Single Idea 12004

[catalogued under 10. Modality / E. Possible worlds / 3. Transworld Objects / c. Counterparts]

Full Idea

The outstanding technical objection to counterpart-theoretic semantics concerns its handling of the logic of identity. In quantified S5 (the orthodox semantics) a = b → □(a = b) is valid, but 'a' must not attach to two objects.

Gist of Idea

Counterpart theory is not good at handling the logic of identity

Source

Graeme Forbes (The Metaphysics of Modality [1985], 3.5)

Book Reference

Forbes,Graeme: 'The Metaphysics of Modality' [OUP 1985], p.66