Abstract
We define a liar-type paradox as a consistent proposition in propositional modal logic which is obtained by attaching boxes to several subformulas of an inconsistent proposition in classical propositional logic, and show several famous paradoxes are liar-type. Then we show that we can generate a liar-type paradox from any inconsistent proposition in classical propositional logic and that undecidable sentences in arithmetic can be obtained from the existence of a liar-type paradox. We extend these results to predicate logic and discuss Yablo’s Paradox in this framework. Furthermore, we define explicit and implicit self-reference in paradoxes in the incompleteness phenomena.
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This work was supported by JSPS KAKENHI Grant Numbers 24540125,12J00654,26887045. The authors would like to thank Hidenori Kurokawa for valuable discussions.
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Kikuchi, M., Kurahashi, T. Liar-type Paradoxes and the Incompleteness Phenomena. J Philos Logic 45, 381–398 (2016). https://doi.org/10.1007/s10992-015-9378-2
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DOI: https://doi.org/10.1007/s10992-015-9378-2