Thales of Miletus · Philosophy

Everything Is Water

Thales of Miletus asked a question no one had asked before - what is everything ultimately made of? - and answered that all things arise from a single underlying stuff: water. With that question, philosophy and science were born.

From the lesson

Around 585 BC, in the bustling Greek port city of Miletus on the coast of Asia Minor, a merchant, engineer, and stargazer named Thales asked a question that, as far as we know, no one had ever asked before - and in asking it, he opened the door to philosophy and natural science at once. The question was breathtakingly simple and breathtakingly ambitious: what is everything ultimately made of? Behind the dazzling variety of the world - earth and sea, fire and air, plants and animals and stones - is there some single, fundamental stuff out of which all of it arises and into which it all returns?

This was a new kind of question because it assumed a new kind of answer. Before Thales, the Greeks explained the world through myth: the sea was Poseidon’s domain, storms were Zeus’ anger, the dawn was the goddess Eos. To ask ‘what is everything made of?’ and to expect an answer in terms of nature itself - not the will of gods - was to assume that the cosmos is an orderly system with a knowable underlying structure. Aristotle, looking back, marked Thales as the founder of the whole tradition precisely for this: he was the first to seek the arche, the originating principle and underlying nature of all things.

Why water? The choice can look arbitrary or even silly to modern eyes, but Thales had genuine reasons, and reconstructing them shows him reasoning like a proto-scientist rather than guessing. According to Aristotle, Thales observed that moisture is bound up with life everywhere: the seeds of all things are moist, nourishment is moist, semen is moist, the warm and the living are damp while the dead dry out. Water seemed to be the medium of life and growth itself.

This is the opening of the lesson. The rest — the dialogue, the primary source, and the recall — is in the app.

What you'll be able to recall

You learned that Thales of Miletus is called the first philosopher because he sought a single underlying principle, the arche , from which all things arise, and proposed that it is water. Explain what an arche is and why asking for one was revolutionary.

Leads to Anaximander.

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