On The Soul
by Aristotle
III.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.
III.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, etc., 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.
III.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.
III.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.
III.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.
III.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.
III.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.
III.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?
III.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.
III.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.
III.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.
III.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.
III.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, etc., 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.
-
Now to Him who is able to keep you from stumbling, and to make you stand in the presence of His glory blameless with great joy, to the only God our Savior, through Jesus Christ our Lord, be glory, majesty, dominion and authority, before all time and now and forever. Amen. Jude 1:24-25
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