The Greeks were able to escape the primitive view of the world and become enlightened as individuals. How?
Part of the story is the geography of Greece: mountainous with areas of extraordinarily fertile land, sitting at the connection of Europe to Asia, and not easy to invade. The mountains separated the people into local tribes, and those human colonies evolved into cities of equals. No aristocracy developed because there was no way to accumulate wealth; no way for a king to buy power. Military leaders ruled because each city had to be able to defend itself. Geography kept the colonies small and homogeneous -- the right setting for evolving the Polis.