What Is Moral Anti-Realism? Definition & Forms

Direct Answer

Moral anti-realism is the family of metaethical views that deny the existence of objective, mind-independent moral truths. The moral realist claims that a sentence like "torture is wrong" is made true or false by the moral facts, just as "water is H2O" is made true by chemical facts, and that these facts hold regardless of what anyone believes, feels, or desires. The anti-realist rejects this picture. The rejection can take three very different shapes. Error theory agrees with realism that moral sentences are truth-apt — they attempt to state facts — but argues that there are no moral facts of the kind they presuppose, so all positive moral claims are false. Non-cognitivism argues that moral sentences are not in the business of stating facts at all; they express emotions, prescriptions, or attitudes, and so are not the kind of thing that can be true or false in the factual sense. Relativism holds that moral claims can be true or false, but only relative to a culture or an individual, so there is no single objective moral truth. These three positions disagree deeply with one another; what unites them is opposition to realism.

Historical Context

Anti-realism has ancient roots. The Sophists, as portrayed by Plato, argued that moral and legal norms are human conventions rather than objective truths. David Hume provided the modern foundation: he argued that morality is grounded in sentiment, not reason, and that moral distinctions are derived from the passions rather than discovered by the understanding. In the twentieth century anti-realism became the dominant position in analytic metaethics. A.J. Ayer's Language, Truth and Logic (1936) made the verification principle the basis of emotivism, holding that moral sentences are neither true nor false because they express emotions rather than verifiable facts. C.L. Stevenson developed emotivism into a sophisticated theory of moral language as a tool for influencing attitudes. In 1977, J.L. Mackie's Ethics: Inventing Right and Wrong defended the error theory, arguing that moral claims presuppose "objective prescriptivity" — values that exist in the world and command us — and that no such values exist. The last decades of the century saw a strong realist reaction, but anti-realism remains a live and influential position.

Key Arguments & Debates

Anti-realists press several arguments against realism. The argument from disagreement notes that moral disagreement across cultures and across history is deep and pervasive, and claims that realism cannot explain this: if moral facts existed, disagreement should eventually be resolvable as scientific disagreement is. The argument from queerness, Mackie's central argument, claims that objective moral properties would be "queer" entities — unlike anything in the natural world — and that we could have no plausible account of how we come to know them. The argument from motivation observes that moral judgments are intrinsically motivating, whereas beliefs about facts are not; this suggests that moral judgments are attitudes rather than beliefs, supporting non-cognitivism. Relativists add that moral codes differ so radically that "true for us" is the best we can manage. The debates are not settled: realists respond that disagreement exists in science too, that naturalistic accounts can explain moral knowledge, and that the motivational premise can be accommodated.

Contemporary Relevance

Anti-realism structures many live disputes. Debates about moral disagreement between cultures — over human rights, for example — often assume relativism without arguing for it. Skeptical claims that morality is "just a matter of opinion" or "just feelings" are amateur versions of non-cognitivism and error theory. At the same time, anti-realism raises the stakes for normative ethics: if moral truths are an illusion, what grounds human rights, justice, and the authority of moral criticism? Philosophers who reject realism often argue that morality can still function as a useful invention or a shared practice. Understanding anti-realism helps you diagnose when a disagreement is genuinely about metaethical foundations and when it is a dispute within a shared moral framework.

Related Concepts

Anti-realism is best understood against its foil: moral realism and anti-realism lays out the dividing line. The error theory is the nihilistic member of the family, while moral nihilism names the broader denial of moral value. Moral relativism is the relativist member, and non-cognitivism — covered in what is non-cognitivism — is the linguistic member. The is-ought problem is the historical engine of anti-realism, and Hume is its patron saint.

Further Learning

See the Stanford Encyclopedia of Philosophy entry on moral anti-realism for a systematic survey, and the Internet Encyclopedia of Philosophy's entry on moral realism for the debate in context. J.L. Mackie's Ethics: Inventing Right and Wrong (Penguin, 1977) is the classic statement of the error theory, and A.J. Ayer's Language, Truth and Logic (Gollancz, 1936) is the classic emotivist manifesto.