On Nature

Introduction

A poem in Greek hexameters, the metre of epic, of which about 160 lines survive, mostly through quotations in the sixth-century commentator Simplicius. It has three parts: a proem in which a young man travels by chariot to a goddess, the “Way of Truth” and the “Way of Opinion”, an account of the visible cosmos of which only fragments remain. The Way of Truth argues that what is not can neither be thought nor said, and deduces that being is ungenerated, indivisible and unchanging. The argument is often called the beginning of ontology, the theory of being, and every later Greek theory of change had to respond to it.

Connections

Criticizes

• Fragmentsc. 500 BCE · Heraclitus disputed

Taken up in

• Timaeusc. 360 BCE · Plato

Answered in

• Parmenidesc. 370 BCE · Plato

Criticized in

• On Non-Beingc. 440 BCE · Gorgias
• Physicsc. 350 BCE · Aristotle