Aristotle
Learn about Aristotle — the Greek philosopher who systematized logic, biology, ethics, and politics, and tutored Alexander the Great.
Aristotle (384–322 BCE) was the most comprehensive thinker of the ancient world and possibly of any age. A student of Plato and tutor to Alexander the Great, he made foundational contributions to virtually every field of knowledge that existed in his time — logic, physics, biology, ethics, politics, rhetoric, poetics, metaphysics, and psychology.
Where Plato looked beyond the physical world to a realm of eternal Forms, Aristotle insisted on careful observation of the world as it is. He classified and categorized everything from constitutions to sea creatures, pioneering the empirical approach that would later become central to scientific method. His system of formal logic — the syllogism — remained the foundation of Western reasoning for two thousand years.
Aristotle's influence is difficult to overstate. His works shaped medieval Islamic philosophy (where he was known simply as 'The Philosopher'), medieval Christian theology (particularly through Thomas Aquinas), and the development of European science. His Nicomachean Ethics, with its concept of virtue as a mean between extremes and its vision of the good life as one of rational activity, remains one of the most widely read and taught works of moral philosophy. When medieval scholars spoke of 'The Philosopher,' they meant Aristotle — and in many ways, his framework of thought remains embedded in how we organize knowledge today.