(348-322 B.C.) The greatest of ancient philosophers, surnamed Stagirite, because he was born at Stagira, a Grecian colony in the Thracian peninsula. He was a pupil of Plato at Athens from his eighteenth to his thirty-seventh year. He next married Pythias, adopted daughter of Hermias, at whose court in Asia Minor he spent three years. Recalled to Stagira by Philip of Macedon, he acquired influence with the young prince Alexander who aided him liberally in getting books and opportunities for research in natural science. About 335 he returned to Athens and opened his school of philosophy known as the Peripatetic School (Greek: peripateo, walk about) because he walked about with his disciples while teaching. Most of his works were composed at this time. They are a complete treatise of human knowledge. He was the first to make logic a science, and to put philosophical study on a sure foundation. He kept clear the distinction between matter and spirit, sense perception and mental, the principle of cause and effect, and the division of the four causes: the formal and material explaining the constitution of matter, the efficient accounting for the origin and changes of things, and the final establishing their purpose and destiny. Forced to leave Athens, his school continued until it was closed by Justinian in 529. Translators and commentators carried on his system in Persia, Armenia, Syria. From these sources the Arabians derived it and they with its followers in Byzantium, who had always cultivated it, were the channels through which it reached the University of Paris in the 12th century. The Scholastics favored it because of its logical method and because it emphasized the reality of things outside human consciousness. They, and principally Saint Thomas Aquinas, purged the system of the materialistic and pantheistic elements the Arabians had introduced into it and by means of it established the consistency of reason with faith. In the revival of Scholastic philosophy by the movement known as neo-Scholasticism, Aristotle is still looked to as the exponent of principles which serve to refute the subjective philosophers which have had vogue since Descartes.