Ramsey's Dialetheism
Vann McGee · 2004
Abstract For accommodating defective utterances within compositional semantics, truth-value gaps (Kleene's 3-valued logic) and gluts (Priest's LP) are equally efficient, but in terms of classical logic gaps yield harmless incompleteness, whereas gluts precipitate collapse; ex contradictione quodlibet. The discrepancy is less deep than first appears, however. A dialetheist dual to van Fraassen's supervaluationism, implicit in Ramsey's ‘Theories,’ counts sentences true if they are true in at least one acceptable model. Divergent illucutionary norms compensate for differing semantics. Subvaluationists (so-called by Varzi) replace the supervaluationist maxim, ‘Do not assert what is untrue,’ by ‘Do not assert what is false.’ Both predict the same verbal behavior.