With the movement in Greek thought which is generally known as sophistic, a new view of popular belief appears. The criticism of the sophists was directed against the entire tradition on which Greek society was based, and principally against the moral conceptions which hitherto had been unquestioned: good and evil, right and wrong. The criticism was essentially negative; that which hitherto had been imagined as absolute was demonstrated to be relative, and the relative was identified with the invalid. Thus they could not help running up against the popular ideas of the gods, and treating them in the same way. A leading part was here played by the sophistic distinction between _nomos_ and _physis_, Law and Nature, _i.e._ that which is based on human convention, and that which is founded on the nature of things. The sophists could not help seeing that the whole public worship and the ideas associated with it belonged to the former—to the domain of “the law.” Not only did the worship and the conceptions of the gods vary from place to place in the hundreds of small independent communities into which Hellas was divided—a fact which the sophists had special opportunity of observing when travelling from town to town to teach; but it was even officially admitted that the whole ritual—which, popularly speaking, was almost identical with religion—was based on convention. If a Greek was asked why a god was to be worshipped in such and such a way, generally the only answer was: because it is the law of the State (or the convention; the word _nomos_ expresses both things). Hence it followed in principle that religion came under the domain of “the law,” being consequently the work of man; and hence again the obvious conclusion, according to sophistic reasoning, was that it was nothing but human imagination, and that there was no _physis_, no reality, behind it at all. In the case of the naturalists, it was the positive foundation of their system, their conception of nature as a whole, that led them to criticise the popular belief. Hence their criticism was in the main only directed against those particular ideas in the popular belief which were at variance with the results of their investigations. To be sure, the sophists were not above making use of the results of natural science in their criticism of the popular belief; it was their general aim to impart the highest education of their time, and of a liberal education natural science formed a rather important part. But their starting-point was quite different from that of the naturalists. Their whole interest was concentrated on man as a member of the community, and it was from consideration of this relation that they were brought into collision with the established religion. Hence their attack was far more dangerous than that of the naturalists; no longer was it directed against details, it laid bare the psychological basis itself of popular belief and clearly revealed its unstable character.