Begin assessment
Tradition

Moral Philosophy

Ancient to present

The discipline of reflecting systematically on ethics, virtue, and the conditions of a good life.

Moral philosophy is the systematic study of how human beings should live, what makes actions right or wrong, and what sort of person it is good to be. It is the parent discipline from which economics, sociology and political science separated, and reading figures like Adam Smith as moral philosophers, not as proto-specialists, recovers what was most distinctive in their thought.

The ancient tradition asked mainly about character and the good life. Aristotle's ethics is an account of virtue, habituation and flourishing, not a procedure for deciding cases. Modern moral philosophy narrowed the question to right action and produced the two frameworks that still structure most argument. Kant grounded rightness in a law reason gives itself and in the requirement to treat persons as ends. The utilitarian line running from Bentham through Mill to Sidgwick grounded it in consequences for wellbeing. Sidgwick's Methods of Ethics (1874) remains the most careful statement of how badly the two fit together.

The twentieth century turned first to metaethics and nearly lost the subject. Moore's charge of the naturalistic fallacy, followed by emotivism's claim that moral statements express attitudes and do not assert facts, left philosophers analyzing moral language instead of moral questions. Anscombe's "Modern Moral Philosophy" (1958) attacked the whole modern project as the residue of a divine-law conception whose lawgiver had been abandoned, and triggered the revival of virtue ethics that MacIntyre's After Virtue (1981) carried into political thought.

Substantive ethics returned decisively with Rawls and with the applied literature that followed: Singer on famine and animals, and the bioethics that medical technology forced into existence. The unresolved question is the oldest one. Persistent disagreement between the frameworks may indicate that moral knowledge is not the kind of thing that converges, or merely that the work is unfinished.

Lineage

Descends from

  • Greek Philosophy6th to 4th century BC

    Socrates, Seneca and Epictetus set the question — what does a good life require of a person — that the tradition has been answering ever since.

  • Natural LawAncient to present

    Eighteenth-century moral philosophy was taught out of Pufendorf and Grotius; the Scottish chairs in particular treated natural jurisprudence as the frame within which ethics was argued.

  • Stoicism3rd century BC to 3rd century AD

    Eighteenth-century moral philosophy was taught partly out of Cicero and Seneca, and Stoic self-command survives in Smith's impartial spectator.

Gave rise to

  • Political Economy18th century to present

    Before economics separated out, its questions were a branch of moral philosophy — Smith held the chair in it, and wrote The Theory of Moral Sentiments first.

  • Utilitarianism18th-19th century

    Hutcheson's formula — the greatest happiness for the greatest numbers — is the literal source of Bentham's principle, as Bentham acknowledged.

Thinkers20
Thinker

Arthur Schopenhauer

1788–1860

Arthur Schopenhauer was a political quietist whose pessimistic philosophy of blind will challenged Enlightenment rationalism and shaped Nietzsche, Freud, and the counter-Enlightenment tradition

Thinker

Francis Hutcheson

1694–1746

The Glasgow professor who argued that moral judgment runs through an innate sense rather than a calculation, coined the greatest-happiness formula, and taught Adam Smith.

Thinker

Henry Home, Lord Kames

1696–1782

The judge who treated law as a historical product rather than a deduction, sketched the four-stage theory of social development, and served as patron to half the Scottish Enlightenment.

Thinker

Thomas Reid

1710–1796

The founder of common-sense philosophy, who answered Hume by rejecting the premise both empiricists and rationalists had shared: that the mind perceives ideas rather than things.

Thinker

Dugald Stewart

1753–1828

The Edinburgh professor who transmitted the Scottish Enlightenment to the nineteenth century, teaching a generation of Whig politicians, editors and economists — James Mill among them.

Thinker

John Duns Scotus

1266–1308

The Subtle Doctor, whose insistence that the will is free even from the intellect's judgment opened the road to voluntarism in ethics, theology and law.

Thinker

Peter Abelard

1079–1142

The logician who made contradiction a method rather than a scandal, argued that sin lies in intention rather than in the act, and was twice condemned for it.

