emotivism

Emotivism is the non-cognitivist meta-ethical theory that ethical judgments are primarily expressions of one's own attitude and imperatives meant to change the attitudes and actions of another. Influenced by the growth of analytic philosophy and logical positivism in the 20th century, the theory was stated most vividly by A. J. Ayer in his 1936 book Language, Truth and Logic, but its development owes even more to C. L. Stevenson. In the 1950s, emotivism appeared in a modified form in the prescriptivism of R. M. Hare.
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