Saturday, February 20, 2010

Doing the (thing you justifiably take to be) best you (justifiably think you) can

Wanted to get right the argument I ran in the Q&A against evidentialism.

Suppose you believe you ought to A.

What should you do? That depends. Suppose you ought-epistemically to believe you ought to A. Given your belief and its normative standing, it's tempting to think you ought-practically to intend to A. That assumes:
(1) O(OBOA --> IA)

Because the reasons that bear on action and intention are the same:
(2) O(OIA --> A)

According to the evidentialist, if you have sufficient evidence, if you take any attitude at all concerning p, you ought to believe p. So, here's the case:

(3) You know that the best thing to do is A.
(4) You know that you can A.

Knowing (3) and (4), you know that you ought to A. I think you cannot say this and say that you _cannot_ satisfy whatever evidential standards the evidentialist says must be satisfied for it to be that you ought to believe you ought to A.

(5) OBOA.

If you A, you do what you ought to do.

Now, imagine an epistemic counterpart of yours with the same evidence. Imagine that this subject cannot A.

In this world, (5) is false. If (5) is false, you cannot have sufficient evidence to believe in this world. So, either you don't in the actual world really have sufficient evidence and (3) or (4) is false. This assumes, of course, that (1) and (2) are true. As they seem true, it seems the evidentialist is in trouble.

One response was to say that I hadn't said what A-ing amounts to. Our obligations, the thought was, are limited to trying to bring about certain ends. Okay, but the worry is that 'A' will be an act that you can perform and every one of your non-factive mental duplicates could perform. I don't think there's such an act. I don't even think trying satisfies _that_. If you cannot justifiably believe you ought to A, I think you cannot justifiably believe both that A-ing is the best option you have and that you can A. That's a pretty skeptical view if you think about it.

Alright, so the other response is to deny (1) or (2) to save evidentialism. They are not their principles, they are mine. Fine, deny them. Imagine a case that serves as a counterexample. You ought to believe that you ought to A & you ought to refrain from intending to act in accordance with your own normative judgment. Do that, and you're crazy. Do the non-crazy thing and you have an intention you oughtn't. Think about forming the intention that is in accordance with the epistemically flawless belief. There's _something_ good about it. I'd think that it's the sort of good that attaches to believing in accordance with the evidence. But, it's not the value that makes the intention permissible. So, why does the value make the belief permissible? I can't think of an answer. [The same is true for the intention-action link.]

So, I think the value driven argument for evidentialism is just a massive failure. If the value that attaches to fitting belief to evidence explains why it is that beliefs have the deontic properties they do, we get skepticism. If the value that attaches to acting in accordance with the epistemically flawless practical judgment doesn't give a permission to act but does give permission to believe, we'll want to know why that value gives permissions sometimes but not others. That this is so, I think, means that intuitions about value cannot be what explains why evidentialism is true (even if it is true (which it clearly isn't!)).

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