Quasi-realism and fundamental moral error1

A common first reaction to expressivist and quasi-realist theories is the thought that, if these theories are right, there's some objectionable sense in which we can't be wrong about morality. This worry turns out to be surprisingly difficult to make stick—an account of moral error as instability under improving changes provides the quasi-realist with the resources to explain many of our concerns about moral error. The story breaks down, though, in the case of fundamental moral error. This is where the initial worry finally sticks—quasi-realism tells me that I can't be fundamentally wrong about morality, though others can.