Thursday, September 28, 2006

What justifies believing? Jack Darach.

What I'm trying to understand is what kind of norms, if any, govern the rational acquisition of belief and the kind of responsibility we have to such norms. A basic division to start with might be between intrinsic and extrinsic norms. Intrinsic norms are those that are based in the concept of belief (whatever that is, I'm still not sure) while extrinsic norms for belief would be based outside of epistemology; for example they could be practical or moral norms. If we accept that the function of belief is to represent accurately how the world is then we move towards an intrinsic evidentialist position. This position suggests: one would be justified in believing that p only when one has sufficient evidence for the truth of p. Obviously this can't be enough as it stands. Evidential considerations alone cannot determine what counts as 'sufficient' evidence. The evidentialist proposal needs to include non-evidential considerations, such as how much time you have to inquire as to whether p; how much of your cognitive resources you can devote to the issue, etc, that help to determine when someone is justified in believing that p. These other considerations do not do any justifying. It is not that by accepting the need for non-evidential considerations one is then giving a space over to practical norms in the rational acquisition of belief that tells you when you can believe that p. And certainly knowing that you haven’t got much time left to inquire as to whether p can’t motivate you to believe that p. But this position arises most naturally when we start with the assumption that the function of belief is to represent the world accurately. (Isn't this a way of stating the oft used, difficult to explain, phrase: belief aims at the truth?) And it is this I'm not sure about and what I need help on. Why is the only function of belief to represent the world accurately? Belief plays a role in our actions; mightn’t it have another function connected to this, to facilitate action (or facilitate successful action)? In which case wouldn't it be better if our beliefs were subject to practical considerations? Specifically about what it would be desireable to believe in order to generate acts that are more likely to satisfy our intentions and desires?

Friday, September 15, 2006

Content Holism: Gabriel Segal.

I think I inadvertently stumbled into what looks like a really good argument for a sort of holism about cognitive content (published in ‘Ignorance of Meaning’ in Alex Barber ed. The Epistemology of Language). It’s tough being a holist about content, if, like me, you are also what might be called a naive realist about content: content is just part of the natural world, along with elms and elephants and everything else. Content, then, is in principle open to scientific investigation. But we seem to be struggling a little with the practicalities of that. And holism may be part of the problem.

The sort of holism I have in mind might be very roughly expressed by saying that the content of an individual’s concept depends on the totality of beliefs in which it features. So, for example, if, one day, Bart thought that measles is more common amongst girls than boys, and the next day he came to believe that it isn’t, then his ‘measles’ concept must have changed. Equally, if Bart thinks that measles is more common amongst girls than boys and Lisa doesn’t, then Bart and Lisa have different ‘measles’ concepts.

Here is a very rough thumbnail sketch of the argument for holism. Suppose that Bart and Lisa disagree on the question of whether measles is more common amongst girls than boys, but agree on pretty much all the other properties of the disease. They also both know that ‘measles’ and ‘rubeola’ are synonyms and they use the terms interchangeably. Now suppose that a naïve subject, Maggie, learns ‘measles’ from Bart and ‘rubeola’ from Lisa. She becomes competent with the terms, sharing most of Bart’s and Lisa’s ‘measles’ and ‘rubeola’ beliefs. Maggie comes to believe that measles is more common amongst girls than boys, but that rubeola isn’t. So, of course, she believes that they are different diseases.

Evidently, by standard Fregean principles, the content of Maggie’s ‘measles’ and ‘rubeola’ concepts differ. Now, by liberal, non-holistic standards of individuation we would want to say that the content of Bart’s and Maggie’s ‘measles’ concepts is the same and that the content of Lisa’s and Maggie’s ‘rubeola’ concepts is the same and that the content of Bart’s and Maggie’s ‘rubeola’ and ‘measles’ concepts are the same. But, given the difference between Maggie’s ‘measles’ and ‘rubeola’ concepts, that’s impossible. So we must deny at least one of the identity claims. But all the identity claims are on the same footing: there is no reason to favour one over another. So we should deny them all. So, it follows from the fact that Bart and Lisa differ in just one little, unimportant belief about measles, that their concepts differ in content.

The argument from the Simpsons generalizes. So holism is true.

Of course, spelling out the argument properly takes some time and patience. But it can be done. So what then? Then we wonder how it is possible coherently to use opaque propositional attitude attributions to talk about the Simpsons. How can they all believe, de dicto, that measles causes spots if the contents of their ‘measles’ concepts are different? Then we see that psychological generalizations work fine because they deploy a flexible standard of sameness of content, with different levels of content-similarity governing the correctness of opaque generalizations, in different conversational contexts. But how does that work? What is the metric of similarity here? Where do we even begin to look?

So the challenge is: either answer those last questions or find a flaw in the argument from the Simpsons.