Anaxagoras (499-428 A. C) was born in Clazomene (at least) and walked to Athens in 453. Bound by friendship and political commitment to Pericles. He was accused of impiety by the enemies of this and was forced to leave the city at 434. Died in Lampsacus. Anaxagoras was, according to Diogenes Laertius, was "the first thing to marteria added intelligence.

The tradition is renewed jonica Anaxagoras, in whose opinion nothing begets nor destroyed, but there are simple mixture and separation. The fundamental question of the pre-Socratic philosophy. The question to be permanent by the explanation in view of developments and changes. Anaxagoras is not resolved by using the assumption of a single principle or by asserting that only being is. "The finest and purest of all things" the nous is so the principle of order but also the animating principle and individuation of things that make up the harmonious order of the universe, but the nous produces the order in a manner expected from forever. Not as a destination, but as a force.

Mechanisms developed from its own center, that is, the center of the whirling motion is therefore nous, the principle of movement, but a movement that extends almost blindly, because it is entertainment rather than compliance a necessary justice. So Aristotle says that the thought of Anaxagoras lacks clarity. Because if it explains the transit from chaos to order as an intervention in the confusion and mixture of pure and without mixture, without justifying explains in turn the purpose of this pure and universal spirit.