Lived c. 610 BC – c 546 BC.

2,600 years ago, Anaximander became the first person in recorded history to recognize that the earth exists as a solitary body which does not need to rest on top of anything else. Fascinated by the structure of the earth, he produced one of the first ever maps of the world. He did not restrict his thinking to astronomy and geography. He also theorised about evolution, concluding that life had first arisen in wet rather than dry conditions. He proposed that the first humans had been produced from fish.
Anaximander was born in the Ancient Greek city of Miletus (now in Turkey). His father’s name was Praxiades. His mother’s name is not known. None of Anaximander’s work survives. What we know of him was written by authors such as Aristotle in later times. One of the most significant features of Anaximander’s early life is that he was born in the city of Miletus. Now largely forgotten, at the time of Anaximander’s birth the city was booming. It had grown into the greatest and wealthiest city in Ancient Greece. About 14 years before Anaximander was born, Miletus had been the birthplace of the first scientist in recorded history, Thales. In fact, Anaximander was possibly a blood relative of Thales.
Thales had travelled to Ancient Egypt, and possibly Babylon, where he had learned mathematics. After returning to Miletus, he had lifted mathematics to new, magnificent heights, inventing deductive proof and establishing pure mathematics as a separate discipline from applied mathematics.
Thales established the Milesian school. In doing so, he set in motion the triumphant journey of mathematics through the islands and cities of Ancient Greece – a journey that would peak three centuries later with the brilliant work of Archimedes.
Anaximander had learned from Thales that the earth is a disk floating in an infinite ocean of water. Thales’ theory suggests that he had looked at the night sky and seen lots of bright disks. Describing the earth as a disk would therefore have seemed perfectly logical. Alternatively the disk idea might have come from the fact that the horizon, provided it’s unobstructed, is circular. Anaximander modified Thales’ theory in a remarkably productive way. He completely discarded the ocean that Thales said supports the earth.
Earth Floats in the Center of the Infinite
Anaximander said there is nothing underneath the earth supporting it. He asserted that the earth floats in the center of infinity, held in position because it is an equal distance from all the other parts of the universe.
This is a strikingly sophisticated argument. More than 2,000 years before Newton’s law of gravity, Anaximander’s point of view seems to incorporate a subtle hint of Newtonian-style thinking, conceiving of a force of attraction between the earth and the planets and stars we see in the heavens.
Anaximander had made an immense conceptual leap. For the first time in history a human mind had grasped the idea that it is possible we live upon a mass that needs nothing below it. It is difficult to overstate how important Anaximander’s revelation was for the future of astronomy and science. Without his insight, Aristarchus and (many years later) Nicolaus Copernicus could never have made the further intellectual leap needed to say that the earth orbits the sun.
He imagined there were three rings of fire around earth – one for the sun, one for the moon, and one for the stars. The fires, he said, were enclosed in rings and hidden from us apart from holes that allowed their light through. The holes could change shape, which accounted for the moon’s phases. The holes could close, accounting for solar eclipses. The fire in the moon’s ring was cooler than the fire in the sun’s ring.
Although he correctly said the moon was closer to us than the sun, he incorrectly placed the stars Anaximander accepted Thales’ idea that the earth is a rather deep disk. We live on one side of the disk. We do not know what exists on the other side. He believed the depth of our disk-world was a third of its width.closer to us than the moon. Anaximander did the same for lightning storms, which he said are caused by disturbances in the air. Lightning results from violent air flow, while thunder results from the collisions of clouds.
Anaximander looked at the life around him and came to the conclusion that it must have evolved from other lifeforms. He believed the world’s first life forms originated in the world’s wetter environments, then evolved into more advanced forms and spread to drier places.