Mereological Indeterminacy: Metaphysical but Not Fundamental

Abstract

What is the nature of indeterminacy concerning the composition of ordinary objects? While orthodoxy sees all mereological indeterminacy as having its source in how we represent the world, there is an increasing interest in the position that some mereological indeterminacy has its source in how the world is, independently of how we represent it—that is, the position that some mereological indeterminacy is metaphysical. Those attracted to metaphysical indeterminacy typically construe it as fundamental, either in the sense that facts about such indeterminacy are not grounded in any more basic, indeterminacy-free facts or in the sense that the operator ‘indeterminately’ is perfectly natural, that it carves nature at the joints. This view incurs significant costs. Many judge the picture of fundamental metaphysical indeterminacy, often conceptualised in terms of multiple actualities, ‘crazy metaphysics’. Furthermore, fundamental metaphysical indeterminacy concerning composition raises the problem of indeterminate coincidence. I claim that there is an alternative to the fundamental view, which avoids these costs. I develop a picture of ordinary mereological indeterminacy, according to which the indeterminacy is metaphysical, in virtue of being representation-independent, but not fundamental; it is derivative metaphysical indeterminacy. The approach rests on an unorthodox quasi-hylomorphic ontology of ordinary objects.