Canonical Custom

Custom in the technical canonical sense is not whatever is familiar, old, or locally popular. Under the Latin Code it must be introduced by a community capable at least of receiving law and observed with the intention of introducing a juridically binding norm. Only a custom approved by the legislator according to the Code's rules obtains the force of law.

This doctrine respects the legal significance of a community's sustained practice without allowing usage to become a private dispensation. An individual habit, tolerated abuse, administrative convenience, or repeated violation of law is not thereby canonical custom.

The Eastern Code describes a reasonable custom introduced by the continuous and peaceful practice of a community capable of receiving law. It can receive force before the prescriptive period through at least the tacit consent of the competent legislator. This formulation should be cited on its own terms rather than silently replaced with the Latin canon's wording.^[1]

No custom contrary to divine law can acquire legal force. A custom contrary to canon law or apart from it must be reasonable, and a custom expressly reprobated by law is not reasonable. Unless the competent legislator specifically approves it, a contrary or extra-legal custom must be observed legitimately for thirty continuous and complete years; only a centenary or immemorial custom can prevail against a law that prohibits future customs.

Custom is the best interpreter of laws because settled lawful practice can disclose how a norm is understood and applied. A contrary custom or law can revoke an existing contrary or extra-legal custom. Universal law does not revoke a particular custom unless it expressly does so, and a later law does not revoke centenary or immemorial customs without express mention, subject always to the Code's special treatment of earlier customs.^[2]