But, even of rules of decision, the smallest part is the result of State action. Every sort of protection of rights by the State begins with enforcing the payment of compensatory damages, which in primitive times the injured party sought to recover on his own authority and by his own power. At the moment when the judgment of a court is substituted for this primitive self-help, there are no rules of decision in existence except those flowing from the very nature of the social organization. In other words, they are derived from such sources as the nature of property in the form it assumed directly under the conditions of primitive ownership; also from the nature of those associations which are of so much importance in primitive society, like the clan, the family, the community, the guild; from the customary subject-matters and forms of the most ancient contracts, and the primitive forms of intercourse, which are mostly older than any sort of legal protection. Decisions are first preserved by oral tradition, then written down, collected, commented upon, generalized, and at last codified. Thus arise those peculiar systems of law in the special keeping of lawyers, which are, in many different forms, characteristic of the early times of all the nations of the world. They are legal science and legal rule all in one, like the old "jus civile" of the Romans which still lives, unchanged in essentials, in the writings of the classical Roman jurists and the great compilation of Justinian.
The decisions, therefore, are not based on the rules of law, but the rules of law are deduced from the decisions. The law on which the decisions are based is the "jus quod est." Paulus, who could still observe the actual working of a living law of this kind, puts what he has learned in actual experience tersely into the famous maxim: "Non ex regula jus sumatur, sed ex jure quod est regula fit." The decisions are older than the rules, - the law of the lawyers older and incomparably richer than the law of legislatures.