 Wright thus argues that even if we concede to the error-theorist that his original scepticism about moral truth is well-founded, the error-theorist’s own positive proposal will be inherently unstable. In recent years, inspired by error-theory, philosophers have developed forms of moral fictionalism, according to which moral claims either are or ought to be “useful fictions”. See Kalderon 2005 and Joyce 2001 for examples. For a book-length treatment of moral error-theory, see Olson 2014.