§ 1. On the Conditions of Legitimate Custom

262. The conditions, in order that custom constitute right, are required partly on the part of the community, partly on the part of the object, partly on the part of the prince.

I. ON THE PART OF THE COMMUNITY. Custom ought to be induced by a community capable of law, or at least by the greater part of it, through public, frequent, free, uninterrupted acts, placed with the intention of constituting right, for a long time.

It is said 1. By a community, not any whatever, but capable of law, that is, which is capable of legislative power for itself, or at least sufficient that true law can be imposed upon it (cf. n. 109, 4.).

2. Or at least by the greater part of it; because obligation is induced by the community, with the prince consenting; but it would not truly be induced by the community if only the lesser part observed the custom. But the greater part already morally represents the community.

3. Through public acts: so that all of the people, or the greater part, can come together in rendering consent, and such a custom can be known to the prince; and therefore the acts ought to be public, at least by notoriety of fact.

4. Through frequent acts; for two or three acts do not suffice, as some have less rightly supposed; but it is required that the acts be repeated several times, according to the judgment of prudent men, so that from them the consent of the community can reasonably be gathered (I, 107, 3.).

5. Through free acts, that is, not exercised from force, fear, or error; for the people cannot be presumed to will to establish right through acts which they themselves place either unwillingly or from mere error: nor is the Superior himself, in adjuncts of this kind, judged to consent (H. Ap., II, 79, 80).

6. Through uninterrupted acts, that is, confirmed by continued use; because if the people have placed one single act contrary to the custom, or the prince has punished the acts of the people, prescription against the law would have to be begun again.

7. Through acts placed with the intention of constituting right, that is, with the intention of imposing a law on themselves, if custom beyond right is introduced; or of exempting themselves from law, if custom against right is introduced. The reason is, because only then is the prince presumed to acquiesce in the community. But the mind of obliging oneself under grave matter is gathered from circumstances, namely if the custom is constantly observed, with not light inconvenience, if transgressors are punished, if thus pious men commonly think (cf. n. 1224, 1. and n. 2204, 3.). See St. Alph., III, 1009, dub. 3; IV, 142, where he treats of the obligation of reciting the office which custom has imposed on nuns and religious.

From this you will infer: 1. Custom beyond law is not induced if the people or the greater part of it acts from devotion, gratitude, or a similar motive, for example, by reciting the angelic salutation at the signal of the bell. 2. Nor does desuetude or custom against law prevail if the law is violated only inconsiderately and with the mind of not satisfying it;¹ for some intention of de-obliging oneself is required. Nevertheless, if a law is not observed for a long time in good faith, namely from ignorance of the law, it can prevail by way of prescription. Namely, it suffices that, with the opinion that the law does not exist, the people in good faith do not observe it (H. Ap., II, 80).

8. Placed for a long time, which nevertheless is diverse according as there is had the personal or legal consent of the prince (cf. n. 264). When personal consent stands on the part of the prince, a time so long-lasting is not required for legitimating custom; but when legal consent stands, a decade suffices, so that custom beyond law, or custom against a law not yet received by use, may be induced, indeed even so that any law whatever, whether civil or ecclesiastical, may be abrogated.

This last thing St. Alphonsus (I, 139) teaches as probable with grave authors, against others who require 40 years. Cf. the assertions of the Holy Doctor, III, 849; Benedict XIV, de Synodo, l. 13, c. 5, n. 4.

Note. On the part of the community, good faith is not required of itself,² so that this custom alone becomes legitimate which began without sin. "In the beginning, those introducing custom against law all sin. In progress, those using it when it has already been introduced by their elders do not sin, but they can be punished. But at the end, those using it when it has already prescribed neither sin nor can be punished." St. Alph., I, 107; ed. G., I, p. 89.

263. II. ON THE PART OF THE OBJECT. Custom ought to be good and reasonable.³ The reason is, because it ought to be, like law, an ordinance of reason. Now indeed, custom must be held good and rational if its object is such that it could have been the matter of a just law. Whence it ought neither to be opposed to natural or divine right, that is, to be evil in itself, nor to be reprobated by canonical right as weakening discipline, nor to furnish license or occasion of sinning, nor to stand against common utility. Thus the custom of not accepting decrees of the Holy See, of not receiving its legates, etc., is of no strength (cf. Reiffenst. in l. I Decr., t. IV, n. 34).

Note. 1. It is not required that custom be positively reasonable, but it suffices that it be negatively consonant with reason, so that nothing impedes it from becoming reasonable in the course of time, or from its being reasonable not to urge its observance further, lest delicts be multiplied.

2. In doubt, and when the judgment of prudent men is lacking, it is to be presumed that a custom is reasonable from its possession, that is, from the fact that it has been introduced.

264. III. ON THE PART OF THE LEGISLATOR. For establishing custom, the consent of the legislator is required, whether personal or legal; because the power of establishing or abrogating laws belongs not to the people, but to the legislator (I, 107). Now indeed:

1. Personal consent is that by which the prince through himself immediately approves the custom, either expressly, by giving license that it be induced; or tacitly, when, conscious that a custom is to be introduced, he does not resist it, although he could easily resist. In this case, custom is said to be introduced by way of connivance, and therefore, if by certain indications the tacit consent of the legislator is clear, a long-lasting time is not required.

But observe that custom is not confirmed by silence commanded by prudence, namely if the Pope or prince is silent on account of fear of a greater evil, for example, schism, rebellion. Whence that common saying: "The Church suffers many things which she does not approve" (cf. 164, 2.).

2. Legal consent, always-presumed, is had when the legislator, even if perhaps he is ignorant of the custom, consents to it through the general will expressed in right of approving any reasonable custom whatever as soon as it has been legitimately prescribed. In this case, custom obtains force by way of prescription. See the things said n. 262, 8.

265. IT IS ASKED. What must be done in doubt concerning custom?

Resp. 1. In invincible doubt whether custom beyond law exists or not, whether it has prescribed, whether there was present the mind of obliging oneself, etc., you are held to nothing; because custom of this kind is a new law, which, if it doubtfully exists, does not oblige. If you doubt whether it obliges under grave or under light matter, to fault or to penalty, the more benign part is to be held.

2. In doubt whether desuetude or custom against law exists already prescribed or not, you are held to the law; because this is in possession, and a certain law does not cease through an uncertain contrary cause. Nevertheless, the statement of an outstanding Doctor, even a modern one, asserting that the law has been abrogated, suffices so that we may be de-obliged from the law; for such authority, when it is not weakened by other Doctors, effects moral certitude (cf. n. 63, 3. and 4.). Read our Holy Doctor, I, 107; ed. G., I, p. 89; III, 290; ed. G., I, p. 560, where he proves the words of Mazzotta: in doubt concerning custom, the precept possesses, and dispensation is to be sought; otherwise, if it is probable that custom is present.