Fitch's proof, verificationism, and the knower paradox

Abstract

Summary I have argued that without an adequate solution to the knower paradox Fitch's Proof is- or at least ought to be-ineffective against verificationism. Of course, in order to follow my suggestion verificationists must maintain that there is currently no adequate solution to the knower paradox, and that the paradox continues to provide prima facie evidence of inconsistent knowledge. By my lights, any glimpse at the literature on paradoxes offers strong support for the first thesis, and any honest, non-dogmatic reflection on the knower paradox provides strong support for the second. Whether verificationists want to go the route I've suggested is not for me todecide. As in the previous section my aim has been that of defending the mere viability of verificationism in the face of what many, many philosophers have taken to be its death-knell, namely Fitch's Proof. But, as the final objection makes clear, showing that verificationism can live in the face of Fitch's Proof is one thing; showing that it should live is another project. If nothing else, I hope that this papershows that verificationists still have a project to pursue; Fitch's Proof, contrary to popular opinion, need not bury verificationism.13 This paper arose in response to Colin Cheyne's ‘Fitch's Proof and Beyond’ (typescript), which was read at the 1998 AAP(NZ) conference at the University of Waikato, Hamilton, NZ. The paper has undergone significant revision in the face of comments from two anonymous referees, comments for which I am very grateful. Thanks to John Bishop, Colin Cheyne, Jay Garfield, Fred Kroon, and especially Graham Priest and Greg Restall for very helpful discussion.