The accounts which have descended to us of the philosophical tenets of Anaxagoras, though somewhat contradictory, serve to prove that he was one of the most skilful philosophers of his age. He taught that material substances are formed of very minute primary particles of different forms and qualities; and that the peculiar nature and properties of each body depend upon the qualities of that class of particles of which it is chiefly composed. The particles of which a bone is composed, he called bony particles; those which pro duce gold, he called golden particles: and so in other instances. The aggregate bodies he supposed to as sume the character of the elementary particles of which they were constituted, and to which he gave the name of Op-oroftcpcial. This theory, it must be acknowledged, is not very profound, as it makes no provision for the transmutation of matter into a variety of new forms, and leaves unexplained the production or dissolution of bodies, as well as the original formation of the consti tuent particles of which the larger masses are made up. It is however exhibited by Lucretius in very pleasing numbers, lib. 1. v. 833, Ste.
—Principium rerum quam dicit homTomcriam ; Ossa videlicet e pauxillis atque minutis Ossibus: sic et de pauxillis atque minutis Visceribus viscus gigni, sanguenque creari. Sanguinis inter se multis coeuntibus guttis ; Ex aurique putat micis consistere posse Aurum, et de terris terram concrescere parvis, • Ignihus ex ignem, humorem ex humoribus esse, Cxtera consimili fingit ratione, putatque.
This theory has an evident analogy to the doctrine of a fortuitous concourse of atoms, borrowed from the Phoenician school, and afterwards matured in Greece into a regular system by Lcucippus, Democritus and Epicurus. It seems to have been on account of this ana logy, that Anaxagoras has, by some authorities, been reckoned among the philosophers who propagated athe istical tenets ; because the advocates for the atomical system denied the influence of a superintending mind in the production of the phenomena of the universe.
Plato and Aristotle have given a very different charac ter of Anaxagoras, to whom they ascribe the honour of being the first philosopher who taught the existence of a disposing mind, the cause of all things ; which, while every thing else was compounded, was itself pure and unmixed. (Phced. and Arist. Metaph. 1. 1. c. 3.) Cicero, Plutarch, and Diogenes Lacrtius, all bear testimony to the same honourable distinction of Anaxagoras, and represent him as the first among the ancients who con ceived mind to be detached from matter, and as acting upon it with intelligence and design in the formation of the universe.
Some of the opinions which Anaxagoras entertained respecting the causes of certain remarkable natural phe nomena, prove him to have been an attentive and judi cious observer of the appearances of nature. He taught that wind was produced by the rarefaction of the air; that the rainbow is the effect of the reflection of the solar rays from a dense cloud placed opposite to it like a mirror ; that the moon is an opaque body enlightened by the sun, and an habitable region, divided into hills, valleys, and waters ; that the comets are wandering stars; and that the fixed stars are situated in a region exterior to those of the sun and moon. Along with this, however, such opinions as the following are ascribed to Anaxagoras, that the sun is a flat circular mass of heated iron, somewhat bigger than the Peloponnesus ; and the stars were originally stones, which -have been whirled from the earth by the violent circumvolution of its sur rounding xther. So dim were the lights which had yet burst through the gloom of ignorance and prejudice, to irradiate the minds even of the most diligent enquirers inio nature. Diog. Laert. in Anaxag. Plat. in Pericles. Sflid. Gen. Diet. Cicero, Acad. Quist. iv. cap. 23 ; Tusc. i. cap. 43. Brucher's and Enfield's Hist. of Phi losophy. (In)