On the Externality of State of Affairs Unification

Abstract This paper examines what it means for the relation of unification in states of affairs to be external. I begin by introducing a tripartite, necessitation-based classification of relations into strongly internal, weakly internal, and external, and consider how it applies to the unification relation. I then focus on the version of this relation endorsed by self-relating internalism, according to which unification relates its relata by itself. Since standard necessity-based definitions of internal and external relations are not directly applicable to such a self-relating relation, I propose suitably modified counterparts. I argue that, even on these revised definitions, the unification relation comes out as external. Finally, assuming that this relation is identical to instantiation, I consider a novel argument against its externality – adapted from one of D.W. Mertz’s objections to bare particulars – and argue that it does not succeed.