I was looking around for stuff by other heretics in the knowledge debate so I googled Crispin Sartwell and found his webpage. 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. 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 doesn’t 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 H’s 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 H’s testimony, S knows that p, since belief based on true testimony from a known to be reliable source constitutes knowledge.
4. Before receiving H’s testimony, S knows that p, since H’s testimony doesn’t improve S’s epistemic position, and she knows that p after receiving H’s testimony.
5. Since the existence of H satisfying the conditions in 1 is irrelevant to whether S knows that p, all S’s 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.