Abstract

The view that identity can be vague holds that there are statements of identity which are neither true nor false. The view that composition can be vague holds that unities can have borderline constituents — that is, elements that are neither parts nor non-parts of some larger unity. The case for vague identity is typically made by way of an argument for the vagueness of composition. In this paper, however, I argue that the thesis that composition can be vague is actually incompatible with the thesis of vague identity. The argument for the incompatibility of these two views arises out of a demonstration of the way in which constituency facts are grounded in the other facts about how a larger unity is configured. Thus, I show that composites that are allegedly vaguely identical are actually different configurations. Hence, the alliance of vague composition with vague identity is taken to be all that is needed in order to show that compositional vagueness is indefensible.