In fact, considering the peculiarities of rival laws, which were either customs of barbarous nations, or corporation privileges, or papal or imperial concessions, this law appeared as the universality of _written reason_. Had it not arrived at the point of regarding human personality in its most abstract and human relations, since a certain Titius is capable of becoming debtor and creditor, of selling and buying, of making a cession, a donation, etc.? Roman law, although elaborated in its last editing at the command of emperors by servile parasites, appeared then, amid the decline of mediaeval institutions, as a revolutionary force, and as such it constituted a great step of progress. This law, so universal that it gave the means of overthrowing barbaric laws, was certainly a law which corresponded to human nature considered under its generic relations; and by its opposition to private laws and privileges it appeared as a natural law. We know, moreover, how this ideology of natural law arose. It acquired its greatest distinction in the seventeenth and eighteenth centuries; but it had long been prepared for by the jurisprudence which took for its base the Roman law, whether it adopted it, revised it, or corrected it. To the formation of the ideology of natural law another element contributed, the Greek philosophy of later epochs. The Greeks, who were the inventors of those definite arts of the mind which are sciences, never, as is known, drew from their multiple local laws a discipline corresponding to that which we call the science of law. On the contrary, by the rapid progress of abstract research in the circle of their democracies, they arrived very soon at a logical, rhetorical and pedagogical discussion on the nature of justice, the state, the law, penalty; and in their philosophy we may trace the rudimentary forms of all later discussions. But it is not until later, that is to say, in the Hellenistic epoch, when the limits of Greek life were sufficiently enlarged to be mingled with those of the civilized world, that, in the cosmopolitan environment which carried with it the need of searching in each man for the generic man, the rationalism of justice arose--of justice or of natural right in the form given it by the stoic philosophy. The Greek rationalism which had already furnished a certain formal element to the logical codification of Roman law reappeared in the eighteenth century in the doctrine of natural right.