Whether the Essence of the Soul Is Its Power?
Objection 1: It would seem that the essence of the soul is its power.
For Augustine says (De Trin. ix, 4), that "mind, knowledge, and love
are in the soul substantially, or, which is the same thing,
essentially": and (De Trin. x, 11), that "memory, understanding, and
will are one life, one mind, one essence."
Obj. 2: Further, the soul is nobler than primary matter. But primary
matter is its own potentiality. Much more therefore is the soul its
own power.
Obj. 3: Further, the substantial form is simpler than the accidental
form; a sign of which is that the substantial form is not intensified
or relaxed, but is indivisible. But the accidental form is its own
power. Much more therefore is that substantial form which is the soul.
Obj. 4: Further, we sense by the sensitive power and we understand by
the intellectual power. But "that by which we first sense and
understand" is the soul, according to the Philosopher (De Anima ii,
2). Therefore the soul is its own power.
Obj. 5: Further, whatever does not belong to the essence is an
accident. Therefore if the power of the soul is something else
besides the essence thereof, it is an accident, which is contrary to
Augustine, who says that the foregoing (see Obj. 1) "are not in the
soul as in a subject as color or shape, or any other quality, or
quantity, are in a body; for whatever is so, does not exceed the
subject in which it is: Whereas the mind can love and know other
things" (De Trin. ix, 4).
Obj. 6: Further, "a simple form cannot be a subject." But the soul is
a simple form; since it is not composed of matter and form, as we
have said above (Q. 75, A. 5). Therefore the power of the soul cannot
be in it as in a subject.
Obj. 7: Further, an accident is not the principle of a substantial
difference. But sensitive and rational are substantial differences;
and they are taken from sense and reason, which are powers of the
soul. Therefore the powers of the soul are not accidents; and so it
would seem that the power of the soul is its own essence.
_On the contrary,_ Dionysius (Coel. Hier. xi) says that "heavenly
spirits are divided into essence, power, and operation." Much more,
then, in the soul is the essence distinct from the virtue or power.
_I answer that,_ It is impossible to admit that the power of the soul
is its essence, although some have maintained it. For the present
purpose this may be proved in two ways. First, because, since power
and act divide being and every kind of being, we must refer a power
and its act to the same genus. Therefore, if the act be not in the
genus of substance, the power directed to that act cannot be in the
genus of substance. Now the operation of the soul is not in the genus
of substance; for this belongs to God alone, whose operation is His
own substance. Wherefore the Divine power which is the principle of
His operation is the Divine Essence itself. This cannot be true
either of the soul, or of any creature; as we have said above when
speaking of the angels (Q. 54, A. 3). Secondly, this may be also
shown to be impossible in the soul. For the soul by its very essence
is an act. Therefore if the very essence of the soul were the
immediate principle of operation, whatever has a soul would always
have actual vital actions, as that which has a soul is always an
actually living thing. For as a form the soul is not an act ordained
to a further act, but the ultimate term of generation. Wherefore,
for it to be in potentiality to another act, does not belong to it
according to its essence, as a form, but according to its power. So
the soul itself, as the subject of its power, is called the first
act, with a further relation to the second act. Now we observe that
what has a soul is not always actual with respect to its vital
operations; whence also it is said in the definition of the soul,
that it is "the act of a body having life potentially"; which
potentiality, however, "does not exclude the soul." Therefore it
follows that the essence of the soul is not its power. For nothing
is in potentiality by reason of an act, as act.
Reply Obj. 1: Augustine is speaking of the mind as it knows and loves
itself. Thus knowledge and love as referred to the soul as known and
loved, are substantially or essentially in the soul, for the very
substance or essence of the soul is known and loved. In the same way
are we to understand what he says in the other passage, that those
things are "one life, one mind, one essence." Or, as some say, this
passage is true in the sense in which the potential whole is
predicated of its parts, being midway between the universal whole,
and the integral whole. For the universal whole is in each part
according to its entire essence and power; as animal in a man and in
a horse; and therefore it is properly predicated of each part. But
the integral whole is not in each part, neither according to its
whole essence, nor according to its whole power. Therefore in no way
can it be predicated of each part; yet in a way it is predicated,
though improperly, of all the parts together; as if we were to say
that the wall, roof, and foundations are a house. But the potential
whole is in each part according to its whole essence, not, however,
according to its whole power. Therefore in a way it can be predicated
of each part, but not so properly as the universal whole. In this
sense, Augustine says that the memory, understanding, and the will
are the one essence of the soul.
Reply Obj. 2: The act to which primary matter is in potentiality is
the substantial form. Therefore the potentiality of matter is nothing
else but its essence.
Reply Obj. 3: Action belongs to the composite, as does existence;
for to act belongs to what exists. Now the composite has substantial
existence through the substantial form; and it operates by the power
which results from the substantial form. Hence an active accidental
form is to the substantial form of the agent (for instance, heat
compared to the form of fire) as the power of the soul is to the
soul.
Reply Obj. 4: That the accidental form is a principle of action is
due to the substantial form. Therefore the substantial form is the
first principle of action; but not the proximate principle. In this
sense the Philosopher says that "the soul is that whereby we
understand and sense."
Reply Obj. 5: If we take accident as meaning what is divided against
substance, then there can be no medium between substance and
accident; because they are divided by affirmation and negation, that
is, according to existence in a subject, and non-existence in a
subject. In this sense, as the power of the soul is not its essence,
it must be an accident; and it belongs to the second species of
accident, that of quality. But if we take accident as one of the five
universals, in this sense there is a medium between substance and
accident. For the substance is all that belongs to the essence of a
thing; whereas whatever is beyond the essence of a thing cannot be
called accident in this sense; but only what is not caused by the
essential principle of the species. For the 'proper' does not belong
to the essence of a thing, but is caused by the essential principles
of the species; wherefore it is a medium between the essence and
accident thus understood. In this sense the powers of the soul may be
said to be a medium between substance and accident, as being natural
properties of the soul. When Augustine says that knowledge and love
are not in the soul as accidents in a subject, this must be
understood in the sense given above, inasmuch as they are compared
to the soul, not as loving and knowing, but as loved and known. His
argument proceeds in this sense; for if love were in the soul loved
as in a subject, it would follow that an accident transcends its
subject, since even other things are loved through the soul.
Reply Obj. 6: Although the soul is not composed of matter and form,
yet it has an admixture of potentiality, as we have said above (Q.
75, A. 5, ad 4); and for this reason it can be the subject of an
accident. The statement quoted is verified in God, Who is the Pure
Act; in treating of which subject Boethius employs that phrase (De
Trin. i).
Reply Obj. 7: Rational and sensitive, as differences, are not taken
from the powers of sense and reason, but from the sensitive and
rational soul itself. But because substantial forms, which in
themselves are unknown to us, are known by their accidents; nothing
prevents us from sometimes substituting accidents for substantial
differences.
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