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.

On the other hand, as Simplicius reports in his _Commentary on the
Predicaments,_ Alexander denied absolutely that habits or
dispositions of the first species are in the body: and held that the
first species of quality belonged to the soul alone. And he held that
Aristotle mentions health and sickness in the _Book on the
Predicaments_ not as though they belonged to the first species of
quality, but by way of example: so that he would mean that just as
health and sickness may be easy or difficult to change, so also are
all the qualities of the first species, which are called habits and
dispositions. But this is clearly contrary to the intention of
Arist