Intellectual superiority of the Greeks Early progress of philosophy The Greek philosophy The Ionian Sophoi Thales and his principles Anaximenes Diogenes of Apollonia Heraclitus of Ephesus Anaxagoras Anaximander Pythagoras and his school Xenophanes Zeno of Elea Empedocles and the Eleatics Loftiness of the Greek philosopher Progress of scepticism The Sophists Socrates