In his papers "The Emotive Meaning of Ethical Terms" (1937) and "Persuasive Definitions" (1938), and his book Ethics and Language (1944), he developed a theory of emotive meaning; which he then used to provide a foundation for his theory of a persuasive definition.
I sina texter "The Emotive Meaning of Ethical Terms" (1937) och "Persuasive Definitions" (1938), samt sin bok Ethics and Language (1944), utvecklade han en teori om emotiv mening som han sedan använde som grund för sin teori om persuasiva definitioner.