Full Idea
Supervaluationists identify truth with 'supertruth'; since validity is necessary preservation of truth, they should identify it with necessary preservation of supertruth. But it plays no role in their definition of 'local' validity.
Gist of Idea
Supervaluationism defines 'supertruth', but neglects it when defining 'valid'
Source
Timothy Williamson (Vagueness [1994], 5.3)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.148
A Reaction
[See text for 'local'] Generally Williamson's main concern with attempts to sort out vagueness is that higher-order and meta-language issues are neglected.
Related Ideas
Idea 21607 Supervaluation has excluded middle but not bivalence; 'A or not-A' is true, even when A is undecided [Williamson]
Idea 21608 Truth-functionality for compound statements fails in supervaluation [Williamson]