Aristotle (384–322 BCE) was a student of [[Plato]], tutor of Alexander the Great, and one of the most comprehensive and influential thinkers who has ever lived. His writings — covering [[Logic]], biology, [[Metaphysics]], physics, [[Ethics]], [[Aesthetics]], rhetoric, and [[Political Philosophy]] — shaped the intellectual tradition of Europe, the Islamic world, and beyond for two millennia.
Born in Stagira in northern Greece, Aristotle came to Athens at seventeen to study at [[Plato]]'s Academy, where he remained for twenty years. After [[Plato]]'s death he left Athens, tutored the young Alexander (later "the Great"), and in 335 BCE founded his own school in Athens: the Lyceum. His followers were called Peripatetics (from the Greek for "walking about"). He fled Athens in 323 BCE after Alexander's death, reportedly saying he would not allow Athens to "sin twice against philosophy" (alluding to [[Socrates]]' execution). He died the following year.
Aristotle invented formal logic. His Organon ("instrument") contains:
- Categories — classification of beings
- Prior Analytics — syllogistic logic
- Posterior Analytics — scientific demonstration
- Topics and Sophistical Refutations — dialectical and fallacious reasoning
See [[Logic]] for the full treatment of his contribution.
Aristotle rejected [[Plato]]'s [[The Forms|Theory of Forms]], arguing that universals do not exist separately from particulars:
- Substance (ousia) is the primary category of being — individual things (this horse, this human)
- Form and matter are inseparable: the form of a thing is what makes it the kind of thing it is; matter is what it is made of
- The four causes explain why anything is what it is: material, formal, efficient, final
- God (the Unmoved Mover) is pure form without matter — the final cause of all motion
See [[Metaphysics]] for comparison with other positions.
Aristotle's [[Ethics]] is developed in the Nicomachean Ethics. Its central concept is eudaimonia — usually translated as "happiness" or "flourishing":
- The good life is one of activity in accordance with virtue
- Virtue (arete) is a mean between two extremes: courage is the mean between cowardice and recklessness
- The highest good is the contemplative life (theoria) — the life of the philosopher
See [[Virtue Ethics]] for a full account of Aristotle's ethical theory.
For Aristotle, humans are political animals (zoon politikon) — we are naturally suited to life in a polis (city-state). In the Politics:
- The polis exists for the sake of the good life, not merely survival
- Constitutions can be good (monarchy, aristocracy, polity) or corrupt forms (tyranny, oligarchy, democracy)
- The best realistic constitution is a mixed polity combining elements of oligarchy and democracy
- Slavery and the subjugation of women were, regrettably, defended as natural
See [[Political Philosophy]] for the broader context.
In the Poetics, Aristotle defended art against [[Plato]]'s suspicions:
- Mimesis (imitation) is natural and educational
- Tragedy produces katharsis — a clarification and purgation of pity and fear
- The best plots involve peripeteia (reversal) and anagnorisis (recognition)
See [[Aesthetics]] for comparison with [[Plato]] and [[Kant]].
Aristotle was the first systematic empirical naturalist — classifying animals, describing embryology, theorizing about the elements. His physics (including the geocentric cosmos) was overturned by Galileo and Newton, but his biological work was largely confirmed only in the 19th century.
- [[Aquinas]] synthesized Aristotle with Christian theology in the 13th century
- The Islamic philosophers (Avicenna, Averroes) preserved and developed Aristotle
- His logic was not superseded until Frege in the 19th century
- His virtue ethics was revived by Alasdair MacIntyre and others in the 20th century
- [[Plato]] — Aristotle's teacher and chief philosophical opponent
- [[Socrates]] — the source of the tradition Aristotle inherited
- [[Logic]] — Aristotle invented formal logic
- [[Metaphysics]] — Aristotle's substance metaphysics vs. Plato's Forms
- [[Ethics]] — Aristotle's Nicomachean Ethics
- [[Virtue Ethics]] — Aristotle as founding figure
- [[Political Philosophy]] — humans as political animals
- [[Aesthetics]] — katharsis and the defence of tragedy
- [[The Forms]] — Aristotle's critique of Plato's theory