Emotivism and Ayer's Non-Cognitivism

Alfred Jules Ayer's Language, Truth and Logic (1936), written when Ayer was only twenty-five and strongly influenced by his exposure to the Vienna Circle's logical positivism, applies the verification principle to ethics in its famous sixth chapter, "Critique of Ethics and Theology." According to the verification principle as Ayer states it, a sentence is factually meaningful only if it is either analytically true (true purely in virtue of the meanings of its terms, like a mathematical truism) or empirically verifiable, at least in principle, by observation. Ordinary ethical statements such as "stealing money is wrong" satisfy neither condition: they are not true by definition, and no possible empirical observation could confirm or disconfirm them, since "wrongness" adds no further, verifiable fact to the purely descriptive claim that an act is an instance of stealing. Ayer concludes that the specifically evaluative component of ethical statements is not a factual assertion at all, and is therefore, on strict verificationist grounds, literally without cognitive meaning.