Debate: Is morality objective?

Moral realism

There are objective moral facts, true independently of what anyone believes, and we can come to know some of them.

Best argument

Some moral claims seem as certain as anything we know: gratuitous cruelty is wrong. Our practice of moral argument, in which we give reasons, correct mistakes and recognise progress, makes sense only if there is something to get right. Derek Parfit and others argue that moral truths are like mathematical truths: not physical objects, but real, and knowable through reason.

Strongest objection

J. L. Mackie's 'argument from queerness': objective moral facts would be utterly unlike anything else in the universe, facts that by their nature tell you what to do. And how could we perceive them? We have no 'moral sense organ'.

The reply

Realists answer that mathematical and logical truths are equally 'queer' by Mackie's standard, and we know them through reasoning, not perception. Naturalist realists argue that moral facts are simply natural facts, about wellbeing and suffering, and are no stranger than facts about health.

Defended by

Plato, Derek Parfit, Immanuel Kant, Russ Shafer-Landau

Relativism

Moral truths are relative to a culture or framework. An act can be right in one society and wrong in another.

Best argument

Moral codes vary enormously across cultures and history, which is what one would expect if they were human creations rather than discoveries. Relativism also seems to encourage tolerance and humility about imposing our values on others.

Strongest objection

It makes moral reformers wrong by definition, since they oppose their culture's standards. It cannot condemn even the worst practices of other societies. And the tolerance it recommends would itself be just one culture's value, with no special authority.

Defended by

Gilbert Harman, David Wong

Expressivism

Moral statements do not describe facts. They express attitudes, like approval or disapproval, or commitments to plans.

Best argument

This explains why moral judgments motivate: they are themselves attitudes, not beliefs about strange facts. It fits a scientific picture with no objective values in it. Modern expressivists like Simon Blackburn argue that, once understood, the view allows us to say almost everything a realist says, including 'cruelty is wrong whatever anyone thinks'.

Strongest objection

The Frege-Geach problem: moral words behave logically like factual ones. 'If lying is wrong, then getting your brother to lie is wrong' is a perfectly good premise in an argument, though no one is expressing disapproval of lying in uttering it. Expressivism struggles to explain this.

The reply

Expressivists have built increasingly sophisticated semantic theories to handle embedded moral claims; whether they succeed is one of the most technical debates in philosophy.

Defended by

David Hume, Simon Blackburn, Allan Gibbard

Error theory

Moral claims try to state objective facts, but there are no such facts, so all of them are false.

Best argument

Mackie argued that ordinary moral talk does presuppose objective, inescapably binding values; that is what we mean by 'wrong'. But the world contains no such values, so our moral talk is systematically in error, like talk of witches.

Strongest objection

It seems to imply that 'torturing children for fun is wrong' is false, which many regard as a decisive reductio. And if we keep using moral language anyway, as Mackie suggested, what has been gained?

Defended by

J. L. Mackie, Richard Joyce

Where you stand

Is morality objective?

Choose one to see how people answer.

For the full background, variations and open questions, read the entry: Is morality objective?.