To the second one proceeds thus. It seems that moral virtue is not distinguished from intellectual virtue. For Augustine says, in the book De Civ. Dei, that virtue is the craft of rightly living. But craft is intellectual virtue. Therefore moral virtue does not differ from intellectual virtue.
Further, most put knowledge in the definition of moral virtues, just as some define that perseverance is knowledge or habitude of those things that must be held or not held, and holiness is knowledge making us faithful and serving in things just before God. But knowledge is intellectual virtue. Thus moral virtue ought not to be distinguished from intellectual.
Further, Augustine says, in Soliloq. I, that virtue is right and complete reason. But this pertains to intellectual virtue, as is clear in Ethic. VI. Therefore moral virtue is not distinct from intellectual.
Further, nothing is distinguished from that which is put in its definition. But intellectual virtue is put in the definition of moral virtue, for the Philosopher says, in Ethic. II, that virtue is choosing habit existing in the mean determined by reason as the wise would determine it. Now this sort of right reason determining the mean of moral virtue pertains to intellectual virtue, as is said in Ethic. VI. Therefore moral is not distinguished from intellectual virtue.
But contrariwise is what is said in Ethic. I, that virtue is determined according to this difference, for we call some of these intellectual but others moral.
I reply that it must be said that the first principle of all human work is reason, and whatever other principles of human works are found, in some way obey reason; but in diverse ways. For some obey reason wholly under its authority [ad nutum], without any contradiction, like bodily members, if it is consistent with their nature, for immediately at the command [imperium] of reason, hand or foot is moved to work. Whence the Philosopher says, in Polit. I, that soul rules body with despotic principality, that is, as lord over slave who has no right to contradict. Thefore some have assumed that all active principles that are in a human being have themselves to reason in this way. Were this true, it would suffice that reason be complete in order to act well. Thus, since virtue is habitude by which we are completed for acting well, it would follow that it is in reason alone, and thus there would be no virtue save the intellectual. And this was the opinion of Socrates, who said that all virtues were prudences, as is said in Ethic. VI. Thus he held that the human being in whom knowledge existed was not able to sin, but whoever sinned, sinned from ignorance.
But this proceeds from a false supposition. For the striving [appetitiva] part obeys reason not wholly under its authority [ad nutum], but with some contradiction; thus the Philosopher says, in Polit. I, that reason commands the striving with civil principality, to wit, that by which one presides over the free, who have the right to contradict in something. Thus Augustine says, on the Psalms, that sometimes understanding precedes and a slow or no affect follows, inasmuch as sometimes this is done inasmuch as passions or habitudes of the striving part act so that the use of reason is impeded. And according to this, it is somewhat true what Socrates said, that knowledge being present, one does not sin; however, only if this is extended to use of reason in particular choice [in particulari eligibili].
So, therefore, in order for a human being to act well, it is required that reason not only be well disposed through habitude of intellectual virtue, but also that the striving impulse be well disposed through habitude of moral virtue. Therefore, just as striving is distinguished from reason, so moral virtue is distinguished from intellectual. Hence, just as striving is the principle of human act according as it participates reason in some way, so moral habitude has the notion of human virtue, inasmuch as it conforms to reason.
To the first therefore it must be said that Augustine commonly uses 'craft' for any right reason. And so under craft is included prudence, which is right reason of enactibles, as craft is right reason of makeables. And according to this, what he says, that virtue is craft of rightly living, is essentially appropriate to prudence, but by participation to other virtues, according as they are directed by prudence.
To the second it must be said that such definitions, by whomsoever they are found to be given, proceeded from the Socratic opinion, and are to be explained in the way that was previously said with respect to craft.
And likewise this must be said to the third.
To the fourth it must be said that right reason, which is according to prudence, is put in the definition of moral virtue, not as part of its essence, but as something participated in all moral virtues, inasmuch as prudence directs all moral virtues.
[Thomas Aquinas, ST 2-1.58.2, my translation. The Latin is here, the Dominican Fathers translation is here.]
