360 POPULAR SCIENCE MONTHLY 



expression of beauty ever made by the human race. In the latter part 

 of this period books, also, were in common use, although not as 

 yet very numerous. Peisistratos had founded a library for those who 

 applied themselves to letters, which had passed through various vicissi- 

 tudes, and the Athenians had increased it with a great deal of care. 

 To the stock of books in existence at that time Anaxagoras made an 

 important addition. His book did not have an original title, being 

 called 7rspt (fjae/x^, or ' On Nature,' like many other productions of 

 Ionian philosophers, but his ideas were original, and it was the first 

 book to be illustrated by diagrams, with the exception of geometrical 

 writings. In Plato's time the book was on sale for a drachma, although 

 it is said to have consisted of several volumes. Probably the volumes 

 may have been rather what we should call chapters. This book, alas, 

 is no longer in existence, although we possess important fragments of 

 it, mostly found in Simplicius's commentary on Aristotle's physics, 

 which was written in the sixth century, at which time a copy of the 

 book was to be had. 



Let us now consider some strange phenomena in connection with 

 the first appearance of the idea of spirit in Greek philosophy. Anax- 

 agoras himself had the characteristics of the idealist, but his world 

 theory and the general trend of his studies were closely allied with the 

 teachings of his materialistic predecessors in Ionia. He could not 

 wholly escape from his age. When Sokrates heard of Anaxagoras's 

 book he was delighted that some one had attributed the universe to an 

 all-pervading spirit, and immediately sent for the book; but he was 

 ;greatly disappointed on reading it, as he did not find there the idealism 

 for which he had sought. Anaxagoras belonged not to the age of 

 ^Sokrates, although he was partly contemporary with him, but he be- 

 longed wholly to the Ionian school of mathematical astronomy. The 

 thought of Anaxagoras was scientific rather than philosophic, and his 

 book was devoted to scientific, mathematical explanations of cosmog- 

 raphy and astronomy. The Nous was not to him the all-important 

 part, but only a necessary cause for the beginning of motion — a sec- 

 ondary first cause, so to speak. Yet the idea of the Nous was sufficient 

 to introduce rationalism into Greece, for it was the first presentation 

 of an existing rational force wholly distinct from matter. Anaxagoras 

 was bent upon scientific discovery, and the important things in his 

 mind were his method and his original theory of matter. How often 

 it happens that what seems secondary to a great man proves after all 

 his most far-reaching service to the world. As, for example, with 

 Plato his philosophy was secondary in his own mind to his ideas of 

 political reform, and, while it is true that the latter have been much 

 regarded, yet the former have revolutionized all philosophic thought. 

 Anaxagoras's rationalism did not enable him to produce a rational 

 theory of matter, yet it rationalized all his thought and was a stepping- 



