On a plenitudinous ontology, in every filled region of spacetime, there is at least one object that’s ‘exactly then and there’; one per each modal profile that the matter in the region satisfies. One of the strongest arguments for plenitude, the “argument from anthropocentrism”, puts pressure on us to accept that members of different communities correctly self-identify under different subject concepts. I explore this consequence and offer an account of selves on which self-determination is both socially and individually variant; we (...) determine our spatiotemporal boundaries, our de re modal properties, and the kind of being that we are. We do this by determining which of many candidate beings has the property of being a self. (shrink)

Radically permissive ontologies like mereological universalism and material plenitude are typically motivated by concerns about arbitrariness or anthropocentrism: it would be objectionably arbitrary, the thought goes, to countenance only those objects that we ordinarily take there to be. Despite the prevalence of this idea, it isn't at all clear what it is for a theory to be “objectionably arbitrary,” or what follows from a commitment to avoiding arbitrariness in metaphysics. This paper aims to clarify both questions, and examines whether arguments (...) from arbitrariness really are the proper foundations for one or both varieties of ontological permissivism. I argue that these considerations (even when made more precise) are far less successful at motivating radical forms of permissivism than we often take them to be. To do better, permissivists must either supply a much more developed metaphysics of material objects, or a controversial (but tempting) conception of what we're doing when we do metaphysics. (shrink)