The persons of whom it is related that they denied the existence of the ancient gods are in themselves few, and they all belong to the highest level of culture; by far the greater part of them are simply professional philosophers. Hence the inquiry will almost exclusively have to deal with philosophers and philosophical schools and their doctrines; of religion as exhibited in the masses, as a social factor, it will only treat by exception. But in its purpose it is concerned with the history of religion, not with philosophy; therefore—in accordance with the definition of its object—it will deal as little as possible with the purely philosophical notions of God that have nothing to do with popular religion. What it aims at illustrating is a certain—if you like, the negative—aspect of ancient religion. But its result, if it can be sufficiently established, will not be without importance for the understanding of the positive religious sense of antiquity. If you want to obtain some idea of the hold a certain religion had on its adherents, it is not amiss to know something about the extent to which it dominated even the strata of society most exposed to influences that went against it. It might seem more natural, in dealing with atheism in antiquity, to adopt the definition current among the ancients themselves. That this method would prove futile the following investigation will, I hope, make sufficiently evident; antiquity succeeded as little as we moderns in connecting any clear and unequivocal idea with the words that signify “denial of God.” On the other hand, it is, of course, impossible to begin at all except from the traditions of antiquity about denial and deniers. Hence the course of the inquiry will be, first to make clear what antiquity understood by denial of the gods and what persons it designated as deniers, and then to examine in how far these persons were atheists in our sense of the word. CHAPTER I Atheism and atheist are words formed from Greek roots and with Greek derivative endings. Nevertheless they are not Greek; their formation is not consonant with Greek usage. In Greek they said _atheos_ and _atheotes_; to these the English words ungodly and ungodliness correspond rather closely. In exactly the same way as ungodly, _atheos_ was used as an expression of severe censure and moral condemnation; this use is an old one, and the oldest that can be traced. Not till later do we find it employed to denote a certain philosophical creed; we even meet with philosophers bearing _atheos_ as a regular surname. We know very little of the men in question; but it can hardly be doubted that _atheos_, as applied to them, implied not only a denial of the gods of popular belief, but a denial of gods in the widest sense of the word, or Atheism as it is nowadays understood.