Question Tenth. On Custom.

200. Definition. The word custom is taken in two ways: a. causally, for acts frequently repeated by a community; b. formally, for the right which, with the consent of the legislator acceding, arises from those acts. Hence custom formally can be defined as a certain right or law introduced by long-standing use of a community, with the approval of him who has care of that community.

The distinction which intervenes between (derogatory) custom and prescription of right, with which custom is sometimes confused, must be carefully noted: for some principles govern custom, others govern prescription; wherefore the same conditions are not required in both. Especially, however: a. good faith is required for prescription; it is not required for custom; b. for prescription the consent of him against whom prescription is made is not required, but for custom the consent of the legislator is required; c. for prescription a time, sometimes longer, sometimes shorter, determined by law is required; for introducing custom, time is indeed ordinarily required, but to be determined by the judgment of prudent men, which nevertheless is not extended beyond ten years.

201. Division. 1. By reason of extension, custom is divided into universal or most general, which is in force in the whole Church; into general (in itself it is particular), which is in force in some whole province; into special, which is in force in smaller societies, but nevertheless perfect ones, i.e. societies capable of laws; and into most special, which is observed by private persons and imperfect societies, namely those which are not capable of law. It is clear that this last does not have the character of law, but after the manner of a privilege is only a faculty of doing or omitting something.¹

2. By reason of relation to law, custom is divided into custom against law, which removes an existing law either altogether or at least in part; custom beyond law, which introduces a new law; custom according to law, which confirms or interprets an existing law by use itself.

a. From this division it is clear that the effect of custom is threefold: a. of interpreting law; b. of introducing a new law; c. of abrogating an existing law.

b. Only a twofold custom must be treated here: a. derogatory custom or custom against law, and b. obligatory custom or custom beyond law.

¹ Cf. Wernz I. n. 187.