Full Idea
If vague utterances in borderline cases fail to say anything, then if 'TW is thin' is vague, and TW has a twin of identical dimensions, it still seems that 'If TW is thin then his twin is thin' must be true, and so it must have said something.
Gist of Idea
If the vague 'TW is thin' says nothing, what does 'TW is thin if his perfect twin is thin' say?
Source
Timothy Williamson (Vagueness [1994], 7.2 (d))
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.196
A Reaction
This an objection to the Fregean 'nihilistic' view of Idea 21614. I am inclined to a solution based on the proposition expressed, rather than the sentence. The first question is whether you are willing to assert 'TW is thin'.
Related Ideas
Idea 21614 The 'nihilist' view of vagueness says that 'heap' is not a legitimate concept [Williamson]
Idea 21617 We can say propositions are bivalent, but vague utterances don't express a proposition [Williamson]