_The Ionian Philosophy Turned the Mind Toward Nature_.--Greek philosophy began in the seventh century before Christ. The first philosopher of note was Thales, born at Miletus, in Asia Minor, about 640 B.C. Thales sought to establish the idea that water is the first principle and cause of the universe. He held that water is filled with life and soul, the essential element in the foundation of all nature. Thales had great learning for his time, being well versed in geometry, arithmetic, and astronomy. He travelled in Egypt and the Orient, and became acquainted with ancient lore. It is said that being impressed with the importance of water in Egypt, where the Nile is the source of all life, he was led to assert the importance of water in animate nature. In his attempts to break away from the {217} old cosmogony, he still exhibits traces of the old superstitions, for he regarded the sun and stars as living beings, who received their warmth and life from the ocean, in which they bathed at the time of setting. He held that the whole world was full of soul, manifested in individual daemons, or spirits. Puerile as his philosophy appears in comparison with the later development of Greek philosophy, it created violent antagonism with mythical theology and led the way to further investigation and speculation. Anaximander, born at Miletus 611 B.C., an astronomer and geographer, following Thales chronologically, wrote a book on "Nature," the first written on the subject in the philosophy of Greece. He held that all things arose from the "infinite," a primordial chaos in which was an internal energy. From a universal mixture things arose by separation, the parts once formed remaining unchanged. The earth was cylindrical in shape, suspended in the air in the centre of the universe, and the stars and planets revolved around it, each fastened in a crystalline ring; the moon and sun revolved in the same manner, only at a farther distance. The generation of the universe was by the action of contraries, by heat and cold, the moist and the dry. From the moisture all things were originally generated by heat. Animals and men came from fishes by a process of evolution. There is evidence in his philosophy of a belief in the development of the universe by the action of heat and cold on matter. It is also evident that the principles of biology and the theory of evolution are hinted at by this philosopher. Also, he was the first to observe the obliquity of the ecliptic; he taught that the moon received its light from the sun and that the earth is round.