Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that habits are not distinguished by their objects. For contraries differ in species. Now the same habit of science regards contraries: thus medicine regards the healthy and the unhealthy. Therefore habits are not distinguished by objects specifically distinct.

Objection 2: Further, different sciences are different habits. But the same scientific truth belongs to different sciences: thus both the physicist and the astronomer prove the earth to be round, as stated in Phys. ii, text. 17. Therefore habits are not distinguished by their objects.

Objection 3: Further, wherever the act is the same, the object is the same. But the same act can belong to different habits of virtue, if it be directed to different ends; thus to give money to anyone, if it be done for God's sake, is an act of charity; while, if it be done in order to pay a debt, it is an act of justice. Therefore the same object can also belong to different habits. Therefore diversity of habits does not follow diversity of objects.

On the contrary, Acts differ in species according to the diversity of their objects, as stated above (Question 18, Article 5). But habits are dispositions to acts. Therefore habits also are distinguished according to the diversity of objects.

I answer that, A habit is both a form and a habit. Hence the specific distinction of habits may be taken in the ordinary way in which forms differ specifically; or according to that mode of distinction which is proper to habits. Accordingly forms are distinguished from one another in reference to the diversity of their active principles, since every agent produces its like in species. Habits, however, imply order to something: and all things that imply order to something, are distinguished according to the distinction of the things to which they are ordained. Now a habit is a disposition implying a twofold order: viz. to nature and to an operation consequent to nature.

Accordingly habits are specifically distinct in respect of three things. First, in respect of the active principles of such dispositions; secondly, in respect of nature; thirdly, in respect of specifically different objects, as will appear from what follows.

Reply to Objection 1: In distinguishing powers, or also habits, we must consider the object not in its material but in its formal aspect, which may differ in species or even in genus. And though the distinction between specific contraries is a real distinction yet they are both known under one aspect, since one is known through the other. And consequently in so far as they concur in the one aspect of cognoscibility, they belong to one cognitive habit.

Reply to Objection 2: The physicist proves the earth to be round by one means, the astronomer by another: for the latter proves this by means of mathematics, e.g. by the shapes of eclipses, or something of the sort; while the former proves it by means of physics, e.g. by the movement of heavy bodies towards the center, and so forth. Now the whole force of a demonstration, which is "a syllogism producing science," as stated in Poster. i, text. 5, depends on the mean. And consequently various means are as so many active principles, in respect of which the habits of science are distinguished.

Reply to Objection 3: As the Philosopher says (Phys. ii, text. 89; Ethic. vii, 8), the end is, in practical matters, what the principle is in speculative matters. Consequently diversity of ends demands a diversity of virtues, even as diversity of active principles does. Moreover the ends are objects of the internal acts, with which, above all, the virtues are concerned, as is evident from what has been said (Question 18, Article 6; Question 19, Article 2, ad 1; Question 34, Article 4).

Articulus 2

Argumentum 1

Ad secundum sic proceditur. Videtur quod habitus non distinguantur secundum obiecta. Contraria enim sunt specie differentia. Sed idem habitus scientiae est contrariorum, sicut medicina sani et aegri. Non ergo secundum obiecta specie differentia, habitus distinguuntur.

Argumentum 2

Praeterea, diversae scientiae sunt diversi habitus.

Sed idem scibile pertinet ad diversas scientias, sicut terram esse rotundam demonstrat et naturalis et astrologus, ut dicitur in II physic..

Ergo habitus non distinguuntur secundum obiecta.

Argumentum 3

Praeterea, eiusdem actus est idem obiectum.

Sed idem actus potest pertinere ad diversos habitus virtutum, si ad diversos fines referatur, sicut dare pecuniam alicui, si sit propter deum, pertinet ad caritatem; si vero sit propter debitum solvendum, pertinet ad iustitiam. Ergo etiam idem obiectum potest ad diversos habitus pertinere. Non ergo est diversitas habituum secundum diversitatem obiectorum.

Sed Contra

Sed contra, actus differunt specie secundum diversitatem obiectorum, ut supra dictum est.

Sed habitus sunt dispositiones quaedam ad actus.

Ergo etiam habitus distinguuntur secundum diversa obiecta.

Corpus

Respondeo dicendum quod habitus et est forma quaedam, et est habitus. Potest ergo distinctio habituum secundum speciem attendi aut secundum communem modum quo formae specie distinguuntur; aut secundum proprium modum distinctionis habituum. Distinguuntur siquidem formae ad invicem secundum diversa principia activa, eo quod omne agens facit simile secundum speciem. Habitus autem importat ordinem ad aliquid. Omnia autem quae dicuntur secundum ordinem ad aliquid, distinguuntur secundum distinctionem eorum ad quae dicuntur. Est autem habitus dispositio quaedam ad duo ordinata, scilicet ad naturam, et ad operationem consequentem naturam.

Sic igitur secundum tria, habitus specie distinguuntur.

Uno quidem modo, secundum principia activa talium dispositionum; alio vero modo, secundum naturam; tertio vero modo, secundum obiecta specie differentia; ut per sequentia explicabitur.

Ad 1

Ad primum ergo dicendum quod in distinctione potentiarum, vel etiam habituum, non est considerandum ipsum obiectum materialiter; sed ratio obiecti differens specie, vel etiam genere. Quamvis autem contraria specie differant diversitate rerum, tamen eadem ratio est cognoscendi utrumque, quia unum per aliud cognoscitur. Et ideo inquantum conveniunt in una ratione cognoscibilis, pertinent ad unum habitum cognoscitivum.

Ad 2

Ad secundum dicendum quod terram esse rotundam per aliud medium demonstrat naturalis, et per aliud astrologus, astrologus enim hoc demonstrat per media mathematica, sicut per figuras eclipsium, vel per aliud huiusmodi; naturalis vero hoc demonstrat per medium naturale, sicut per motum gravium ad medium, vel per aliud huiusmodi. Tota autem virtus demonstrationis, quae est syllogismus faciens scire, ut dicitur in I poster., dependet ex medio. Et ideo diversa media sunt sicut diversa principia activa, secundum quae habitus scientiarum diversificantur.

Ad 3

Ad tertium dicendum quod, sicut philosophus dicit, in II physic. Et in VII ethic., ita se habet finis in operabilibus, sicut principium in demonstrativis. Et ideo diversitas finium diversificat virtutes sicut et diversitas activorum principiorum. Sunt etiam ipsi fines obiecta actuum interiorum, qui maxime pertinent ad virtutes, ut ex supradictis patet.