Whether the Soul Is the Subject of Habit in Respect of Its Essence or
in Respect of Its Power?
Objection 1: It would seem that habit is in the soul in respect of
its essence rather than in respect of its powers. For we speak of
dispositions and habits in relation to nature, as stated above (Q.
49, A. 2). But nature regards the essence of the soul rather than the
powers; because it is in respect of its essence that the soul is the
nature of such a body and the form thereof. Therefore habits are in
the soul in respect of its essence and not in respect of its powers.
Obj. 2: Further, accident is not the subject of accident. Now habit
is an accident. But the powers of the soul are in the genus of
accident, as we have said in the First Part (Q. 77, A. 1, ad 5).
Therefore habit is not in the soul in respect of its powers.
Obj. 3: Further, the subject is prior to that which is in the
subject. But since habit belongs to the first species of quality, it
is prior to power, which belongs to the second species. Therefore
habit is not in a power of the soul as its subject.
_On the contrary,_ The Philosopher (Ethic. i, 13) puts various habits
in the various powers of the soul.
_I answer that,_ As we have said above (Q. 49, AA. 2, 3), habit
implies a certain disposition in relation to nature or to operation.
If therefore we take habit as having a relation to nature, it cannot
be in the soul--that is, if we speak of human nature: for the soul
itself is the form completing the human nature; so that, regarded in
this way, habit or disposition is rather to be found in the body by
reason of its relation to the soul, than in the soul by reason of its
relation to the body. But if we speak of a higher nature, of which
man may become a partaker, according to 2 Pet. 1, "that we may be
partakers of the Divine Nature": thus nothing hinders some habit,
namely, grace, from being in the soul in respect of its essence, as
we shall state later on (Q. 110, A. 4).
On the other hand, if we take habit in its relation to operation, it
is chiefly thus that habits are found in the soul: in so far as the
soul is not determined to one operation, but is indifferent to many,
which is a condition for a habit, as we have said above (Q. 49, A.
4). And since the soul is the principle of operation through its
powers, therefore, regarded in this sense, habits are in the soul in
respect of its powers.
Reply Obj. 1: The essence of the soul belongs to human nature, not as
a subject requiring to be disposed to something further, but as a
form and nature to which someone is disposed.
Reply Obj. 2: Accident is not of itself the subject of accident. But
since among accidents themselves there is a certain order, the
subject, according as it is under one accident, is conceived as the
subject of a further accident. In this way we say that one accident
is the subject of another; as superficies is the subject of color, in
which sense power is the subject of habit.
Reply Obj. 3: Habit takes precedence of power, according as it
implies a disposition to nature: whereas power always implies a
relation to operation, which is posterior, since nature is the
principle of operation. But the habit whose subject is a power, does
not imply relation to nature, but to operation. Wherefore it is
posterior to power. Or, we may say that habit takes precedence of
power, as the complete takes precedence of the incomplete, and as act
takes precedence of potentiality. For act is naturally prior to
potentiality, though potentiality is prior in order of generation and
time, as stated in _Metaph._ vii, text. 17; ix, text. 13.
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