Friday, January 05, 2007

Epistemic 'Ought' Does Not Imply 'Can'

Happy New Year everyone!

Yesterday Michael Smith visited ANU and gave a fun paper called 'Two Kinds of Consequentialism'. Afterwards the pub conversation turned to whether epistemic 'ought' implies 'can'. My hunch is that many different things may be expressed by epistemic uses of 'ought' in different contexts, and (more familiarly) the same kind of thing goes for 'can'. And it might be that for each epistemic 'ought' there's a corresponding 'can' which it implies. Nonetheless, I suspect that all or most (or at least most of the common) uses of the epistemic 'ought' express things which don't imply the things usually expressed by 'can'.

There's a recipe for creating counterexamples to 'ought' implies 'can' in the epistemic case which helps convince me of this. Take your favourite case of someone holding an irrational belief that she epistemically ought not to hold. (E.g. Carrie's believing at 5.40pm that aliens are invading the Earth despite there being absolutely no evidence to that effect.) Then make it so that the subject's holding that belief is beyond her control in your favourite sense. (E.g. Specify that Daniel has attached a brain-manipulating device to Carrie's head so that when he presses his remote control button at 5.40pm she will start believing that aliens are invading the Earth, despite having absolutely no evidence to that effect.) These will be cases where the subject epistemically ought to refrain from believing the proposition in question yet it's not the case that she can refrain from believing it.
It seems to be possible to follow this recipe for various different kinds of epistemic 'ought' (corresponding to various notions of epistemic irrationality) and various kinds of everyday 'can's (corresponding to various notions of control). It doesn't work for the weak 'can' of bare metaphysical possibility, of course, but 'ought'-implies-'can' isn't very interesting unless the 'can' is at least a bit stronger than that.

6 comments:

Anonymous said...

Hi Carrie,

Here's one common sense of "can": the sense in which I can (/am able to) speak Finnish, in virtue of having a normally functioning human brain, voice-box etc. (On this reading of "can", though not on others, the contingent feature that I never got around to learning Finnish is regarded as irrelevant).

If epistemic-ought entails can in some sense, I reckon this is a pretty plausible candidate for what that sense is.

I'm wondering now about the dialectic force of your kind of example. Presumably, you'll try to generalize the case as follows.

Suppose that Daniel has a brain-manipulating device that has removed even the biological basis of the capacity to believe anything other than that aliens are invading. Then, by activating his device, he'll make it the case that one can't believe otherwise, in the relevant sense.

The whole issue will then turn on whether or not, in the relevant sense, you ought not believe that aliens are invading. And I'm wondering how you'll make the case. It seems to me non-crazy to maintain that there's no such normative fact here. Whaddya think?

I guess the general point here is that in describing your case, not only have you got to get a mechanism that disrupts the capacities of the person (and so makes it the case that they can't fail to believe p); you've also got to maintain that messing around with their capacities doesn't change the normative facts about what they ought or ought not believe. And I don't at present see a dialectically effective way of securing the latter.

all best
Robbie

Carrie Jenkins said...

Hi Robbie,

I agree, that kind of 'can' sounds like as plausible a candidate as any. I'm afraid I can only report my intuition that if Daniel (say) removes my capacity for ordinary reasoning at 5.40, the epistemic ought fact remains in place. I guess I think it is being a creature that has beliefs, rather than being a creature with certain reasoning capacities, that entangles you in epistemic oughts.

I also think epistemic oughts are generally fairly insensitive to what we're capable of as far as reasoning goes. That's evinced by the fact that why we happily attribute epistemic irrationality to stupid people, rather than saying this sort of assessment just doesn't apply to them. (And I mean stupid people here - not clever people who aren't using their brains.)

Not dialectically effective, I know, but then the recipe itself was only supposed to be an intuition pump for people who were already disposed to be on my side!

Anonymous said...

I'm happy that there's one sort of epistemic normativity that goes that way (i.e. insensitive to abilities). But do you think that *every* important sort of epistemic normativity goes like that? That's a really strong claim, and I'm not seeing why I should believe it.

How about animals? I'm not so happy to attribute epistemic irrationality to them, though I am perfectly happy to attribute beliefs. I exactly give them a "get out of jail free" when their beliefs are "hardwired".

I take the point about normal practice of attributing irrationality to stupidity. But I think there's noise here, because lacking these capacities is so atypical in humans. The animal case seems cleaner to me, and I think returns the opposite verdict.

Of course, the debate would immediately switch to: which sort of epistemic normativity is interesting? And i think there's a case for the can-implying sense being interesting. I'd be reluctant to blame someone for Phi-ing when they couldn't have done otherwise than Phi, given their physiological/biological setup. That goes for the moral case, but also I think for the epistemic case. And so if you generally want your "ought"s to track the relevant sort of blameworthiness, strikes me that the can-entailing epitemic ought is what we need.

cheers
R

Anonymous said...

Sorry: "attributing irrationality to stupidity" in the above, should be replaced with something like "that we're willing to attribute irrationality to people who lack relevant capacities".

R

Carrie Jenkins said...

Animals may be blameless in some sense when it comes to the epistemic irrationality of certain of their beliefs, but my intuition is that that doesn't alter the epistemic ought facts. (And there might be a kind of epistemic blame which goes along with the ought facts, in which case they will be blameworthy in this sense.)

I think that kinds of epistemic ought which don't imply can are interesting and in general use. I'm not convinced yet that a kind of ought which doesn't imply can has either property! :)

Anonymous said...

Quacky the duckling sees me, imprints, and gets the belief that I'm her mother. She's biologically hardwired to imprint on whoever she sees first. And you think Quacky is epistemically blameworthy for that belief?!? Poor little mite: wasn't her fault that she's landed with that belief, the biology did it.

Maybe our intuitions are just way out of sync here. But I'm thinking that you're making a much stronger claim than I am: you have to say that there's no genuine notion of epistemic normativity that makes the above little speech correct (assuming that "ought not" and "being at fault" are interchangable). I'm happy to think there are (interesting) senses of "ought" in which Quacky ought not believe that I'm her mother. But also that there's a perfectly reasonable sense in which she's not at fault for believing I'm her mother (/it is not the case that she ought not to believe as she does).

Robbie