more from David Wiggins

Single Idea 11864

[catalogued under 9. Objects / F. Identity among Objects / 1. Concept of Identity]

Full Idea

The simple proof (from Ruth Barcan Marcus) is: Hesperus is necessarily Hesperus, so if Phosphorus is Hesperus, then Phosphorus is necessarily Hesperus.

Gist of Idea

Hesperus=Hesperus, and Phosphorus=Hesperus, so necessarily Phosphorus=Hesperus


David Wiggins (Sameness and Substance Renewed [2001], 4.3)

Book Reference

Wiggins,David: 'Sameness and Substance Renewed' [CUP 2001], p.116

A Reaction

This is the famous idea which she noticed well before Kripke. The point is that the simple logic of the case bestows a necessity on the identity. We shouldn't be confused by the a posteriori and contingent nature of the discovery.