A: "R" believes "X'
B: "R" is justified in his/her belief of "X"
C: "X" is true
Just in case you had forgotten.
However, there occasionally arise cases in which conditions A,B and C above are all satisfied, but "R" doesn't really know "X."
For example, James (the observer "R") goes out to a party. Earlier James had spoken to his friend Chris, who said he would also be at the party. When James gets to the party, he sees Chris' identical twin Craig. James concludes that Chris is at the party ("X"). James is justified in this belief, because Chris said he would be at the party, and James saw someone who looks exactly like Chris at the party. Coincidentally, Chris was at the party, but he was in a completely different area than James. Thus, the conditions A, B and C for James to know via justified true belief are all met, but does James really know if Chris is at the party or not?
Just a thought.
~WG
2 comments:
Will, this is incredible. It would seem that you have independently put forth what is sometimes considered the greatest epistemic challenge of the latter 20th century, a challenge that was, in fact, put forth in a three page paper published in 1963 by Edmund Gettier. The problem you set forth is exactly that of Gettier, whose paper can be found here: http://www.ditext.com/gettier/gettier.html. Wikipedia has a good piece about Gettier himself.
Furthermore, The Cambridge Dictionary of Philosophy, in its discussion of the Gettier problem, cites an example that is almost identical to yours. So, first of all, congratulations on such high-level thinking!
The Gettier problem, which I am inclined now to call the Gering problem, has not been definitively solved. In fact, the Cambridge entry concludes by saying, "Epistemologists thus need a defensible solution to the Gettier problem, however complex that solution is." What seems to be necessary is a fourth condition that, along with justification, truth, and belief, would yield knowledge.
One thought is that there must be a "defeasibility condition." For example, if R has knowledge that p, then there must not be a true proposition q such that, if q became justified for R, p would no longer be justified for R. This could solve the particular scenario you put forth. For example:
James only has knowledge that Chris is at the party (proposition p) if and only if (this is abbreviated in logic "iff") all the conditions you set for James hold and there is no twin for Chris. If there is, then it would be said that James did not have knowledge at the moment he thought he did.
So the observer "R" would have knowledge of "X" i.f.f:
A: "X" and "Y" are mutually exclusive
B: "R" believes "X" and "not-Y"
C: "R" is justified in his/her belief of "X" and "not-Y"
D: "X" is true
In the previous example, Chris either has a twin or he does not (so "X" and "Y" are mutually exclusive). James doesn't believe Chris has a twin ("R" believes "not-Y"), and he is justified in believing so because Chris has never mentioned a twin and James has never seen this twin before. However, if James realizes Chris has a twin, then he may rethink his belief that Chris is at the party ("R" would believe "Y" and "not-X", and be justified in doing so). Therefore, James would not know whether Chris was at the party or not ("R" does not have knowledge of "X").
By no means a comprehensive solution, but perhaps a step in the right direction?
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