Full Idea
The common objects of moral approval and disapproval are not particular actions so much as classes of actions.
Gist of Idea
Moral approval and disapproval concerns classes of actions, rather than particular actions
Source
A.J. Ayer (Introduction to 'Language Truth and Logic' [1946], p.27)
Book Reference
Ayer,A.J.: 'Language, Truth and Logic' [Penguin 1974], p.27
A Reaction
This 1946 revision of his pure emotivism looks like a move towards Hare's prescriptivism, where classes, rules and principles are seen as the window-dressing of emotivism. It's still a bad theory.