Anaxagoras

500 - 428 BC, was a pre-Socratic Greek philosopher. Anaxagoras responded to the arguments of Parmenides, who argued that change is impossible. The world, for Anaxagoras, was a mixture of primary imperishable ingredients. 

He introduced the concept of Nous to the degree that it was an ordering force. This cosmic mind, arranges all other things in their proper order. 

The universe would be made of infinitely divisible matter. Ever bit of each thing, could become anything. 

The notion of Panspermia actually began with Anaxagoras, who said that life could exist anywhere in the universe. He also deduced the correct explanation for eclipses and even described the Sun as a fiery mass, larger than Peloponnese, a peninsula in Southern Greece.