theories, however, seemed satisfactory to Anaxagoras. How then could he start the whirl in chaos? Long years of meditation were doubtless necessary before he evolved his great idea, which revealed a dim understanding of the power of reason in the origin of being. To start a whirl he must have an outside something, and if reason is the strongest element of human power, why should there not be some form of reason which is independent of matter and able to originate the whirl in chaos, and then to retire from the scene of action and return to the separate and lonely existence of its unknown past? Thus was born the idea of the Nous. The Nous is half spirit and half matter, as yet a vague force, the beginning of a conception of the thinking element in the universe. There is only one fragment preserved from the sayings of Anaxagoras which would imply a kind of personality in the Nous, in which he speaks of its having knowledge of the past, present and future. In general, however, we find that Anaxagoras's understanding of the Nous was rather that of a kind of matter, a thinking essence, the lightest of all things, a semi-material force.
When Anaxagoras was forty years old, having partially at least formulated his world theory, he went to Athens, the first philosopher to live there. Athens was then in the dawn of its brightest day. Perikles was coming into power, and his mind was seething with all the possibilities which the development of the Athenian democracy provided, and he was ripe for the strongest idealistic teaching of his age. Anaxagoras's migration to Athens has sometimes been attributed to Aspasia, who, herself from Miletos, would be desirous of bringing to Athens as much as possible of the brilliancy and culture of Ionia. There are chronological difficulties, however, against this supposition, as Aspasia must have been too young at that time to have gained influence over Athenian society; in fact, it may be quite possible, on the contrary, that Anaxagoras was himself the cause of Aspasia's going to Athens. Perikles, in his desire for the best for his beautiful Athens, very probably himself invited Anaxagoras from Ionia to Greece.
Anaxagoras's influence over Perikles was strong, and from the congenial counsels of these two great men was brought forth a wonderful atmosphere of love of freedom and reign of reason in Athens. We can picture Athens as she was in the beginning of Perikles's power from the excavations of Dr. Dörpfeld, president of the German School of Archeology in Athens, begun in 1891, on the northwest side of the Akropolis—a primitive town with small, insignificant houses and narrow streets—and it was during the three decades of Anaxagoras's life in Athens that the marvelous changes there were produced by Perikles. Eager pursuit of knowledge and art arose. Astronomy was influencing the reckoning of time. A new Athens was building with straight, broad streets and graceful columns. Music and gymnastics were being made prominent, and on the Akropolis was beginning to blossom the highest