is a united mass, a result due to the smoothness of the surface
with which the air is in contact at the other end.
What has the power of producing sound is what has the power of
setting in movement a single mass of air which is continuous from the impinging
body up to the organ of hearing. The organ of hearing is physically united
with air, and because it is in air, the air inside is moved concurrently
with the air outside. Hence animals do not hear with all parts of their
bodies, nor do all parts admit of the entrance of air; for even the part
which can be moved and can sound has not air everywhere in it. Air in itself
is, owing to its friability, quite soundless; only when its dissipation
is prevented is its movement sound. The air in the ear is built into a
chamber just to prevent this dissipating movement, in order that the animal
may accurately apprehend all varieties of the movements of the air outside.
That is why we hear also in water, viz. because the water cannot get into
the air chamber or even, owing to the spirals, into the outer ear. If this
does happen, hearing ceases, as it also does if the tympanic membrane is
damaged, just as sight ceases if the membrane covering the pupil is damaged.
It is also a test of deafness whether the ear does or does not reverberate
like a horn; the air inside the ear has always a movement of its own, but
the sound we hear is always the sounding of something else, not of the
organ itself. That is why we say that we hear with what is empty and echoes,
viz. because what we hear with is a chamber which contains a bounded mass
of air.
Which is it that 'sounds', the striking body or the struck? Is
not the answer 'it is both, but each in a different way'? Sound is a movement
of what can rebound from a smooth surface when struck against it. As we
have explained' not everything sounds when it strikes or is struck, e.g.
if one needle is struck against another, neither emits any sound. In order,
therefore, that sound may be generated, what is struck must be smooth,
to enable the air to rebound and be shaken off from it in one
piece.
The distinctions between different sounding bodies show themselves
only in actual sound; as without the help of light colours remain invisible,
so without the help of actual sound the distinctions between acute and
grave sounds remain inaudible. Acute and grave are here metaphors, transferred
from their proper sphere, viz. that of touch, where they mean respectively
(a) what moves the sense much in a short time, (b) what moves the sense
little in a long time. Not that what is sharp really moves fast, and what
is grave, slowly, but that the difference in the qualities of the one and
the other movement is due to their respective speeds. There seems to be
a sort of parallelism between what is acute or grave to hearing and what
is sharp or blunt to touch; what is sharp as it were stabs, while what
is blunt pushes, the one producing its effect in a short, the other in
a long time, so that the one is quick, the other slow.
Let the foregoing suffice as an analysis of sound. Voice is a kind
of sound characteristic of what has soul in it; nothing that is without
soul utters voice, it being only by a metaphor that we speak of the voice
of the flute or the lyre or generally of what (being without soul) possesses
the power of producing a succession of notes which differ in length and
pitch and timbre. The metaphor is based on the fact that all these differences
are found also in voice. Many animals are voiceless, e.g. all non-sanuineous
animals and among sanguineous animals fish. This is just what we should
expect, since voice is a certain movement of air. The fish, like those
in the Achelous, which are said to have voice, really make the sounds with
their gills or some similar organ. Voice is the sound made by an animal,
and that with a special organ. As we saw, everything that makes a sound
does so by the impact of something (a) against something else, (b) across
a space, (c) filled with air; hence it is only to be expected that no animals
utter voice except those which take in air. Once air is inbreathed, Nature
uses it for two different purposes, as the tongue is used both for tasting
and for articulating; in that case of the two functions tasting is necessary
for the animal's existence (hence it is found more widely distributed),
while articulate speech is a luxury subserving its possessor's well-being;
similarly in the former case Nature employs the breath both as an indispensable
means to the regulation of the inner temperature of the living body and
also as the matter of articulate voice, in the interests of its possessor's
well-being. Why its former use is indispensable must be discussed
elsewhere.
The organ of respiration is the windpipe, and the organ to which
this is related as means to end is the lungs. The latter is the part of
the body by which the temperature of land animals is raised above that
of all others. But what primarily requires the air drawn in by respiration
is not only this but the region surrounding the heart. That is why when
animals breathe the air must penetrate inwards.
Voice then is the impact of the inbreathed air against the 'windpipe',
and the agent that produces the impact is the soul resident in these parts
of the body. Not every sound, as we said, made by an animal is voice (even
with the tongue we may merely make a sound which is not voice, or without
the tongue as in coughing); what produces the impact must have soul in
it and must be accompanied by an act of imagination, for voice is a sound
with a meaning, and is not merely the result of any impact of the breath
as in coughing; in voice the breath in the windpipe is used as an instrument
to knock with against the walls of the windpipe. This is confirmed by our
inability to speak when we are breathing either out or in-we can only do
so by holding our breath; we make the movements with the breath so checked.
It is clear also why fish are voiceless; they have no windpipe. And they
have no windpipe because they do not breathe or take in air. Why they do
not is a question belonging to another inquiry.
Part 9
Smell and its object are much less easy to determine than what
we have hitherto discussed; the distinguishing characteristic of the object
of smell is less obvious than those of sound or colour. The ground of this
is that our power of smell is less discriminating and in general inferior
to that of many species of animals; men have a poor sense of smell and
our apprehension of its proper objects is inseparably bound up with and
so confused by pleasure and pain, which shows that in us the organ is inaccurate.
It is probable that there is a parallel failure in the perception of colour
by animals that have hard eyes: probably they discriminate differences
of colour only by the presence or absence of what excites fear, and that
it is thus that human beings distinguish smells. It seems that there is
an analogy between smell and taste, and that the species of tastes run
parallel to those of smells-the only difference being that our sense of
taste is more discriminating than our sense of smell, because the former
is a modification of touch, which reaches in man the maximum of discriminative
accuracy. While in respect of all the other senses we fall below many species
of animals, in respect of touch we far excel all other species in exactness
of discrimination. That is why man is the most intelligent of all animals.
This is confirmed by the fact that it is to differences in the organ of
touch and to nothing else that the differences between man and man in respect
of natural endowment are due; men whose flesh is hard are ill-endowed by
nature, men whose flesh is soft, wellendowed.
As flavours may be divided into (a) sweet, (b) bitter, so with
smells. In some things the flavour and the smell have the same quality,
i.e. both are sweet or both bitter, in others they diverge. Similarly a
smell, like a flavour, may be pungent, astringent, acid, or succulent.
But, as we said, because smells are much less easy to discriminate than
flavours, the names of these varieties are applied to smells only metaphorically;
for example 'sweet' is extended from the taste to the smell of saffron
or honey, 'pungent' to that of thyme, and so on.
In the same sense in which hearing has for its object both the
audible and the inaudible, sight both the visible and the invisible, smell
has for its object both the odorous and the inodorous. 'Inodorous' may
be either (a) what has no smell at all, or (b) what has a small or feeble
smell. The same ambiguity lurks in the word 'tasteless'.
Smelling, like the operation of the senses previously examined,
takes place through a medium, i.e. through air or water-I add water, because
water-animals too (both sanguineous and non-sanguineous) seem to smell
just as much as land-animals; at any rate some of them make directly for
their food from a distance if it has any scent. That is why the following
facts constitute a problem for us. All animals smell in the same way, but
man smells only when he inhales; if he exhales or holds his breath, he
ceases to smell, no difference being made whether the odorous object is
distant or near, or even placed inside the nose and actually on the wall
of the nostril; it is a disability common to all the senses not to perceive
what is in immediate contact with the organ of sense, but our failure to
apprehend what is odorous without the help of inhalation is peculiar (the
fact is obvious on making the experiment). Now since bloodless animals
do not breathe, they must, it might be argued, have some novel sense not
reckoned among the usual five. Our reply must be that this is impossible,
since it is scent that is perceived; a sense that apprehends what is odorous
and what has a good or bad odour cannot be anything but smell. Further,
they are observed to be deleteriously effected by the same strong odours
as man is, e.g. bitumen, sulphur, and the like. These animals must be able
to smell without being able to breathe. The probable explanation is that
in man the organ of smell has a certain superiority over that in all other
animals just as his eyes have over those of hard-eyed animals. Man's eyes
have in the eyelids a kind of shelter or envelope, which must be shifted
or drawn back in order that we may see, while hardeyed animals have nothing
of the kind, but at once see whatever presents itself in the transparent
medium. Similarly in certain species of animals the organ of smell is like
the eye of hard-eyed animals, uncurtained, while in others which take in
air it probably has a curtain over it, which is drawn back in inhalation,
owing to the dilating of the veins or pores. That explains also why such
animals cannot smell under water; to smell they must first inhale, and
that they cannot do under water.
