The proper treatment of identity in dialetheic metaphysics

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According to one prominent strand of mainstream logic and metaphysics, identity is indistinguishability. Priest has recently argued that this permits counterexamples to the transitivity and substitutivity of identity within dialetheic metaphysics, even in paradigmatically extensional contexts. This paper investigates two alternative regimentations of indistinguishability. Although classically equivalent to the standard regimentation on which Priest focuses, these alternatives are strictly stronger than it in dialetheic settings. Both regimentations are transitive, and one satisfies substitutivity. It is argued that both regimentations provide better candidates to occupy the core theoretical role of numerical identity than does the standard regimentation.


Original languageEnglish
Pages (from-to)1-28
Number of pages28
JournalThe Philosophical Quarterly
Publication statusPublished - 18 Jul 2019


  • identity, indistinguishability, dialetheism, second-order quantification, binary quantification

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