I answer that, A thing may be said to be greater or less in two ways:  first, simply; secondly, relatively.  For nothing hinders something from being better simply, e.g. “learning than riches,” and yet not better relatively, i.e. “for one who is in want” [Aristotle, _Topic._ iii.].  Now to consider a thing simply is to consider it in its proper specific nature.  Accordingly, a virtue takes its species from its object, as explained above (Q. 54, A. 2; Q. 60, A. 1).  Hence, speaking simply, that virtue is more excellent, which has the more excellent object.  Now it is evident that the object of the reason is more excellent than the object of the appetite:  since the reason apprehends things in the universal, while the appetite tends to things themselves, whose being is restricted to the particular.  Consequently, speaking simply, the intellectual virtues, which perfect the reason, are more excellent than the moral virtues, which perfect the appetite.

But if we consider virtue in its relation to act, then moral virtue, which perfects the appetite, whose function it is to move the other powers to act, as stated above (Q. 9, A. 1), is more excellent.  And since virtue is so called from its being a principle of action, for it is the perfection of a power, it follows again that the nature of virtue agrees more with moral than with intellectual virtue, though the intellectual virtues are more excellent habits, simply speaking.

Reply Obj. 1:  The moral virtues are more lasting than the intellectual virtues, because they are practised in matters pertaining to the life of the community.  Yet it is evident that the objects of the sciences, which are necessary and invariable, are more lasting than the objects of moral virtue, which are certain particular matters of action.  That the moral virtues are more necessary for human life, proves that they are more excellent, not simply, but relatively.  Indeed, the speculative intellectual virtues, from the very fact that they are not referred to something else, as a useful thing is referred to an end, are more excellent.  The reason for this is that in them we have a kind of beginning of that happiness which consists in the knowledge of truth, as stated above (Q. 3, A. 6).

Reply Obj. 2:  The reason why man is said to be good simply, in respect of moral virtue, but not in respect of intellectual virtue, is because the appetite moves the other powers to their acts, as stated above (Q. 56, A. 3).  Wherefore this argument, too, proves merely that moral virtue is better relatively.

Reply Obj. 3:  Prudence directs the moral virtues not only in the choice of the means, but also in appointing the end.  Now the end of each moral virtue is to attain the mean in the matter proper to that virtue; which mean is appointed according to the right ruling of prudence, as stated in Ethic. ii, 6; vi, 13. ________________________

FOURTH ARTICLE [I-II, Q. 66, Art. 4]