|A 3rd century mosaic showing|
Anaximander holding a sundial
He claimed that life sprang from the sea, and that human beings were initially hatched from a race of fish-people. He talks about the fish-people rearing human babies.
Censorinus, the 3rd century Roman thinker, says in his De Die Natali: “Anaximander of Miletus considered that from warmed up water and earth emerged either fish or entirely fishlike animals. Inside these animals, men took form and embryos were held prisoners until puberty; only then, after these animals burst open, could men and women come out, now able to feed themselves.”
Anaximander probably had some kind of an experience with human fetuses in early stages of development. To him, the earliest stage of the fetus must have seemed like a fish and this could have led him to conjecture that the fish-people were the ancestors of the human race in the evolutionary chain.