Friday, December 07, 2007

Eliminative materialism

II. Why Propositional Attitudes Can’t Be Eliminated

Eliminative materialism is a frequently misunderstood position according to which there are no propositional attititudes. Its primary advocates have been Paul and Patricia Churchland. If would be a mistake to say, as some commentators have, that eliminative materialism is the view that there are no mental states. Nor, at least in some significant sense, can it be said that eliminative materialists deny the existence of intentionality. What I have described earlier as simple representation will certainly not be denied by eliminative materialists. What the eliminative materialist denies is the existence of propositional attitudes. These would include believing a proposition, doubting a proposition, fearing that a proposition is true, desiring that a proposition be true. So it is true that eliminative materialist claims that there are no beliefs.

To be fair, the eliminativist position is somewhat more complex than that. Eliminativism maintains that “belief” and “desire” are not mental states we are directly aware of, as “seeing red” or “feeling sick” would be, but are posits of a theory called “folk psychology.” In the history of science, “folk” theories have been succeeded by scientific theories. Sometimes the scientific theories absorb the “folk” theories in such a way that the “folk” theory is taken to be fundamentally right; just standing in need of some development by the scietific theory. In other cases, such as the move from Ptolemaic astronomy to Copernican, the succeeding theory showed the previous theory to be dead wrong, and the posits of the theory to be nonexistent. The Churchlands maintain that when neuroscience “looks under the hood” of the brain it will not find objects in it corresponding to “belief” and “desire.” Hence the right thing for science to do given this state of affairs is to deny the existence of beliefs and desires in much the way present-day science denies the existence of phogiston and ether.

The self-referential rebuttal is pretty obvious. “Come on Paul, you expect me to believe that, Paul?” Or, we could even present an argument that if eliminative materialism were true, no one could possibly know that it was true.

1. Knowledge is justified, true, belief (plus maybe a fourth condition).

2. If eliminativism is true, then no one believes that eliminative materialism is true, since there are no beliefs.

3. Hence, if eliminativism is true, no one knows that eliminativism is true (consequence of 1 and 2).

Here the Churchlands would reply that our standard definitions of knowledge are, of course, laden with folk-psychological assumptions, and when those are overthrown and a new theory based on neuroscience is developed, a fully adequate conception of knowledge will emerge.

Now the promise of successor concepts seems to many people to be, at best, a huge promissory note drawn on future science, and we are told very little about that the successors are actually going to look like. The successor concepts are going to have to do everything for us that we thought propositional attitudes did, except that these will be a more neurophysiologically accurate way of talking about human behavior and will not be propositional states.

Now propositional attitude psychology does a lot of work for us, in everyday life, and in science as well. Lynne Baker makes this point:

Suppose I dialed your phone number and said “Would you join us for dinner at our house on Saturday at 7:00?” You replied “yes.” On Saturday, I act in the way I should act if I believed that you were coming to dinner. But if neither of us had any beliefs, intentions, or other states attributed by “that”-clauses, it would me amazing if I actually prepared dinner for you and if you actually showed up.

Consider the whole practice of political polling which is very often able to predict the outcome of elections before they occur. Pollsters ask respondents who they intend to vote for, or who they believe is best equipped to deal with health care or terrorism.

What is most critical, however, is that if science is what every naturalist I know says that it is, a rational method for discovering the truth, then it we have to be able to know the precise content of the terms and concepts we are using. This is especially true in the area of mathematical reasoning, which is at the heart of physics. We have to be adding, not quadding. The definite integral has to be definite if it is to do the job assigned to it. There has to be some state of the person that recognizes the mathematical content of, say, Maxwell’s Equations (which to me is the propositional attitude of understanding that p), and if there has to be such a state, why should we not call this a propositional attitude.

It seems to me that there is an introspectively accessible state of knowing what one means when one says something. Now it may be that the full and complete content of what we know when we say it is not known to us. For example, I can say “I want a glass of water” without having any idea of the exact chemical composition of water. But there has to be an internally accessible content of the term “water” which will allow me to recognize whether I have been given a glass of water or a glass of coke. Of course there can be errors here, if it turns out that “What he thought was H2O was H2SO4.” But one might be tempted to think that sulfuric acid was water, but it would be unlikely to be tempted by the likelihood that Coca-Cola is water, because Coke doesn’t look at all like water, but sulfuric acid sort of does. All of which suggests to me that we do have internally understood concepts of what we mean by words, and if we didn’t we wouldn’t be able to get through life. I don’t see how you can accept the existence of internally understood concepts of what we mean by words without also accepting propositional attitudes. I also fail to see the possibility that further brain-mapping is going to change this situation. This seems to me to be an insuperable difficulty for eliminative materialism.

