 First, MMR might be defended as a consequence of the general relativist thesis that the truth or justification of all judgments is not absolute or universal, but relative to some group of persons. For example, this general position might be maintained on the ground that each society has its own conceptual framework and that conceptual frameworks are incommensurable with one another. Hence, we can only speak of truth or justification in relative terms (see the discussion of incommensurability in the Summer 2015 archived version of the entry on  relativism  (section 4.2)). This position might be thought to have the disadvantage that it can only be put forward as true or justified relative to some conceptual framework (the suggestion is usually that this framework is our own), and many find it implausible with regard to common sense judgments and judgments in the natural sciences. However, this is one avenue to MMR. But most proponents of MMR focus on distinctive features of morality and reject general relativism. In fact, they often contrast morality and science with respect to issues of truth and justification. For example, Harman (2000b), Prinz (2007) and Wong (1996 and 2006) all associate moral relativism with naturalism, a position that usually presupposes the objectivity of the natural sciences.