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Ontological Vagueness, Existence Monism and Metaphysical Realism


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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.

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  • Horgan, T. and Potrč, M. (2008). Austere Realism: Contextual Semantics Meets Minimal Ontology. Cambridge: MIT Press.

  • Horgan, T. and Potrč, M. (2012) Existence monism trumps priority monism. In: Goff, P (ed.) Spinoza on Monism. Houndsmills: Palgrave Macmillan, pp. 51–76

  • Lowe, E. J. (1994). Vague Identity and Quantum Indeterminacy. Analysis 54: 110–114.

    Article  Google Scholar 

  • Lowe, E. J. (1995). The Problem of the Many and the Vagueness of Constitution. Analysis 55: 179–182.

    Article  Google Scholar 

  • Lowe, E. J. (1998). The Possibility of Metaphysics: Substance, Identity, and Time. Oxford: Clarendon Press.

  • Lowe, E. J. (2005). Identity, Vagueness, and Modality. In: J. L. Bermúdez. (ed.) Thought, Reference, and Experience: Themes from the Philosophy of Gareth Evans, Oxford: Oxford University Press.

    Google Scholar 

  • Schaffer, J. (2010). Monism: The Priority of the Whole. Philosophical Review 119: 31–76. Reprinted in Goff (ed.) 2012.

    Article  Google Scholar 

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Correspondence to E. J. Lowe.

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Lowe, E.J. Ontological Vagueness, Existence Monism and Metaphysical Realism. Int Ontology Metaphysics 14, 265–274 (2013).

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