Responding to the claims of Parmenides on the impossibility of change, Anaxagoras introduced the concept of Nous (Cosmic Mind) as an ordering force.

He also gave several novel scientific accounts of natural phenomena, including the notion of panspermia, that life exists throughout the universe and could be distributed everywhere.

He deduced a correct explanation for eclipses and described the Sun as a fiery mass larger than the Peloponnese, and also attempted to explain rainbows and meteors.

[6] He introduced the concept of nous (cosmic mind) as an ordering force, which moved and separated the original mixture, which was homogeneous or nearly so.

Mind is no less unlimited than the chaotic mass, but it stood pure and independent, a thing of finer texture, alike in all its manifestations and everywhere the same.

[10] He was the first to give a correct explanation of eclipses, and was both famous and notorious for his scientific theories, including the claims that the Sun is a mass of red-hot metal, that the Moon is earthy, and that the stars are fiery stones.

[11][12] He attempted to give a scientific account of eclipses, meteors, rainbows, and the Sun, which he described as a mass of blazing metal, larger than the Peloponnese; he also said that the Moon had mountains, and he believed that it was inhabited.

[k] Anaxagoras wrote a book of philosophy, but only fragments of the first part of this have survived, through preservation in the work of Simplicius of Cilicia in the 6th century AD.

In the Phaedo, Plato portrays Socrates saying of Anaxagoras as a young man: 'I eagerly acquired his books and read them as quickly as I could'.

[14][n] Dante Alighieri places Anaxagoras in the First Circle of Hell (Limbo) in his Divine Comedy (Inferno, Canto IV, line 137).

Friedrich Nietzsche also frequently mentions Anaxagoras in the later chapters of his book entitled Philosophy in the Tragic Age of the Greeks.

He speaks fondly of Anaxagoras's nous, and defends the idea by claiming philosophers had "failed to recognize the meaning of Anaxagoras's [nous] ..." and believed that it was "perfectly sufficient for his insight to have found a motion which is capable of creating visible order in a thoroughly mixed chaos, by means of a simple continuous action.

"[15] Nietzsche believes it is essential to understand Anaxagoras's nous as a sort of act of free will, not determined by any previous action before.