Whether the Soul Understands Corporeal Things Through Its Essence?
Objection 1: It would seem that the soul understands corporeal things
through its essence. For Augustine says (De Trin. x, 5) that the soul
"collects and lays hold of the images of bodies which are formed in
the soul and of the soul: for in forming them it gives them something
of its own substance." But the soul understands bodies by images of
bodies. Therefore the soul knows bodies through its essence, which it
employs for the formation of such images, and from which it forms
them.
Obj. 2: Further, the Philosopher says (De Anima iii, 8) that "the
soul, after a fashion, is everything." Since, therefore, like is known
by like, it seems that the soul knows corporeal things through itself.
Obj. 3: Further, the soul is superior to corporeal creatures. Now
lower things are in higher things in a more eminent way than in
themselves, as Dionysius says (Coel. Hier. xii). Therefore all
corporeal creatures exist in a more excellent way in the soul than in
themselves. Therefore the soul can know corporeal creatures through
its essence.
_On the contrary,_ Augustine says (De Trin. ix, 3) that "the mind
gathers knowledge of corporeal things through the bodily senses." But
the soul itself cannot be known through the bodily senses. Therefore
it does not know corporeal things through itself.
_I answer that,_ The ancient philosophers held that the soul knows
bodies through its essence. For it was universally admitted that
"like is known by like." But they thought that the form of the thing
known is in the knower in the same mode as in the thing known. The
Platonists however were of a contrary opinion. For Plato, having
observed that the intellectual soul has an immaterial nature, and an
immaterial mode of knowledge, held that the forms of things known
subsist immaterially. While the earlier natural philosophers,
observing that things known are corporeal and material, held that
things known must exist materially even in the soul that knows them.
And therefore, in order to ascribe to the soul a knowledge of all
things, they held that it has the same nature in common with all. And
because the nature of a result is determined by its principles, they
ascribed to the soul the nature of a principle; so that those who
thought fire to be the principle of all, held that the soul had the
nature of fire; and in like manner as to air and water. Lastly,
Empedocles, who held the existence of our four material elements and
two principles of movement, said that the soul was composed of these.
Consequently, since they held that things exist in the soul
materially, they maintained that all the soul's knowledge is
material, thus failing to discern intellect from sense.
But this opinion will not hold. First, because in the material
principle of which they spoke, the various results do not exist save
in potentiality. But a thing is not known according as it is in
potentiality, but only according as it is in act, as is shown
_Metaph._ ix (Did. viii, 9): wherefore neither is a power known
except through its act. It is therefore insufficient to ascribe to
the soul the nature of the principles in order to explain the fact
that it knows all, unless we further admit in the soul natures and
forms of each individual result, for instance, of bone, flesh, and
the like; thus does Aristotle argue against Empedocles (De Anima i,
5). Secondly, because if it were necessary for the thing known to
exist materially in the knower, there would be no reason why things
which have a material existence outside the soul should be devoid of
knowledge; why, for instance, if by fire the soul knows fire, that
fire also which is outside the soul should not have knowledge of fire.
We must conclude, therefore, that material things known must needs
exist in the knower, not materially, but immaterially. The reason of
this is, because the act of knowledge extends to things outside the
knower: for we know things even that are external to us. Now by
matter the form of a thing is determined to some one thing. Wherefore
it is clear that knowledge is in inverse ratio of materiality. And
consequently things that are not receptive of forms save materially,
have no power of knowledge whatever--such as plants, as the
Philosopher says (De Anima ii, 12). But the more immaterially a thing
receives the form of the thing known, the more perfect is its
knowledge. Therefore the intellect which abstracts the species not
only from matter, but also from the individuating conditions of
matter, has more perfect knowledge than the senses, which receive the
form of the thing known, without matter indeed, but subject to
material conditions. Moreover, among the senses, sight has the most
perfect knowledge, because it is the least material, as we have
remarked above (Q. 78, A. 3): while among intellects the more perfect
is the more immaterial.
It is therefore clear from the foregoing, that if there be an
intellect which knows all things by its essence, then its essence
must needs have all things in itself immaterially; thus the early
philosophers held that the essence of the soul, that it may know all
things, must be actually composed of the principles of all material
things. Now this is proper to God, that His Essence comprise all
things immaterially as effects pre-exist virtually in their cause.
God alone, therefore, understands all things through His Essence:
but neither the human soul nor the angels can do so.
Reply Obj. 1: Augustine in that passage is speaking of an imaginary
vision, which takes place through the image of bodies. To the
formation of such images the soul gives part of its substance, just
as a subject is given in order to be informed by some form. In this
way the soul makes such images from itself; not that the soul or some
part of the soul be turned into this or that image; but just as we
say that a body is made into something colored because of its being
informed with color. That this is the sense, is clear from what
follows. For he says that the soul "keeps something"--namely, not
informed with such image--"which is able freely to judge of the
species of these images": and that this is the "mind" or "intellect."
And he says that the part which is informed with these
images--namely, the imagination--is "common to us and beasts."
Reply Obj. 2: Aristotle did not hold that the soul is actually
composed of all things, as did the earlier philosophers; he said that
the soul is all things, "after a fashion," forasmuch as it is in
potentiality to all--through the senses, to all things
sensible--through the intellect, to all things intelligible.
Reply Obj. 3: Every creature has a finite and determinate essence.
Wherefore although the essence of the higher creature has a certain
likeness to the lower creature, forasmuch as they have something in
common generically, yet it has not a complete likeness thereof,
because it is determined to a certain species other than the species
of the lower creature. But the Divine Essence is a perfect likeness
of all, whatsoever may be found to exist in things created, being the
universal principle of all.
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