Traditionally, histories of philosophy begin in sixth-century BCE Greek Ionia, with the Milesian thinkers Thales, Anaximander, and Anaximenes. My book (in preparation) shows this is a mistake. Through the Bronze and Iron Ages, in a macro-region stretching from the Mediterranean to the floodplains of the Ganges, many cultures developed professional communities of intellectuals responsible for the invention and preservation of cosmological theories. Milesian philosophy—and so Greek philosophy—emerged in dialogue with these traditions. I spend most time on cultures in direct contact with Miletus (Egypt and Iran), but show also how Mesopotamian and Indian philosophy help us understand Greek thought.

But I'm not just showing that Greek philosophy takes its cues from non-Greek traditions. I argue that intercultural exchange is constitutive of philosophy as we know it. Dialogues with non-Greek traditions not only shaped the theories of early Greek thinkers, they were central to the institutional formation of the discipline: adapting the professionalized intellectual traditions of nearby civilizations, early Greek thinkers invented new textual genres for presenting a new type of claim, and derived the very idea of inquiry into nature as an occupation. The book therefore sets Greek philosophy within a geographically broader and chronologically deeper history of philosophy in the ancient world—a social and institutional history as much as a history of ideas.