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Thales

What is the world made of?

Physics· BC 585· Miletus · Thales· Ask

1min readUpdated 2026-09-29

That time, that place

Miletus was a port on the Ionian coast. Ships brought more than goods — Egyptian surveying and Babylonian sky records arrived with them. Into a Greece that explained the world through myth, foreign methods of calculation had landed.

Why this question

Myth tells you who did it — the sea rages because Poseidon is angry. Thales asked something else: not who, but what is it made of. He began looking for causes inside things rather than above them.

What was found

His answer was water. Wrong, of course. But what matters is not the answer — it is the shape of the question: that there is some underlying stuff which takes many forms, and that the answer must come with reasons rather than stories.

So those who followed argued back. Air, said one. Fire, said another. Something boundless and unnameable, said a third. What began was not an answer but a debate.

The old idea

The world is as the gods decided it

The evidence

Fragments quoted by later writers — not one line of his own survives

What followed

The question begun in Miletus runs on, two centuries later, into atomism