How Composition Could be Identity

The paper argues that, as far as logic and abstract metaphysics go, the claim that composition is identity could be true, despite wellmotivated arguments against the coherence of the claim. The key to answering the arguments is to reject a principle of universal substitutivity of “identical” plural expressions while retaining Leibniz’ Law, that identicals have the same properties, relations, and so forth. We present a metaphysics and semantics that naturally motivates our rejection of univeral substitutivity, and show how the resulting conception of collective identity can be used to analyze mereological notions.