Aristotle

Greek philosopher. A pupil of Plato, the tutor of Alexander the Great, and the author of works on logic, metaphysics, ethics, natural sciences, politics, and poetics, he profoundly influenced Western thought. In his philosophical system, which led him to criticize what he saw as Plato's metaphysical excesses, theory follows empirical observation and logic, based on the syllogism, is the essential method of rational inquiry.