Every big idea arrives
wrapped in a strange word.

Athens — The Greek city where Socrates, Plato, and Aristotle taught; the cradle of Western philosophy.

The Academy — Plato's school outside Athens, often called the first university in the Western world.

The Lyceum — Aristotle's school, where he lectured while walking, giving his followers the name Peripatetics.

The Stoa Poikile — The "painted porch" in Athens where Zeno taught; it gave Stoicism its name.

The Garden — Epicurus's school and community on the edge of Athens, famous for friendship and simple pleasure.

Delphi — Home of the Oracle of Apollo, where the command "know thyself" was carved into the temple.

Mount Olympus — The mythical mountain home of the Greek gods.

The Underworld — The realm of the dead in Greek myth, ruled by Hades.

Troy — The besieged city of Homer's Iliad, the stage for Achilles and the heroes.

Jerusalem — Holy city of Judaism, Christianity, and Islam; shorthand for faith as against "Athens," reason.

Mount Sinai — Where, in the Hebrew Bible, Moses receives the Law from God.

Bodh Gaya — The place in India where the Buddha is said to have reached enlightenment under the Bodhi tree.

Rome — Capital of the empire that Marcus Aurelius governed by Stoic principle, and later the seat of the Catholic Church.

The Sistine Chapel — In the Vatican, home to Michelangelo's Creation of Adam, the West's defining image of God and humanity.

Königsberg — The Prussian city where Immanuel Kant spent his entire life, and reportedly never left.

The state of nature — Not a real place but a thought experiment: humanity imagined before any government existed, used to reason about what a state is for.

The Greeks

Heraclitus — Pre-Socratic who taught that everything flows: "you cannot step into the same river twice."

Xenophanes — Pre-Socratic who mocked the human-shaped gods of Homer and argued for one abstract god.

Socrates — The Athenian who turned philosophy into relentless questioning, and was executed for it in 399 BCE.

Plato — Socrates' student; the theory of Forms, the Republic, and the immortal soul.

Aristotle — Plato's student; logic, the golden mean, the Unmoved Mover, and tutor to Alexander the Great.

Epicurus — Taught that tranquil pleasure is the highest good and that death is nothing to fear.

Zeno of Citium — Founder of Stoicism in Athens around 300 BCE.

Epictetus, Marcus Aurelius, Seneca — The great Roman Stoics: a former slave, an emperor, and a statesman.

The East

Laozi — Legendary author of the Tao Te Ching; the Tao and wu wei.

Zhuangzi — Taoist who prized spontaneity and questioned every fixed distinction (the butterfly dream).

Confucius — Chinese teacher of ethics, ritual, and the well-ordered society.

Mencius and Xunzi — Rival Confucians who argued that human nature is good, or that it needs cultivation.

The Buddha — Founder of Buddhism; the Four Noble Truths and the path beyond suffering.

Faith and the Middle Ages

Augustine — Fused Christianity with Platonism; treated evil as a privation of good.

Anselm — Gave the ontological argument and the motto "faith seeking understanding."

Aquinas — Fused Aristotle with Christianity; the Five Ways for God's existence.

Pascal — Mathematician who helped invent probability, then turned it on God with his wager.

Kierkegaard — The leap of faith, and a founder of existentialism.

The Moderns

Hobbes — Leviathan; the social contract born of fear and the need for order.

Locke — Natural rights and limited government by consent; father of liberalism.

Rousseau — The general will, and the claim that society corrupts a naturally decent human being.

Hume — The great skeptic; his critique still shadows the design argument.

Kant — The categorical imperative and the limits of reason.

Burke — Father of modern conservatism; tradition as accumulated wisdom.

Mill — On Liberty, the harm principle, and utilitarianism.

Marx — Class struggle, alienation, and the critique of capitalism.

Nietzsche — "God is dead"; the Apollonian and Dionysian.

Rawls and Nozick — The modern classic: justice as fairness versus libertarian entitlement.

Hannah Arendt — The origins of totalitarianism and the banality of evil.

Greek thought and myth

Hubris — Overreaching pride that, in Greek thought, invites downfall.

Fate vs. free will — Whether our lives are written in advance or genuinely chosen.

The examined life — Socrates' conviction that "the unexamined life is not worth living."

The Form of the Good — Plato's highest reality, the source of truth and being.

The Unmoved Mover — Aristotle's first cause of all motion, later borrowed by Aquinas.

Eudaimonia — "Flourishing," the aim of a good life in Greek ethics.

The golden mean — Aristotle's idea that virtue lies between two extremes.

Stoicism — Live by reason, and accept what lies outside your control.

The Apollonian and Dionysian — Nietzsche's pairing of order and clarity against ecstasy and chaos.

Religion and the divine

Theism and deism — Belief in a personal God, versus a distant creator who does not intervene.

Monotheism vs. polytheism — One God versus many gods; see from Zeus to God.

Theology — Reasoning about God and the divine within a tradition.

Theodicy — The attempt to justify God's goodness in the face of evil.

The cosmological, ontological, and design arguments — The three classic cases for God's existence.

Pascal's wager — Believing in God treated as the rational bet under uncertainty.

Faith and reason — The long question of whether belief needs, or resists, proof.

Dukkha — The Buddhist term for suffering and the unsatisfactoriness of ordinary life.

Anatta — The Buddhist teaching of "no-self"; see do we have a soul?

Nirvana and sunyata — The Buddhist end of craving, and the "emptiness" behind all things.

The Tao — The nameless source and way of all things, at the heart of Taoism.

Wu wei — Taoist "effortless action," moving with the flow rather than forcing it.

The Logos — For the Stoics, the rational order that runs through the cosmos and is God and nature at once.

Karma — Moral cause and effect carried across actions and, in some traditions, lives.

The leap of faith — Kierkegaard's commitment made beyond what reason can prove.

Ideology and politics

Ideology — Belief hardened into a program for how society should be organized.

The social contract — The imagined agreement that founds legitimate government.

The general will — Rousseau's shared common interest of a people ruling itself.

Negative and positive liberty — Freedom from interference, versus freedom to actually achieve your ends.

The harm principle — Mill's rule that freedom may be limited only to prevent harm to others.

The veil of ignorance — Rawls's test: choose society's rules without knowing who you will be in it.

Alienation and surplus value — Marx's account of how capitalism separates and underpays labor; see socialism & Marxism.

False consciousness — Marx's term for accepting ideas that quietly serve the powerful.

The categorical imperative — Kant's supreme moral rule: act only on principles you could will to be universal law.