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4 Comments:

At 12/07/2007 11:45:00 AM , Blogger Blue Devil Knight said...

Is this your writing? I think the characterization of EM at the beginning is pretty good.

Even worse for the standard self-refutation arguments is that they beg the question. To argue against EM you can't just assert that knowledge is true justified belief (where belief is taken in the prop-att sense rather than disposition to give assent or something).

You say little but promissory notes are given, but this is wrong. In 1979 you could have saiud that (Scientific realism and plasticity of mind), but look at Paul Churchland's two book-length treatments of what he thinks the alternative is. (Neurocomputational perspective, and Neurophilosophy at work).

I'll have to think more about the last bit on content recognition and introspection. At least the bits we haven't gone over, as it seems you try to get at twinearth type concerns with the water-coke example. I'll have to chew on that a bit.

 
At 12/08/2007 06:57:00 AM , Anonymous Anonymous said...

"What the eliminative materialist denies is the existence of propositional attitudes. These would include believing a proposition, doubting a proposition, fearing that a proposition is true, desiring that a proposition be true. So it is true that eliminative materialist claims that there are no beliefs."


I am in complete agreement with you in the view that eliminative materialism is irrmediably flawed. However, I don't share all of your reasons for thinking so.

The ‘propositional attitude’ conception of belief is quite mistaken. I’ve tried to indicate one clue as to why this is so by highlighting the ‘that’ following ‘fearing’ and ‘desiring’. You see, believing that p is not the same as believing the proposition that p. I believe the same thing that I also may fear and desire, but I cannot fear and desire a proposition.

P.M.S. Hacker expresses it better than I can:
To be sure, one can believe propositions, as one can believe stories, rumours, declarations and statements. But since what I believe, when I believe that p, may be what you fear or suspect, and since to fear or suspect that p is not to fear or suspect the proposition that p, what I believe when I believe that p cannot be a proposition. Only language users can believe stories, rumours, declarations, statements and propositions, but both small children and higher animals can believe that things are thus and so, so what they believe cannot be propositions. To believe that p is to believe things to be so; to believe the proposition that p is to believe things to be as the proposition that p describes them as being.

This from his article “Of the Ontology of Belief”, which can be found online on this page.
In that article he also gives some detailed reasons as to why a belief is not a mental state.

By the way, you may be interested in going to this site
which has an audio link to a discussion between D. Dennett, Searle, Hacker and Bennett concerning Hacker and Bennett’s book: “Philosophical Foundations of Neuroscience.” They are extremely critical of Dennet’s ideas in that book.



"Sometimes the scientific theories absorb the “folk” theories in such a way that the “folk” theory is taken to be fundamentally right; just standing in need of some development by the scietific theory."


“Folk” theories are not really theories at all. This is an incorrect assumption on the Churchlands part. There is little reason to assume that our ordinary psychological concepts are theoretical concepts in the way that phlogiston was.

Hacker and Bennet explain why this is so in their book

 
At 12/08/2007 07:28:00 AM , Blogger Rino said...

Hi Victor,

Could you clear a definition up for me? What do you mean by 'proposition'?

a) the words 'the sky is blue'
b) the non-linguistic concept (understanding??) in individual minds that the sky is blue
c) the corresponding objective fact of the matter in the material mind-independent world
d) some platonic/ideal objective idea that the sky is blue
e) Something different: _________

You seem to have (b) in mind at the end of your comments. Is this correct?

If you have the time, I would also appreciate an exact definition of 'intentional', since I've heard so many different definitions of this term. Thanks!!

Hi BDK,

If a belief is a disposition, would this mean that it has no truth value? Ie, how can a disposition to take out the trash on Monday's be true/false? Also, if a belief is a disposition, how is it any different than any other compulsion in the world, ie, the tree is disposed to lose its leaves in October, is this a belief? Finally, if a belief is a disposition to give assent, then how do we know what is being assented to? Ie, if I believe the sky is blue because I am disposed to say 'yes' whenever someone asks 'is the sky blue', how do we know that I am actually not disposed to say 'yes' whenever a four worded question is being asked of me?

 
At 12/11/2007 09:38:00 AM , Blogger Blue Devil Knight said...

Something anonymous said made me realize one thing I don't like about your bit: the core is that they don't think that our internal representational contents are propositionally structured. That is why there are no propositional attitudes: there are no internal propositions! It sounds silly almost to say someone doesn't desire something, believe something. Only in the context of denying propositions, and clarifying that they are denying internal sentential representational structures, a speculative psychological theory, that it makes any sense to be an eliminativist.

To just tell a person on the street "You don't have beliefs" would be disingenuous. Of course they would be incredulous. If you told them "Your representational contents are not propositionally structured," they would probably not care too much.

 

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