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Single Idea 10797

[filed under theme 9. Objects / F. Identity among Objects / 2. Defining Identity ]

Full Idea

Substitutivity 'salve veritate' cannot define identity since two expressions may be everywhere intersubstitutable and not refer at all.

Clarification

'Salve veritate' means truth-preserving

Gist of Idea

Substitutivity won't fix identity, because expressions may be substitutable, but not refer at all

Source

Ruth Barcan Marcus (Nominalism and Substitutional Quantifiers [1978], p.167)

Book Ref

'Philosophy of Logic: an anthology', ed/tr. Jacquette,Dale [Blackwell 2002], p.167