various schools of Roman jurisprudence. The passages of Roman law which touch the natural law have their source mostly in Stoic philosophical literature.
Stoicism thus reached its height at a time when the society of the ancient world was definitively splitting into two classes. On the one side stood the plebeian proletariat, kept tractable by largesses of food and other articles and by shows; on the other side stood the new aristocracy and bourgeoisie, largely given over to unrestrained pleasure-seeking and vice. Over both classes, deified and sometimes crazed Caesars eventually established a despotic rule. This environment conditioned the eclecticism of the Stoa, that circle of the few from all ranks and provinces of the world empire who placed the idea of a virtuous life and of attaining happiness of mind through the true, the good, and the beautiful above base sensuality, pursuit of wealth, and pride of life. The Stoics were individualists but, unlike the Sophists, they were not militantly opposed to the polis; indeed, the city-state no longer existed, only the world empire. Therefore they extolled, besides the individual, the social impulses and feelings. They drew upon and assimilated the intellectual goods of Heraclitus, Socrates, Plato, and Aristotle.
The core of Stoic teaching is ethics with its Socratic and, in final analysis, general Greek stamp of intellectualism, according to which correct knowledge is the basis of ethics, and the unity of knowledge and conduct forms the ideal of the sage. This last and most striking representative of the spirit of the declining civilization of antiquity comes closest to the grander representative of Christianity, the saint.
The sage is the man who carries his happiness within himself, who in inner self-sufficiency remains undisturbed by external events. Knowledge and conduct are not dependent on the irregular influences of the world: the sage is calm, unmoved by passion. It is owing to the passions and their excesses that clearness of perception and judgment becomes impossible. For this reason man does not attain to a clear knowledge and judgment of what is truly worth striving for. This consists essentially in conformableness to the rational nature of the sage. Virtue consists in the positive determination of conduct through will power in accordance with rational insight into man’s essential nature. Virtue is right reason. Nature and reason are one. Right reason and the universal law of nature, which holds undisputed sway throughout the universe, are also one. Obedience to the eternal world law in a life lived according to reason: such, embraced with religious fervor, is the ethical principle of Stoicism. It thus means to live in harmony with oneself, to live in accordance with one’s rational nature; for the latter manifests the world law.
Law, too, has its basis in nature. Man has an inborn notion of right and wrong, and law in its very essence rests not upon the arbitrary will of a ruler or upon the decree of a multitude, but upon nature, i.e., upon innate ideas (non scripta sed nata lex).10 Cicero (106–43 B.C.) was the interpreter and transmitter of the Stoic doctrine of natural law. The LEX NATA, the law within us, he regards as the foundation of law in general. It is not to be gathered, as a general concept by way of abstraction, from the law of the Twelve Tables or from the praetor’s edict—that is, from the positive law—but EX INTIMA PHILOSOPHIA. Since it is identical with right reason, it is universally valid, unchangeable and incapable of being abrogated; for its author is the divine reason itself—taken, of course, in a pantheistic, impersonal sense. It is also called eternal law. Cicero could thus write: “If the principles of Justice were founded on the decrees of peoples, the edicts of princes, or the decisions of judges, then Justice would sanction robbery and adultery and forgery of wills, in case these acts were approved by the votes or decrees of the populace. But if so great a power belongs to the decisions and decrees of fools that the laws of Nature can be changed by their votes, then why do they not ordain that what is bad and baneful shall be considered good and salutary? Or, if a law can make Justice out of Injustice, can it not also make good out of bad? But in fact we can perceive the difference between good laws and bad by referring them to no other standard than Nature: indeed, it is not merely Justice and Injustice which are distinguished by Nature, but also and without exception things which are honourable and dishonourable. For since an intelligence common to us all makes things known to us and formulates them in our minds, honourable actions are ascribed by us to virtue, and dishonourable actions to vice; and only a madman would conclude that these judgments are matters of opinion, and not fixed by Nature.”11 Time and again the gifted rhetorician contrasts in this manner the law of nature, as the measure and inner source of validity, with the positive law, which to him is a shadow and reflected image of the true law.12
Epictetus (cir. A.D. 60–110) likewise called attention to the diversity of the laws that prevail at various times and among different peoples. He taught that the test of whether or not a law accords with nature consists in its agreement or non-agreement with reason. The laws that upheld slavery he called laws of the dead, an abysmal crime. Seneca (d. A.D. 65), in the teeth of the prevailing institution of slavery, gladiatorial combats, and shows featuring the throwing of human beings to beasts, voiced this magnificent sentiment apropos of human dignity: homo sacra res homini.13 What were originally Sophist doctrines were gaining fresh currency: the dignity of the human being and the natural-law basis of freedom and equality. Slaves, too, are men, blood relations and brethren. Like freemen, they are God’s own children, members of a great community. The city-state has thus lost its power, and with it has disappeared the differentiation of mankind into Greeks and barbarians, into freemen and slaves. “All that you behold, that which comprises both god and man, is one—we are the parts of one great body. Nature produced us related to one another since she created us from the same source and to the same end. She engendered in us mutual affection, and made us prone to friendships. She established fairness and justice.”14 A magnificent statement of the civitas maxima, the great society or world state, and of its fundamental law, the natural law! As Marcus Aurelius expressed it: “My city and country, so far as I am Antoninus, is Rome, but so far as I am a man, it is the world.”15
These Stoic views are singularly impressive in an environment that was replete with despotic brutality and contempt for man, with excesses and misuse of power, with a many-sided suppression of freedom. It is of far greater consequence, however, that they penetrated into Roman law, led to a recognition of the individual in private law, and elevated to the dignity of natural law the more liberal principles of the ius gentium which had developed out of the law of foreigners. Above all, they brought to the original tribalism and formalism of Roman law a universalism which fitted it “to survive, as a world law, the life of the nation in which it had originated” (Puchta). Among the later Stoics, too, we find the doctrine of a state of nature, a happy condition of mankind in which all the Stoic ideals of right and freedom had been realized and where the pure natural law had consequently been in force.16 The status civilis, on the other hand, with slavery organized and protected by the positive law, was looked upon as a state of affairs in which the natural law, though continuing in force, no longer holds sole sway.
In Stoicism, then, the mind of the ancient world had come to embrace whatever views Heraclitus, Plato, Aristotle, and the moderate Sophists had held regarding the natural law—all that they had taught touching the lex aeterna, recta ratio, lex naturalis, ius naturale, as well as concerning the connections of these with positive law and their evaluating force in relation to it. It thus preserved the “seeds of the Logos,” and it found the literary forms or word vessels into which the Christian spirit was to pour its own ideas, which eventually matured into a new, yet related, doctrine of natural law.
Under the influence of Stoic philosophy the doctrine of the natural law passed into Roman law. The great jurists of the golden age of Roman law were for the most part also philosophers. Through the medium of eclectic Stoicism they were acquainted with Aristotle’s teaching on justice and with Zeno’s work On the Laws; especially, however, they were familiar with the writings of Cicero, the popular philosopher of Stoicism. Besides, the forensic orators were interested in philosophy in their pleadings at the bar. Among these Cicero held first place, but there were also Q. Mucius Scaevola, Calpurnius, and Rutilius, as Cicero himself informs us. This philosophical bent is likewise evidenced by the frequency with which the jurists cite the philosophers. Gaius, for example, quotes Aristotle and Xenophon; Ulpian and Celsus quote Cicero; Paulus
