 Anti-realists follow verificationists in rejecting the intelligibility of such states of affairs and tend to base their rules for assertion on intuitionistic logic, which rejects the universal applicability of the Law of Bivalence (the principle that every statement is either true or false). This law is thought to be a foundational semantic principle for classical logic. However, some question whether classical logic requires bivalence [e.g. Sandqvist 2009]. Others dispute the idea that acceptance or rejection of bivalence has any metaphysical (rather than meaning-theoretic) consequences [Edgington, 1981; McDowell 1976; Pagin 1998; Gaiffman 1996]. There is, in addition, a question as to whether the anti-realist’s preferred substitute for realist truth-conditions in verification-conditions (or proof-conditions) satisfies the requirement of exhaustive manifestability [Pagin 2009]. 