 Another major problem for the realist version of Color Primitivism is one that Hardin (2004, 2008) and Cohen (2009) have especially stressed. They draw attention to a vast range of facts concerning the variety of conditions under which objects appear to have the colors they do, and the variety of classes of observers for whom the colors appear. Since the only way to determine what primitivist color a body has is by the way it appears, this raises the question of which is the body’s real color. Normal perceivers, for example, divide into different groups on whether a body’s color is, say, unique blue, or rather, a slightly reddish-blue, an even more reddish blue, or, alternatively, a greenish blue. Cohen and Hardin argue that there is no non-arbitrary way to pick out one group of perceivers as identifying the “real” color. At most, one group is correct, but we would not know which; for all we know, none of the groups is identifying the real color. Averill (1992) presents a pair of arguments that also depend on difficulties that stem from trying to give a non-arbitrary account of normal observers and standard viewing conditions. We can easily suppose changes in either our eyes (and hence in normal observers) or in standard viewing conditions, such that some objects that previously were yellow would look red, and others would still look yellow—while remaining otherwise physically unchanged. If primitive colors are supposed to be supervenient on physical microstructures, then it is difficult to see how we could accommodate this sort of change. A possible, but radical, response to this problem is to modify the Realist position and to hold that objects can have more than one color (indeed have many colors). See Kalderon 2007 and Mizrahi 2006 for a defense of this view.