Thursday, April 13, 2006

More dialogue with BDK on Churchland

Blue Devil Knight wrote:

Under those assumptions, EM would make knowledge impossible (not just scientific knoweldge!). So, if EM is true, either knowledge is not possible, or the above philosophical account of knowledge gets it wrong. Which seems more likely? Perhaps it would just point out that philosophy needs an epistemology that is actually sensitive to neuropsychological details, not just detritus from the days of philosophical conceptual analysis.

But I believe I do know what knowledge is. Justified true belief may not be sufficient, but it is a darn good start. Amplification of my understanding of knowledge based on neuroscience is one thing. Being given a scientific story that essentially changes the subject and calling that an account of knowledge is a completely different thing. I like the way Fodor put it:

If it isn’t literally true that my wanting is causally responsible for my reaching, and my itching is causally responsible for my scratching, and my believing is causally responsible for my saying ..., if none of that is literally true, then practically everything I believe about anything is false and it’s the end of the world.

A Theory of Content and Other Essays. Cambridge, Mass.: Bradford Books/MIT Press, (1990) p. 156.

Luckily for progress, most scientists make free use of math, language, words such as "truth", and the like, without worrying about their ultimate ontology or truth-conditions. Does using X imply an implicit endorsement of certain philosophical ideas about X? Clearly not.

Clearly yes, it seems to me, unless a face-saving alternative analysis is on the horizon. And not a subject-changing one. If I am going to argue with you, I am presupposing that there are arguments, and that it is logically possible for you to be persuaded by them. Otherwise, I'll try brainwashing.

As for Churchland's view, Paul is a realist with a pragmatic attitude (his first book, Scientific Realism and Plasticity of mind, lays this out, as he also does in his edited volume Images of Science, where he and a bunch of people gang up on van Frasen).

How he handles truth, or its mental homologue, is that it is a mapping between brain models and the world. Such models can match up better or worse. We make such judgments all the time in science (how well does our model fit the data). The internal brain models are not propositional, but high-dimensional internal neuronal maps (exactly analogous to street maps: it isn't the intrinsic features of the street map that are important, but the metric relations among features of the street map).

From reading the van Fraassen essay it looked as if "realism" was simply a refusal to accept a van Fraassen-style non-realism in which we treat scientific claims about observables as true and claims about unobservables as only empirically adequate. Churchland rejects that distinction, so that makes him a realist??? Truth, as we know it and understand it traditionally, seems to be explicitly set aside. Yes, there can be better or worse mappings from a pragmatic standpoint, but it is the utility of those maps, and not the correspondence between the propositional contents and reality, that make it real knowledge as opposed to not knowledge.

As an aside, if you are that much of a pragmatist, how do you resist Pascal's Wager?

One more thing. Churchland thinks that, because our future psychology, which will dovetail with neuroscience, will be much more pragmatically useful than belief-desire psychology. Its explanatory resources will be much richer, and people will willingly abandon the explanitorily anemic resources of propositional-attitude psychology mainly because it is more useful for understanding their own minds and behavior.

No thank you. I think I'll pass on the Brooklyn Bridge.


BensonBear said...

"people will willingly abandon the explanitorily anemic resources of propositional-attitude psychology"

Talk about faith in an afterlife...

Blue Devil Knight said...

Victor said:
If I am going to argue with you, I am presupposing that there are arguments, and that it is logically possible for you to be persuaded by them.

And we are doing it. We are throwing around language, which contains sentences, arguments. It is a useful social medium in which I can express my thoughts. Show me the propositional attitudes.

I am familiar with the psychological speculations on both sides of this debate, and they both do a fair job of accounting for perceptual and cognitive data (linguistics, visual psychophysics, etc). I think the connectionists do a better job overall, but ultimately we need to wait for neuroscience to catch up. Right now it is a classic case of underdetermination of theory by the data.

I can understand the historical reasons why philosophy is so invested in propositional attitude psychology, but I'd rather wait for the relevant experiments than stick up for an old Oxbridge conceptual analysis.

I know, first-hand (and first-person) that most scientists use the notions of 'truth', use language, etc., without worrying about the ontology or truth conditions of such things, and without aligning with any particular philosophical school of thought on those topics. This doesn't mean things like truth don't exist, but the mere fact that scientists use the term cannot be taken as evidence that one of those philosophical schools of thought is right! Even if the scientists did agree on a philosophical conception of knowedge, but did it without any evidence to back it up, that wouldn't mean squat anyway.

Victor is right that Paul's older stuff on realism that I mentioned is fairly explicitly pragmatist, to the extent that it is not clear that it is a realism at all (Victor, check out the last paragraph of his essay on van Frasen for his somewhat unsatisfying justification of his reason to still call himself a realist). That's why I mentioned his more recent work on how he gets the cognitive homologue of truth as a good fit between the brain's model and the actual world. This paper by Pat and Paul goes into this. They call it 'domain portrayal semantics.' It isn't the map's utility, but its informational fit to the world, that captures what the old propositional/linguistic model captures with its epistemic norm of truth.

Also, while he strangely doesn't do this, Paul can still dump all the work of truth out onto public language, which is parasitic on the nonpropositional dynamics of neurocomputational states. The resources he has at his disposal are quite rich, and I think he hasn't exploited them fully.

When in grad school in philosophy, it usually took about six months for the new grad students who came to study Kant with Henry Alison to realize that the Churchlands weren't utterly insane. I've tried to make the case that they aren't insane here, to give what I think are good reasons to take their view seriously. The biggest roadblock is the view, as common as it is ignorant, that the Churchland's claim that mental states will be eliminated.

At any rate, the general public won't become eliminative materialists without good evidence, because by definition, they are attached to folk psychology.

I've written quite a bit here over the past two weeks, and am starting to repeat myself a lot. Here are the main threads, which give a pretty full picture with differing degrees of clarity and grammatical adherence:

I'll try to shut my pie hole until I see a point that isn't addressed in the four posts on the topic.

Victor Reppert said...

Are the Churchlands still eliminativists? After reading Carrier's attempt to defend them, I wonder.

Blue Devil Knight said...

I assume they are, but it just isn't the focus for them any more. They have both been more focused on positive stories lately (though their book 'On the Contrary' is basically responding to critics).