The above information explains the origin of the legend. Two fixed points were in existence: the pious poet of _c._ 460 and the atheist who was outlawed in 415; a bridge was constructed between them by the story of the stolen ode. This disposes of the whole supposition of atheism growing out of a basis of experience. But, furthermore, it must be admitted that it is doubtful whether the poet and the atheist are one and the same person. The interval of time between them is itself suspicious, for the poet, according to the ancient system of calculation, must have been about forty years old in 464, consequently between eighty and ninety in 415. (There is general agreement that the treatise, the title of which has been quoted, must have been a later forgery.) If, in spite of all, I dare not absolutely deny the identity of the two Diagorases of tradition, the reason is that Aristophanes, where he mentions the decree concerning Diagoras, seems to suggest that his attack on the Mysteries was an old story which was raked up again in 415. But for our purpose, at any rate, nothing remains of the copious mass of legend but the fact that one Diagoras of Melos in 415 was outlawed in Athens on the ground of his attack on the Mysteries. Such an attack may have been the outcome of atheism; there was no lack of impiety in Athens at the end of the fifth century. But whether this was the case or not we cannot possibly tell; and to throw light on free-thinking tendencies in Athens at this time, we have other and richer sources than the historical notice of Diagoras.
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. Their criticism was fundamental and central, not casual and circumstantial.