virtue, as
stated in _Ethic._ vi, 13. Therefore moral virtue does not differ
from intellectual.

_On the contrary,_ It is stated in _Ethic._ i, 13 that "there are two
kinds of virtue: some we call intellectual; some moral."

_I answer that,_ Reason is the first principle of all human acts; and
whatever other principles of human acts may be found, they obey
reason somewhat, but in various ways. For some obey reason blindly
and without any contradiction whatever: such are the limbs of the
body, provided they be in a healthy condition, for as soon as reason
commands, the hand or the foot proceeds to action. Hence the
Philosopher says (Polit. i, 3) that "the soul rules the body like a
despot," i.e. as a master rules his slave, who has no right to rebel.
Accordingly some held that all the active principles in man are
subordinate to reason in this way. If this were true, for man to act
well it would suffice that his reason be perfect. Consequently, since
virtue is a habit perfecting man in view of his doing good actions,
it would follow that it is only in the reason, so that there would be
none but intellectual virtues. This was the opinion of Socrates, who
said "every virtue is a kind of prudence," as stated in _Ethic._ vi,
13. Hence he maintained that as long as man is in possession of
knowledge, he cannot sin; and that every one who sins, does so
through ignorance.

Now this is based on a false supposition. Because the appetitive
faculty obeys the reason, not blindly, but with a certain power of
opposition; wherefore the Philosopher says (Polit. i, 3) that "reason
commands the appetitive faculty by a politic power," whereby a man
rules over subjects that are free, having a certain right of
opposition. Hence Augustine says on Ps. 118 (Serm. 8) that "sometimes
we understand (what is right) while desire is slow, or follows not at
all," in so far as the habits or passions of the appetitive faculty
cause the use of reason to be impeded in some particular action. And
in this way, there is some truth in the saying of Socrates that so
long as a man is in possession of knowledge he does not sin:
provided, however, that this knowledge is made to include the use of
reason in this individual act of choice.

Accordingly for a man to do a good deed, it is requisite not only
that his reason be well disposed by means of a habit of intellectual
virtue; but also that his appetite be well disposed by means of a
habit of moral virtue.