  It is perhaps these ‘surface’ features of moral discourse, those that make it look like moral claims are assertions, and hence expressions of belief, and so truth-evaluable, and that moral disagreement appears to be genuine moral disagreement, that later tempted Ayer to consider Mackie’s ‘error’ theory of moral language (Mackie 1977) as closer to the truth (in Ayer 1984). The details of emotivism tended to disappear from the metaethical scene in the latter half of the twentieth century, but its guiding thoughts have remained very much alive in the expressivism of Blackburn 1984, 1998, and Gibbard 1990. (See Altham, 1979, for a sympathetic defense of these guiding thoughts, and Schroeder, 2010, for a thorough treatment of the development of expressivism, with particular attention paid to subsequent attempts to tackle the Frege-Geach problem.)