Anaxagoras, a native of Clazomenae, had brought…

Anaxagoras, a native of Clazomenae, had brought philosophy and the spirit of scientific inquiry from Ionia to Athens.

His observations of the celestial bodies have led him to form new theories of the universal order.

Anaxagoras describes the cosmos as a continuous field in which different qualities flow and mingle.

He suggests that are not four but possibly thousands of elements and that, as no element can become another, there is no real change but only the illusion of change manifested by the combination, separation and recombination of elements.

He attempts to give a scientific account of eclipses, meteors, rainbows and the sun, which he describes as a mass of blazing metal, larger than the Peloponnese.

The heavenly bodies, he asserts, are masses of stone torn from the earth and ignited by rapid rotation.

However, these theories bring him into collision with the popular faith; Anaxagoras' views on such things as heavenly bodies are considered "dangerous."

This new Ionian science is not well-received by the Athenian public, who view Anaxagoras’ teachings—that the divine mind in this system does not have a human body, and that the Luminaries are not gods but rocks—as deeply irreligious.

Anaxagoras is arrested by Pericles' political opponents on a charge of contravening the established dogmas of religion (some say the charge was one of Medism).

It takes Pericles' power of persuasion to secure his release.

Even so he is forced to retire from Athens to Lampsacus in Ionia in about 434-433 BCE.