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.  And so moral differs from intellectual virtue, even as the appetite differs from the reason.  Hence just as the appetite is the principle of human acts, in so far as it partakes of reason, so are moral habits to be considered virtues in so far as they are in conformity with reason.

Reply Obj. 1:  Augustine usually applies the term “art” to any form of right reason; in which sense art includes prudence which is the right reason about things to be done, even as art is the right reason about things to be made.  Accordingly, when he says that “virtue is the art of right conduct,” this applies to prudence essentially; but to other virtues, by participation, for as much as they are directed by prudence.

Reply Obj. 2:  All such definitions, by whomsoever given, were based on the Socratic theory, and should be explained according to what we have said about art (ad 1).

The same applies to the Third Objection.

Reply Obj. 4:  Right reason which is in accord with prudence is included in the definition of moral virtue, not as part of its essence, but as something belonging by way of participation to all the moral virtues, in so far as they are all under the direction of prudence. ________________________

THIRD ARTICLE [I-II, Q. 58, Art. 3]

Whether Virtue Is Adequately Divided into Moral and Intellectual?

Objection 1:  It would seem that virtue is not adequately divided into moral and intellectual.  For prudence seems to be a mean between moral and intellectual virtue, since it is reckoned among the intellectual virtues (Ethic. vi, 3, 5); and again is placed by all among the four cardinal virtues, which are moral virtues, as we shall show further on (Q. 61, A. 1).  Therefore virtue is not adequately divided into intellectual and moral, as though there were no mean between them.

Obj. 2:  Further, continency, perseverance, and patience are not reckoned to be intellectual virtues.  Yet neither are they moral virtues; since they do not reduce the passions to a mean, and are consistent with an abundance of passion.  Therefore virtue is not adequately divided into intellectual and moral.