pre-Socratic philosophy

'Pre-Socratic philosophy' is a term applied to the thought of the early Greek philosophers (c. 600–400 BC) whose work came before the influence of Socrates. Their works survive mostly in obscure fragments, but their fame and importance lie in their being the first to attempt rational explanations of the universe. They are grouped into the Ionian school in Asia Minor (Thales, Anaximander, Anaximenes, Xenophanes, Heraclitus, Anaxagoras, and the Atomists, Leucippus and Democritus) and Pythagoras and the Eleatics Parmenides, Zeno, and Empedocles in southern Italy and Sicily. Protagoras and the pre-Sophists are usually also included.