Eo modo ars habet rationem virtutis, sicut et habitus speculativi, quia ars, nec habitus speculativus, faciunt bonum opus quantum ad usum, quod est proprium virtutis perficientis appetitum, sed solum quantum ad facultatem bene agendi.
Art has the formal aspect of a virtue in the same way as the speculative habits, because neither art nor speculative habit makes a good work as regards the use of the habit, which is the property of a virtue that perfects the appetite, but only as regards the aptness to work well.
Ars, proprie loquendo, habitus operativus est. Et tamen in aliquo convenit cum habitibus speculativis, quia etiam ad ipsos habitus speculativos pertinet qualiter se habeat res quam considerant, non autem qualiter se habeat appetitus humanus ad illas.
Art, properly speaking, is an operative habit. And yet it has something in common with the speculative habits, since the quality of the object considered by the latter is a matter of concern to them also, but not how the human appetite may be affected towards that object.
Sicut scientia se habet semper ad bonum, ut dictum est, ita et ars; et secundum hoc dicitur virtus. In hoc tamen deficit a perfecta ratione virtutis, quia non facit ipsum bonum usum, sed ad hoc aliquid aliud requiritur, quamvis bonus usus sine arte esse non possit.
Just as science has always a relation to good, as stated above (q57 a2 ad 3), so it is with art; and it is on account of this that it is called a virtue. And yet it falls short of the perfect formal aspect of virtue, because it does not make its possessor to use it well, for which purpose something further is requisite, although there cannot be a good use without the art.
Quia ad hoc ut homo bene utatur arte quam habet, requiritur bona voluntas, quae perficitur per virtutem moralem; ideo philosophus dicit quod artis est virtus: scilicet moralis, inquantum ad bonum usum eius aliqua virtus moralis requiritur. Manifestum est enim quod artifex per iustitiam, quae facit voluntatem rectam, inclinatur ut opus fidele faciat.
In order that man may make good use of the art he has, he needs a good will, which is perfected by moral virtue; and for this reason the Philosopher says that there is a virtue of art: namely, a moral virtue, insofar as the good use of art requires a moral virtue. For it is evident that a craftsman is inclined by justice, which rectifies his will, to do his work faithfully.
Etiam in ipsis speculabilibus est aliquid per modum cuiusdam operis: puta constructio syllogismi aut orationis congruae aut opus numerandi vel mensurandi. Et ideo quicumque ad huiusmodi opera rationis habitus speculativi ordinantur, dicuntur per quandam similitudinem artes, sed liberales, ad differentiam illarum artium quae ordinantur ad opera per corpus exercita, quae sunt quodammodo serviles, inquantum corpus serviliter subditur animae, et homo secundum animam est liber.
Even in speculative matters there is something by way of operation: e.g., the making of a syllogism or of a fitting speech, or the work of counting or measuring. Hence whatever habits are ordained to such like operations of the speculative reason, are, by a kind of comparison, called arts indeed, but "liberal" arts, in order to distinguish them from those arts that are ordained to works done by the body, which arts are, in a fashion, servile, inasmuch as the body is in servile subjection to the soul, and man, as regards his soul, is free [liber].
Illae vero scientiae quae ad nullum huiusmodi opus ordinantur, simpliciter scientiae dicuntur, non autem artes.
On the other hand, those sciences which are not ordained to any such like work, are simply called sciences, and not arts.