 Retention of classical logic and bivalence is supposed to be a chief advantage of the epistemic approach over other views (e.g., Williamson 1992: 162). Indeed, because bivalence is widely supposed to entail sharp boundaries, many theorists of vagueness believe that, for all intents and purposes, epistemicism is the only theory that can employ a bivalent semantics (e.g., Rosenkranz 2003, Keefe  2000).[6]  In particular, they believe that no semantic theory of vagueness can be classical. Subsequent developments cast doubt on this view, however; see  §3.3.5.  