operations several things
must concur which may vary in their relative adjustability, it
follows that habit is necessary.

Reply Obj. 1: By the form the nature of a thing is perfected: yet the
subject needs to be disposed in regard to the form by some
disposition. But the form itself is further ordained to operation,
which is either the end, or the means to the end. And if the form is
limited to one fixed operation, no further disposition, besides the
form itself, is needed for the operation. But if the form be such
that it can operate in diverse ways, as the soul; it needs to be
disposed to its operations by means of habits.

Reply Obj. 2: Power sometimes has a relation to many things: and then
it needs to be determined by something else. But if a power has not a
relation to many things, it does not need a habit to determine it, as
we have said. For this reason the natural forces do not perform their
operations by means of habits: because they are of themselves
determined to one mode of operation.

Reply Obj. 3: The same habit has not a relation to good and evil, as
will be made clear further on (Q. 54, A. 3): whereas the same power
has a relation to good and evil. And, therefore, habits are necessary
that the powers be determined to good.
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QUESTION 50

OF THE SUBJECT OF HABITS
(In Six Articles)

We consider next the subject of habits: and under this head there are
six points of inquiry:

(1) Whether there is a habit in the body?

(2) Whether the soul is a subject of habit, in respect of its essence
or in respect of its power?

(3) Whether in the powers of the sensitive part there can be a habit?

(4) Whether there is a habit in the intellect?

(5) Whether there is a habit in the will?

(6) Whether there is a habit in separate substances?
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FIRST ARTICLE [I-II, Q. 50, Art. 1]

Whether There Is a Habit in the Body?

Objection 1: It would seem that there is not a habit in the body.
For, as the Commentator says (De Anima iii), "a habit is that whereby
we act when we will." But bodily actions are not subject to the will,
since they are natural. Therefore there can be no habit in the body.

Obj. 2: Further, all bodily dispositions are easy to change. But
habit is a quality, difficult to change. Therefore no bodily
disposition can be a habit.

Obj. 3: Further, all bodily dispositions are subject to change. But
change can only be in the third species of