Smells come from what is dry as flavours from what is moist. Consequently
the organ of smell is potentially dry.
Part 10
What can be tasted is always something that can be touched, and
just for that reason it cannot be perceived through an interposed foreign
body, for touch means the absence of any intervening body. Further, the
flavoured and tasteable body is suspended in a liquid matter, and this
is tangible. Hence, if we lived in water, we should perceive a sweet object
introduced into the water, but the water would not be the medium through
which we perceived; our perception would be due to the solution of the
sweet substance in what we imbibed, just as if it were mixed with some
drink. There is no parallel here to the perception of colour, which is
due neither to any blending of anything with anything, nor to any efflux
of anything from anything. In the case of taste, there is nothing corresponding
to the medium in the case of the senses previously discussed; but as the
object of sight is colour, so the object of taste is flavour. But nothing
excites a perception of flavour without the help of liquid; what acts upon
the sense of taste must be either actually or potentially liquid like what
is saline; it must be both (a) itself easily dissolved, and (b) capable
of dissolving along with itself the tongue. Taste apprehends both (a) what
has taste and (b) what has no taste, if we mean by (b) what has only a
slight or feeble flavour or what tends to destroy the sense of taste. In
this it is exactly parallel to sight, which apprehends both what is visible
and what is invisible (for darkness is invisible and yet is discriminated
by sight; so is, in a different way, what is over brilliant), and to hearing,
which apprehends both sound and silence, of which the one is audible and
the other inaudible, and also over-loud sound. This corresponds in the
case of hearing to over-bright light in the case of sight. As a faint sound
is 'inaudible', so in a sense is a loud or violent sound. The word 'invisible'
and similar privative terms cover not only (a) what is simply without some
power, but also (b) what is adapted by nature to have it but has not it
or has it only in a very low degree, as when we say that a species of swallow
is 'footless' or that a variety of fruit is 'stoneless'. So too taste has
as its object both what can be tasted and the tasteless-the latter in the
sense of what has little flavour or a bad flavour or one destructive of
taste. The difference between what is tasteless and what is not seems to
rest ultimately on that between what is drinkable and what is undrinkable
both are tasteable, but the latter is bad and tends to destroy taste, while
the former is the normal stimulus of taste. What is drinkable is the common
object of both touch and taste.
Since what can be tasted is liquid, the organ for its perception
cannot be either (a) actually liquid or (b) incapable of becoming liquid.
Tasting means a being affected by what can be tasted as such; hence the
organ of taste must be liquefied, and so to start with must be non-liquid
but capable of liquefaction without loss of its distinctive nature. This
is confirmed by the fact that the tongue cannot taste either when it is
too dry or when it is too moist; in the latter case what occurs is due
to a contact with the pre-existent moisture in the tongue itself, when
after a foretaste of some strong flavour we try to taste another flavour;
it is in this way that sick persons find everything they taste bitter,
viz. because, when they taste, their tongues are overflowing with bitter
moisture.
The species of flavour are, as in the case of colour, (a) simple,
i.e. the two contraries, the sweet and the bitter, (b) secondary, viz.
(i) on the side of the sweet, the succulent, (ii) on the side of the bitter,
the saline, (iii) between these come the pungent, the harsh, the astringent,
and the acid; these pretty well exhaust the varieties of flavour. It follows
that what has the power of tasting is what is potentially of that kind,
and that what is tasteable is what has the power of making it actually
what it itself already is.
Part 11
Whatever can be said of what is tangible, can be said of touch,
and vice versa; if touch is not a single sense but a group of senses, there
must be several kinds of what is tangible. It is a problem whether touch
is a single sense or a group of senses. It is also a problem, what is the
organ of touch; is it or is it not the flesh (including what in certain
animals is homologous with flesh)? On the second view, flesh is 'the medium'
of touch, the real organ being situated farther inward. The problem arises
because the field of each sense is according to the accepted view determined
as the range between a single pair of contraries, white and black for sight,
acute and grave for hearing, bitter and sweet for taste; but in the field
of what is tangible we find several such pairs, hot cold, dry moist, hard
soft, &c. This problem finds a partial solution, when it is recalled that
in the case of the other senses more than one pair of contraries are to
be met with, e.g. in sound not only acute and grave but loud and soft,
smooth and rough, &c.; there are similar contrasts in the field of colour.
Nevertheless we are unable clearly to detect in the case of touch what
the single subject is which underlies the contrasted qualities and corresponds
to sound in the case of hearing.
To the question whether the organ of touch lies inward or not (i.e.
whether we need look any farther than the flesh), no indication in favour
of the second answer can be drawn from the fact that if the object comes
into contact with the flesh it is at once perceived. For even under present
conditions if the experiment is made of making a web and stretching it
tight over the flesh, as soon as this web is touched the sensation is reported
in the same manner as before, yet it is clear that the or is gan is not
in this membrane. If the membrane could be grown on to the flesh, the report
would travel still quicker. The flesh plays in touch very much the same
part as would be played in the other senses by an air-envelope growing
round our body; had we such an envelope attached to us we should have supposed
that it was by a single organ that we perceived sounds, colours, and smells,
and we should have taken sight, hearing, and smell to be a single sense.
But as it is, because that through which the different movements are transmitted
is not naturally attached to our bodies, the difference of the various
sense-organs is too plain to miss. But in the case of touch the obscurity
remains.
There must be such a naturally attached 'medium' as flesh, for
no living body could be constructed of air or water; it must be something
solid. Consequently it must be composed of earth along with these, which
is just what flesh and its analogue in animals which have no true flesh
tend to be. Hence of necessity the medium through which are transmitted
the manifoldly contrasted tactual qualities must be a body naturally attached
to the organism. That they are manifold is clear when we consider touching
with the tongue; we apprehend at the tongue all tangible qualities as well
as flavour. Suppose all the rest of our flesh was, like the tongue, sensitive
to flavour, we should have identified the sense of taste and the sense
of touch; what saves us from this identification is the fact that touch
and taste are not always found together in the same part of the body. The
following problem might be raised. Let us assume that every body has depth,
i.e. has three dimensions, and that if two bodies have a third body between
them they cannot be in contact with one another; let us remember that what
is liquid is a body and must be or contain water, and that if two bodies
touch one another under water, their touching surfaces cannot be dry, but
must have water between, viz. the water which wets their bounding surfaces;
from all this it follows that in water two bodies cannot be in contact
with one another. The same holds of two bodies in air-air being to bodies
in air precisely what water is to bodies in water-but the facts are not
so evident to our observation, because we live in air, just as animals
that live in water would not notice that the things which touch one another
in water have wet surfaces. The problem, then, is: does the perception
of all objects of sense take place in the same way, or does it not, e.g.
taste and touch requiring contact (as they are commonly thought to do),
while all other senses perceive over a distance? The distinction is unsound;
we perceive what is hard or soft, as well as the objects of hearing, sight,
and smell, through a 'medium', only that the latter are perceived over
a greater distance than the former; that is why the facts escape our notice.
For we do perceive everything through a medium; but in these cases the
fact escapes us. Yet, to repeat what we said before, if the medium for
touch were a membrane separating us from the object without our observing
its existence, we should be relatively to it in the same condition as we
are now to air or water in which we are immersed; in their case we fancy
we can touch objects, nothing coming in between us and them. But there
remains this difference between what can be touched and what can be seen
or can sound; in the latter two cases we perceive because the medium produces
a certain effect upon us, whereas in the perception of objects of touch
we are affected not by but along with the medium; it is as if a man were
struck through his shield, where the shock is not first given to the shield
and passed on to the man, but the concussion of both is
simultaneous.
