The relativity of plural identity

Against the prevailing view in the literature on the so-called thesis of Composition as Identity, Joongol Kim has recently argued that composition—the relation of parts to their sum—is a strict relation of identity which satisfies substitutivity of identity. Among various attempts to defend Composition as Identity against worries about substitutivity Kim's strategy is unique in that it appeals to what he calls the ‘relativity of plural identity’. But it would seem that Kim's invocation of the relativity of plural identity raises more problems than it solves. Especially, it might seem that the relativity of plural identity causes undesirable complications such as indeterminacy and ambiguity in plural reference and quantification. This paper argues that on the contrary the relativity of plural identity is not only harmless but firmly embedded in our ordinary discourse about composite things.