Wednesday, June 18, 2008

Evidentialism about absolutely everything (normative)!

Suppose, as evidentialists do, that the truth-conditions for claims about what you ought to believe are cashed out in terms of a particular believer's evidence. You'll likely think that:

(1) S ought to believe p if S has sufficient evidence for believing p.

Don't worry about what 'sufficient' means. With one or two exceptions, those who hold the view allow that there can be sufficient evidence for believing a proposition about some contingent matter of fact about the external world even if that proposition is false.

Now, supposing this is correct, we have a quick and dirty argument for evidentialism about absolutely everything normative. Let 'p' be a proposition that represents some action of the agent's as one that ought to be done. Let 'p', for example, denote the proposition that I ought to give to charity. While it seems from my point of view that what makes it the case that I ought to give to charity is (in part) that those in need would be helped by my charitable giving, that's not true. The truth-conditions for 'She ought to give to charity' should be cashed out in evidentialist terms. For, it seems that the following rule admits of no exceptions:

(2) S ought to believe S ought to X only if S ought to X.

Since S could have sufficient evidence for believing that she ought to X even if she did not if that fact about what she should do depended on more than just what supervenes on her evidence, we can argue from (1) and (2) that whether she ought to give to charity depends not on the needs of those she is in a position to help. It depends on what sort of evidence she has.

I think that this view is silly (to put it mildly). I think it shows what's silly about the appeal to the subject's perspective in arguments for internalism. But, that's me. I can't see how to be an evidentialist about epistemic 'ought's without being an evidentialist about them all. Since I think we have as good a reason to reject evidentialism as a thesis about all 'ought's as we have for rejecting any philosophical view, I'm happy to dispense with (1).

6 comments:

Timmo said...

Clayton,

Usually, evidentialism is taken to be the biconditional:

(E) S ought to believe that p if and only if S has sufficient evidence for p.

This is stronger than the condition (1) you suggest. William James, a critic of evidentialism, accepts (1) in his 'Will to Believe' paper. So, (1) can not be evidentialism.

Plus, an evidentialist does not need to suppose that (E) an analysis of what it means for an agent to have an epistemic obligation. The left-side of the biconditional is not synonymous with the right-hand side of the biconditional. (E) is not a way of "cashing out" the truth conditions of sentences of the form 'S ought to believe that p'.

Consider, for example:

(H) X is a human if and only if X is a featherless biped.

While (H) is true, it is clear that the left-hand side of the biconditional does not have the same truth-conditions as the right-hand side of the biconditional. (H) is not a way of "cashing out" the truth-conditions of sentences of the form 'x is human'. Why can't evidentialists understand (E) in this way?

Your argument against evidentialism goes like this:

(1) For any proposition p, if S has sufficient evidence for p, then S ought to believe p.

(2) If S ought to believe that S ought to X, then S ought to X.

(3) Therefore, if S has sufficient evidence that S ought to X, then S ought to X.

I agree that this conclusion silly, but evidentialists are not committed to (2). The general principle here is this:

(T) If S ought to believe p, then p.

Clearly, (T) is untrue. Sometimes we ought to believe things which turn out to be false. If the evidence decisively weighs toward p, then we ought to assent to p. However, it might turn out that p is false anyway!

Clayton said...

Hey Timmo,

All good points (as usual).

I don't think that 'evidentialism' is a natural kind term. I had in mind only evidentialists such as Conee, Feldman, and perhaps Adler. You're right that evidentialists typically defend the biconditional, but I'm only interested in the one direction here.

I think you're right that the evidentialist does not _need_ to offer an analysis of epistemic obligation or what "ought" claims mean, but I'm pretty sure that Conee and Feldman do the former.

I agree that evidentialists are not committed to (2). But, (2) is true!

Obviously, I offered no argument for it here. Note, however, that (2) is far weaker than (T). It only applies to a special range of beliefs--beliefs about actions that ought to be done. A surprising number of people have accepted (2) and unsurprisingly they reject (T).

I've argued for (2) elsewhere. My most detailed defense of (2) is found in my "It's the end of the world as we know it" (here).

I really don't understand why people are so convinced that (T) is false. (I've argued that there are no good reasons to reject it and reason a plenty to accept it.) You accept the following:
Sometimes we ought to believe things which turn out to be false. If the evidence decisively weighs toward p, then we ought to assent to p. However, it might turn out that p is false anyway!

Q1: What's wrong with saying that you followed the evidence to a false conclusion and thus ought to be excused for failing to believe what you should have?

Q2: What's wrong with someone running the same sort of reasoning in favor of the view that what you do is what your evidence suggests will turn out for the best? Anyone whose actions turn out for the worse can say, "If the evidence decisively weighs towards doing X, then we ought to do X. However, it might turn out that X is not for the best anyway!" Why does evidence not justify the action when it justifies the belief the adoption of which makes it such that you'll thereby perform the relevant action?

exapologist said...

Interesting post, Clayton! I'm currently under the spell of something like the version of evidentialism defended in Connee and Feldman's recent book.

Timmo said...

Clayton,

Fair enough. Evidentialism is not a natural kind! :-P

I'll definitely check out your paper. Even before reading it, I will bravely and clumsily try to answer your pair of Q's with a pair of A's.

