To the third one proceeds thus. It seems that craft is not intellectual virtue. For Augustine says, in De Libero Arbitrio, that no one uses virtue badly. But some use craft badly. For a craftsman is able to work badly according to the knowledge of his craft. Therefore craft is not virtue.
Further, there is no virtue of virtue, but there is some virtue of craft, as is said in Ethic. VI. Therefore craft is not virtue.
Further, crafts of the free person [artes liberales] are more excellent than crafts of the engineer [artes mechanicae]. But as crafts of the engineer are practical, so crafts of the free person are reflective [speculativa]. Therefore if craft were intellectual virtue, it would have to be enumerated as reflective virtue.
But contrariwise is that the Philosopher, in Ethic. VI, posits craft to be virtue, yet he does not number it with speculative virtues, which he places in the knowing part of the soul.
I reply that it must be said that craft is nothing other than right reason for making some works. However, the good of these things does not consist in that human striving [appetitus] has itself [se habet] in some way but in that the work itself that is done is in itself good. For it does not pertain to the praise of the craftsman inasmuch as he is a craftsman, that he willingly does the work but what kind of work he does. Therefore craft, properly speaking, is working habitude. And yet in some ways it converges on [convenit cum] reflective habitudes because it also pertains to reflective habitudes how they have themselves to the things they consider, but not how human striving has itself to them. For provided that the the geometer demonstrates the true, it does not matter how he has himself in his striving part, whether he is glad or angry, just as it does not matter in the craftsman, as was said. And so in this way craft has the notion of virtue in the same way as reflective habitudes, inasmuch as neither craft nor reflective habitude produce good work with respect to use, which is proper to virtue completing striving, but only with respect to the faculty of acting well.
To the first therefore it must be said that when someone who has craft works bad craftsmanship, this is not a work of craft but is contrary to craft, just as when someone who knows the true lies, what is said is not according to knowledge but contrary to knowledge. Thus, just as knowledge always has itself to good, as was said, so also craft, and in this respect it is called virtue. In this, however, it is lacking the complete notion of virtue, because it does not do the good use itself, but something else is required for it, although good use without craft is not able to be.
To the second it must be said that because good will, which is completed by moral virtue, is required for a human being to make good use of craft, therefore the Philosopher says that craft is virtue, namely moral, inasmuch as some moral virtue is required for its good use. For it is manifest that the craftsman is inclined by justice, which makes the will right, to make the work faithfully.
To the third it must be said that even in reflective matters there is something by way of a sort of work, such as construction of a deduction or a suitable sentence or the work of counting and measuring. And thus whatever habitudes are ordered to such works of reflective reason, are called by a kind of likeness crafts, but for the free person, in distinction from those crafts which are ordered to works exercised through the body, which are in a way for slaves, inasmuch as the body is subject slavishly to the soul, and man is free according to soul. But those kinds of knowledge which are not ordered to any such work, are simply called kinds of knowledge, not crafts. Nor is it needful, if crafts of the free person are more noble, that the notion of craft be more suitable to them.
[Thomas Aquinas, ST 2-1.57.3, my translation. The Dominican Fathers translation is here, the Latin is here.]