In general, flesh and the tongue are related to the real organs
of touch and taste, as air and water are to those of sight, hearing, and
smell. Hence in neither the one case nor the other can there be any perception
of an object if it is placed immediately upon the organ, e.g. if a white
object is placed on the surface of the eye. This again shows that what
has the power of perceiving the tangible is seated inside. Only so would
there be a complete analogy with all the other senses. In their case if
you place the object on the organ it is not perceived, here if you place
it on the flesh it is perceived; therefore flesh is not the organ but the
medium of touch.
What can be touched are distinctive qualities of body as body;
by such differences I mean those which characterize the elements, viz,
hot cold, dry moist, of which we have spoken earlier in our treatise on
the elements. The organ for the perception of these is that of touch-that
part of the body in which primarily the sense of touch resides. This is
that part which is potentially such as its object is actually: for all
sense-perception is a process of being so affected; so that that which
makes something such as it itself actually is makes the other such because
the other is already potentially such. That is why when an object of touch
is equally hot and cold or hard and soft we cannot perceive; what we perceive
must have a degree of the sensible quality lying beyond the neutral point.
This implies that the sense itself is a 'mean' between any two opposite
qualities which determine the field of that sense. It is to this that it
owes its power of discerning the objects in that field. What is 'in the
middle' is fitted to discern; relatively to either extreme it can put itself
in the place of the other. As what is to perceive both white and black
must, to begin with, be actually neither but potentially either (and so
with all the other sense-organs), so the organ of touch must be neither
hot nor cold.
Further, as in a sense sight had for its object both what was visible
and what was invisible (and there was a parallel truth about all the other
senses discussed), so touch has for its object both what is tangible and
what is intangible. Here by 'intangible' is meant (a) what like air possesses
some quality of tangible things in a very slight degree and (b) what possesses
it in an excessive degree, as destructive things do.
We have now given an outline account of each of the several
senses.
Part 12
The following results applying to any and every sense may now be
formulated.
(A) By a 'sense' is meant what has the power of receiving into
itself the sensible forms of things without the matter. This must be conceived
of as taking place in the way in which a piece of wax takes on the impress
of a signet-ring without the iron or gold; we say that what produces the
impression is a signet of bronze or gold, but its particular metallic constitution
makes no difference: in a similar way the sense is affected by what is
coloured or flavoured or sounding, but it is indifferent what in each case
the substance is; what alone matters is what quality it has, i.e. in what
ratio its constituents are combined.
(B) By 'an organ of sense' is meant that in which ultimately such
a power is seated.
The sense and its organ are the same in fact, but their essence
is not the same. What perceives is, of course, a spatial magnitude, but
we must not admit that either the having the power to perceive or the sense
itself is a magnitude; what they are is a certain ratio or power in a magnitude.
This enables us to explain why objects of sense which possess one of two
opposite sensible qualities in a degree largely in excess of the other
opposite destroy the organs of sense; if the movement set up by an object
is too strong for the organ, the equipoise of contrary qualities in the
organ, which just is its sensory power, is disturbed; it is precisely as
concord and tone are destroyed by too violently twanging the strings of
a lyre. This explains also why plants cannot perceive. in spite of their
having a portion of soul in them and obviously being affected by tangible
objects themselves; for undoubtedly their temperature can be lowered or
raised. The explanation is that they have no mean of contrary qualities,
and so no principle in them capable of taking on the forms of sensible
objects without their matter; in the case of plants the affection is an
affection by form-and-matter together. The problem might be raised: Can
what cannot smell be said to be affected by smells or what cannot see by
colours, and so on? It might be said that a smell is just what can be smelt,
and if it produces any effect it can only be so as to make something smell
it, and it might be argued that what cannot smell cannot be affected by
smells and further that what can smell can be affected by it only in so
far as it has in it the power to smell (similarly with the proper objects
of all the other senses). Indeed that this is so is made quite evident
as follows. Light or darkness, sounds and smells leave bodies quite unaffected;
what does affect bodies is not these but the bodies which are their vehicles,
e.g. what splits the trunk of a tree is not the sound of the thunder but
the air which accompanies thunder. Yes, but, it may be objected, bodies
are affected by what is tangible and by flavours. If not, by what are things
that are without soul affected, i.e. altered in quality? Must we not, then,
admit that the objects of the other senses also may affect them? Is not
the true account this, that all bodies are capable of being affected by
smells and sounds, but that some on being acted upon, having no boundaries
of their own, disintegrate, as in the instance of air, which does become
odorous, showing that some effect is produced on it by what is odorous?
But smelling is more than such an affection by what is odorous-what more?
Is not the answer that, while the air owing to the momentary duration of
the action upon it of what is odorous does itself become perceptible to
the sense of smell, smelling is an observing of the result
produced?
On the Soul
By Aristotle
Book III
Part 1
That there is no sixth sense in addition to the five enumerated-sight,
hearing, smell, taste, touch-may be established by the following
considerations:
If we have actually sensation of everything of which touch can
give us sensation (for all the qualities of the tangible qua tangible are
perceived by us through touch); and if absence of a sense necessarily involves
absence of a sense-organ; and if (1) all objects that we perceive by immediate
contact with them are perceptible by touch, which sense we actually possess,
and (2) all objects that we perceive through media, i.e. without immediate
contact, are perceptible by or through the simple elements, e.g. air and
water (and this is so arranged that (a) if more than one kind of sensible
object is perceivable through a single medium, the possessor of a sense-organ
homogeneous with that medium has the power of perceiving both kinds of
objects; for example, if the sense-organ is made of air, and air is a medium
both for sound and for colour; and that (b) if more than one medium can
transmit the same kind of sensible objects, as e.g. water as well as air
can transmit colour, both being transparent, then the possessor of either
alone will be able to perceive the kind of objects transmissible through
both); and if of the simple elements two only, air and water, go to form
sense-organs (for the pupil is made of water, the organ of hearing is made
of air, and the organ of smell of one or other of these two, while fire
is found either in none or in all-warmth being an essential condition of
all sensibility-and earth either in none or, if anywhere, specially mingled
with the components of the organ of touch; wherefore it would remain that
there can be no sense-organ formed of anything except water and air); and
if these sense-organs are actually found in certain animals;-then all the
possible senses are possessed by those animals that are not imperfect or
mutilated (for even the mole is observed to have eyes beneath its skin);
so that, if there is no fifth element and no property other than those
which belong to the four elements of our world, no sense can be wanting
to such animals.
Further, there cannot be a special sense-organ for the common sensibles
either, i.e. the objects which we perceive incidentally through this or
that special sense, e.g. movement, rest, figure, magnitude, number, unity;
for all these we perceive by movement, e.g. magnitude by movement, and
therefore also figure (for figure is a species of magnitude), what is at
rest by the absence of movement: number is perceived by the negation of
continuity, and by the special sensibles; for each sense perceives one
class of sensible objects. So that it is clearly impossible that there
should be a special sense for any one of the common sensibles, e.g. movement;
for, if that were so, our perception of it would be exactly parallel to
our present perception of what is sweet by vision. That is so because we
have a sense for each of the two qualities, in virtue of which when they
happen to meet in one sensible object we are aware of both contemporaneously.
If it were not like this our perception of the common qualities would always
be incidental, i.e. as is the perception of Cleon's son, where we perceive
him not as Cleon's son but as white, and the white thing which we really
perceive happens to be Cleon's son.
But in the case of the common sensibles there is already in us
a general sensibility which enables us to perceive them directly; there
is therefore no special sense required for their perception: if there were,
our perception of them would have been exactly like what has been above
described.
The senses perceive each other's special objects incidentally;
not because the percipient sense is this or that special sense, but because
all form a unity: this incidental perception takes place whenever sense
is directed at one and the same moment to two disparate qualities in one
and the same object, e.g. to the bitterness and the yellowness of bile,
the assertion of the identity of both cannot be the act of either of the
senses; hence the illusion of sense, e.g. the belief that if a thing is
yellow it is bile.
