Like the other founders of Greek philosophy, Xenophanes lived in Ionia and investigated natural phenomena such as the basic substances, the history and structure of the cosmos, and weather phenomena. He is best known for his criticisms of religious beliefs and practices, for his own conception of the divine, and for being the earliest philosopher to discuss epistemological questions. A poet who traveled widely in Greek lands, he composed his philosophical work in verse, presumably for performance, which suggests that his radical theological views were not abhorrent to his audiences. Some forty fragments of his writings survive, more than one hundred lines, far more than what remains from any earlier philosopher.

His theological fragments consist in statements that seemingly criticize the anthropomorphic polytheism of Greek tradition and in pronouncements on the true nature of...