I was looking around for stuff by other heretics in the knowledge debate so I googled “Crispin Sartwell”:http://www.crispinsartwell.com/ and found his “webpage”:http://www.crispinsartwell.com/. Despite not containing much epistemology, it is a lot of fun. I rather liked (despite not at all agreeing with) his “ranking of major philosophers on a 1-10 scale”:http://www.crispinsartwell.com/philosophy.htm. On that note, yet another argument that knowledge is justified true belief is below the fold. (Exercise for the readers – find where if anywhere I’ve appealed to justification in this argument.)
This one isn’t entirely original – it’s just a variation of an argument John Hawthorne has discussed on various occasions.
1. S is a speaker and H a hearer such that
* S JTBs p and S doesnt know that p
* S and H know each other to be generally reliable informants
* S tells H that p, although S is uncertain whether H already knows that p
* On this basis H comes to believe that p
* Then H tells S that p
* S comes to regard Hs testimony as her primary reason for believing that p
2. H knows that p, since belief based on true testimony from a known to be reliable source constitutes knowledge.
3. After receiving Hs testimony, S knows that p, since belief based on true testimony from a known to be reliable source constitutes knowledge.
4. Before receiving Hs testimony, S knows that p, since Hs testimony doesnt improve Ss epistemic position, and she knows that p after receiving Hs testimony.
5. Since the existence of H satisfying the conditions in 1 is irrelevant to whether S knows that p, all Ss such that they JTB that p know that p.
Premise 1 is just a setup, the work is done in 2, 3, 4 and 5. Someone who doesn’t believe the JTB thesis has to deny one of these inferences. I think each of them is individually plausible, though obviously that doesn’t imply very much about the plausibility of their conjunction.