Thursday, January 8, 2009

The value of knowledge

Your best friend, Sally, has just been acquitted of murder. A remote acquaintance of yours, Ravi, has a justified true belief that Sally is innocent. Ravi is mistrustful of the legal system and the fact that Sally was acquitted carries no weight. But what does carry weight for him is that he believes his friend Patricia had seen Sally at a McDonald's at exactly the time the crime was being committed (and, no, he never told the authorities). Patricia, however, did not see Sally at McDonald's—she saw someone else who looked like her from the distance (a distance normally sufficient for distinguishing people, but this lookalike was pretty close). On the other hand, you know that Helga really did see Sally at a Burger King at that time, and indeed saw her closely enough that Ravi's report is not a defeater for Helga. So, Ravi does not know that Sally is innocent, while both you and Helga do.

If knowledge has a value over and beyond that of justified true belief, then Ravi is missing out on something of value that Helga has. This would imply that you have a reason out of charity for Ravi to tell him that Patricia did not see Sally, but Helga did. Moreover, you have two reasons out of charity for Ravi to tell him this. One reason is generated simply by the value of replacing a false belief (that Patricia saw Sally) with a true one (that Helga saw Sally). This reason is pretty weak, since the question of who saw Sally is intrinsically pretty unimportant, and while all truth has value, unimportant truths have but little value. The second reason is there if and only if knowledge has a value over beyond justified true belief: this is the value of Ravi's knowing Sally to be innocent, rather than merely having a justified true belief about it.

Oddly enough, I find myself having the intuition that I have a moderately strong reason to ensure that Ravi knows my best friend Sally to be innocent. What is odd about it is that this intuition conflicts with my theoretical views on which knowledge, as compared to mere justified true belief, has only instrumental value (potential to generate more in the way of true beliefs, etc.). When I initially set out the case, I thought I would have the intuition that I only have a weak reason to tell Ravi that he's wrong about Patricia seeing Sally.

Maybe, though, I can reconcile with my intuitions as follows. Maybe the moderately strong reason I have is generated merely by the reason in charity to replace Ravi's false belief about Patricia seeing Sally with a true belief about Helga seeing Sally. It would seem like this belief is fairly inconsequential in itself, and so the reason generated this way would be weak. But maybe the importance of a belief depends in part on the importance of the things derived from it. And since Sally's innocence is important, Ravi's false belief is important. If so, then the case doesn't undercut my theoretical views.

And here's a further intuition: It is very important that Ravi believe Sally to be innocent; the value of his knowing Sally to be innocent, even if greater, is only a little greater.


chris said...

I'm not very educated in the field of epistemology and that sort of thing, so this may be an empty question, but it would seem that the instrumental value of knowledge occurs because there is an intrinsic value in being correct. To me (and this may be where I just don't know my terminology) it seems that knowledge is also being correct in your belief.

Maybe in your example, if Ravi does discover that Patricia never actually saw Sally at McDonald's, then that changes his whole belief concerning Sally's innocence. I would think that arguing wrongly for a right thing is no good reason to continue believing in that thing, as long as the wrong arguing is the only arguing we have to go on.

Maybe I'm confusing my metaphysics with my Epist. but Clifford said in the Ethics of Belief, as soon as we start believing wrongly (on unjustified information) we open ourselves up to being incorrect on more things in the future (this gets back to your instrumental value). So I would say it does appear that we should inform Ravi for that reason.

Enigman said...

What a weird scenario, is my thought! My first thought is that I wouldn't bother to tell Ravi, on the grounds that he never bothered to inform the authorities. You say at the end that it's very important that Ravi believe Sally to be innocent, but given that he didn't even try to help get Sally off, I wonder. But then I wonder, what if he had a good reason for that, etc. And so I get the feeling that there're lots of variables in ths scenario, which you're probably clear about in your own head. But I do wonder (based on what you say about the instrumental value of K minus JTB, do you think that a fully justified belief might not be infallibly true?