Ancient Philosophy

Summaries of many Presocratic philosophers are included below.
See also: Socrates and Plato and Aristotle

Anaximander followed Thales and proposed the Apeiron
The third of the prominent Milesians who began Western Philosophy
Heraclitus, who spoke of all things being in flux.
Parmenides – Extreme Monism Part 1
Zeno, famous for a paradox of motion
Xenophanes did philosophy of religion and cultural criticism