Whether the Interior Senses Are Suitably Distinguished?
Objection 1: It would seem that the interior senses are not suitably
distinguished. For the common is not divided against the proper.
Therefore the common sense should not be numbered among the interior
sensitive powers, in addition to the proper exterior senses.
Obj. 2: Further, there is no need to assign an interior power of
apprehension when the proper and exterior sense suffices. But the
proper and exterior senses suffice for us to judge of sensible things;
for each sense judges of its proper object. In like manner they seem
to suffice for the perception of their own actions; for since the
action of the sense is, in a way, between the power and its object, it
seems that sight must be much more able to perceive its own vision, as
being nearer to it, than the color; and in like manner with the other
senses. Therefore for this there is no need to assign an interior
power, called the common sense.
Obj. 3: Further, according to the Philosopher (De Memor. et Remin.
i), the imagination and the memory are passions of the "first
sensitive." But passion is not divided against its subject. Therefore
memory and imagination should not be assigned as powers distinct from
the senses.
Obj. 4: Further, the intellect depends on the senses less than any
power of the sensitive part. But the intellect knows nothing but what
it receives from the senses; whence we read (Poster. i, 8), that
"those who lack one sense lack one kind of knowledge." Therefore much
less should we assign to the sensitive part a power, which they call
the "estimative" power, for the perception of intentions which the
sense does not perceive.
Obj. 5: Further, the action of the cogitative power, which consists
in comparing, adding and dividing, and the action of the
reminiscence, which consists in the use of a kind of syllogism for
the sake of inquiry, is not less distant from the actions of the
estimative and memorative powers, than the action of the estimative
is from the action of the imagination. Therefore either we must add
the cognitive and reminiscitive to the estimative and memorative
powers, or the estimative and memorative powers should not be made
distinct from the imagination.
Obj. 6: Further, Augustine (Gen. ad lit. xii, 6, 7, 24) describes
three kinds of vision; namely, corporeal, which is the action of the
sense; spiritual, which is an action of the imagination or phantasy;
and intellectual, which is an action of the intellect. Therefore there
is no interior power between the sense and intellect, besides the
imagination.
_On the contrary,_ Avicenna (De Anima iv, 1) assigns five interior
sensitive powers; namely, "common sense, phantasy, imagination, and
the estimative and memorative powers."
_I answer that,_ As nature does not fail in necessary things, there
must needs be as many actions of the sensitive soul as may suffice
for the life of a perfect animal. If any of these actions cannot be
reduced to the same one principle, they must be assigned to diverse
powers; since a power of the soul is nothing else than the proximate
principle of the soul's operation.
Now we must observe that for the life of a perfect animal, the animal
should apprehend a thing not only at the actual time of sensation, but
also when it is absent. Otherwise, since animal motion and action
follow apprehension, an animal would not be moved to seek something
absent: the contrary of which we may observe specially in perfect
animals, which are moved by progression, for they are moved towards
something apprehended and absent. Therefore an animal through the
sensitive soul must not only receive the species of sensible things,
when it is actually affected by them, but it must also retain and
preserve them. Now to receive and retain are, in corporeal things,
reduced to diverse principles; for moist things are apt to receive,
but retain with difficulty, while it is the reverse with dry things.
Wherefore, since the sensitive power is the act of a corporeal organ,
it follows that the power which receives the species of sensible
things must be distinct from the power which preserves them.
Again we must observe that if an animal were moved by pleasing and
disagreeable things only as affecting the sense, there would be no
need to suppose that an animal has a power besides the apprehension of
those forms which the senses perceive, and in which the animal takes
pleasure, or from which it shrinks with horror. But the animal needs
to seek or to avoid certain things, not only because they are pleasing
or otherwise to the senses, but also on account of other advantages
and uses, or disadvantages: just as the sheep runs away when it sees a
wolf, not on account of its color or shape, but as a natural enemy:
and again a bird gathers together straws, not because they are
pleasant to the sense, but because they are useful for building its
nest. Animals, therefore, need to perceive such intentions, which the
exterior sense does not perceive. And some distinct principle is
necessary for this; since the perception of sensible forms comes by an
immutation caused by the sensible, which is not the case with the
perception of those intentions.
