What is "determinatio"

A determinatio is an authoritative determination by the legislator concerning the application of practical principles, that is not necessitated by deduction from natural or divine law but is based on the contingencies of practical judgement within the possibilities allowed by reason.

In natural law jurisprudence, determinatio is the process of making natural law into positive law In Catholic canon law, determinatio is the act by which natural law or divine positive law is made determinate in the canonical legal system as specific norms of law, although the content of such law is still essentially that of divine law, which, together with canon law, forms "a single juridical system of law".

The concept derives from the legal philosophy of Thomas Aquinas, and continues to be a part of discussions in natural law theory.