Non-cognitivism

Non-cognitivism is the meta-ethical view that ethical sentences do not express propositions (i.e., statements) and thus cannot be true or false (they are not truth-apt). A noncognitivist denies the cognitivist claim that "moral judgments are capable of being objectively true, because they describe some feature of the world." If moral statements cannot be true, and if one cannot know something that is not true, noncognitivism implies that moral knowledge is impossible.

Non-cognitivism entails that non-cognitive attitudes underlie moral discourse and this discourse therefore consists of non-declarative speech acts, although accepting that its surface features may consistently and efficiently work as if moral discourse were cognitive. The point of interpreting moral claims as non-declarative speech acts is to explain what moral claims mean if they are neither true nor false (as philosophies such as logical positivism entail). Utterances like "Boo to killing!" and "Don't kill" are not candidates for truth or falsity, but have non-cognitive meaning.

Emotivism, associated with A. J. Ayer, the Vienna Circle and C. L. Stevenson, suggests that ethical sentences are primarily emotional expressions of one's own attitudes and are intended to influence the actions of the listener. Under this view, "Killing is wrong" is translated as "Killing, boo!" or "I disapprove of killing."

A close cousin of emotivism, developed by R. M. Hare, is called universal prescriptivism. Prescriptivists interpret ethical statements as being universal imperatives, prescribing behavior for all to follow. According to prescriptivism, phrases like "Thou shalt not murder!" or "Do not steal!" are the clearest expressions of morality, while reformulations like "Killing is wrong" tend to obscure the meaning of moral sentences.

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