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22 June, 2006

Don’t Defer!

Philip Petit has a very good paper in the latest Analysis on the issue of when you should defer to majority wisdom. (Philip Petit, “When to Defer to Majority Testimony – And When Not,” Analysis 66.3, July 2006, pp. 179–87.) Those of you who have Analysis should go read it, and come back here when you’re done. So I’m a blogger so I’m going to pick on a relatively minor technical point, but see at the bottom of the post for more substantive points of agreement with the paper.

Now Philip’s overall position is relatively subtle, but one of the key points he makes is that deferring to the majority view on all positions is likely to be inconsistent, so you shouldn’t do it. This should be a fairly well known point, but it is worth rehearsing the proof.

Imagine that there are two atomic propositions under discussion, p and q. And there are three people in your group, A, B and C. (It won’t matter which you are.) A and B believe that p, but C thinks it is false. B and C believe that q, but A thinks it is false. So the majority believes that p, the majority believes that q, and the majority believes not-p&q. If you follow majority ‘wisdom’ on all counts, you’ll end up with inconsistent views.

Surprisingly, Philip suggests that a supermajoritarian position works better. (He doesn’t say this is a good idea to follow in all cases, but he does seem to think it avoids this problem.)

There is another sort of approach that will do better, however. This is not to allow just any majoritarian challenge to reverse a belief but to allow only a certain sort of supermajoritarian challenge to do so. This would amount to a policy of global supermajoritarian revision. In order to see why this approach need not involve the same problems as the majoritarian counterpart, imagine that you are prepared to defer only to a supermajority of 70%, and to every such supermajority. And suppose that, as before, you are confronted by a situation in which a majority of others hold that p, that q, and that not p & q, where you hold that not p, not q and not-p&q. Suppose in particular that 70% hold by p and that 70% hold by q, giving you a reason to defer to the group on those issues. Will such supermajoritarian deference raise a problem? No, as it happens, it won’t. You will be led to adopt the majority view that p, and the majority view that q, since each proposition commands the requisite supermajority of 70%. But you will also be allowed to revise your belief that not-p&q, thereby ensuring that your beliefs are consistent. You will not be forced, inconsistently, to hold by the majority view that not-p&q, since this will not be supported by a majority of 70%. (184-5)

Philip has an argument for why the supermajoritarian position avoids this particular problem, but it seems to me it runs into a very similar problem. Change the case so that there are four people in the group, and three propositions under discussion. Their opinions are:

Now a 75% supermajority believes each of p, q, r and not-p&q&r. So the supermajoritarian gets led into inconsistency. So supermajoritarian deference seems like a bad idea.

So in the context of this paper, this isn’t a very big deal I think, since what I’m objecting to could be excised without damaging the main theme. What’s really important is the point Philip makes in leading off, about the key reason you shouldn’t defer about matters of extreme epistemic importance.

It would be objectionably self-abasing to revise your belief on matters like intelligent design or the wrongness of abortion just in virtue of finding that others whom you respect take a different view. Or so most of us think. To migrate towards the views of others, even under the sorts of assumptions given, would seem to be an abdication of epistemic responsibility: a failure to take seriously the evidence as it presents itself to your own mind. (181)

That seems exactly right to me. The view Philip is arguing against here is a kind of epistemic collectivism, a view that we should let our beliefs be guided by the majority opinion amongst suitably informed, suitably intelligent, suitably impartial judges. The view he is arguing for is a personal responsibility view. At risk coming off all Ronald Reagan on y’all, at some level people just have to take responsibility for their own beliefs, not regard themselves as merely a jury member with a single vote about the most important issues they consider. The collectivist view tends to run into technical problems, even paradoxes, when we try to develop it. But apart from that it suggests a deeply unappealing picture of our epistemic agency, one that we should firmly reject.

Hopefully I’ll post more on this over upcoming weeks, but for now there’s a football team to cheer for…

Posted by Brian Weatherson at 2:42 pm

4 Comments »

20 June, 2006

Hijacked!

The domain name under which I keep my philosophy blog and personal webpage seems to have been taken over by a domain name hijacker. (You might wonder how this could happen; there are a few details below the fold.) So I’ve had to move everything around. For anyone who links to those sites, or read them, the domain name is now weatherson.org rather than weatherson.net. Similarly the domain name of my email address has changed so it now ends .org rather than .net. Read the rest of this entry »

Posted by Brian Weatherson at 6:51 pm

1 Comment »

14 June, 2006

Fundamentalism and Knowledge

I spent a fun few days over the break at the NYU Causation Conference held at La Pietra just outside Florence. I’m not sure how widely disseminated anything said there was meant to be, but I think it isn’t too much of a violation of netiquette to talk about one of the big issues that came up.

