 The favored response to this problem is to say, for example, that a given color, red, say, is not a specific color reflectance, but a type of reflectance, i.e., one that is a member of a certain group. However, there are still problems. Averill (1992, 2005), for example, presents some interesting arguments, which are based on plausible conjectures about how normal observers and standard conditions might easily enough change, with consequent metameric change. The color physicalist seems to be committed to a very arbitrary grouping of reflectances into the various types.