Anaximander proposed the apeiron, an indefinite origin from which opposites emerge and to which they return according to an ordered account of justice.
Intellectual setting
He belongs to the Milesian tradition as reconstructed from Aristotle, Theophrastus, and later doxography, alongside reports of cosmological and geographical innovation.
Key ideas
The apeiron
The indefinite is not one familiar element but a boundless source able to generate opposing qualities.
Cosmic order
The extant fragment describes things paying recompense to one another, joining physical change to a rule-like order.
Legacy
The apeiron remains a central challenge in accounts of how early Greek thinkers moved beyond a familiar elemental substrate.