In many areas of philosophy there is a debate between those who think a certain kind of feature of the world is fundamental, and those who think it is reducible to, or a feature of, other features. Consider, for instance, the debate between Descartes and Ryle. Descartes thinks that minds are fundamental features of reality, things that can (at least to a great extent) vary freely of physical facts. Ryle denies that minds are fundamental. Though there is some scholarly dispute over what his positive view is, we can all agree that he denies Cartesian fundamentalism about the mental.

Ryle makes an argument against Cartesian fundamentalism that is used by many other anti-fundamentalists. (Indeed, this style of argument came up at the conference.) The argument is as follows.

  1. If fundamentalism is true, then certain kinds of situations where the fundamental facts vary widely from other facts are possible. (E.g. the situation Ryle makes much of is that many people around us have no mental states at all.)
  2. If these situations are possible, we need to have a reason to rule them out before we know they are not actual.
  3. We have no such reasons.
  4. But we do know that such situations are not actual. (E.g. we know, for example, that Einstein was a genius, and hence had a mental life.)
  1. So fundamentalism is false.

Now there is a lot that can be said against premise 2. The best thing to say, as Brad Skow said at the conference, is that any such principle seems to lead to scepticism. We think that brain-in-vat situations are possible. And any sense of ‘reason’ strong enough to make premise 3 true will probably imply we have no reason to believe such situations are not actual. So we don’t, after all, know anything. (There are several gratuitous appeals to closure principles in both the argument and my reply, but I assume readers can fill in the details appropriately.)

At the conference there was a lot of discussion about whether this line of reply to the anti-fundamentalist argument worked in general, or on particular occasions. I wanted to make here one point that no one made there, and which for all I know hasn’t been made in the literature.

Assume for reductio that this epistemological argument really raises a problem for the fundamentalist. Then it seems there is just as much of a problem for the anti-fundamentalist. That is, assume Ryle is true that we don’t have a reason to rule out the kind of wacky situations the Cartesian says are possible, i.e. situations where physical behaviour and mental properties are totally out of whack. The point I want to press is that saying these situations are impossible doesn’t obviously help.

Most philosophers, not all but most, say that at least some of the time in order to know that p, we need to rule out certain impossible situations in which p is false. For instance, to know that Fermat’s Last Theorem is true, we need to rule out the situations, every one of them impossible, in which it is false. The obvious conclusion is that the impossibility of a situation is no reason to conclude we need not have a positive reason in order to know that it does not obtain.

There is more to be said here, and I might try and follow this up later, but I think that there is a big problem here for arguments like Ryle’s. If we have epistemological standards high enough that knowledge requires ruling out outlandish possibilities, such as the possibility of various properties that are always correlated in the actual world (and in most salient counterfactual worlds) coming apart, then we should also say that knowledge requires ruling out salient impossibilities. And then the Rylean argument that we can’t rule out those situations will imply an absence of knowledge, whether Cartesian fundamentalism is true or not.

Disclaimer: I don’t for a minute believe in Cartesian fundamentalism, or in most other kinds of fundamentalism that are philosophically popular. I just don’t think we can prove much metaphysically by going via epistemology, hence this little rant.

Posted by Brian Weatherson at 4:55 pm

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Speaking about Cheesesteaks (cross-posted at CT)

The LA Times reports on the Philadelphia cheesesteak place that refuses to serve customers who don’t order in English. The message to customers is This is America. When Ordering “Speak English”. Just a few observations.

  1. I’m not sure what rule of English requires, or even permits, quote marks around the last two words in that sentence. I’m no prescriptivist, so I’m happy to be shown that this falls under some generally followed pattern, but it’s no pattern I’m familiar with.
  2. I’m very pleased that no place had a similar sign when I was trying to get fed in Paris using what could, charitably, be described as schoolboy French, as long as the schoolboy in question spent every class watching football rather than, say, studying French. And that pleasure is not just because if I had seen such a sign I’d have been like, Holy Cow, the Americans have captured Paris.
  3. This being the LA Times, they have to describe what a cheesesteak is: “a cholesterol-delivery device consisting of grilled strips of beef, melted cheese, onions and peppers on an Italian roll.” They also misquote the sign by removing the errant quote marks and adding a ‘please’. Those polite Southern Californians!

Posted by Brian Weatherson at 4:18 pm

6 Comments »