Thinker

Michel de Montaigne

1533–1592

The inventor of the essay, whose skeptical self-examination made the ordinary self a legitimate subject and supplied Europe with its most durable case for toleration.

Thinker

Blaise Pascal

1623–1662

Mathematician and Jansenist who founded probability theory, wrote the deadliest polemic in French, and argued that reason cannot reach the questions that matter most.

Thinker

Ralph Cudworth

1617–1688

The Cambridge Platonist who argued against Hobbes that morality is eternal and immutable, not the creation of any will — human, sovereign or divine.

Thinker

William Paley

1743–1805

The archdeacon whose theological utilitarianism was the standard English moral textbook for fifty years, and whose watchmaker argument set the terms of the design debate.

Thinker

Confucius

551–479 BCE

Confucius was the Chinese philosopher who grounded political order in cultivated character and ritual obligation rather than law — and whose transmission to Europe gave the Enlightenment a working model of government by merit without a priesthood.

Thinker

Henry Sidgwick

1838–1900

The Cambridge philosopher whose Methods of Ethics is the most careful statement utilitarianism ever received, and who could not close the gap it left open.

Thinker

Epictetus

50–135

Epictetus was a Stoic philosopher and former slave who taught that true freedom is internal — embodying Stoicism's radical egalitarianism, in which liberty depends on judgment rather than circumstance

Thinker

Seneca

4–65

Seneca was a Roman Stoic philosopher and statesman who preached virtue and detachment while amassing great wealth and steering Nero's early reign — a life more complicated than his philosophy

Thinker

Socrates

470–399 BCE

Socrates was the founding figure of Western philosophy, whose relentless questioning of Athenian politicians and poets — and his acceptance of an unjust death sentence — made him philosophy's first martyr

Thinker

Charles Sanders Peirce

1839–1914

The mathematician and logician who founded American pragmatism — arguing that the meaning of any concept lay in its practical consequences, and that inquiry was an inherently social and self-correcting process

Thinker

Bertrand Russell

1872–1970

Bertrand Russell was a philosopher and anti-war campaigner — imprisoned for opposing the First World War, though he reluctantly supported the Second as a lesser evil — who spent his last decades organizing against nuclear weapons

Thinker

Reinhold Niebuhr

1892–1971

Reinhold Niebuhr was the theologian of Cold War liberalism who gave American politics a doctrine of original sin — the insistence that every political program is corrupted by the pride of those who wield it

Thinker

Adam Smith

1723–1790

Adam Smith was the Scottish Enlightenment moral philosopher who founded modern liberal political economy and grounded markets in human sympathy rather than selfishness

Voices today4 living

Living writers, politicians and public figures working in this tradition today. Association, not endorsement: a figure appears where their stated commitments place them, and is reachable by role and search like everyone else.

Thinker

Nick Bostrom

1973–

Nick Bostrom is a transhumanist, longtermist philosopher in a broadly liberal, technology-optimistic tradition who made existential risk and superintelligent AI central questions of governance

Thinker

Eliezer Yudkowsky

1979–

Eliezer Yudkowsky is an American writer whose warnings about unaligned artificial intelligence and evangelism for human rationality shaped a whole subculture's approach to existential risk and public reason.

Thinker

Jonathan Haidt

1963–

Jonathan Haidt is a moral psychologist and critic of academia's liberal monoculture whose moral foundations research explains why the left consistently underestimates what conservatives actually care about

Thinker

Peter Singer

1946–

Peter Singer is an Australian moral philosopher whose utilitarian arguments on animal suffering and global poverty reshaped how people reason about the ethical reach of politics.

Related through shared thinkers6
Archetype

Pragmatic Centrist

4 shared thinkers

Archetype

Independent Localist

3 shared thinkers

Archetype

Techno-Progressive

3 shared thinkers

Archetype

Moderate Liberal

2 shared thinkers

Archetype

Social Liberal

2 shared thinkers

Archetype

Reactionary Strongman

1 shared thinker

Back to traditions