Full Idea
Fuzzy boundaries do not in any way require vague identity. Objects are identical only if their boundaries have exactly the same fuzziness.
Gist of Idea
Equally fuzzy objects can be identical, so fuzziness doesn't entail vagueness
Source
Timothy Williamson (Vagueness [1994], 9.2)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.255
A Reaction
This all rests on the Fregean idea that determinate existence requires the ability to participate in an identity statement.