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 quality, which is divided against habit.  Therefore there is no habit in the body.

On the contrary, The Philosopher says in the Book of Predicaments (De Categor. vi) that health of the body and incurable disease are called habits.

I answer that, As we have said above (Q. 49, AA. 2 seqq.), habit is a disposition of a subject which is in a state of potentiality either to form or to operation.  Therefore in so far as habit implies disposition to operation, no habit is principally in the body as its subject.  For every operation of the body proceeds either from a natural quality of the body or from the soul moving the body.  Consequently, as to those operations which proceed from its nature, the body is not disposed by a habit:  because the natural forces are determined to one mode of operation; and we have already said (Q. 49, A. 4) that it is when the subject is in potentiality to many things that a habitual disposition is required.  As to the operations which proceed from the soul through the body, they belong principally to the soul, and secondarily to the body.  Now habits are in proportion to their operations:  whence “by like acts like habits are formed” (Ethic. ii, 1, 2).  And therefore the dispositions to such operations are principally in the soul.  But they can be secondarily in the body:  to wit, in so far as the body is disposed and enabled with promptitude to help in the operations of the soul.

If, however, we speak of the disposition of the subject to form, thus a habitual disposition can be in the body, which is related to the soul as a subject is to its form.  And in this way health and beauty and such like are called habitual dispositions.  Yet they have not the nature of habit perfectly:  because their causes, of their very nature, are easily changeable.