Logic Journal of IGPL Advance Access published online on February 26, 2008
Logic Journal of IGPL, doi:10.1093/jigpal/jzn003
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On ignorance and contradiction considered as truth-values*
IRIT-CNRS, Université Paul Sabatier Toulouse, Université de Toulouse, France. E-mail: dubois{at}irit.fr
| Abstract |
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A critical view of the alleged significance of Belnap four-valued logic for reasoning under inconsistent and incomplete information is provided. The difficulty lies in the confusion between truth-values and information states, when reasoning about Boolean propositions. So our critique is along the lines of previous debates on the relevance of many-valued logics and especially of the extension of the Boolean truth-tables to more than two values as a tool for reasoning about uncertainty. The critique also questions the significance of partial logic.
*This paper is based on an invited talk entitled "Some remarks on truth-values and degrees of belief" given at the Workshop "The Challenge of Semantics" Vienna, Austria, July 2004