Tuesday, April 11, 2006

More on eliminative materialism

Blue Devil Knight wrote: The most important part of all their work (Sellars, Rorty, Feyerabend, the Churchlands) is that our psychological theories do not self-verify, as some people would claim (e.g., those who like to say that their propositional attitudes are just "given": this is the whole point of Sellars' great work Empiricism and the Philosophy of Mind). This fact, that we don't know how our minds work by inspection, has interesting consequences.

But doesn't the very operation of science presuppose that humans have perceive the truth of certain propositions; mathematical, observational, and inferential? If we are just wrong about our mental processes, so much so that we think we have propositional attitudes but really don't doesn't that undermine at least the traditional conception of science as the pursuit of truth.

But, as I remember when I wrote my reply to Bill Ramsey on the self-refutation argument, that Paul Churchland (In A Neurocomputational Perspective) was redefining science in pragmatist terms and was ready to get rid of the notion of truth. But pragmatism, it seems to me, puts folk psychology in the driver's seat for sure. Even if you think folk psychology isn't true, you at least have to admit it's pragmatically useful.

I remember spending a number of mornings in Carrow's Restaurant near my house poring over NCP, and thinking that his radical philosophy of mind and radical philosophy of science probably don't go together very well.

Here's the reference for my reply to Ramsey.

Reppert, V. 1991. Ramsey on eliminativism and self-refutation. Inquiry


Blue Devil Knight said...

This is long, but your question is very complicated, and I have strong feelings which makes me verbose. I am turning into Jason (:))

Let's assume, with analytic philosophy, that to know X is to have a justified true belief that X. Let's also assume that having a belief that X implies that there is an internal mental state with the content 'X' in propositional form (whatever that means).

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.

The nature of knowledge is something we will continue to discover, as it is just another natural phenomenon. It is not something to fix via a conceptual analysis that doesn't do the phenomenon justice. The best philosophy comes after the science is done, not before (how much interest is there in philosophy of Aristotelian mechanics?). (This is one of the reasons I left philosophy for science: there isn't enough good mind science to do good philosophy of mind!).

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.

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).

I'm not endorsing Churchland's view, just stating it. Personally, I am less a strong eliminativist than a weak reductionist wrt propositional attitudes: I think that many features of propositional attitudes will remain, and be reduced to, neuronal properties, like thermodynamic temperature was reduced to mean kinetic energy of molecules in a gas. Time will tell.

My strongest opinion is that being dogmatic at this point is just foolish. Neither EM nor its negation is an a priori fact to be seen by inspection of one's mental states, and we don't have enough data to decide where on the continuum between a smooth reduction and a violent elimination the propositional attitudes will end up. When I say I am a soft reductionist, that is merely a prediction about how the relationship between neuroscience and propositional attitude psychology will turn out.

Blue Devil Knight said...

Note you can also be an eliminative *dualist* wrt propositional attitudes, so eliminativism is orthogonal to the ontological questions of the reducing base. You can be a dualist who thinks that the internal mental contents are nonpropositional. The psychological arguments and data against propositional contents should stand or fall independently of such implementation-level details (i.e., whether the contents are implemented in souls or brains).

Blue Devil Knight said...

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.

Phogiston theory of heat, to its proponents, seemed very useful, but thermodyamics/statistical mechanics is even more useful, and true to boot!