History of Western Philosophy - Bertrand Russell [41]
Anaxagoras held that everything is infinitely divisible, and that even the smallest portion of matter contains some of each element. Things appear to be that of which they contain most. Thus, for example, everything contains some fire, but we only call it fire if that element preponderates. Like Empedocles, he argues against the void, saying that the clepsydra or an inflated skin shows that there is air where there seems to be nothing.
He differed from his predecessors in regarding mind (nous) as a substance which enters into the composition of living things, and distinguishes them from dead matter. In everything, he says, there is a portion of everything except mind, and some things contain mind also. Mind has power over all things that have life; it is infinite and self-ruled, and is mixed with nothing. Except as regards mind, everything, however small, contains portions of all opposites, such as hot and cold, white and black. He maintained that snow is black (in part).
Mind is the source of all motion. It causes a rotation, which is gradually spreading throughout the world, and is causing the lightest things to go to the circumference, and the heaviest to fall towards the centre. Mind is uniform, and is just as good in animals as in man. Man's apparent superiority is due to the fact that he has hands; all seeming differences of intelligence are really due to bodily differences.
Both Aristotle and the Platonic Socrates complain that Anaxagoras, after introducing mind, makes very little use of it. Aristotle points out that he only introduces mind as a cause when he knows no other. Whenever he can, he gives a mechanical explanation. He rejected necessity and chance as giving the origins of things; nevertheless, there was no 'Providence' in his cosmology. He does not seem to have thought much about ethics or religion; probably he was an atheist, as his prosecutors maintained. All his predecessors influenced him, except Pythagoras. The influence of Parmenides was the same in his case as in that of Empedocles.
In science he had great merit. It was he who first explained that the moon shines by reflected light, though there is a cryptic fragment in Parmenides suggesting that he also knew this. Anaxagoras gave the correct theory of eclipses, and knew that the moon is below the sun. The sun and stars, he said, are fiery stones, but we do not feel the heat of the stars because they are too distant. The sun is larger than the Peloponnesus. The moon has mountains, and (he thought) inhabitants.
Anaxagoras is said to have been of the school of Anaximenes; certainly he kept alive the rationalist and scientific tradition of the Ionians. One does not find in him the ethical and religious preoccupations which, passing from the Pythagoreans to Socrates and from Socrates to Plato, brought an obscurantist bias into Greek philosophy. He is not quite in the first rank, but he is important as the first to bring philosophy to Athens, and as one of the influences that helped to form Socrates.
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9
THE ATOMISTS
The founders of atomism were two, Leucippus and Democritus. It is difficult to disentangle them, because they are generally mentioned together, and apparently some of the works of Leucippus were subsequently attributed to Democritus.
Leucippus, who seems to have flourished about 440 B.C.,1 came from Miletus, and carried on the scientific rationalist philosophy associated with that city. He was much influenced by Parmenides and Zeno. So little is known of him that Epicurus (a later follower of Democritus) was thought