If one were to compare in a single word the history of Greece before the Persian Wars with that after the Persian Wars, he would say that the former was traditional and the latter was critical. Nevertheless, at the beginning of the Cosmological Period Greek traditional customs were being weakened by attacks upon them. Religious ideas were threatened by the Cosmologists. The subordination of the gods to the cosmic substance was an attack upon the established polytheism of the Epic, and the attack became direct in the hands of Xenophanes. It was “the divestiture of Nature of its gods by science.” The Mysteries were a part of this departure from the traditional religion. But the new and more critical scientific attitude toward traditional religion was only incidental to the growing criticism of law. In the days of the oligarchy there were two self-evident political assumptions: (1) that law has validity because it is law; (2) that obedience to law is for one’s advantage. When, however, the political disturbances began, a self-conscious individualism developed among the Greeks. The Gnomic Poets had been the first to appeal to the individual consciousness of the people. All through the sixth century B. C. Greece had stern experiences, and the individual found himself questioning the sanctity of tradition and of time-honored laws. There was no longer a tacit acquiescence in established order, and the claims of authority were no longer, as formerly, unchallenged. Confidence in political assumptions began to waver, and a critical attitude was taken toward laws which changed from year to year. The appearance everywhere of the tyrant, the vigorous personality who could set up his will against the will of a traditional aristocracy, impressed the age with the power of individual egoism. The seat of authority was shifted from tradition to the individual reason, and all institutions were brought under individual criticism. The Persian Wars mark the point of transition from the traditional attitude to the critical attitude of the Greek mind. In themselves the Persian Wars were a great moral uplift, and were a return for a time to the traditional institutions. The changes long since begun were suspended for a time in the united effort of the Greek nation. But the tendencies became more insistent when the danger was past. The Persian Wars had cleared the atmosphere of its pessimism and had given freedom to the intellectual movement. Then later, in the heat of that intellectual movement, individualism and criticism came to fullest fruitage. Doubt grew into positive skepticism.