Full Idea
'Admissible' interpretations respect all the theoretical and ostensive connections. ...'Supervaluation' is the assignment of truth to the statements true on all admissible valuations, falsity to the false one, and neither to the rest.
Gist of Idea
Supervaluation assigns truth when all the facts are respected
Source
Timothy Williamson (Vagueness [1994], 5.2)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.144
A Reaction
So 'he is bald' is true if when faced with all observations and definitions it is acceptable. Prima facie, that doesn't sound like a solution to the problem. Supervaluation started in philosophy of science. [p.156 'Admissible seems vague']
Related Idea
Idea 21607 Supervaluation has excluded middle but not bivalence; 'A or not-A' is true, even when A is undecided [Williamson]