Thus, therefore, for the reception of sensible forms, the "proper
sense" and the _common sense_ are appointed, and of their distinction
we shall speak farther on (ad 1, 2). But for the retention and
preservation of these forms, the "phantasy" or "imagination" is
appointed; which are the same, for phantasy or imagination is as it
were a storehouse of forms received through the senses. Furthermore,
for the apprehension of intentions which are not received through the
senses, the "estimative" power is appointed: and for the preservation
thereof, the "memorative" power, which is a storehouse of such-like
intentions. A sign of which we have in the fact that the principle of
memory in animals is found in some such intention, for instance, that
something is harmful or otherwise. And the very formality of the past,
which memory observes, is to be reckoned among these intentions.
Now, we must observe that as to sensible forms there is no difference
between man and other animals; for they are similarly immuted by the
extrinsic sensible. But there is a difference as to the above
intentions: for other animals perceive these intentions only by some
natural instinct, while man perceives them by means of coalition of
ideas. Therefore the power by which in other animals is called the
natural estimative, in man is called the "cogitative," which by some
sort of collation discovers these intentions. Wherefore it is also
called the "particular reason," to which medical men assign a certain
particular organ, namely, the middle part of the head: for it compares
individual intentions, just as the intellectual reason compares
universal intentions. As to the memorative power, man has not only
memory, as other animals have in the sudden recollection of the past;
but also "reminiscence" by syllogistically, as it were, seeking for a
recollection of the past by the application of individual intentions.
Avicenna, however, assigns between the estimative and the imaginative,
a fifth power, which combines and divides imaginary forms: as when
from the imaginary form of gold, and imaginary form of a mountain, we
compose the one form of a golden mountain, which we have never seen.
But this operation is not to be found in animals other than man, in
whom the imaginative power suffices thereto. To man also does Averroes
attribute this action in his book _De sensu et sensibilibus_ (viii).
So there is no need to assign more than four interior powers of the
sensitive part--namely, the common sense, the imagination, and the
estimative and memorative powers.
Reply Obj. 1: The interior sense is called "common" not by
predication, as if it were a genus; but as the common root and
principle of the exterior senses.
Reply Obj. 2: The proper sense judges of the proper sensible by
discerning it from other things which come under the same sense; for
instance, by discerning white from black or green. But neither sight
nor taste can discern white from sweet: because what discerns between
two things must know both. Wherefore the discerning judgment must be
assigned to the common sense; to which, as to a common term, all
apprehensions of the senses must be referred: and by which, again,
all the intentions of the senses are perceived; as when someone sees
that he sees. For this cannot be done by the proper sense, which only
knows the form of the sensible by which it is immuted, in which
immutation the action of sight is completed, and from immutation
follows another in the common sense which perceives the act of vision.
Reply Obj. 3: As one power arises from the soul by means of another,
as we have seen above (Q. 77, A. 7), so also the soul is the subject
of one power through another. In this way the imagination and the
memory are called passions of the "first sensitive."
Reply Obj. 4: Although the operation of the intellect has its origin
in the senses: yet, in the thing apprehended through the senses, the
intellect knows many things which the senses cannot perceive. In like
manner does the estimative power, though in a less perfect manner.
Reply Obj. 5: The cogitative and memorative powers in man owe their
excellence not to that which is proper to the sensitive part; but to
a certain affinity and proximity to the universal reason, which, so
to speak, overflows into them. Therefore they are not distinct
powers, but the same, yet more perfect than in other animals.
Reply Obj. 6: Augustine calls that vision spiritual which is effected
by the images of bodies in the absence of bodies. Whence it is clear
that it is common to all interior apprehensions.
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