It might be asked why we have more senses than one. Is it to prevent
a failure to apprehend the common sensibles, e.g. movement, magnitude,
and number, which go along with the special sensibles? Had we no sense
but sight, and that sense no object but white, they would have tended to
escape our notice and everything would have merged for us into an indistinguishable
identity because of the concomitance of colour and magnitude. As it is,
the fact that the common sensibles are given in the objects of more than
one sense reveals their distinction from each and all of the special
sensibles.
Part 2
Since it is through sense that we are aware that we are seeing
or hearing, it must be either by sight that we are aware of seeing, or
by some sense other than sight. But the sense that gives us this new sensation
must perceive both sight and its object, viz. colour: so that either (1)
there will be two senses both percipient of the same sensible object, or
(2) the sense must be percipient of itself. Further, even if the sense
which perceives sight were different from sight, we must either fall into
an infinite regress, or we must somewhere assume a sense which is aware
of itself. If so, we ought to do this in the first case.
This presents a difficulty: if to perceive by sight is just to
see, and what is seen is colour (or the coloured), then if we are to see
that which sees, that which sees originally must be coloured. It is clear
therefore that 'to perceive by sight' has more than one meaning; for even
when we are not seeing, it is by sight that we discriminate darkness from
light, though not in the same way as we distinguish one colour from another.
Further, in a sense even that which sees is coloured; for in each case
the sense-organ is capable of receiving the sensible object without its
matter. That is why even when the sensible objects are gone the sensings
and imaginings continue to exist in the sense-organs.
The activity of the sensible object and that of the percipient
sense is one and the same activity, and yet the distinction between their
being remains. Take as illustration actual sound and actual hearing: a
man may have hearing and yet not be hearing, and that which has a sound
is not always sounding. But when that which can hear is actively hearing
and which can sound is sounding, then the actual hearing and the actual
sound are merged in one (these one might call respectively hearkening and
sounding).
If it is true that the movement, both the acting and the being
acted upon, is to be found in that which is acted upon, both the sound
and the hearing so far as it is actual must be found in that which has
the faculty of hearing; for it is in the passive factor that the actuality
of the active or motive factor is realized; that is why that which causes
movement may be at rest. Now the actuality of that which can sound is just
sound or sounding, and the actuality of that which can hear is hearing
or hearkening; 'sound' and 'hearing' are both ambiguous. The same account
applies to the other senses and their objects. For as the-acting-and-being-acted-upon
is to be found in the passive, not in the active factor, so also the actuality
of the sensible object and that of the sensitive subject are both realized
in the latter. But while in some cases each aspect of the total actuality
has a distinct name, e.g. sounding and hearkening, in some one or other
is nameless, e.g. the actuality of sight is called seeing, but the actuality
of colour has no name: the actuality of the faculty of taste is called
tasting, but the actuality of flavour has no name. Since the actualities
of the sensible object and of the sensitive faculty are one actuality in
spite of the difference between their modes of being, actual hearing and
actual sounding appear and disappear from existence at one and the same
moment, and so actual savour and actual tasting, &c., while as potentialities
one of them may exist without the other. The earlier students of nature
were mistaken in their view that without sight there was no white or black,
without taste no savour. This statement of theirs is partly true, partly
false: 'sense' and 'the sensible object' are ambiguous terms, i.e. may
denote either potentialities or actualities: the statement is true of the
latter, false of the former. This ambiguity they wholly failed to
notice.
If voice always implies a concord, and if the voice and the hearing
of it are in one sense one and the same, and if concord always implies
a ratio, hearing as well as what is heard must be a ratio. That is why
the excess of either the sharp or the flat destroys the hearing. (So also
in the case of savours excess destroys the sense of taste, and in the case
of colours excessive brightness or darkness destroys the sight, and in
the case of smell excess of strength whether in the direction of sweetness
or bitterness is destructive.) This shows that the sense is a
ratio.
That is also why the objects of sense are (1) pleasant when the
sensible extremes such as acid or sweet or salt being pure and unmixed
are brought into the proper ratio; then they are pleasant: and in general
what is blended is more pleasant than the sharp or the flat alone; or,
to touch, that which is capable of being either warmed or chilled: the
sense and the ratio are identical: while (2) in excess the sensible extremes
are painful or destructive.
Each sense then is relative to its particular group of sensible
qualities: it is found in a sense-organ as such and discriminates the differences
which exist within that group; e.g. sight discriminates white and black,
taste sweet and bitter, and so in all cases. Since we also discriminate
white from sweet, and indeed each sensible quality from every other, with
what do we perceive that they are different? It must be by sense; for what
is before us is sensible objects. (Hence it is also obvious that the flesh
cannot be the ultimate sense-organ: if it were, the discriminating power
could not do its work without immediate contact with the
object.)
Therefore (1) discrimination between white and sweet cannot be
effected by two agencies which remain separate; both the qualities discriminated
must be present to something that is one and single. On any other supposition
even if I perceived sweet and you perceived white, the difference between
them would be apparent. What says that two things are different must be
one; for sweet is different from white. Therefore what asserts this difference
must be self-identical, and as what asserts, so also what thinks or perceives.
That it is not possible by means of two agencies which remain separate
to discriminate two objects which are separate, is therefore obvious; and
that (it is not possible to do this in separate movements of time may be
seen' if we look at it as follows. For as what asserts the difference between
the good and the bad is one and the same, so also the time at which it
asserts the one to be different and the other to be different is not accidental
to the assertion (as it is for instance when I now assert a difference
but do not assert that there is now a difference); it asserts thus-both
now and that the objects are different now; the objects therefore must
be present at one and the same moment. Both the discriminating power and
the time of its exercise must be one and undivided.
But, it may be objected, it is impossible that what is self-identical
should be moved at me and the same time with contrary movements in so far
as it is undivided, and in an undivided moment of time. For if what is
sweet be the quality perceived, it moves the sense or thought in this determinate
way, while what is bitter moves it in a contrary way, and what is white
in a different way. Is it the case then that what discriminates, though
both numerically one and indivisible, is at the same time divided in its
being? In one sense, it is what is divided that perceives two separate
objects at once, but in another sense it does so qua undivided; for it
is divisible in its being but spatially and numerically undivided. is not
this impossible? For while it is true that what is self-identical and undivided
may be both contraries at once potentially, it cannot be self-identical
in its being-it must lose its unity by being put into activity. It is not
possible to be at once white and black, and therefore it must also be impossible
for a thing to be affected at one and the same moment by the forms of both,
assuming it to be the case that sensation and thinking are properly so
described.
The answer is that just as what is called a 'point' is, as being
at once one and two, properly said to be divisible, so here, that which
discriminates is qua undivided one, and active in a single moment of time,
while so far forth as it is divisible it twice over uses the same dot at
one and the same time. So far forth then as it takes the limit as two'
it discriminates two separate objects with what in a sense is divided:
while so far as it takes it as one, it does so with what is one and occupies
in its activity a single moment of time.
About the principle in virtue of which we say that animals are
percipient, let this discussion suffice.
Part 3
There are two distinctive peculiarities by reference to which we
characterize the soul (1) local movement and (2) thinking, discriminating,
and perceiving. Thinking both speculative and practical is regarded as
akin to a form of perceiving; for in the one as well as the other the soul
discriminates and is cognizant of something which is. Indeed the ancients
go so far as to identify thinking and perceiving; e.g. Empedocles says
'For 'tis in respect of what is present that man's wit is increased', and
again 'Whence it befalls them from time to time to think diverse thoughts',
and Homer's phrase 'For suchlike is man's mind' means the same. They all
look upon thinking as a bodily process like perceiving, and hold that like
is known as well as perceived by like, as I explained at the beginning
of our discussion. Yet they ought at the same time to have accounted for
error also; for it is more intimately connected with animal existence and
the soul continues longer in the state of error than in that of truth.
They cannot escape the dilemma: either (1) whatever seems is true (and
there are some who accept this) or (2) error is contact with the unlike;
for that is the opposite of the knowing of like by like.
