Whether the Powers of the Soul Flow from Its Essence?
Objection 1: It would seem that the powers of the soul do not flow
from its essence. For different things do not proceed from one
simple thing. But the essence of the soul is one and simple. Since,
therefore, the powers of the soul are many and various, they cannot
proceed from its essence.
Obj. 2: Further, that from which a thing proceeds is its cause.
But the essence of the soul cannot be said to be the cause of the
powers; as is clear if one considers the different kinds of causes.
Therefore the powers of the soul do not flow from its essence.
Obj. 3: Further, emanation involves some sort of movement. But
nothing is moved by itself, as the Philosopher proves (Phys. vii,
1,2); except, perhaps, by reason of a part of itself, as an animal
is said to be moved by itself, because one part thereof moves and
another is moved. Neither is the soul moved, as the Philosopher
proves (De Anima i, 4). Therefore the soul does not produce its
powers within itself.
_On the contrary,_ The powers of the soul are its natural properties.
But the subject is the cause of its proper accidents; whence also it
is included in the definition of accident, as is clear from _Metaph._
vii (Did. vi, 4). Therefore the powers of the soul proceed from its
essence as their cause.
_I answer that,_ The substantial and the accidental form partly agree
and partly differ. They agree in this, that each is an act; and that
by each of them something is after a manner actual. They differ,
however, in two respects. First, because the substantial form makes
a thing to exist absolutely, and its subject is something purely
potential. But the accidental form does not make a thing to exist
absolutely but to be such, or so great, or in some particular
condition; for its subject is an actual being. Hence it is clear that
actuality is observed in the substantial form prior to its being
observed in the subject: and since that which is first in a genus is
the cause in that genus, the substantial form causes existence in its
subject. On the other hand, actuality is observed in the subject of
the accidental form prior to its being observed in the accidental
form; wherefore the actuality of the accidental form is caused by the
actuality of the subject. So the subject, forasmuch as it is in
potentiality, is receptive of the accidental form: but forasmuch as
it is in act, it produces it. This I say of the proper and _per se_
accident; for with regard to the extraneous accident, the subject is
receptive only, the accident being caused by an extrinsic agent.
Secondly, substantial and accidental forms differ, because, since that
which is the less principal exists for the sake of that which is the
more principal, matter therefore exists on account of the substantial
form; while on the contrary, the accidental form exists on account of
the completeness of the subject.
Now it is clear, from what has been said (A. 5), that either the
subject of the soul's powers is the soul itself alone, which can be
the subject of an accident, forasmuch as it has something of
potentiality, as we have said above (A. 1, ad 6); or else this subject
is the composite. Now the composite is actual by the soul. Whence it
is clear that all the powers of the soul, whether their subject be the
soul alone, or the composite, flow from the essence of the soul, as
from their principle; because it has already been said that the
accident is caused by the subject according as it is actual, and is
received into it according as it is in potentiality.
Reply Obj. 1: From one simple thing many things may proceed
naturally, in a certain order; or again if there be diversity of
recipients. Thus, from the one essence of the soul many and various
powers proceed; both because order exists among these powers; and
also by reason of the diversity of the corporeal organs.
Reply Obj. 2: The subject is both the final cause, and in a way the
active cause, of its proper accident. It is also as it were the
material cause, inasmuch as it is receptive of the accident. From
this we may gather that the essence of the soul is the cause of all
its powers, as their end, and as their active principle; and of some
as receptive thereof.
Reply Obj. 3: The emanation of proper accidents from their subject is
not by way of transmutation, but by a certain natural resultance;
thus one thing results naturally from another, as color from light.
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