Full Idea
Logic requires expressions to have the same referents wherever they occur; vague natural languages violate this contraint.
Gist of Idea
Vagueness undermines the stable references needed by logic
Source
Timothy Williamson (Vagueness [1994], 2.2)
Book Reference
Williamson,Timothy: 'Vagueness' [Routledge 1996], p.44
A Reaction
This doesn't mean that logic has to win. Maybe it is important for philosophers who see logic as central to be always aware of vagueness as the gulf between their precision and the mess of reality. Precision is worth trying for, though.
Related Ideas
Idea 21597 Logical connectives have the highest precision, yet are infected by the vagueness of true and false [Russell, by Williamson]
Idea 21602 Many-valued logics don't solve vagueness; its presence at the meta-level is ignored [Williamson]