Little is known for certain concerning his philosophical views or the nature of his alleged atheism. All that is known for certain on the point is that Diagoras was offended by the worship of the Athenian
national gods.
Ancient anecdotes Cicero, writing in the 1st century BC, tells of how a friend of Diagoras tried to convince him of the existence of the gods, by pointing out how many votive pictures tell about people being saved from storms at sea by "dint of vows to the gods", to which Diagoras replied that "there are nowhere any pictures of those who have been shipwrecked and drowned at sea." And Cicero goes on to give another example, where Diagoras was on a ship in hard weather, and the crew thought that they had brought it on themselves by taking this ungodly man on board. He then wondered if the other boats out in the same storm also had a Diagoras on board. This and similar anecdotes accurately describe the relation in which he stood to the popular religion. That he maintained his own position with great firmness, and perhaps with more freedom, wit, and boldness than was advisable, seems to be attested by the fact that he in particular obtained the epithet of atheist in antiquity. It is possible that he merely denied the direct interference of gods with the world, but that, since he did not believe in the personal existence of the Athenian gods and their human mode of acting, the Athenians could hardly have regarded him as other than an atheist. The Christian writer
Athenagoras of Athens (2nd century AD) writes about Diagoras: To return to the accusation against Diagoras which obliged him to quit Athens, the time was one in which
scepticism was beginning to undermine the foundations of the ancient popular belief. The trial of those who had broken down the statues of
Hermes, the profanation of the
mysteries, and the accusation of Alcibiades, are symptoms which show that the unbelief, nourished by the speculations of
philosophers and the
sophists, began to appear very dangerous to the conservative party at Athens. There is no doubt that Diagoras paid no regard to the established religion of the people, and he may occasionally have ridiculed it; but he also ventured on direct attacks upon public institutions of the Athenian worship, such as the
Eleusinian Mysteries, which he endeavoured to lower in public estimation, and he is said to have prevented many persons from becoming initiated in them. These at least are the points of which the ancients accuse him, and the historian
Melanthius, in his work on the mysteries, mentions the decree passed against Diagoras. There were undoubtedly political motives in all these religious disputes. Diagoras was a Melian, and consequently belonged to the
Dorian race; he was a friend of the Dorian
Mantineia, which was hated by Athens, and had only recently given up its alliance with Athens; the Dorians and
Ionians were opposed to each other in various points of their worship, and this spark of hostility was kindled into a growing hatred by the
Peloponnesian War. Diagoras fled from Athens in time to escape the consequences of the attacks which his enemies had made upon him. He was therefore condemned, and the
psephisma was engraved on a column, promising a prize for his head, and one
talent to the person who should bring his dead body to Athens, and two talents to him who should deliver him up alive to the Athenians.
Modern appraisal J. M. Robertson writes on Diagoras that: The relation of Diagoras to the popular religion and theology of his age can not be explained without going back to the opinions of the
Natural philosophers, and the intellectual movement of the time. The
Pre-Socratic philosophers had increasingly explained natural phenomena in terms of natural laws without the need for divine intervention. In particular, the
atomism of Democritus had substituted for a world-governing god the relation of cause and effect as the sources of all things. Democritus explained the widespread belief in gods as the result of fear of unusual and unaccountable phenomena in nature; and, starting from this principle, Diagoras, at a time when the ancient popular belief had already been shaken, especially in the minds of the young, came forward with the doctrine that there were no gods at all. His attacks seem to have been mainly directed against the dogmas of Greek
theology and
mythology, as well as against the established forms of worship. According to the fashion of the sophists, which is caricatured by Aristophanes in
The Clouds, he substituted the active powers of nature for the activity of the gods; and some isolated statements that have come down to us render it probable that he did this in a witty manner.
Jennifer Michael Hecht writes on Diagoras that: == Editions ==