Working in the 6th century BCE, Xenophanes developed a number of ideas about the nature of divinity. The anthropomorphic gods of Homer and Hesiod received the title of "divine," though they had the same immorality and strife as mere mortals. Xenophanes seems to have reasoned that if the divine is good, then gods must not be like the gods described by Homer and Hesiod. He concludes that it is the nature of divinity to be one thing, good, unchanging, and eternal.
Indeed, Xenophanes challenges the characterization of the gods in the mythopoetic tradition when he says:
"Praise the man who after drinking behaves nobly in that he possesses memory and aims for excellence and relates neither battles of Titans nor Giants nor Centaurs - the fictions of our fathers - nor violent conflicts; there is no use in these, but it is good always to have high regard for the gods" (Curd, 32).
He specifically calls the traditional myths "fictions." These stories, he seems to think, mischaracterize the gods. However, he does not reject the entire notion of divinity. He thinks that men should be pious, despite these incorrect myths.
How then, if the myths are false, can humankind hope to know truth? Xenophanes posits natural reason as a means of coming to knowledge. He says, "By no means did the gods intimate all things to mortals from the beginning, but in time, inquiring, they discover better" (Curd, 34). Hence he rejects revelation, so often invoked of the Muses in the poetic tradition of the time. Instead of divine inspiration, humans come to truth through rational inquiry.
Additionally, Xenophanes seems to think that it is possible to learn things about the divine using human reason. He holds that there is "One god, greatest among gods and men, not at all like mortals in form or thought" (Curd, 35). Unfortunately, only fragments of his ideas remain today. His reasoning is not fully recorded. However, he probably recognized that if a god is the highest being, then there cannot be anything higher. Furthermore, anything which is different from the best is not itself the best. In all likelihood, this line of reasoning led him to conclude that the divine is one. It may also explain his belief that god is immutable and eternal.
Ultimately, Xenophanes applies the ideas of natural philosophy to the mythopoetic tradition which he had inherited. He recognizes that the ideas of divinity in the tradition entail certain necessary consequences which are different from the characterizations of the gods found in the myths of the day. Consequently, he argues for a modified conception of the gods based on a prime divinity which is immutable and eternal.