Anaximander

'A verse of Homer remarks that the Great Bear is the only constellation that never bathes in Oceanus. The Great Bear is so close to the polestar that it always remains above the horizon during the daily revolution of the heavens.

But in Egypt that is not the case. There the Great Bear sinks into the sands of the desert for a short while every night. The Greek philosopher Thales must have observed this when he was in Egypt, for his disciple Anaximander drew the conclusion that the Earth could not be a flat disc; if it were, the Great Bear would be everywhere equally high above the horizon. Hence, he argued, the earth must be a sphere floating freely in the universe, with the sky, itself spherical in shape, at an equidistance from it on all sides. . . .

To conceive of the Earth as spherical required a degree of intellectual freedom which Greek culture alone was capable of . . . [and] when it was first conceived, around 600 B.C., it was intoxicating. . . . The Greeks began pondering whether antipodes existed on the lower half of the sphere, and wondering what force prevented them from plunging into the abyss. They reveled in the pleasure of having discovered that the purest geometrical form, the sphere, was fundamental to the structure of the universe.'

'Rudolf Thiel, from And There was Light, translated from the German by Richard and Clara Winston, 1957.