But it is a received principle that error as well as knowledge
in respect to contraries is one and the same.
That perceiving and practical thinking are not identical is therefore
obvious; for the former is universal in the animal world, the latter is
found in only a small division of it. Further, speculative thinking is
also distinct from perceiving-I mean that in which we find rightness and
wrongness-rightness in prudence, knowledge, true opinion, wrongness in
their opposites; for perception of the special objects of sense is always
free from error, and is found in all animals, while it is possible to think
falsely as well as truly, and thought is found only where there is discourse
of reason as well as sensibility. For imagination is different from either
perceiving or discursive thinking, though it is not found without sensation,
or judgement without it. That this activity is not the same kind of thinking
as judgement is obvious. For imagining lies within our own power whenever
we wish (e.g. we can call up a picture, as in the practice of mnemonics
by the use of mental images), but in forming opinions we are not free:
we cannot escape the alternative of falsehood or truth. Further, when we
think something to be fearful or threatening, emotion is immediately produced,
and so too with what is encouraging; but when we merely imagine we remain
as unaffected as persons who are looking at a painting of some dreadful
or encouraging scene. Again within the field of judgement itself we find
varieties, knowledge, opinion, prudence, and their opposites; of the differences
between these I must speak elsewhere.
Thinking is different from perceiving and is held to be in part
imagination, in part judgement: we must therefore first mark off the sphere
of imagination and then speak of judgement. If then imagination is that
in virtue of which an image arises for us, excluding metaphorical uses
of the term, is it a single faculty or disposition relative to images,
in virtue of which we discriminate and are either in error or not? The
faculties in virtue of which we do this are sense, opinion, science,
intelligence.
That imagination is not sense is clear from the following considerations:
Sense is either a faculty or an activity, e.g. sight or seeing: imagination
takes place in the absence of both, as e.g. in dreams. (Again, sense is
always present, imagination not. If actual imagination and actual sensation
were the same, imagination would be found in all the brutes: this is held
not to be the case; e.g. it is not found in ants or bees or grubs. (Again,
sensations are always true, imaginations are for the most part false. (Once
more, even in ordinary speech, we do not, when sense functions precisely
with regard to its object, say that we imagine it to be a man, but rather
when there is some failure of accuracy in its exercise. And as we were
saying before, visions appear to us even when our eyes are shut. Neither
is imagination any of the things that are never in error: e.g. knowledge
or intelligence; for imagination may be false.
It remains therefore to see if it is opinion, for opinion may be
either true or false.
But opinion involves belief (for without belief in what we opine
we cannot have an opinion), and in the brutes though we often find imagination
we never find belief. Further, every opinion is accompanied by belief,
belief by conviction, and conviction by discourse of reason: while there
are some of the brutes in which we find imagination, without discourse
of reason. It is clear then that imagination cannot, again, be (1) opinion
plus sensation, or (2) opinion mediated by sensation, or (3) a blend of
opinion and sensation; this is impossible both for these reasons and because
the content of the supposed opinion cannot be different from that of the
sensation (I mean that imagination must be the blending of the perception
of white with the opinion that it is white: it could scarcely be a blend
of the opinion that it is good with the perception that it is white): to
imagine is therefore (on this view) identical with the thinking of exactly
the same as what one in the strictest sense perceives. But what we imagine
is sometimes false though our contemporaneous judgement about it is true;
e.g. we imagine the sun to be a foot in diameter though we are convinced
that it is larger than the inhabited part of the earth, and the following
dilemma presents itself. Either (a while the fact has not changed and the
(observer has neither forgotten nor lost belief in the true opinion which
he had, that opinion has disappeared, or (b) if he retains it then his
opinion is at once true and false. A true opinion, however, becomes false
only when the fact alters without being noticed.
Imagination is therefore neither any one of the states enumerated,
nor compounded out of them.
But since when one thing has been set in motion another thing may
be moved by it, and imagination is held to be a movement and to be impossible
without sensation, i.e. to occur in beings that are percipient and to have
for its content what can be perceived, and since movement may be produced
by actual sensation and that movement is necessarily similar in character
to the sensation itself, this movement must be (1) necessarily (a) incapable
of existing apart from sensation, (b) incapable of existing except when
we perceive, (such that in virtue of its possession that in which it is
found may present various phenomena both active and passive, and (such
that it may be either true or false.
The reason of the last characteristic is as follows. Perception
(1) of the special objects of sense is never in error or admits the least
possible amount of falsehood. (2) That of the concomitance of the objects
concomitant with the sensible qualities comes next: in this case certainly
we may be deceived; for while the perception that there is white before
us cannot be false, the perception that what is white is this or that may
be false. (3) Third comes the perception of the universal attributes which
accompany the concomitant objects to which the special sensibles attach
(I mean e.g. of movement and magnitude); it is in respect of these that
the greatest amount of sense-illusion is possible.
The motion which is due to the activity of sense in these three
modes of its exercise will differ from the activity of sense; (1) the first
kind of derived motion is free from error while the sensation is present;
(2) and (3) the others may be erroneous whether it is present or absent,
especially when the object of perception is far off. If then imagination
presents no other features than those enumerated and is what we have described,
then imagination must be a movement resulting from an actual exercise of
a power of sense.
As sight is the most highly developed sense, the name Phantasia
(imagination) has been formed from Phaos (light) because it is not possible
to see without light.
And because imaginations remain in the organs of sense and resemble
sensations, animals in their actions are largely guided by them, some (i.e.
the brutes) because of the non-existence in them of mind, others (i.e.
men) because of the temporary eclipse in them of mind by feeling or disease
or sleep.
About imagination, what it is and why it exists, let so much
suffice.
Part 4
Turning now to the part of the soul with which the soul knows and
thinks (whether this is separable from the others in definition only, or
spatially as well) we have to inquire (1) what differentiates this part,
and (2) how thinking can take place.
If thinking is like perceiving, it must be either a process in
which the soul is acted upon by what is capable of being thought, or a
process different from but analogous to that. The thinking part of the
soul must therefore be, while impassible, capable of receiving the form
of an object; that is, must be potentially identical in character with
its object without being the object. Mind must be related to what is thinkable,
as sense is to what is sensible.
Therefore, since everything is a possible object of thought, mind
in order, as Anaxagoras says, to dominate, that is, to know, must be pure
from all admixture; for the co-presence of what is alien to its nature
is a hindrance and a block: it follows that it too, like the sensitive
part, can have no nature of its own, other than that of having a certain
capacity. Thus that in the soul which is called mind (by mind I mean that
whereby the soul thinks and judges) is, before it thinks, not actually
any real thing. For this reason it cannot reasonably be regarded as blended
with the body: if so, it would acquire some quality, e.g. warmth or cold,
or even have an organ like the sensitive faculty: as it is, it has none.
It was a good idea to call the soul 'the place of forms', though (1) this
description holds only of the intellective soul, and (2) even this is the
forms only potentially, not actually.
Observation of the sense-organs and their employment reveals a
distinction between the impassibility of the sensitive and that of the
intellective faculty. After strong stimulation of a sense we are less able
to exercise it than before, as e.g. in the case of a loud sound we cannot
hear easily immediately after, or in the case of a bright colour or a powerful
odour we cannot see or smell, but in the case of mind thought about an
object that is highly intelligible renders it more and not less able afterwards
to think objects that are less intelligible: the reason is that while the
faculty of sensation is dependent upon the body, mind is separable from
it.
Once the mind has become each set of its possible objects, as a
man of science has, when this phrase is used of one who is actually a man
of science (this happens when he is now able to exercise the power on his
own initiative), its condition is still one of potentiality, but in a different
sense from the potentiality which preceded the acquisition of knowledge
by learning or discovery: the mind too is then able to think
itself.
