Abstract

Recently, Terry Horgan and Matjaž Potrč have defended the thesis of ‘existence monism’, according to which the whole cosmos is the only concrete object. Their arguments appeal largely to considerations concerning vagueness. Crucially, they claim that ontological vagueness is impossible, and one key assumption in their defence of this claim is that vagueness always involves ‘sorites-susceptibility’. I aim to challenge both the claim and this assumption. As a consequence, I seek to undermine their defence of existence monism and support a common-sense pluralist ontology of ‘ordinary objects’ as being fully consistent with a thoroughgoing metaphysical realism.