Thales of Miletus
The first philosopher — sought the single stuff behind all things.
Overview
Thales is traditionally counted as the first Western philosopher and one of the Seven Sages of Greece. He broke with mythological explanation by seeking natural, rational causes for the world. He famously predicted a solar eclipse (traditionally 585 BCE), measured the height of the pyramids by their shadows, and treated the cosmos as something the mind could understand through observation and reason rather than through the gods. No writing of his survives; we know him through Aristotle and later doxographers.
What they supported — and why
Water is the first principle (archē)
SupportedAll things ultimately arise from, and are sustained by, water.
WhyLife depends on moisture, seeds and nourishment are moist, and the earth seems to float on water — so water looked like the underlying substance from which everything else derives.
The cosmos is intelligible
SupportedNatural events have natural causes that reason can uncover.
WhyBy predicting an eclipse and explaining phenomena without myth, he showed nature follows discoverable regularities.
Causes championed
- Rational inquiry over myth
- Practical use of knowledge (astronomy, geometry, navigation)
Issues wrestled with
- What is the fundamental substance of reality?
- Can natural events be predicted?
Hurdles faced
- No prior tradition of natural philosophy to build on
- Working before any written prose culture of argument existed
Works & books
2 catalogued. Status shows how much survives to today.
On the Solstice
LostAttributed astronomical work; not preserved.
On the Equinox
LostAttributed astronomical work; not preserved.
The influence network
See Thales of Miletus in the map →Influenced by
Influenced
In their words
“Know thyself.”
— traditionally ascribed to the Seven Sages
“All things are full of gods.”
— reported by Aristotle, De Anima
Legacy
He inaugurated the search for a rational, unified account of nature — the founding move of both philosophy and science.
Essays
Pieces from the Journal that take up Thales of Miletus in more depth.
Follow their questions
This thinker is a stop on these paths through philosophy.
Further reading
Cross-checked against these authoritative references.