The man who took the boldest step to making the underlying substrata of the world a god was Xenophanes, a Pythagorean of the sixth century. In his best known statement he attacked all anthropomorphic conceptions of gods.

Mortals imagine that the gods are begotten, and that the gods wear clothes like their own, and have voice (or language) and form like the voice and form of mortals... but if oxen and horses or lions had hands or could draw and do the work with their hands that men do, horses would have drawn the form of gods like horses, and oxen gods like oxen, and they would represent the bodies of the gods as just like their own forms.

He expressed explicitly what had been evolving for the past century or so, an idea that was to find fertile ground two centuries later in Aristotle, and a millennia later in the Theology of St. Thomas Aquinas. The idea that the underlying substrata is not a substance, or a material, it was pure causation. This, he said, was developed through reasoning. "The gods have not revealed all things to mortals from the beginning, but by searching out, in the course of time, that which is better." His final conclusion is straight forward and clear.

Ethiopians make their gods sub-nosed and black; Thracians make theirs blue-eyed and red-haired. ..There is One God, greatest among gods and men, not like mortals in form or in thought. . . The One God is all sight, and is all thought , and is all hearing. . . But the One God without effort brandishes all things by the thought of his mind. . . The One God abides ever in the same, never moving; nor is it fitting that he travel now in this direction, now in that.

Pythagorus worshiped the one, but he contrasted it with the many, the changing. For Xenophanes the changing many faded into a mere world of phenomena. The many gods of the past became mere appearances, mere phenomena of nature. His One God belonged to truth and reality. Xenophanes glorified his One God by removing from it all unworthy attributes. However, it is not the kind of God the moderns imagine. His God was a pure abstraction.