Thursday, December 16, 2010

Eastern APA

I'll be giving a talk in Boston on the 28th @ 3:00 p.m.. I'd tell you where if I knew, but I don't. It's the second talk in the "What Epistemology is Not" colloquium (III-H).

Here's a handout.

Abstract: Mentalists say that two subjects have the same evidence if these subjects are in the same non-factive mental states. Mentalism doesn’t tell us what evidence is. Mentalism doesn’t tell us it is to have evidence. The mentalist could say that evidence consists of facts or true propositions. The mentalist could say that our evidence will include any proposition that we know by means of observation. Mentalism could say either of these things, but it cannot say both of these things. That’s why we know that the mentalist is mistaken. Or, so I argue. After showing that we have evidence the mentalist says we cannot, I offer an argument for externalism about justified belief. I argue that our experiential beliefs can be non-inferentially justified only if they are true.


Jon M. said...

Do mentalists say that, or only that two subjects in the same mental states are justified in believing the same propositions?
It seems like mentalists could say that both those things counted as evidence, but in a way that didn't make for a difference in justification.
Perhaps you are assuming the following: more evidence entails more justification.

Clayton said...

Hey Jon,
I do get around to the more evidence/more justification issue. Consider two things a menalist might say:
M1 Non-factive mental duplicates have the same evidence;
M2 Non-factive mental duplicates have equally justified beliefs.

I thought that the mentalists would want to defend M1 as a rule since it follows from the supervenience theses it seems they want to defend. Conee did, however, say in conversation once that he was more concerned about M2 than M1 and it was M2 that pushed him towards accepting M1 but conceded that he'd be happy to drop M1 if pushed to do so.

Someone could deny M1 but maintain that M2 is true. Perhaps that's what you have in mind. The end of the paper, I offer an argument to the effect that it would be unwise to hold that view and very unwise to try to turn M2 into an argument for M1.

The trouble has to do with two claims. The first is that to have a justified belief, one's belief must be based on (appropriate) evidence. The second is that facts about a subject's non-factive mental states determine which bits of evidence (if any) a belief is based on. Since some of our beliefs are based on propositions about the external world, it turns out that it is difficult to defend M2.