Thinker · 540 BCE–480 BCE

Heraclitus

Heraclitus used compressed fragments to argue that change, opposition, and a shared logos belong together in an ordered but often misunderstood world.

Intellectual setting

His work survives through quotations shaped by later Platonist, Stoic, and Christian interpretations, making reconstruction especially contested.

Key ideas

Logos

A common account or structure is available, yet people often fail to understand the order expressed in their experience.

Unity of opposites

Tension between opposites is not mere disorder but helps explain transformation and balance.

Legacy

Heraclitus's fragments continue to animate debates over flux, logos, interpretation, and the philosophical use of aphoristic writing.

At a glance

Dates: 540 BCE–480 BCE · approximate

Places: Ephesus

Connections: 3 influences

Schools: Presocratic philosophy

Selected works

Heraclitus’s book is lost; the surviving record consists of quotations and reports preserved by later authors.

Connections

Influenced Plato (documented influence): Plato reads Heraclitus at Cratylus 402a as holding that all things pass and nothing stays, and builds the flux doctrine into his own arguments; scholarship treats that reading as Plato's interpretation rather than a neutral report of the fragments.
Influenced by Pythagoras (documented influence): Fragment B40 names Pythagoras alongside Hesiod, Xenophanes and Hecataeus, and elsewhere Heraclitus calls him a fraud; the surviving text attests direct engagement with Pythagorean claims to wisdom, again as rejection rather than inheritance.
Influenced by Xenophanes (documented influence): Heraclitus names Xenophanes in fragment B40 among the polymaths whose learning failed to produce understanding, so the engagement is attested in his own surviving words; what moved is a target of criticism rather than a doctrine adopted.

Sources

Heraclitus , Stanford Encyclopedia of Philosophy
A New History of Western Philosophy: Ancient Philosophy , Coverage of Heraclitus and the surrounding tradition, Oxford University Press