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Synthese (2012) 184:247259
DOI 10.1007/s11229-010-9773-8
Received: 27 April 2010 / Accepted: 5 August 2010 / Published online: 21 August 2010 Springer Science+Business Media B.V. 2010
Abstract Is knowledge justied true belief? Most philosophers believe that the answer is clearly no, as demonstrated by Gettier cases. But Gettier cases dont obviously refute the traditional view that knowledge is justied true belief (JTB). There are ways of resisting Gettier cases, at least one of which is partly successful. Nevertheless, when properly understood, Gettier cases point to a aw in JTB, though it takes some work to appreciate just what it is. The nature of the aw helps us better understand the nature of knowledge and epistemic justication. I propose a crucial improvement to the traditional view, relying on an intuitive and independently plausible metaphysical distinction pertaining to the manifestation of intellectual powers, which supplements the traditional components of justication, truth and belief.
Keywords Knowledge Gettier problem Epistemic justication
Manifestation Stephen Hetherington Brian Weatherson
The explication of knowledge as justied true belief, though it involves many pitfalls[,] . . . is,
I believe, essentially sound.
Sellars (1975, p. 99)
1 The end of an era
The textbooks tell us that Edmund Gettier (1963) paper Is Justied True Belief Knowledge? changed the course of epistemology by refuting the traditional view that knowledge is justied true belief (hereafter JTB) (e.g. Chisholm 1989, 90 ff; Moser 1992; Feldman 2003, 25 ff.). Gettier produced two cases wherein intuitively
J. Turri (B)
University of Waterloo, Waterloo, ON, Canada e-mail: [email protected]
Is knowledge justied true belief?
John Turri
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248 Synthese (2012) 184:247259
the subject gains a justied true belief but fails thereby to know, demonstrating that justied true belief does not sufce for knowledge. Examples in this mold we call Get-tier cases. Gettier was not the rst to produce Gettier cases, but that neednt concern us here.1
Gettier cases follow a recipe (Zagzebski 1996, pp. 288289; compare Sosa 1991,p. 238). Start with a belief sufciently justied to meet the justication requirement for knowledge. Then add an element of bad luck that would normally prevent the justied belief from being true. Lastly add a dose of good luck that cancels out the bad, so the belief ends up true anyhow. It has proven...