SOPhiA 2021

Salzburgiense Concilium Omnibus Philosophis Analyticis

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Programme - Talk

Can there be vague quantum objects?
(Metaphysics and Ontology, )

A Ontically vague identity - the idea that the identity of certain objects may be vague because the world itself is vague - is often accused of incoherence. The most famous attack comes from Evans. In his famous one-page paper, Evans (1978) demonstrates that the assumption of ontically vague identity leads to a contradiction. However, this is not the last word on this matter. In fact, Evans' argument is challenged by Lowe (1994), who provides an example of ontically vague identity based on quantum mechanics. In this work, I criticize both Lowe_s and Evans_ stance. On the one hand, I show that Lowe_s proposal fails in refuting the argument against vague identity. More generally, I explain that quantum mechanics-based counterexamples do not work against Evans_ argument because his understanding of indeterminacy differs from the one relevant in the framework of quantum mechanics. On the other hand, I argue against Evans' claim that ontic indeterminacy of identity is incoherent. In fact, quantum mechanics establishes a meaningful way in which there is ontically vague identity, which is not captured by Evans. Consequently, quantum mechanics-based counterexamples are not affected by Evans' argument. On the contrary, they demonstrate the limits of his understanding of indeterminacy. I conclude by outlining two promising routes to defend the thesis that there are quantum objects whose identity is ontically vague.

Chair: Bogdan Dumitrescu
Time: 11:20-11:50, 11 September 2021 (Saturday)
Location: SR 1.003
Remark: (Online Talk)

Marta Pedroni 
(University of Italian Switzerland, )

Testability and Meaning deco