Philosophy is a talkative subject, and it must have begun in conversation. Unfortunately, all we have from the early period is texts, and these are not abundant. But if evidence for the use of writing in philosophy before Plato is fragmentary, evidence for oral performance in this period is almost nonexistent. What little we know is generally derived from Plato, like the picture of Zeno reading his arguments before a small audience in the Parmenides. But how well informed was Plato about practices a century earlier? Was Heraclitus' book designed to be read aloud before such an audience? Or does the report that Heraclitus deposited his book in the temple of Artemis mean that he wanted to keep it out of circulation? Did Parmenides and Empedocles compose their verses for public performance, or only for easier memorization? We do not have answers to such questions, and I will have little to say about conditions of performance or publication.

My topic, then, is the written use of prose and poetry in the development of Greek philosophy in its first two centuries, from Thales to Plato. I am using philosophy here as an abbreviation for “philosophy and science.” The distinction is not always a useful one to draw in the Presocratic period. It is characteristic of Greek philosophy in its formative period – as again of European philosophy in the seventeenth century – that it develops in close conjunction with mathematics and natural science.