Dennis’ last post generated lots of great discussion. In the comment thread, Declan Smithies proposed a modified version of principle JK that Dennis and others argued against. Declan’s version of JK, what I’ll call ‘DJK’, goes as follows:
DJK: If you have justification to believe P, then: you have justification to believe that you know P, if you believe P
I think the following is a counterexample.
But before presenting the example, a couple caveats to bear in mind. First, on Declan’s view, having justification to be confident, to whatever degree, that P does not entail that you have justification to believe that P. Second, Declan’s proposal concerns propositional justification, which does not entail that the belief is doxastically justified (or, as it is sometimes put, properly based or well grounded).
Now for the example. Suppose:
(1) S has justification to believe P.
(2) S believes P.
(3) S believes P on the basis of a very bad reason, one that does not in fact help justify P for him.
(4) S recognizes that his belief’s basis is inadequate, but cannot be bothered to do anything about it. (Perhaps S is presently psychologically incapable of doing anything about it.)
(5) S knows that knowledge requires that reason-based belief be properly based on adequate reasons.
In such a case, S is not justified in believing that he knows that P. (If anything, he’s justified in believing that he does not know that P.) Yet he satisfies the conditions set out in DJK.