A1: It sounds innocent enough saying that we ought to believe what's true! After all, one does not want to say that we can permissibly believe false things. However, I think we are apt to be confused by conversational implicature here. When we declare "You ought to believe what's true!" we are usually in situations where we are trying to wake people up to the importance of finding out facts about the world. In such a context, it is just a violation of the Gricean maxim of quantity to include lots of conditions or special restrictions on what we are saying. Probably the other maxims would be violated as well.

It sounds bad to deny that we ought to believe what is true, but that's just the way it sounds.

Capablanca lost the World Chess Championship to Alekhine in 1927. Let's suppose, for the sake of argument, that at a crucial moment during one of the games, Capablanca decided to trade bishops with Alekhine over advancing a pawn. The bishop-trade looked like the best move to Capablanca given his spatial advantage, the relative material strength of each side, and so forth. Capablanca, at this key moment in the game, made the best move he was able to find.

As it turned out, however, trading bishops was not the right move to make. Consequently, Alekhine swept the floor with Capablanca, forcing him to resign. Instead, the right move was for Capablanca to advance his pawn.

We can easily imagine Capablanca saying, "Aww, shucks! I should have advanced my pawn!"

Capablanca could mean two things by this:

(1) I should have disregarded my best judgment and moved my pawn.

(2) I should have had better judgment, judgment which would have allowed me to see that moving my pawn was a better move than the one I in fact made.

I think (2) is the more plausible interpretation. And, that's the kind interpretation I would like to make of someone who turned out to be wrong about psaying "Aww, shucks! I should have believed that p!" Do we really want to say that this person means they should have -- should have in the sense that they had an epistemic obligation -- disregarded prudent judgment?

We want to believe true propositions. Compiling evidence is the best way we have for coming to belief in large classes of true propositions. It is certainly better than making large lists of propositions, and randomly believing half of them and the negations of the other half!

A2: "If the evidence decisively weighs towards doing X, then we ought to do X. However, it might turn out that X is not for the best anyway!" Evidence is supposed to be truth-conductive (isn't it?). If so, then if S has a preponderance of evidence that p, then it is likely that p for S. Unless you are an infallibilist, then no amount of evidence, however strong and numerous, will ever guarantee with a probability identical to unity that the proposition for which you have evidence is true. The race does not always go to swift -- but that's the way to bet!

Doka Dotty Wine said...

What is up with the exclamation marks lately? Either you are very excited this week or you enjoy finding the factorials in everything. :P

Professor, you lost me when you started talking about your personal opinion. I don't understand why you dislike evidentialism. From all that you said in the post, it seems to make sense. When you say that you think it is silly, it is making me think that you think that people are driven by not only their own desires, but what they think other people desire. Or something like that. If you reject (1), what would you rather have instead?

Clayton said...

Doka,

Factorials everywhere. Except that sentence!

I'm allergic to the idea that normative appraisal is limited to the evidence an agent/subject has at hand.

Timmo,

I don't think that the appeal to conversational implicature is going to help. For one, I don't think "believe what's true" has any ring of truth to it. What I think _does_ have the ring of truth is the prohibition against believing the false.

If one party knows another's belief about some matter is mistaken, that warrants the assertion 'You shouldn't believe that' all by itself. On the view that chalks this up to conversational implicature, this would be literally false but proper to assert because it would further some conversational aim. That won't work because the speaker may well be aware of the fact that the speaker's normative claim might not have any impact on the second speaker's beliefs. (It might be that second speaker is pig headed or it might be common knowledge that the second speaker thinks (rightly) that there is exceptionally strong evidence for the belief in question--so strong that it would be unreasonable for the second speaker to re-evaluate her belief.)

You wrote:
Compiling evidence is the best way we have for coming to belief in large classes of true propositions. It is certainly better than making large lists of propositions, and randomly believing half of them and the negations of the other half!

Agreed. Is there an argument that our best ways of pursuing our aims cannot possibly fail to lead us to believe what we should? I can't think of one. I can, however, think of plenty of reasons to think that our best ways of pursuing an aim can be put to use _and_ we can fail to thereby believe or do what we should. To pursue your ends in ways you know not to be best is irresponsible. There is more to permissibility than responsibility.

I'm not sure I follow your A2, but here's the challenge. Consider the agent who follows the evidence at hand and performs some action A. If she were conscientious, we'd say that she was responsible, reasonable, praiseworthy, etc... But, if (2) is false, this is consistent with her having acted wrongly. Now, look at the rationale people offer for saying that there can be false, justified beliefs when someone follows the evidence to a false conclusion. They will say that the subject was reasonable, rational, responsible, etc... They will offer the same rationale we have just rejected for saying that following the evidence ensures that you do not act wrongly. So, why accept the rationale that fails for the practical case in the theoretical case?

Anyway, the case for (2) is pretty damn strong. Here it is. For there to be counterexamples to (2), situations would have to arise where two things happen:
(i) S ought to believe she ought to A.
(ii) S ought not A.

Suppose A is some present action, not some future action. Can a minimally rational subject satisfy (i) without thereby forming the intention that leads her to A? I think not. If you accept judgment motivational internalism, if a minimally rational subject judges she ought to A she will thereby be motivated to A. So, such a subject cannot judge that she ought to A and not thereby be motivated to do so. We're getting awfully close to a violation of "ought" implies "can".

If (2) is false, "I know she should believe she should A, but what should she do?" should be an open question. It's not.