Full Idea
Ayer defends emotivism, which is his own favoured form of expressivism.
Gist of Idea
Ayer defends the emotivist version of expressivism
Source
report of A.J. Ayer (Language,Truth and Logic [1936], Ch.6) by Michael Smith - The Moral Problem 2.1
Book Reference
Smith,Michael: 'The Moral Problem' [Blackwell 1994], p.17
A Reaction
A helpful distinction of terminology. Expressivism is the broad theory, and emotivism is a sub-type, saying that it is emotions which are expressed. The alternative (such as Prescriptivism) is to express pro- and con- attitudes.