A customary practice of those whose role it is to apply primary rules, a rule of recognition provides criteria of legal validity by determining which acts create law. So the fundamental constitution of a legal system does not rest on moral justifications or logical presuppositions, but on this customary social rule created by ‘a complex … practice of the courts, officials, and private persons’ (107).

H. L. A Hart, The Concept of Law, loc. 56