Since we can distinguish between a spatial magnitude and what it
is to be such, and between water and what it is to be water, and so in
many other cases (though not in all; for in certain cases the thing and
its form are identical), flesh and what it is to be flesh are discriminated
either by different faculties, or by the same faculty in two different
states: for flesh necessarily involves matter and is like what is snub-nosed,
a this in a this. Now it is by means of the sensitive faculty that we discriminate
the hot and the cold, i.e. the factors which combined in a certain ratio
constitute flesh: the essential character of flesh is apprehended by something
different either wholly separate from the sensitive faculty or related
to it as a bent line to the same line when it has been straightened
out.
Again in the case of abstract objects what is straight is analogous
to what is snub-nosed; for it necessarily implies a continuum as its matter:
its constitutive essence is different, if we may distinguish between straightness
and what is straight: let us take it to be two-ness. It must be apprehended,
therefore, by a different power or by the same power in a different state.
To sum up, in so far as the realities it knows are capable of being separated
from their matter, so it is also with the powers of
mind.
The problem might be suggested: if thinking is a passive affection,
then if mind is simple and impassible and has nothing in common with anything
else, as Anaxagoras says, how can it come to think at all? For interaction
between two factors is held to require a precedent community of nature
between the factors. Again it might be asked, is mind a possible object
of thought to itself? For if mind is thinkable per se and what is thinkable
is in kind one and the same, then either (a) mind will belong to everything,
or (b) mind will contain some element common to it with all other realities
which makes them all thinkable.
(1) Have not we already disposed of the difficulty about interaction
involving a common element, when we said that mind is in a sense potentially
whatever is thinkable, though actually it is nothing until it has thought?
What it thinks must be in it just as characters may be said to be on a
writingtablet on which as yet nothing actually stands written: this is
exactly what happens with mind.
(Mind is itself thinkable in exactly the same way as its objects
are. For (a) in the case of objects which involve no matter, what thinks
and what is thought are identical; for speculative knowledge and its object
are identical. (Why mind is not always thinking we must consider later.)
(b) In the case of those which contain matter each of the objects of thought
is only potentially present. It follows that while they will not have mind
in them (for mind is a potentiality of them only in so far as they are
capable of being disengaged from matter) mind may yet be
thinkable.
Part 5
Since in every class of things, as in nature as a whole, we find
two factors involved, (1) a matter which is potentially all the particulars
included in the class, (2) a cause which is productive in the sense that
it makes them all (the latter standing to the former, as e.g. an art to
its material), these distinct elements must likewise be found within the
soul.
And in fact mind as we have described it is what it is what it
is by virtue of becoming all things, while there is another which is what
it is by virtue of making all things: this is a sort of positive state
like light; for in a sense light makes potential colours into actual
colours.
Mind in this sense of it is separable, impassible, unmixed, since
it is in its essential nature activity (for always the active is superior
to the passive factor, the originating force to the matter which it
forms).
Actual knowledge is identical with its object: in the individual,
potential knowledge is in time prior to actual knowledge, but in the universe
as a whole it is not prior even in time. Mind is not at one time knowing
and at another not. When mind is set free from its present conditions it
appears as just what it is and nothing more: this alone is immortal and
eternal (we do not, however, remember its former activity because, while
mind in this sense is impassible, mind as passive is destructible), and
without it nothing thinks.
Part 6
The thinking then of the simple objects of thought is found in
those cases where falsehood is impossible: where the alternative of true
or false applies, there we always find a putting together of objects of
thought in a quasi-unity. As Empedocles said that 'where heads of many
a creature sprouted without necks' they afterwards by Love's power were
combined, so here too objects of thought which were given separate are
combined, e.g. 'incommensurate' and 'diagonal': if the combination be of
objects past or future the combination of thought includes in its content
the date. For falsehood always involves a synthesis; for even if you assert
that what is white is not white you have included not white in a synthesis.
It is possible also to call all these cases division as well as combination.
However that may be, there is not only the true or false assertion that
Cleon is white but also the true or false assertion that he was or will
he white. In each and every case that which unifies is
mind.
Since the word 'simple' has two senses, i.e. may mean either (a)
'not capable of being divided' or (b) 'not actually divided', there is
nothing to prevent mind from knowing what is undivided, e.g. when it apprehends
a length (which is actually undivided) and that in an undivided time; for
the time is divided or undivided in the same manner as the line. It is
not possible, then, to tell what part of the line it was apprehending in
each half of the time: the object has no actual parts until it has been
divided: if in thought you think each half separately, then by the same
act you divide the time also, the half-lines becoming as it were new wholes
of length. But if you think it as a whole consisting of these two possible
parts, then also you think it in a time which corresponds to both parts
together. (But what is not quantitatively but qualitatively simple is thought
in a simple time and by a simple act of the soul.)
But that which mind thinks and the time in which it thinks are
in this case divisible only incidentally and not as such. For in them too
there is something indivisible (though, it may be, not isolable) which
gives unity to the time and the whole of length; and this is found equally
in every continuum whether temporal or spatial.
Points and similar instances of things that divide, themselves
being indivisible, are realized in consciousness in the same manner as
privations.
A similar account may be given of all other cases, e.g. how evil
or black is cognized; they are cognized, in a sense, by means of their
contraries. That which cognizes must have an element of potentiality in
its being, and one of the contraries must be in it. But if there is anything
that has no contrary, then it knows itself and is actually and possesses
independent existence.
Assertion is the saying of something concerning something, e.g.
affirmation, and is in every case either true or false: this is not always
the case with mind: the thinking of the definition in the sense of the
constitutive essence is never in error nor is it the assertion of something
concerning something, but, just as while the seeing of the special object
of sight can never be in error, the belief that the white object seen is
a man may be mistaken, so too in the case of objects which are without
matter.
Part 7
Actual knowledge is identical with its object: potential knowledge
in the individual is in time prior to actual knowledge but in the universe
it has no priority even in time; for all things that come into being arise
from what actually is. In the case of sense clearly the sensitive faculty
already was potentially what the object makes it to be actually; the faculty
is not affected or altered. This must therefore be a different kind from
movement; for movement is, as we saw, an activity of what is imperfect,
activity in the unqualified sense, i.e. that of what has been perfected,
is different from movement.
To perceive then is like bare asserting or knowing; but when the
object is pleasant or painful, the soul makes a quasi-affirmation or negation,
and pursues or avoids the object. To feel pleasure or pain is to act with
the sensitive mean towards what is good or bad as such. Both avoidance
and appetite when actual are identical with this: the faculty of appetite
and avoidance are not different, either from one another or from the faculty
of sense-perception; but their being is different.
To the thinking soul images serve as if they were contents of perception
(and when it asserts or denies them to be good or bad it avoids or pursues
them). That is why the soul never thinks without an image. The process
is like that in which the air modifies the pupil in this or that way and
the pupil transmits the modification to some third thing (and similarly
in hearing), while the ultimate point of arrival is one, a single mean,
with different manners of being.
With what part of itself the soul discriminates sweet from hot
I have explained before and must now describe again as follows: That with
which it does so is a sort of unity, but in the way just mentioned, i.e.
as a connecting term. And the two faculties it connects, being one by analogy
and numerically, are each to each as the qualities discerned are to one
another (for what difference does it make whether we raise the problem
of discrimination between disparates or between contraries, e.g. white
and black?). Let then C be to D as is to B: it follows alternando that
C: A:: D: B. If then C and D belong to one subject, the case will be the
same with them as with and B; and B form a single identity with different
modes of being; so too will the former pair. The same reasoning holds if
be sweet and B white.
The faculty of thinking then thinks the forms in the images, and
as in the former case what is to be pursued or avoided is marked out for
it, so where there is no sensation and it is engaged upon the images it
is moved to pursuit or avoidance. E.g.. perceiving by sense that the beacon
is fire, it recognizes in virtue of the general faculty of sense that it
signifies an enemy, because it sees it moving; but sometimes by means of
the images or thoughts which are within the soul, just as if it were seeing,
it calculates and deliberates what is to come by reference to what is present;
and when it makes a pronouncement, as in the case of sensation it pronounces
the object to be pleasant or painful, in this case it avoids or persues
and so generally in cases of action.
That too which involves no action, i.e. that which is true or false,
is in the same province with what is good or bad: yet they differ in this,
that the one set imply and the other do not a reference to a particular
person.
