mode of thought and intense moral earnestness, the notion of duty as a distinct moral concept does not seem to have been grasped by the Greek Stoics. In the term καθῆκον, 'the suitable,' 'the fitting,' 'the proper,' we have the 'lineal antecedent' of our duty. This is the term which was translated into Latin by officium. It was probably under the influence of the Roman sternness of character and reverence for law that this notion of duty as the correlate of law first came to consciousness.
The Stoics exalted the individual in contrast with the institutions and laws of human states, but only to subordinate him again to the universal Reason and the laws of the cosmic state. The cosmopolitanism of the Stoics was an integral part of their moral philosophy. It was a cosmopolitanism, too, in the broadest etymological sense of the term; it not only brought the individual into a common citizenship and brotherhood of all nations, but also made him as a rational being a partaker of the rational life of the whole cosmos. The universe is one city governed by one law of nature; and hence all rational beings, as subjects of this law, must be fellow-citizens of the one world-city. Plato had sunk the individual in the state. The Sophists regarded men as lawless atoms, essentially unrelated. By the doctrine of the universal Reason and the law of nature, the Stoics escaped both of these extremes. While doing full justice to the individual, they still emphasized his subordination to law and order. Due weight had been given to the moral significance of the state and legal institutions in the earlier systems, but the Stoics were the first to take the term 'law' out of its strictly jural sense and apply it in a wider and more distinctively moral field.
The notion of law thus borrowed from jurisprudence was destined to be returned with interest. The most signal triumph of the Stoic doctrine of natural law was in its influence on Roman law. The conception of a law of nature furnished the statesmen and jurists of Rome with a moral basis for their law and an ideal by which to direct its reformation and development. From the middle of the second century B.C. on, Greek
