As to the relation of the Cyrenaic school to the popular faith, the general proposition has been handed down to us that the wise man could not be “deisidaimon,” _i.e._ superstitious or god-fearing; the Greek word can have both senses. This does not speak for piety at any rate, but then the relationship of the Cyrenaics to the gods of popular belief was different from that of the other followers of Socrates. As they set up pleasure—the momentary, isolated feeling of pleasure—as the supreme good, they had no use for the popular conceptions of the gods in their ethics, nay, these conceptions were even a hindrance to them in so far as the fear of the gods might prove a restriction where it ought not to. In these circumstances we cannot wonder at finding a member of the school in the list of _atheoi_. This is Theodorus of Cyrene, who lived about the year 300. He really seems to have been a downright denier of the gods; he wrote a work _On the Gods_ containing a searching criticism of theology, which is said to have exposed him to unpleasantness during a stay at Athens, but the then ruler of the city, Demetrius of Phalerum, protected him. There is nothing strange in a manifestation of downright atheism at this time and from this quarter. More remarkable is that interest in theology which we must assume Theodorus to have had, since he wrote at length upon the subject. Unfortunately it is not evident from the account whether his criticism was directed mostly against popular religion or against the theology of the philosophers. As it was asserted in antiquity that Epicurus used his book largely, the latter is more probable. Whereas in the case of the “imperfect Socratics” as well as of all the earlier philosophers we must content ourselves with more or less casual notes, and at the best with fragments, and for Socrates with second-hand information, when we come to Plato we find ourselves for the first time in the presence of full and authentic information. Plato belongs to those few among the ancient authors of whom everything that their contemporaries possessed has been preserved to our own day. There would, however, be no cause to speak about Plato in an investigation of atheism in antiquity, had not so eminent a scholar as Zeller roundly asserted that Plato did not believe in the Greek gods—with the exception of the heavenly bodies, in the case of which the facts are obvious. On the other hand, it is impossible here to enter upon a close discussion of so large a question; I must content myself with giving my views in their main lines, with a brief statement of my reasons for holding them.