  That portion of our positive law which consists of legal principles or rules giving effect to purposes such as those just listed was often named, by natural law theories, ius [or jus] gentium. Minted by jurists of classical Roman law such as Gaius (c. 165 AD), this name—literally “the law of peoples”—alludes to the set of rules and principles found in similar if not identical forms in virtually all legal systems. The reason for their ubiquity is, generally speaking, that any reasonable consideration of what it takes for individuals, families and other associations to live together in political society, tolerably well, will identify these principles and rules as necessary. In modern law they are picked out, in principle, by names such as “the general principles of law recognized by civilized nations” (Statute of the International Court of Justice, art. 38), ius cogens erga omnes (literally “law that is compelling [obligatory without agreement or enactment or other forms of adoption] in relation to [for/on, ‘against’] everyone”), “higher law”, or “fundamental human rights.” In Aquinas’s theory of law, they are referred to as conclusions (entailments) of the very highest-level, most general moral principles. In the common law tradition, the legal wrongs picked out by such principles have been called mala in se, as distinct from mala prohibita—things wrong in themselves as distinct from things wrong only because prohibited by (positive) law—and this distinction remains, for good reason, in use in judicial reasoning.