Both these classes of thinkers sought for some central unity beneath the outward phenomena.  Thales the Milesian (B.C. 600) said it was water.  His disciple, Anaximander, called it a chaotic matter, containing in itself a motive-power which would take the universe through successive creations and destructions.  His successor, Anaximenes, concluded the infinite substance to be air.  Heraclitus of Ephesus (B.C. 500) declared it to be fire; by which he meant, not physical fire, but the principle of antagonism.  So, by water, Thales must have intended the fluid element in things.  For that Thales was not a mere materialist appears from the sayings which have been reported as coming from him, such as this:  “Of all things, the oldest is God; the most beautiful is the world; the swiftest is thought; the wisest is time.”  Or that other, that, “Death does not differ at all from life.”  Thales also taught that a Divine power was in all things.  The successor of Heraclitus, Anaxagoras (B.C. 494), first distinguished God from the world, mind from matter, leaving to each an independent existence.

While the Greek colonies in Asia Minor developed thus the Asiatic form of philosophy, the colonies in Magna Graecia unfolded the Italian or ideal side.  Of these, Pythagoras was the earliest and most conspicuous.  Born at Samos (B.C. 584), he was a contemporary of Thales of Miletus.  He taught that God was one; yet not outside of the world, but in it, wholly in every part, overseeing the beginnings of all things and their combinations.[242]

The head of the Italian school, known as Eleatics, was Xenophanes (born B.C. 600), who, says Zeller,[243] both a philosopher and a poet, taught first of all a perfect monotheism.  He declared God to be the one and all, eternal, almighty, and perfect being, being all sight, feeling, and perception.  He is both infinite and finite.  If he were only finite, he could not be; if he were only infinite, he could not exist.  He lives in eternity, and exists in time.[244]

Parmenides, scholar and successor of Xenophanes at Elea, taught that God, as pure thought, pervaded all nature.  Empedocles (about B.C. 460)[245] followed Xenophanes, though introducing a certain dualism into his physics.  In theology he was a pure monotheist, declaring God to be the Absolute Being, sufficient for himself, and related to the world as unity to variety, or love to discord.  We can only recognize God by the divine element in ourselves.  The bad is what is separate from God, and out of harmony with him.

After this came a sceptical movement, in which Gorgias, a disciple of Empedocles (B.C. 404) and Protagoras the Abderite, taught the doctrine of nescience.  The latter said:  “Whether there are gods or not we cannot say, and life is too short to find out."[246] Prodicus explained religion as founded in utility, Critias derived it from statecraft.  They argued that if religion was founded in human