Intellectus est subiectum virtutis quia bonum uniuscuiusque est finis eius; et ideo, cum verum sit finis intellectus, cognoscere verum est bonus actus intellectus. Unde habitus perficiens intellectum ad verum cognoscendum, vel in speculativis vel in practicis, dicitur virtus.
The intellect is the subject of virtue because the good of each thing is its end; and therefore, as truth is the end of the intellect, so to know truth is the good act of the intellect. Whence the habit, which perfects the intellect in regard to the knowledge of truth, whether speculative or practical, is a virtue.
Subiectum igitur habitus qui secundum quid dicitur virtus, potest esse intellectus, non solum practicus, sed etiam intellectus speculativus, absque omni ordine ad voluntatem, sic enim philosophus, in VI Ethic., scientiam, sapientiam et intellectum, et etiam artem, ponit esse intellectuales virtutes.
The subject of a habit which is called a virtue in a relative sense, can be the intellect, and not only the practical intellect, but also the speculative, without any reference to the will: for thus the Philosopher (Ethic. vi, 3) holds that science, wisdom and understanding, and also art, are intellectual virtues.
Virtus est habitus quo quis bene operatur. Dupliciter autem habitus aliquis ordinatur ad bonum actum. Uno modo, inquantum per huiusmodi habitum acquiritur homini facultas ad bonum actum, sicut per habitum grammaticae habet homo facultatem recte loquendi. Non tamen grammatica facit ut homo semper recte loquatur, potest enim grammaticus barbarizare aut soloecismum facere. Et eadem ratio est in aliis scientiis et artibus. Alio modo, aliquis habitus non solum facit facultatem agendi, sed etiam facit quod aliquis recte facultate utatur, sicut iustitia non solum facit quod homo sit promptae voluntatis ad iusta operandum, sed etiam facit ut iuste operetur.
A virtue is a habit by which we work well. Now a habit may be directed to a good act in two ways. First, in so far as by the habit a man acquires an aptness to a good act; for instance, by the habit of grammar man has the aptness to speak correctly. But grammar does not make a man always speak correctly: for a grammarian may be guilty of a barbarism or make a solecism: and the case is the same with other sciences and arts. Secondly, a habit may confer not only aptness to act, but also the right use of that aptness: for instance, justice not only gives man the prompt will to do just actions, but also makes him act justly.
Et quia bonum, sicut et ens, non dicitur simpliciter aliquid secundum id quod est in potentia, sed secundum id quod est in actu; ideo ab huiusmodi habitibus simpliciter dicitur homo bonum operari, et esse bonus, puta quia est iustus vel temperatus; et eadem ratio est de similibus. Et quia virtus est quae bonum facit habentem, et opus eius bonum reddit, huiusmodi habitus simpliciter dicuntur virtutes, quia reddunt bonum opus in actu, et simpliciter faciunt bonum habentem. Primi vero habitus non simpliciter dicuntur virtutes, quia non reddunt bonum opus nisi in quadam facultate, nec simpliciter faciunt bonum habentem. Non enim dicitur simpliciter aliquis homo bonus, ex hoc quod est sciens vel artifex, sed dicitur bonus solum secundum quid, puta bonus grammaticus, aut bonus faber. Et propter hoc, plerumque scientia et ars contra virtutem dividitur, quandoque autem virtutes dicuntur, ut patet in VI Ethic.
And since good, and, in like manner, being, is said of a thing simply, in respect, not of what it is potentially, but of what it is actually: therefore from having habits of the latter sort, man is said simply to do good, and to be good; for instance, because he is just, or temperate; and in like manner as regards other such virtues. And since virtue is that "which makes its possessor good, and his work good likewise," these latter habits are called virtuous simply: because they make the work to be actually good, and the subject good simply. But the first kind of habits are not called virtues simply: because they do not make the work good except in regard to a certain aptness, nor do they make their possessor good simply. For through being gifted in science or art, a man is said to be good, not simply, but relatively; for instance, a good grammarian or a good smith. And for this reason science and art are often divided against virtue; while at other times they are called virtues (Ethic. vi, 2).
Subiectum vero habitus qui simpliciter dicitur virtus, non potest esse nisi voluntas; vel aliqua potentia secundum quod est mota a voluntate. Cuius ratio est, quia voluntas movet omnes alias potentias quae aliqualiter sunt rationales, ad suos actus, ut supra habitum est, et ideo quod homo actu bene agat, contingit ex hoc quod homo habet bonam voluntatem. Unde virtus quae facit bene agere in actu, non solum in facultate, oportet quod vel sit in ipsa voluntate; vel in aliqua potentia secundum quod est a voluntate mota.
But the subject of a habit which is called a virtue simply, can only be the will, or some power insofar as it is moved by the will. And the reason of this is, that the will moves to their acts all those other powers that are in some way rational, as we have said above (9, 1; 17, A1,5; I, 82, 4): and therefore if man do well actually, this is because he has a good will. Therefore the virtue which makes a man to do well actually, and not merely to have the aptness to do well, must be either in the will itself; or in some power as moved by the will.
Contingit autem intellectum a voluntate moveri, sicut et alias potentias, considerat enim aliquis aliquid actu, eo quod vult. Et ideo intellectus, secundum quod habet ordinem ad voluntatem, potest esse subiectum virtutis simpliciter dictae. Et hoc modo intellectus speculativus, vel ratio, est subiectum fidei, movetur enim intellectus ad assentiendum his quae sunt fidei, ex imperio voluntatis; nullus enim credit nisi volens. Intellectus vero practicus est subiectum prudentiae. Cum enim prudentia sit recta ratio agibilium, requiritur ad prudentiam quod homo se bene habeat ad principia huius rationis agendorum, quae sunt fines; ad quos bene se habet homo per rectitudinem voluntatis, sicut ad principia speculabilium per naturale lumen intellectus agentis. Et ideo sicut subiectum scientiae, quae est ratio recta speculabilium, est intellectus speculativus in ordine ad intellectum agentem; ita subiectum prudentiae est intellectus practicus in ordine ad voluntatem rectam.
Now it happens that the intellect is moved by the will, just as are the other powers: for a man considers something actually, because he wills to do so. And therefore the intellect, in so far as it is subordinate to the will, can be the subject of virtue absolutely so called. And in this way the speculative intellect, or the reason, is the subject of Faith: for the intellect is moved by the command of the will to assent to what is of faith: for "no man believeth, unless he will" [Augustine: Tract. xxvi in Joan.]. But the practical intellect is the subject of prudence. For since prudence is the right reason of things to be done, it is a condition thereof that man be rightly disposed in regard to the principles of this reason of things to be done, that is in regard to their ends, to which man is rightly disposed by the rectitude of the will, just as to the principles of speculative truth he is rightly disposed by the natural light of the active intellect. And therefore as the subject of science, which is the right reason of speculative truths, is the speculative intellect in its relation to the active intellect, so the subject of prudence is the practical intellect in its relation to the right will.