 Lawrence Shapiro (2000) also contends that philosophers are too quick to claim that a single given kind is multiply realized. Some properties of the realizers are relevant to the purposes, activities, or capacities that define a given functional kind, but other properties are not. Consider corkscrews. That functional kind can be “multiply realized” in two tokens that differ only in their color. That physical difference does not make them genuinely different realizations of corkscrew, however, because that one makes no relevant difference, that is, no difference to their performances as corkscrews. Similarly for two corkscrews that differ only in that one is made of aluminum and the other of steel. Although that compositional difference might matter for some functional kinds, it doesn’t matter for corkscrews. As Shapiro notes, 