Thales _ Anaximander _ Anaximenes _ Pythagoras _ Philolaus _ Archytas _ Empedocles _ Heraclitus _ Parmenides _ Zeno of Elea _ Melissus _ Xenophanes _ Anaxagoras _ Leucippus _ Democritus _ Protagoras _ Gorgias _ Prodicus _ Hippias _ Pherecydes