Thales of Miletus

The twenty-eighth of May, 585 BCE, on the banks of the Halys in Asia Minor. The armies of Lydia and Media had faced each other for six years when, in the middle of the day, the sun went out. The soldiers let their weapons fall and made peace on the spot. Fifty kilometres to the west, in the port of Miletus, one man had known it was coming. He had not consulted an oracle or killed a beast on an altar – he had calculated. His name was Thales, and that darkened noon is taken as the hour philosophy was born.

It was born as an act of nerve. For tens of thousands of years human beings had held the world together with myth: the Nile flooded because a goddess wept, and the sun rose because the community kept its ritual faithfully. To ask what a thing was made of was close to blasphemy, since one does not run a test on the god who feeds one. Thales asked exactly that forbidden question – and answered with a word instead of a name. Everything, he said, is at bottom water: the same wet that is in the sea, in blood, in the sap of plants, in the mist over a morning field. The answer amuses us, and the weight of it is the gesture. He swapped a myth for a hypothesis, and a hypothesis is the first cell of both science and philosophy. For the first time a human mind supposed that beneath the gods lay an order it could reach.

Of Thales the man we have mostly stories, and even if they were invented they were invented well. His neighbours sneered that philosophy is a luxury for those who cannot earn; so, reading the winter signs for a heavy olive harvest, he quietly leased every oil-press in Miletus and Chios cheap and out of season, and when autumn came and everyone scrambled for them he named his price – proving that a wise man will be rich when he chooses, and that he simply chooses otherwise. The other story is crueller: gazing up at the stars, he fell into a well, and a Thracian servant girl laughed that he was so eager to know what happened in the heavens that he could not see what lay at his feet. Both stories are about one thing – a man whose eyes are turned where no one else is looking. Almost none of his own words survive; we know him through Aristotle, who named him the first to seek an underlying stuff, through Herodotus, and through Diogenes Laërtius.

Weigh how much stands behind that single question. Every laboratory, every equation, everyone who has ever said "let us check," is a descendant of Thales. He got almost nothing right, and it does not matter. He opened an organ that had not existed before: the supposition that the universe is intelligible and that a mortal, simply by thinking, can understand it. It is the most dangerous and most fruitful wager a human being has made, and the West still rests on it. The next two and a half thousand years are the story of the people in whom that same organ opened again, and of what it cost them.