Parallels Between Gaps and Gluts

This paper compares two proposed solutions to the liar paradox, both of which involve revisions to classical semantics. The first, that of truth value gaps, denies that all sentences are true or false. The second, that of truth value gluts, asserts that some sentences are true and false. A natural question about these proposals is, ‘Do they offer equally good (or bad) solutions, or is one better than the other?’ Parsons 1990 Parsons, Terence. 1990. True Contradictions. Canadian Journal of Philosophy, 20/3: 335–54. [Web of Science ®] , [Google Scholar] suggested an answer to this question, arguing that for every problem for one solution, there is a parallel problem for the other. Since then, several people have given arguments for and against the idea that the two face parallel problems. This paper advances the debate in two ways. First, it answers four attempts by Graham Priest to reject the parallel. In particular, it discusses alleged advantages for the gap solution with regard to the teleological account of truth, an extended liar paradox, Berry's paradox, and inexpressibility. Second, it discusses where, if anywhere, the parallel may be broken.