In what measure these moralists and philosophers whom we have quoted really represented their times it is of course impossible to say; but probably we would not be wrong in assuming that they appealed to a certain public sentiment, and that the doctrines they taught evoked consenting response from the moral consciousness of more than a few in every rank of Roman society. [Sidenote: The Stoic doctrine of the Law of Nature and its ethical influence] The doctrine of the Law of Nature, upon which such emphasis was laid by the Stoic philosophers, had such consequences for the evolution of Roman morals and so great an influence upon the moral philosophers of later times, particularly upon the speculations of the philosophers of the eighteenth century, that we must in the present connection endeavor to gain some idea of what the Stoics meant by this phrase, and the ethical value of the conception.[566] The Law of Nature is merely the Stoic designation of a law which, under other names, all the ages have revered as the supreme law of the universe. It is practically the law of conscience, the inner law written on the hearts of men.[567] It is that law which is in the background of our consciousness when we say, “We must obey God rather than man.” It is that holy law which came to Hebrew prophet as the word of Jehovah. It is that inviolable law which Antigone feared to break, “a law not proclaimed by men, and which lives not for to-day nor yesterday, but evermore.”[568] It is what the Supreme Court of the United States in a recent decision calls “the rule of reason,” that inborn sense of what is reasonable and just. This Law of Nature being thus the expression of what is most constituent and essential in man as man, it necessarily results that there is a large common element in the customs and the rules of conduct of all peoples who are in the same or nearly the same stage of culture; hence the substantial conformity between the Law of Nature and the Laws of Nations. The conformity, however, is not perfect. The moral task of humanity is to make it perfect. It is of course the ethical imperative of the Law of Nature which has rendered it such a revolutionary and reconstructive force in history. During the medieval period it was seldom invoked because the Church and not the normal human reason was regarded as the supreme authority in the domain of morals. But after the Renaissance and the Reformation had proclaimed the autonomy of the individual spirit and the ultimate authority of the individual conscience in the realm of moral right and wrong, then came naturally an appeal from the rules and conventions of society to the unwritten Law of Nature; hence the prominence it assumed in the writings of the philosophers of the eighteenth century, who prepared the way for the French Revolution.