The so-called abstract objects the mind thinks just as, if one
had thought of the snubnosed not as snub-nosed but as hollow, one would
have thought of an actuality without the flesh in which it is embodied:
it is thus that the mind when it is thinking the objects of Mathematics
thinks as separate elements which do not exist separate. In every case
the mind which is actively thinking is the objects which it thinks. Whether
it is possible for it while not existing separate from spatial conditions
to think anything that is separate, or not, we must consider
later.
Part 8
Let us now summarize our results about soul, and repeat that the
soul is in a way all existing things; for existing things are either sensible
or thinkable, and knowledge is in a way what is knowable, and sensation
is in a way what is sensible: in what way we must inquire.
Knowledge and sensation are divided to correspond with the realities,
potential knowledge and sensation answering to potentialities, actual knowledge
and sensation to actualities. Within the soul the faculties of knowledge
and sensation are potentially these objects, the one what is knowable,
the other what is sensible. They must be either the things themselves or
their forms. The former alternative is of course impossible: it is not
the stone which is present in the soul but its form.
It follows that the soul is analogous to the hand; for as the hand
is a tool of tools, so the mind is the form of forms and sense the form
of sensible things.
Since according to common agreement there is nothing outside and
separate in existence from sensible spatial magnitudes, the objects of
thought are in the sensible forms, viz. both the abstract objects and all
the states and affections of sensible things. Hence (1) no one can learn
or understand anything in the absence of sense, and (when the mind is actively
aware of anything it is necessarily aware of it along with an image; for
images are like sensuous contents except in that they contain no
matter.
Imagination is different from assertion and denial; for what is
true or false involves a synthesis of concepts. In what will the primary
concepts differ from images? Must we not say that neither these nor even
our other concepts are images, though they necessarily involve
them?
Part 9
The soul of animals is characterized by two faculties, (a) the
faculty of discrimination which is the work of thought and sense, and (b)
the faculty of originating local movement. Sense and mind we have now sufficiently
examined. Let us next consider what it is in the soul which originates
movement. Is it a single part of the soul separate either spatially or
in definition? Or is it the soul as a whole? If it is a part, is that part
different from those usually distinguished or already mentioned by us,
or is it one of them? The problem at once presents itself, in what sense
we are to speak of parts of the soul, or how many we should distinguish.
For in a sense there is an infinity of parts: it is not enough to distinguish,
with some thinkers, the calculative, the passionate, and the desiderative,
or with others the rational and the irrational; for if we take the dividing
lines followed by these thinkers we shall find parts far more distinctly
separated from one another than these, namely those we have just mentioned:
(1) the nutritive, which belongs both to plants and to all animals, and
(2) the sensitive, which cannot easily be classed as either irrational
or rational; further (3) the imaginative, which is, in its being, different
from all, while it is very hard to say with which of the others it is the
same or not the same, supposing we determine to posit separate parts in
the soul; and lastly (4) the appetitive, which would seem to be distinct
both in definition and in power from all hitherto enumerated.
It is absurd to break up the last-mentioned faculty: as these thinkers
do, for wish is found in the calculative part and desire and passion in
the irrational; and if the soul is tripartite appetite will be found in
all three parts. Turning our attention to the present object of discussion,
let us ask what that is which originates local movement of the
animal.
The movement of growth and decay, being found in all living things,
must be attributed to the faculty of reproduction and nutrition, which
is common to all: inspiration and expiration, sleep and waking, we must
consider later: these too present much difficulty: at present we must consider
local movement, asking what it is that originates forward movement in the
animal.
That it is not the nutritive faculty is obvious; for this kind
of movement is always for an end and is accompanied either by imagination
or by appetite; for no animal moves except by compulsion unless it has
an impulse towards or away from an object. Further, if it were the nutritive
faculty, even plants would have been capable of originating such movement
and would have possessed the organs necessary to carry it out. Similarly
it cannot be the sensitive faculty either; for there are many animals which
have sensibility but remain fast and immovable throughout their
lives.
If then Nature never makes anything without a purpose and never
leaves out what is necessary (except in the case of mutilated or imperfect
growths; and that here we have neither mutilation nor imperfection may
be argued from the facts that such animals (a) can reproduce their species
and (b) rise to completeness of nature and decay to an end), it follows
that, had they been capable of originating forward movement, they would
have possessed the organs necessary for that purpose. Further, neither
can the calculative faculty or what is called 'mind' be the cause of such
movement; for mind as speculative never thinks what is practicable, it
never says anything about an object to be avoided or pursued, while this
movement is always in something which is avoiding or pursuing an object.
No, not even when it is aware of such an object does it at once enjoin
pursuit or avoidance of it; e.g. the mind often thinks of something terrifying
or pleasant without enjoining the emotion of fear. It is the heart that
is moved (or in the case of a pleasant object some other part). Further,
even when the mind does command and thought bids us pursue or avoid something,
sometimes no movement is produced; we act in accordance with desire, as
in the case of moral weakness. And, generally, we observe that the possessor
of medical knowledge is not necessarily healing, which shows that something
else is required to produce action in accordance with knowledge; the knowledge
alone is not the cause. Lastly, appetite too is incompetent to account
fully for movement; for those who successfully resist temptation have appetite
and desire and yet follow mind and refuse to enact that for which they
have appetite.
Part 10
These two at all events appear to be sources of movement: appetite
and mind (if one may venture to regard imagination as a kind of thinking;
for many men follow their imaginations contrary to knowledge, and in all
animals other than man there is no thinking or calculation but only
imagination).
Both of these then are capable of originating local movement, mind
and appetite: (1) mind, that is, which calculates means to an end, i.e.
mind practical (it differs from mind speculative in the character of its
end); while (2) appetite is in every form of it relative to an end: for
that which is the object of appetite is the stimulant of mind practical;
and that which is last in the process of thinking is the beginning of the
action. It follows that there is a justification for regarding these two
as the sources of movement, i.e. appetite and practical thought; for the
object of appetite starts a movement and as a result of that thought gives
rise to movement, the object of appetite being it a source of stimulation.
So too when imagination originates movement, it necessarily involves
appetite.
That which moves therefore is a single faculty and the faculty
of appetite; for if there had been two sources of movement-mind and appetite-they
would have produced movement in virtue of some common character. As it
is, mind is never found producing movement without appetite (for wish is
a form of appetite; and when movement is produced according to calculation
it is also according to wish), but appetite can originate movement contrary
to calculation, for desire is a form of appetite. Now mind is always right,
but appetite and imagination may be either right or wrong. That is why,
though in any case it is the object of appetite which originates movement,
this object may be either the real or the apparent good. To produce movement
the object must be more than this: it must be good that can be brought
into being by action; and only what can be otherwise than as it is can
thus be brought into being. That then such a power in the soul as has been
described, i.e. that called appetite, originates movement is clear. Those
who distinguish parts in the soul, if they distinguish and divide in accordance
with differences of power, find themselves with a very large number of
parts, a nutritive, a sensitive, an intellective, a deliberative, and now
an appetitive part; for these are more different from one another than
the faculties of desire and passion.
Since appetites run counter to one another, which happens when
a principle of reason and a desire are contrary and is possible only in
beings with a sense of time (for while mind bids us hold back because of
what is future, desire is influenced by what is just at hand: a pleasant
object which is just at hand presents itself as both pleasant and good,
without condition in either case, because of want of foresight into what
is farther away in time), it follows that while that which originates movement
must be specifically one, viz. the faculty of appetite as such (or rather
farthest back of all the object of that faculty; for it is it that itself
remaining unmoved originates the movement by being apprehended in thought
or imagination), the things that originate movement are numerically
many.
