AN'AXAG'ORAS (Gk. 'Arcieny6pac) (c. 500 435 B.e.). The last great philosopher of the Ionian School. He was born between 500 and 496 B.C. at Clazomeme, in Ionia, the son of liege sibulus. Ills family was wealthy and distin guished, so that the young Anaxagoras was able to devote himself to intellectual pursuits. Soon after the Persian Wars he moved to Athens, where he lived anal taught many years, thus transplanting philosophy from Ionia to Attica, which was destined to be its home for many centuries. Among his pupils were some of the most distinguished Athenians. Pericles, Euripi des, possibly Socrates and Arehelaus. But after about thirty years' residence he was charged with impiety toward the gods, apparently by the opponents of Pericles. who took advantage of Anaxagoras's novel explanations of natural phe nomena to injure the statesman through his friend. The eloquence of Pericles. however, se cured a reduction of the sentence from death to banishment for life, and Anaxagoras. after some wandering,s, settled at Lampsacus, on the Helles pont, where he died in 425 W.C.
The teachings of .Anaxagoras cannot be ex actly determined in all points. Of his work On Nature, in which he set forth his system, we have only fragments. But it is clear that he made a distinct advance over the earlier Ionian philoso phers in that he defined a new principle, intern gene(' or mind as operating on ?Haller, thus introducing a dualistic explanation of the universe in contrast to the materialistic monism of his predecessors. This dualism was further developed by Plato and Aristotle. The varied processes of change. growth, and decay were ap parently explained to be the combining and sepa rating of matter under the directing influence of intelligence. It was taught that matter is single in its nature, and consists of an infinite nnmher of invisible atoms inconceivably small (arippara, "seeds," named opotopepil by Aris totle) ; these in their original condition make the unformed primitive material, possessing no char acteristics. When acted on by intelligence, they form individual objects we see about us; i.e.,
bars of gold, or iron, or copper are made up of the same material, but in each case intelligence has caused a result different from the others; and further, the processes of change produced by the spiritual principle are what we call natural phenomena. Intelligence acts from a point, the pale, setting the "seeds of matter" into spherical motion. this movement the lighter parts are separated from the heavier, the former to be the clear, glowing upper air (ether), the latter to gather in the centre, and, by cooling, to become water, land, stones, and minerals. The heavenly bodies are masses of stone cast from the revolv ing earth into the fiery ether, where they are heated and continue their courses, the sun being a mass larger than the Peloponnesus. Anaxn goras's notions with regard to the moon's light, the cause of the rainbow, of winds, and of sound were fairly aeeurate. Plants, the lower animals, and man owe their existence and continued life to the Supreme Intelligence which resides in them. In his doctrine of atoms, his "seeds," An axago•as approaches the teaching of the Atomic School. (See DE310C1t1TUS. ) Naturally Anaxa did not conceive the nature of his spiritual principle clearly enough to be able to explain de tails satisfactorily, as Aristotle remarks in his Metaphysics; but his great service was that he turned philosophy from thought about things to the consideration of thought itself, and made that one of the most important subjects of specu lative inquiry thereafter. Anaxagoras was also classed by Eudemus among the Greek geometri cians. Plutarch ascribes to him a work on the quadrature of the circle, and asserts on the au thority of Vitruvius that he wrote a theory on perspective. Consult Zeller, Urschichtc der gric chischcn Philosophic (Leipzig, 1893). The frag ments are edited by Sehaubach (Leipzig, 1827) ; Seho•n (Bonn, 1829) ; Bitter and Preller, his torian Philosophici' (seventh editiomflotha, 1888) ; and Lange, History of Materialism, Eng. trans. (Boston, 1886).