Aristotle was an ancient Greek philosopher who is known as the founder of a philosophy of realism. Aristotle lived from 384-322 B.C.E. His educational philosophy was unique because it bridged the transition from Greek city-states to the Hellenistic empire. Aristotle is considered a founding father of Western philosophy based on key elements of his Natural Realism. His philosophy of education emphasized human reason to give definition, meaning and purpose to life. His ideas changed human destiny from being considered a toy of the gods to a "purposeful world governed by rationality" in Greek philosophy. Aristotle was intrigued by science and emphasized natural sciences in his theory to explain reality. He traveled the Greek world teaching government to restore polis vitality against the Macedonian empire. Aristotle was born in Stagira, Macedonia, the son of a court physician. As a boy he collected and catalogued mineral, plant and animal specimens until age 17 when he went to Athens to study with Plato.