All movement involves three factors, (1) that which originates
the movement, (2) that by means of which it originates it, and (3) that
which is moved. The expression 'that which originates the movement' is
ambiguous: it may mean either (a) something which itself is unmoved or
(b) that which at once moves and is moved. Here that which moves without
itself being moved is the realizable good, that which at once moves and
is moved is the faculty of appetite (for that which is influenced by appetite
so far as it is actually so influenced is set in movement, and appetite
in the sense of actual appetite is a kind of movement), while that which
is in motion is the animal. The instrument which appetite employs to produce
movement is no longer psychical but bodily: hence the examination of it
falls within the province of the functions common to body and soul. To
state the matter summarily at present, that which is the instrument in
the production of movement is to be found where a beginning and an end
coincide as e.g. in a ball and socket joint; for there the convex and the
concave sides are respectively an end and a beginning (that is why while
the one remains at rest, the other is moved): they are separate in definition
but not separable spatially. For everything is moved by pushing and pulling.
Hence just as in the case of a wheel, so here there must be a point which
remains at rest, and from that point the movement must
originate.
To sum up, then, and repeat what I have said, inasmuch as an animal
is capable of appetite it is capable of self-movement; it is not capable
of appetite without possessing imagination; and all imagination is either
(1) calculative or (2) sensitive. In the latter an animals, and not only
man, partake.
Part 11
We must consider also in the case of imperfect animals, sc. those
which have no sense but touch, what it is that in them originates movement.
Can they have imagination or not? or desire? Clearly they have feelings
of pleasure and pain, and if they have these they must have desire. But
how can they have imagination? Must not we say that, as their movements
are indefinite, they have imagination and desire, but
indefinitely?
Sensitive imagination, as we have said, is found in all animals,
deliberative imagination only in those that are calculative: for whether
this or that shall be enacted is already a task requiring calculation;
and there must be a single standard to measure by, for that is pursued
which is greater. It follows that what acts in this way must be able to
make a unity out of several images.
This is the reason why imagination is held not to involve opinion,
in that it does not involve opinion based on inference, though opinion
involves imagination. Hence appetite contains no deliberative element.
Sometimes it overpowers wish and sets it in movement: at times wish acts
thus upon appetite, like one sphere imparting its movement to another,
or appetite acts thus upon appetite, i.e. in the condition of moral weakness
(though by nature the higher faculty is always more authoritative and gives
rise to movement). Thus three modes of movement are
possible.
The faculty of knowing is never moved but remains at rest. Since
the one premiss or judgement is universal and the other deals with the
particular (for the first tells us that such and such a kind of man should
do such and such a kind of act, and the second that this is an act of the
kind meant, and I a person of the type intended), it is the latter opinion
that really originates movement, not the universal; or rather it is both,
but the one does so while it remains in a state more like rest, while the
other partakes in movement.
Part 12
The nutritive soul then must be possessed by everything that is
alive, and every such thing is endowed with soul from its birth to its
death. For what has been born must grow, reach maturity, and decay-all
of which are impossible without nutrition. Therefore the nutritive faculty
must be found in everything that grows and decays.
But sensation need not be found in all things that live. For it
is impossible for touch to belong either (1) to those whose body is uncompounded
or (2) to those which are incapable of taking in the forms without their
matter.
But animals must be endowed with sensation, since Nature does nothing
in vain. For all things that exist by Nature are means to an end, or will
be concomitants of means to an end. Every body capable of forward movement
would, if unendowed with sensation, perish and fail to reach its end, which
is the aim of Nature; for how could it obtain nutriment? Stationary living
things, it is true, have as their nutriment that from which they have arisen;
but it is not possible that a body which is not stationary but produced
by generation should have a soul and a discerning mind without also having
sensation. (Nor yet even if it were not produced by generation. Why should
it not have sensation? Because it were better so either for the body or
for the soul? But clearly it would not be better for either: the absence
of sensation will not enable the one to think better or the other to exist
better.) Therefore no body which is not stationary has soul without
sensation.
But if a body has sensation, it must be either simple or compound.
And simple it cannot be; for then it could not have touch, which is indispensable.
This is clear from what follows. An animal is a body with soul in it: every
body is tangible, i.e. perceptible by touch; hence necessarily, if an animal
is to survive, its body must have tactual sensation. All the other senses,
e.g. smell, sight, hearing, apprehend through media; but where there is
immediate contact the animal, if it has no sensation, will be unable to
avoid some things and take others, and so will find it impossible to survive.
That is why taste also is a sort of touch; it is relative to nutriment,
which is just tangible body; whereas sound, colour, and odour are innutritious,
and further neither grow nor decay. Hence it is that taste also must be
a sort of touch, because it is the sense for what is tangible and
nutritious.
Both these senses, then, are indispensable to the animal, and it
is clear that without touch it is impossible for an animal to be. All the
other senses subserve well-being and for that very reason belong not to
any and every kind of animal, but only to some, e.g. those capable of forward
movement must have them; for, if they are to survive, they must perceive
not only by immediate contact but also at a distance from the object. This
will be possible if they can perceive through a medium, the medium being
affected and moved by the perceptible object, and the animal by the medium.
just as that which produces local movement causes a change extending to
a certain point, and that which gave an impulse causes another to produce
a new impulse so that the movement traverses a medium the first mover impelling
without being impelled, the last moved being impelled without impelling,
while the medium (or media, for there are many) is both-so is it also in
the case of alteration, except that the agent produces produces it without
the patient's changing its place. Thus if an object is dipped into wax,
the movement goes on until submersion has taken place, and in stone it
goes no distance at all, while in water the disturbance goes far beyond
the object dipped: in air the disturbance is propagated farthest of all,
the air acting and being acted upon, so long as it maintains an unbroken
unity. That is why in the case of reflection it is better, instead of saying
that the sight issues from the eye and is reflected, to say that the air,
so long as it remains one, is affected by the shape and colour. On a smooth
surface the air possesses unity; hence it is that it in turn sets the sight
in motion, just as if the impression on the wax were transmitted as far
as the wax extends.
Part 13
It is clear that the body of an animal cannot be simple, i.e. consist
of one element such as fire or air. For without touch it is impossible
to have any other sense; for every body that has soul in it must, as we
have said, be capable of touch. All the other elements with the exception
of earth can constitute organs of sense, but all of them bring about perception
only through something else, viz. through the media. Touch takes place
by direct contact with its objects, whence also its name. All the other
organs of sense, no doubt, perceive by contact, only the contact is mediate:
touch alone perceives by immediate contact. Consequently no animal body
can consist of these other elements.
Nor can it consist solely of earth. For touch is as it were a mean
between all tangible qualities, and its organ is capable of receiving not
only all the specific qualities which characterize earth, but also the
hot and the cold and all other tangible qualities whatsoever. That is why
we have no sensation by means of bones, hair, &c., because they consist
of earth. So too plants, because they consist of earth, have no sensation.
Without touch there can be no other sense, and the organ of touch cannot
consist of earth or of any other single element.
It is evident, therefore, that the loss of this one sense alone
must bring about the death of an animal. For as on the one hand nothing
which is not an animal can have this sense, so on the other it is the only
one which is indispensably necessary to what is an animal. This explains,
further, the following difference between the other senses and touch. In
the case of all the others excess of intensity in the qualities which they
apprehend, i.e. excess of intensity in colour, sound, and smell, destroys
not the but only the organs of the sense (except incidentally, as when
the sound is accompanied by an impact or shock, or where through the objects
of sight or of smell certain other things are set in motion, which destroy
by contact); flavour also destroys only in so far as it is at the same
time tangible. But excess of intensity in tangible qualities, e.g. heat,
cold, or hardness, destroys the animal itself. As in the case of every
sensible quality excess destroys the organ, so here what is tangible destroys
touch, which is the essential mark of life; for it has been shown that
without touch it is impossible for an animal to be. That is why excess
in intensity of tangible qualities destroys not merely the organ, but the
animal itself, because this is the only sense which it must
have.
All the other senses are necessary to animals, as we have said,
not for their being, but for their well-being. Such, e.g. is sight, which,
since it lives in air or water, or generally in what is pellucid, it must
have in order to see, and taste because of what is pleasant or painful
to it, in order that it may perceive these qualities in its nutriment and
so may desire to be set in motion, and hearing that it may have communication
made to it, and a tongue that it may communicate with its
fellows.
THE END
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