Moral Realism vs Anti-Realism: Key Differences

Direct Answer

Moral realism and anti-realism are the two great camps of metaethics, the branch of philosophy that asks what moral claims are and whether they can be true. The dispute is not about which actions are right — it is about whether there is anything for "right" and "wrong" to be true of.

| Dimension | Moral Realism | Anti-Realism | |-----------|---------------|--------------| | Core claim | Moral truths exist independently of opinion | Moral truths are not objective in the realist's sense | | Example | "Cruelty is wrong" is true like "2+2=4" | "Cruelty is wrong" is an error, an attitude, or a relative standard | | Leading figures | Moore (intuitionist), Parfit, Railton | Mackie (error theory), Ayer (emotivism), Harman (relativism) | | Strength | Explains moral disagreement and objectivity | Explains moral diversity and avoids strange entities | | Weakness | Must explain how we know moral facts | Struggles to explain why moral judgments seem binding |

Moral realism says moral statements express beliefs about objective facts: "torture is wrong" is true or false in the same way "water boils at 100 degrees Celsius" is true or false, regardless of what anyone believes. Anti-realism is a family of positions united only in denying this. The most famous members are the error theory, which says moral claims aim at truth but systematically fail (they are all false); non-cognitivism, which says moral claims do not state facts at all but express attitudes or emotions; and relativism, which says moral truth varies with culture or individual.

Historical Context

The modern debate begins with G. E. Moore. In Principia Ethica (1903) he argued that "good" is a simple, non-natural property that cannot be defined in natural terms — the so-called naturalistic fallacy — and that we know basic moral truths by intuition. Moore thereby defended a strong realism. His students soon revolted: A. J. Ayer and the emotivists argued that moral language expresses emotions rather than describing facts, and J. L. Mackie later argued in Ethics: Inventing Right and Wrong that moral properties would have to be "queer" entities, unlike anything else in the universe, and therefore do not exist. In recent decades realists have fought back — Derek Parfit defended non-naturalist realism in On What Matters, while naturalists argued moral facts are natural facts — and the debate remains fully open.

Key Differences

The differences turn on three questions. First, ontology: are there objective moral properties, or not? Second, semantics: do moral sentences state facts (cognitivism) or express attitudes (non-cognitivism)? Realists are cognitivists, but so is the error theorist — the error theorist agrees moral sentences state facts and adds that the facts do not exist. Third, epistemology: how, if at all, could we know moral truths? Realists owe us an account of moral knowledge; anti-realists argue that no such account exists. A further divide separates global anti-realists, who reject all moral truth, from relativists, who keep "truth" but make it relative — and relativism itself can be understood either as a theory of meaning or as a claim about the facts.

Examples & Applications

The dispute shows up in ordinary disagreement. If a realist and a relativist both say "female genital mutilation is wrong," they mean different things: the realist claims an objective fact, the relativist claims a judgment of a particular culture. The is-ought problem — that you cannot derive an "ought" from an "is" — is often pressed against realism: if moral facts are natural facts, says the anti-realist, you still need an argument that they are normative. The error theorist's conclusion is striking: since moral claims are all false, we should either stop making them or treat them as useful fictions. In practical terms, the realism debate underwrites how seriously we can take human rights claims: universal rights language presupposes something like moral realism.

Which Position Is Stronger

The burden of proof sits with the realists, who must explain the existence of a distinctive realm of moral facts and our access to it; but anti-realists have their own burden, explaining why moral language looks and functions so much like factual discourse. Mackie's queerness argument convinced many, yet recent realism has powerful responses: Parfit argues that some truths, like those of mathematics and logic, are neither physical nor subjective, so non-natural moral truth is not as strange as Mackie assumed. Few philosophers have changed camps, but most agree the arguments have grown much stronger on both sides, and the question remains one of the deepest open problems in philosophy.

Related Concepts

Start with what is moral realism vs anti-realism and what is metaethics, then follow the threads to what is moral nihilism, what is moral naturalism, the is-ought problem, and the naturalistic fallacy. Moore's Principia Ethica and Parfit's Reasons and Persons are the natural next readings.

Further Learning

For a deeper study, see the Stanford Encyclopedia of Philosophy entries on Moral Realism, Moral Anti-Realism, and Moral Relativism.