Anaximander (c. 610–c. 546 BC)

Greek astronomer and philosopher. He claimed that the Earth was a cylinder three times wider than it is deep, motionless at the centre of the universe, and that the celestial bodies were fire seen through holes in the hollow rims of wheels encircling the Earth. According to Anaximander, the first animals came into being from moisture and the first humans grew inside fish, emerging once fully developed.

He was born in Miletus, in what is now Turkey, and was a pupil of Thales. He is thought to have been the first to determine solstices and equinoxes, by means of a sundial, and he is credited with drawing the first geographical map of the whole known world. He believed that the universe originated as a formless mass containing within itself the contraries of hot and cold, and wet and dry, from which land, sea, and air were formed out of the union and separation of these opposites. Perpetual rotation in the universe created cosmic order by sorting heavier from lighter matter.

Overall, he seems to have shared the early Greek philosophical urge to explain the universe with a tiny number of general laws.