Custom (canon law)

Custom in Catholic canon law is the repeated and constant performance of certain acts for a defined period of time, which, with the approval of the competent legislator, thereby acquire the force of law. A custom is an unwritten law introduced by the continuous acts of the faithful with the consent of the legitimate legislator.

Custom may be considered as a fact and as a law. As a fact, it is simply the frequent and free repetition of acts concerning the same thing; as a law, it is the result and consequence of that fact. Hence its name, which is derived from consuesco or consuefacio and denotes the frequency of the action. (Cap. Consuetudo v, Dist. I.)

In order for custom to become a source of law, it must be approved by the competent legislator. Custom in canon law is not simply created by the people through their constant performance of a certain act, but it is the constant performance of a certain act, with the intention of making a custom, which is approved by the competent legislator, thereby acquiring the force of law. This is because of the Catholic ecclesiological teaching on the constitution of the Catholic Church, which states that Christ constituted the Church by divine delegation of power to the hierarchical authorities; the Church was not created by the consent of the governed, but by the direct will of Christ.

The true efficient cause of an ecclesiastical custom, in as far as it constitutes law, is solely the consent of the competent legislating authority. All church laws imply spiritual jurisdiction, which resides in the hierarchy alone, and, consequently, the faithful have no legislative power, either by Divine right or canonical statute. Therefore, the express or tacit consent of the church authority is necessary to give a custom the force of an ecclesiastical law. This consent is denominated legal when, by general statute and antecedently, reasonable customs receive approbation. Ecclesiastical custom differs, therefore, radically from civil custom. For, though both arise from a certain conspiration and accord between the people and the lawgivers, yet in the Church the entire juridical force of the custom is to be obtained from the consent of the hierarchy while in the civil state, the people themselves are one of the real sources of the legal force of custom. Custom, as a fact, must proceed from the community, or at least from the action of the greater number constituting the community. These actions must be free, uniform, frequent, and public, and performed with the intention of imposing an obligation. The usage, of which there is question. must also be of a reasonable nature. Custom either introduces a new law or abrogates an old one. But a law, by its very concept, is an ordination of reason, and so no law can be constituted by an unreasonable custom. Moreover, as an existing statute cannot be revoked except for just cause, it follows that the custom which is to abrogate the old law must be reasonable, for otherwise the requisite justice would be wanting. A custom, considered as a fact, is unreasonable when it is contrary to Divine law, positive or natural; or when it is prohibited by proper ecclesiastical authority; or when it is the occasion of sin and opposed to the common good.

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