 Sharon Street (2006), Richard Joyce (2006: ch. 6), and Allan Gibbard (2003: ch. 13) all present early versions of this argument, though it has spawned an extensive literature. The argument is typically aimed at moral realism, but it is clear that mind-independence is the tenet of realism that is supposed to be causing the problem. (This is explicit in various places, e.g., Street 2006: 110). However, it could certainly be argued that it is not mind-independence in general that causes the problem, but non-naturalistic views in particular (see the debate between Street 2008 and Copp 2008). We’ll put that debate aside for now and present the argument according to most of its proponents’ view of it – that it targets mind-independence in general.