Thales a celebrated Greek philosopher, and the first of the seven wise men of Greece, was born at Miletus about B.C. 640. After acquiring the usual learning of his own country, he traveled into Egypt and several parts of Asia' to learn astronomy, geometry, mystical divinity, natural knowledge, or philosophy; etc. Returning to his own country, he communicated the knowledge he had acquired to many disciples, among the principal of whom were Anaximander, Anaximenes, and Pythagoras. He was the founder of the Ionian sect of philosophers. Laertes and several other writers agree that he was the father of the Greek philosophy, being the first that made any researches into natural science and mathematics. His doctrine is that water is the principle of which all the bodies in the universe are composed; that the world is the work of God; and that God sees the most secret thoughts in the heart of man. He taught that in order to live well we ought to abstain from what we find fault with in others; that bodily felicity consists in health; and that of the mind in knowledge. That the most ancient of beings is God, because he is uncreated; that nothing is more beautiful than the world, because it is the work of God; nothing more extensive than space, quicker than spirit, stronger than necessity wiser than time. He used to observe that we ought never to say that to any one which may be turned to our prejudice; and that we should live with our friends as with persons that may become our enemies. In geometry Thales was a considerable inventor as well as an improver; while in astronomy his knowledge and improvements were very considerable. His morals were as just as his mathematics well-grounded, and his judgment in civil affairs equal to either. He died about B.C. 550. Concerning his writings, it remains doubtful whether he left any behind him; at least, none have come down to us. See Chalmers, Biog. Dict. s.v.; Smith, Dict. of Class. Biog. s.v.