Full Idea
My thesis is that vagueness is an epistemic phenomenon. In cases of unclarity, statements remain true or false, but speakers of the language have no way of knowing which. Higher-order vagueness consists in ignorance about ignorance.
Gist of Idea
Vagueness is epistemic. Statements are true or false, but we often don't know which
Source
Timothy Williamson (Vagueness [1994], Intro)
A Reaction
He has plumped for the intuitively least plausible theory. It means that a hair dropping out of someone's head triggers a situation where they are 'bald', but none of us know when that was. And Rembrandt became 'old' in an instant.
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.3