 While agreeing to the type (2) response advocated by supervaluationists, Burgess and Humberstone (1987) take issue with the theory’s much-discussed retention of the law of excluded middle, adopting instead a variant of supervaluationist logic that abandons the classical law in the face of apparent counter-examples presented by vagueness. (For discussion and criticism from a supervaluationist perspective see Keefe 2000: ch.7.)