an eminent philosopher of antiquity, was born in the first year of the 76th Olympiad, or 500 years before Christ. Leaving his lands to be cultivated and enjoyed by his friends, Anaxagoras placed himself under the care of Anaximenes the Milesian. About the age of twenty he went to Athens and entered upon the study of philosophy, where he continued thirty years. Some suppose that he was the first disciple of the Ionian school, founded by Thales, a teacher of philosophy in Athens. When Anaxagoras assumed the character of a public teacher of philosophy, he quickly rose to high eminence, and produced many famous scholars, among whom were Euripides, Pericles, and Socrates. This philosopher contented himself with serving the republic in his own station, without interfering in any of the public affairs of the state. Both by the principles of wisdom which he inspired into the minds of the Athenian youth, and also by his daily advice in the most important affairs, particularly in the case of Pericles, he was of singular service to his country. But neither the friendship of Pericles, nor his own general disinterestedness of character, nor his immense stores of learning, could ward off the shafts of persecution. Cleo accused him of impiety, and the introduction of new opinions concerning the gods, because he taught that the sun was a burning mass of stone, or an inanimate fiery substance. By this opinion he was said to rob the sun of its divinity, because in the popular opinion he was deemed Apollo, one of the greatest deities. But although Cleo made religion the avowed cause of the accusation of Anaxagoras, it is highly probable that civil causes chiefly operated towards his condemnation. It is, however, abundantly evident that he did not hesitate to expose the vulgar superstitions on several occasions; but the evidence is not sufficient which pretends to prove that he was condemned for teaching the doctrine of a supreme intelligence, the creator of this world. His judges condemned him to death; but Pericles appearing in his defence, the sentence was changed from that of death to banishment and a pecuniary fine.

Expelled from Athens, Anaxagoras passed the remainder of his days at Lampsacus, teaching philosophy in the school of his deceased master Anaximenes, until the infirmities of nature terminated his life in the year 428 before Christ. Diogenes Laertius has collected, with little care and judgment, the details concerning this philosopher, which were scattered through various writings. It appears, that in the midst of some extravagant conceptions, Anaxagoras held opinions which indicate a considerable acquaintance with the laws of nature. His idea of the heavens seems to have been, that they were a solid vault, originally composed of stones, elevated from the earth by the violent motion of the ambient ether, inflamed by its heat, and by the circular motion of the heavens fixed in their respective places. The testimonies of several writers, among which is that of Xenophon, unite in proving that he considered the sun to be a large fiery stone; and Xenophon introduces Socrates as refuting that doctrine, and delivering an unfavourable opinion concerning his other writings. From his perceiving that the rainbow is the effect of the reflection of the solar rays from a dark cloud, and that wind is produced by the rarefaction, and sound by the percussion, of the air, he seems to have paid considerable attention to the phenomena of nature.

Our information is more correct concerning his opinions of the principles of nature and the origin of things. He imagined that in nature there are as many kinds of principles as there are species of compound bodies; and that the peculiar form of the primary particles of which any body is composed is the same with the quality of the compound body itself. For instance, he supposed that a piece of gold is composed of small particles which are themselves gold, and a bone of a great number of small bones: thus, according to Anaxagoras, bodies of every kind are generated from similar particles. That part of his system is more agreeable to reason which explains the active principle in nature. According to Diogenes Laertius, Anaxagoras taught that "the universe consists of small bodies composed of similar parts, and that mind is the beginning of motion." "He was the first," says the same writer, "who superadded mind to matter, opening his work in this pleasing and sublime language: 'All things were confused; then came mind and disposed them in order.'" Plato informs us that this philosopher taught the existence of a disposing mind, the cause of all things. Anaxagoras, according to Aristotle, taught that mind was "the cause of the world, and of all order; and that while all things else are compounded, this alone is pure and unmixed;" and that "he ascribes to this principle two powers—to know and to move—saying that mind put the universe in motion." Cicero expressly asserts that Anaxagoras was the first who taught that "the arrangement and order of all things was contrived and accomplished by the understanding and power of an infinite mind."