Law, however, though it also contains much that is of moral importance, can and does contain just such rules, and the arbitrary distinctions, formalities, and highly specific detail which would be most difficult to understand as part of morality, are consequently natural and easily comprehensible features of law. For one of the typical functions of law, unlike morality, is to introduce just these elements in order to maximize certainty and predictability and to facilitate the proof or assessments of claims.

H. L. A Hart, The Concept of Law, loc. 534