Final answer:
Anaximander did propose the idea that humans arose from fish-like creatures, but he did not claim that they did so as fully mature beings. He believed in the theory of species evolving from one another over time in response to the need to adapt. However, the idea of humans arising from fish-like creatures as fully mature is not supported by scientific evidence.
Step-by-step explanation:
Anaximander did propose the idea that humans arose from fish-like creatures, but he did not claim that they did so as fully mature beings.
Anaximander believed in the theory of species evolving from one another over time in response to the need to adapt.
He speculated that all life originated in the sea and moved onto the land.
However, the idea of humans arising from fish-like creatures as fully mature is not supported by scientific evidence.