384–322 BC · Stagira, Chalcidice
"We are what we repeatedly do. Excellence, then, is not an act, but a habit."
— Nicomachean EthicsAristotle was a Greek philosopher and polymath who, alongside his teacher Plato and his student Alexander the Great, helped lay the foundations of Western philosophy and science. Born in Stagira, a small town in northern Greece, he spent two decades at Plato's Academy in Athens before founding his own school, the Lyceum. His writings span logic, metaphysics, ethics, politics, biology, physics, and poetics—forming one of the most comprehensive intellectual systems in history.
Born in Stagira; father Nicomachus was court physician to King Amyntas of Macedon.
Moved to Athens; joined Plato's Academy, where he studied for nearly twenty years.
Left Athens after Plato's death; traveled to Assos and Lesbos, conducting biological research.
Summoned by Philip II to tutor the young Alexander (later Alexander the Great).
Returned to Athens; founded the Lyceum, a school and research center.
Fled Athens after Alexander's death amid anti-Macedonian sentiment.
Died in Chalcis, Euboea, at age 62.
Aristotle held that to understand any thing, one must grasp four types of explanation: material (what it's made of), formal (its structure or essence), efficient (what produced it), and final (its purpose or telos).
Substance is a compound of matter (hyle) and form (morphe). Matter is potential; form actualizes it. The soul is the form of a living body—its organizing principle and life.
Moral virtue lies in the mean between extremes. Courage, for instance, is the mean between cowardice and recklessness. Virtue is cultivated through habit and practical wisdom (phronesis).
Aristotle invented formal logic. The syllogism—a deductive argument with two premises and a conclusion—became the foundation of logical reasoning for over two millennia.
Change is the actualization of potential. An acorn has the potential to become an oak; when it does, that potential is actualized. The universe moves from potentiality toward full actuality.
The highest human good is eudaimonia—often translated as "flourishing" or "living well." It is achieved through a life of virtue, reason, and activity in accordance with excellence.
Aristotle founded the Lyceum (Lykeion) in Athens around 335 BC, named after the nearby temple of Apollo Lyceus. Unlike Plato's Academy, which emphasized mathematics and abstract dialectic, the Lyceum was a center for empirical research. Aristotle and his students gathered biological specimens, compiled constitutions of Greek city-states, and conducted systematic investigations across the natural and human sciences. He is said to have lectured while walking the covered walkways (peripatoi), giving his followers the name "Peripatetics."
Aristotle's influence is immeasurable. His logic dominated Western thought until the 19th century. His physics and cosmology shaped medieval scholasticism and persisted until the Scientific Revolution. His ethics and politics remain central to contemporary virtue ethics and political theory. His biological observations—though often wrong—exemplified empirical method. Through Islamic scholars who preserved and commented on his works, and through Thomas Aquinas and the medieval universities, Aristotelian thought became the backbone of Western education for centuries.
"It is the mark of an educated mind to be able to entertain a thought without accepting it."
— Attributed to Aristotle