Summa: Studiousness and Temperance

As the Philosopher says (Ethic. ii, 93) in order to be virtuous we must avoid those things to which we are most naturally inclined. Hence it is that, since nature inclines us. chiefly to fear dangers of death, and to seek pleasures of the flesh, fortitude is chiefly commended for a certain steadfast perseverance against such dangers, and temperance for a certain restraint from pleasures of the flesh.

But as regards knowledge, man has contrary inclinations. For on the part of the soul, he is inclined to desire knowledge of things; and so it behooves him to exercise a praiseworthy restraint on this desire, lest he seek knowledge immoderately: whereas on the part of his bodily nature, man is inclined to avoid the trouble of seeking knowledge.

Accordingly, as regards the first inclination studiousness is a kind of restraint, and it is in this sense that it is reckoned a part of temperance. But as to the second inclination, this virtue derives its praise from a certain keenness of interest in seeking knowledge of things; and from this it takes its name. The former is more essential to this virtue than the latter: since the desire to know directly regards knowledge, to which studiousness is directed, whereas the trouble of learning is an obstacle to knowledge, wherefore it is regarded by this virtue indirectly, as by that which removes an obstacle.