Doubting the Gods' Work: How Science Was Born in Miletus

The episode opens with a definition of science. The yardstick that the great twentieth-century natural investigators converged on is the formula of Karl Popper: scientific knowledge claims no certainty, stays open to error, and survives only insofar as it withstands criticism. The narrator adds that the remarks of Heisenberg on uncertainty are sometimes mistaken for a fundamental objection to this picture, though philosophers occasionally conflate two separate issues. The point is not that nature is blurry, but that our claims must be testable.

Then comes a personal memory. As a student, the narrator was advised to walk into the field with an empty head, map the rocks, and let truth reveal itself; he objected — where do you even start mapping if you do not know what to look at? First survey the literature of the area, learn what has already been said. One of his teachers told him he was not as alone as he felt, and named Popper — a name the young student had never heard. He got hold of the slim book in which Bryan Magee explains Popper overnight, read it, and ordered the complete Popper works from the university bookstore the next day. The receipt dated 24 March — his birthday — is the garnish on this discovery story.

The Popper yardstick grounds the harshest verdict of the episode: science in the present sense existed neither in Mesopotamia nor Egypt, neither in China nor India. Those civilizations accumulated knowledge, observation and record-keeping — but no science advancing through open testing and criticism. The same severity applies to mathematics: using zero and computing correctly is not science by itself. Mathematics is described here as a language, a construction of logic; what starts science is not numbers themselves but opening number-built claims to criticism.

The hero of the story is Thales, a wealthy man of Miletus. He travels to Egypt and watches the great yearly floods of the Nile: the river feeds the fertile land, yet the thin clay layer it leaves behind wipes out the field boundaries. A profession was born to redraw them — surveyors using geometrical methods built on similar triangles, with traces of the relation later attributed to Pythagoras visible in the practice. Research in the line of Neugebauer has written up the parallel Mesopotamian record in thick volumes. But what strikes Thales is not the technical detail: this knowledge was reached without any god's help.

Because, as the narrator tells it, every natural event in the world Thales grew up in had its god: Zeus made the storms, Poseidon caused the earthquakes with his triple spear, healing was expected from Asclepius. Sacrifices were cut — bulls for Zeus, mares for Poseidon, cocks for Asclepius — yet storms did not calm, tremors continued, the sick still died. That is the breaking point for Thales: geometrical knowledge must hold everywhere in the universe, and its proof owes nothing to the gods. The arrival of the concept of proof with the Greeks is therefore told here not as a technical footnote but as a moment of liberation.

Thales inherits an old Sumerian design of the universe: a world floating in the middle, ringed by ocean, capped by the sky-dome, underlaid by the netherworld. Kept by priests beyond debate, he carries this design to Miletus and serves it back to Anaximander with a new question: if a great storm broke over the surrounding ocean, would the floating world not shake — might that be what we call an earthquake? Reports from merchants passing through Miletus feed the picture too: captains hauling tin from the direction of Britain, men who had seen the Indian Ocean, all strengthening the impression of a world girt by waters. The link between cassiterite, the tin mineral, and the legendary Cassiterides islands is a small sample of that seafarers web of knowledge.

The answer of Anaximander suits the title of the episode: I am not convinced. A listener interjection — does this recall Pangaea, the single-continent age — is firmly dismissed: no humans existed then, not even dinosaurs. Then comes the famous falsification: we live on a world made of stone; throw a stone into water and it sinks, so the floating-earth claim stands refuted. And the deeper the defense goes, the bigger the problem grows: if water holds the world, what holds the water — and what holds that? The hypothesis does not solve the problem, it only pushes it away. The lesson the narrator keeps hammering is this: for an idea to count as science it must be criticizable, not consecrated — and that objection is exactly what Thales expected of his junior.

When Thales returns the question, Anaximander states his own proposal: the world resembles a drum, a column capital — a cylinder hanging in the void, its height matching its diameter one to one. The ratio may be invented, but the form of the claim is new: open to observation and checking. Two reasons are offered: there is no reason for the world to move this way or that, so we must stand at the center of the universe — which the narrator counts as the first known scientific statement of the centered-universe design. A painted terracotta plate, read by French historian of science Marcel Conche, is shown as supporting evidence: at one end Prometheus, chained by the Caucasus with an eagle tearing his liver; at the other Atlas shouldering the firmament. The two ends of the Greek world — the Phasis river and the pillars of Heracles — are pictured on either side, and in the reading of Conche this plate is the illustrated counterpart of the world of Anaximander.

Anaximander also drew the map of the face we inhabit: Ocean around, two continents within, the Danube above, the Nile below, the pillars of Heracles on one side and the Caucasian Phasis on the other — a symmetrical world compiled from merchant and temple reports. As the story goes, he had the map worked onto a copper plate, nailed it to a pole in the harbor, and called to the captains: come, criticize it, add whatever new knowledge you carry. The counter-pole of the episode is the Babylonian world map in the British Museum: waters around again, Tigris-Euphrates lines and cities within, unreachable holy mountains beyond — but an unchanging, sacred design closed to criticism. The chain proving the difference is given too: Hecataeus takes the map and improves it; Aristagoras carries it to Sparta while begging help against Persian pressure, and the Spartans who laugh at the distance of the Persians learn their error the hard way; Herodotus mocks these maps drawn round with the world set inside. Even the mockery proves the map was on the debating table.

Two bold claims close the episode. The first is chronological: the passage of Job that plunges the north into darkness and hangs the world upon nothing, given as chapter 25 verse 7, is dated about a century after Anaximander — so the idea of a world standing in the void was first spoken in Miletus. Common datings in modern study of the Hebrew Bible fit this frame, though the difficulty of fixing date coordinates in sacred texts is openly debated in the episode. The second claim belongs to literary history: Anaximander is the first in the Greek tradition to write his book in prose, since everything until then was versified for memorability. That the opening lines of the Gallic War of Caesar stick in memory after two or three readings is offered as proof of the power of artistic prose. The episode closes with the jest that teachers who drilled texts into pupils at school raised great men.