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2008 Fitch's Argument and Typing Knowledge
Alexander Paseau
Notre Dame J. Formal Logic 49(2): 153-176 (2008). DOI: 10.1215/00294527-2008-005


Fitch's argument purports to show that if all truths are knowable then all truths are known. The argument exploits the fact that the knowledge predicate or operator is untyped and may thus apply to sentences containing itself. This article outlines a response to Fitch's argument based on the idea that knowledge is typed. The first part of the article outlines the philosophical motivation for the view, comparing it to the motivation behind typing truth. The second, formal part presents a logic in which knowledge is typed and demonstrates that it allows nonlogical truths to be knowable yet unknown.


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Alexander Paseau. "Fitch's Argument and Typing Knowledge." Notre Dame J. Formal Logic 49 (2) 153 - 176, 2008.


Published: 2008
First available in Project Euclid: 15 May 2008

zbMATH: 1141.03003
MathSciNet: MR2402039
Digital Object Identifier: 10.1215/00294527-2008-005

Primary: 03B42

Keywords: epistemic logic , epistemic paradox , Fitch , knowability , knowledge , type theory

Rights: Copyright © 2008 University of Notre Dame

Vol.49 • No. 2 • 2008
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