Aristotle (384–322 BC) was the Greek philosopher who built the first complete system of human knowledge — logic, ethics, politics, biology, physics and metaphysics — and whose authority over science and philosophy endured for nearly two thousand years after his death, from Baghdad to Paris.
Student of Plato, tutor of Alexander the Great and founder of the Lyceum school in Athens, he insisted that knowledge begins not in abstract ideals but in observation. His works — lecture notes compiled by his students — became the textbooks of the Islamic Golden Age, medieval Christianity and Renaissance science alike.
