Thomas Aquinas, Summa Theologiae

Objection 1: It would seem that the natural law is a habit. Because, as the Philosopher says (Ethic. ii, 5), "there are three things in the soul: power, habit, and passion." But the natural law is not one of the soul's powers: nor is it one of the passions; as we may see by going through them one by one. Therefore the natural law is a habit.

Objection 2: Further, Basil says that the conscience or "synderesis is the law of our mind"; which can only apply to the natural law. But the "synderesis" is a habit, as was shown in the 1, Question 79, Article 12. Therefore the natural law is a habit.

Objection 3: Further, the natural law abides in man always, as will be shown further on (Article 6). But man's reason, which the law regards, does not always think about the natural law. Therefore the natural law is not an act, but a habit.

On the contrary, Augustine says (De Bono Conjug. xxi) that "a habit is that whereby something is done when necessary." But such is not the natural law: since it is in infants and in the damned who cannot act by it. Therefore the natural law is not a habit.

I answer that, A thing may be called a habit in two ways. First, properly and essentially: and thus the natural law is not a habit. For it has been stated above (Question 90, Article 1, ad 2) that the natural law is something appointed by reason, just as a proposition is a work of reason. Now that which a man does is not the same as that whereby he does it: for he makes a becoming speech by the habit of grammar. Since then a habit is that by which we act, a law cannot be a habit properly and essentially.

Secondly, the term habit may be applied to that which we hold by a habit: thus faith may mean that which we hold by faith. And accordingly, since the precepts of the natural law are sometimes considered by reason actually, while sometimes they are in the reason only habitually, in this way the natural law may be called a habit. Thus, in speculative matters, the indemonstrable principles are not the habit itself whereby we hold those principles, but are the principles the habit of which we possess.

Reply to Objection 1: The Philosopher proposes there to discover the genus of virtue; and since it is evident that virtue is a principle of action, he mentions only those things which are principles of human acts, viz. powers, habits and passions. But there are other things in the soul besides these three: there are acts; thus "to will" is in the one that wills; again, things known are in the knower; moreover its own natural properties are in the soul, such as immortality and the like.

Reply to Objection 2: "Synderesis" is said to be the law of our mind, because it is a habit containing the precepts of the natural law, which are the first principles of human actions.

Reply to Objection 3: This argument proves that the natural law is held habitually; and this is granted.

To the argument advanced in the contrary sense we reply that sometimes a man is unable to make use of that which is in him habitually, on account of some impediment: thus, on account of sleep, a man is unable to use the habit of science. In like manner, through the deficiency of his age, a child cannot use the habit of understanding of principles, or the natural law, which is in him habitually.

Articulus 1

Argumentum 1

Ad primum sic proceditur. Videtur quod lex naturalis sit habitus.

Quia ut philosophus dicit, in II ethic., tria sunt in anima, potentia, habitus et passio.

Sed naturalis lex non est aliqua potentiarum animae, nec aliqua passionum, ut patet enumerando per singula.

Ergo lex naturalis est habitus.

Argumentum 2

Praeterea, basilius dicit quod conscientia, sive synderesis, est lex intellectus nostri, quod non potest intelligi nisi de lege naturali. Sed synderesis est habitus quidam, ut in primo habitum est.

Argumentum 3

Praeterea, lex naturalis semper in homine manet, ut infra patebit.

Sed non semper ratio hominis, ad quam lex pertinet, cogitat de lege naturali.

Ergo lex naturalis non est actus, sed habitus.

Sed Contra

Sed contra est quod Augustinus dicit, in libro de bono coniugali, quod habitus est quo aliquid agitur cum opus est.

Sed naturalis lex non est huiusmodi, est enim in parvulis et damnatis, qui per eam agere non possunt.

Ergo lex naturalis non est habitus.

Corpus

Respondeo dicendum quod aliquid potest dici esse habitus dupliciter. Uno modo, proprie et essentialiter, et sic lex naturalis non est habitus.

Dictum est enim supra quod lex naturalis est aliquid per rationem constitutum, sicut etiam propositio est quoddam opus rationis. Non est autem idem quod quis agit, et quo quis agit, aliquis enim per habitum grammaticae agit orationem congruam.

Cum igitur habitus sit quo quis agit, non potest esse quod lex aliqua sit habitus proprie et essentialiter.

Alio modo potest dici habitus id quod habitu tenetur, sicut dicitur fides id quod fide tenetur. Et hoc modo, quia praecepta legis naturalis quandoque considerantur in actu a ratione, quandoque autem sunt in ea habitualiter tantum, secundum hunc modum potest dici quod lex naturalis sit habitus. Sicut etiam principia indemonstrabilia in speculativis non sunt ipse habitus principiorum, sed sunt principia quorum est habitus.

Ad 1

Ad primum ergo dicendum quod philosophus intendit ibi investigare genus virtutis, et cum manifestum sit quod virtus sit quoddam principium actus, illa tantum ponit quae sunt principia humanorum actuum, scilicet potentias, habitus et passiones.

Praeter haec autem tria sunt quaedam alia in anima, sicut quidam actus, ut velle est in volente; et etiam cognita sunt in cognoscente; et proprietates naturales animae insunt ei, ut immortalitas et alia huiusmodi.

Ad 2

Ad secundum dicendum quod synderesis dicitur lex intellectus nostri, inquantum est habitus continens praecepta legis naturalis, quae sunt prima principia operum humanorum.

Ad 3

Ad tertium dicendum quod ratio illa concludit quod lex naturalis habitualiter tenetur. Et hoc concedimus.

Ad 4

Ad id vero quod in contrarium obiicitur, dicendum quod eo quod habitualiter inest, quandoque aliquis uti non potest propter aliquod impedimentum, sicut homo non potest uti habitu scientiae propter somnum. Et similiter puer non potest uti habitu intellectus principiorum, vel etiam lege naturali, quae ei habitualiter inest, propter defectum aetatis.