Aristotle

Aristotle (384 – 322 BCE) was born in Stagira, in northern Greece, the son
of a court physician. At seventeen he travelled to Athens to study at Plato's
Academy, where he remained for some twenty years until his teacher's death.
He later tutored the young Alexander of Macedon and, returning to Athens,
founded his own school, the Lyceum, whose followers were called Peripatetics
after the covered walkway in which they discussed philosophy.

Where Plato looked beyond the sensible world to a realm of Forms, Aristotle
turned his gaze toward nature itself. For him the form of a thing is not a
separate archetype but is immanent in the thing, inseparable from the matter
it organizes. This shift grounds an immense programme of empirical inquiry:
Aristotle wrote on physics, biology, meteorology, the motion of the heavens,
the parts and generation of animals, ethics, politics, rhetoric, poetry, and
the structure of reasoning itself.

His logic, set out in the works later collected as the Organon, supplied the
West with its first formal theory of inference. The syllogism — a pattern in
which a conclusion follows necessarily from two premises — dominated the study
of reasoning until the nineteenth century. His doctrine of the four causes —
material, formal, efficient, and final — offered a framework for explaining
why anything is as it is, with the final cause, the end or purpose, holding
pride of place in his account of living things.

In ethics Aristotle located the human good in eudaimonia, usually rendered
"flourishing" or "well-being," achieved through the exercise of virtue across
a complete life. Virtue itself he defined as a mean between extremes:
courage, for instance, lies between cowardice and recklessness. This is no
mechanical rule but a disposition cultivated by habit and guided by practical
wisdom. The good life, on his view, is also a social one, for the human being
is by nature a political animal.

Translated into Arabic and then Latin, Aristotle's corpus became the
backbone of medieval university learning, so authoritative that scholastic
writers referred to him simply as "the Philosopher." Though modern science
has overturned much of his physics and cosmology, his contributions to logic,
biology, and ethics remain living parts of the tradition he helped to found.