Full Idea
If 'Britain is large' and 'Italy is large' lack truth values, then so must 'Britain or Italy is large' - so on the supervaluationist account the truth value of a disjunction is not determined by the truth values of its disjuncts.
Gist of Idea
In the supervaluationist account, disjunctions are not determined by their disjuncts
Source
Leon Horsten (The Tarskian Turn [2011], 06.2)
Book Reference
Horsten,Leon: 'The Tarskian Turn' [MIT 2011], p.73
A Reaction
Compare Idea 15362 to get the full picture here.
Related Idea
Idea 15362 If 'Italy is large' lacks truth, so must 'Italy is not large'; but classical logic says it's large or it isn't [Horsten]