Jaegwon Kim on Reductionism and Eliminativism

I've been studying Jaegwon Kim's Physicalism, or Something Near Enough (Princeton UP, 2005).  Here are some notes and questions.

1. It's clear that mental causation must be saved.  If Kim is right that nonreductive physicalism is not viable, then by his lights our only hope of saving mental causation is via "physical reductionism." (159).  It is of course easy to see how such reductionism, if true, would save mental causation.  Surely my desire for a beer together with my belief that there is beer in the reefer are part of the etiology of my getting out of my chair and heading to the kitchen.  If beliefs and desires are physical states, then there is no in-principle difficulty in understanding the etiology of my behavior.  Reductionism insures the physical efficacy of the mental.  What was a thorny problem on dualist approaches is no problem at all for the physical reductionist. 

2. At this point some of us are going to wonder whether reductionism collapses into eliminativism.  I tend to think that it does.  Kim of course must disagree.  His project is to find safe passage between  nonreductive physicalism and eliminativism.  But first I want to concede something to Kim.

3. Kim rightly points out (160) that we cannot assume that the mental cannot be physical in virtue of the very meaning of 'mental.'  We cannot assume that 'mental' means 'nonphysical.'  The following argument is not compelling and begs the question against the physicalist:

Beliefs and desires are mental
Whatever is mental is nonphysical
Ergo
Beliefs and desires are not physical.

The physicalist finds nothing incoherent in the notion that what is mental could also be physical.  So he will either reject the second premise, or, if he accepts it, deny the first and maintain that beliefs and desires are not mental in the sense in which his opponents think they are.  It seems clear, then, that one cannot mount a merely semantic argument against the physicalist based on a preconceived  meaning of 'mental.'

4.  Is my present state of consciousness real and yet reducible to a pattern of electrical activity in a network of neurons?  Can we secure reduction without elimination?  Reductionist: there are Fs but what they are are Gs.  Eliminativist: There are no Fs.  There at least appears to be a difference in these two sorts of claims.  Kim claims that "There is an honest difference between elimination and conservative reduction."  (160) Phlogiston got eliminated; temperature and heat got reduced.  Witches got eliminated; the gene got reduced. The reductionist thinks he can secure or "conserve" the reality of the Fs while reducing them to the Gs.  In the present case, the physical reductionist in the philosophy of mind thinks that he can maintain both that mental states are real and that they reduce to physical states.

5.  Let's note two obvious logical points.  The first is that identity is a symmetrical relation.  The second is that reduction is asymmetrical.  Thus,

I.  Necessarily, for any x, y, if x = y, then y = x.
R. Necessarily, for any x, y, if x reduces to y, then it is not the case that y reduces to x.

It is clear, then, that identity and reduction are not the same relation.  And yet if particular a reduces to particular b, then a is nothing other than b, and is therefore identical to b.  If you think about it, reduction is a strange and perhaps incoherent notion.  For if a reduces to b, a is identical to b, but, since reduction is asymmetrical,  b is not identical to a!  Reduction is asymmetrical identity.  Amd that smacks of radical incoherence.   This is what inclines me to say that reduction collapses into elimination.  For if a reduces to b, and is therefore identical to b, while b is not identical to a, then it follows that there simply is no a.  And so if my present mental state reduces to a pattern of electrical activity in a network of neurons, then my mental state does not exist; all that exists is the electrical activity.

6.  Kim wants to have it both ways at once.  He wants mental states to be both real and reducible.  He wants to avoid both eliminativism and dualism. My claim is that it is impossible to have it both ways.  Kim thinks that reduction somehow "conserves" that which is reduced.  But how could it?  If my desire for a beer is nothing other than a brain state, then then it is a purely physical state and everything mental about it has vanished.  If 'two' things are identical, then there is only one thing, and if you insist that that one thing is physical, then it cannot also be mental.

7.  My present thinking about a dog is intrinsically intentional, intrinsically object-directed.  But no physical state is intrinsically object-directed.  So, by the Indiscernibility of Identicals, my present thinking about a dog simply cannot be identical to any brain state, and so cannot reduce to any brain state. Kim of course thinks that intentional properties are functionalizable.  I have already  argued against that view here.  Whatever causal role my thinking about a dog plays in terms of behavioral inputs and outputs, causal role occupancy cannot be make makes my thinking  intentional.  For it is intentional intrinsically, not in virtue of causal relations.

8. Kim speaks of the functional reducibility of intentional/cognitive properties.  But surely it is not properties that need reducing but particular meetal acts.  Properties are not conscious of anything.  Nor are causal roles.  It is the realizers of the roles that are bearers of intentionality, and it simply makes no sense to think of these as purely physical.

9. Once one starts down the reductive road there is no stopping short of eliminativism.  The latter, however, is surely a reductio ad absurdum of physicalism as I explain in this post on Rosenberg's eliminativism. 

Comments

[godddinpotty]

On Edward Feser's blog I was trying to explain how intentionality can be a product of much simpler physical systems than a brain:
http://edwardfeser.blogspot.com/2011/12/reading-rosenberg-part-v.html?showComment=1325138254598#c6023449936579624078 (and following)

That seems to have died out, may as well try to revive the discussion here.

[Jan]

Dr Vallicella,

We agreed elsewhere that for the argument put forward in the post 'The Irreducibility of Intentionality: An Argument From the Indeterminacy of the Physical' to be valid an additional premise needs to be added:

P3. If x is reducible to y, then for every property P (Px => Py).

You think (P3) is true, I think it is not. In the current post you state:

R. Necessarily, for any x, y, if x reduces to y, then it is not the case that y reduces to x.

I agree (with reservations about the case of trivial reduction, i.e. reducing x to x). I will prove that (P3) implies that the relation of reduction is symmetric. In particular, it will show that (P3) => ¬(R). xRy will denote 'x is reducible to y'.

1. Suppose xRy and ¬yRx (for reductio ad absurdum).
2. xRy => (Px <=> Py) (from (P3) by substituting ¬P for P).
3. yRy (by (1) x has the property of reducing to y. By (2) y has this property also).
4. ¬yRy (by (1) x has the property of not being a reduction of y. By (2) y has this property also).

Contradiction. Therefore ¬(1.) and xRy implies yRx. In other words R is symmetric. Does (P3) or (R) give way? I say (P3) on pain of making the notion of reduction incoherent.

[Bill Vallicella]

Jan,

Thanks for the comment. You are right about the trivial case of reduction. It can be excluded with a little tweaking of (R).

That's a very clever argument, but an argument that leads to the conclusion that reduction is symmetric has to have gone wrong somewhere.

Suppose we see a particular lightning bolt. That lightning bolt is just an atmospheric electrical discharge. This is an example of reduction: the lightning bolt reduces to the electrical discharge. In reality, the first is nothing other than the second. In reality, there are not two particulars, but one, the first reducing to the second, but not vice versa. Clearly, the electrical discharge does not reduce to the lighning bolt.

This, I take it, is perfectly self-evident. Apparently, you are operating with some idiosyncratic notion of reduction that I simply don't understand.

But I'll think about it some more.

[Bill Vallicella]

goddin,

There is a question whether intentionality is found below the level of mind, but that is a huge separate topic. The topic right now is whether mental intentionality and mental states generally are physically reducible.

[Jan]

Dr Vallicella,

I've been clear from the beginning of our conversation about what I think is wrong --- it's (P3). The proof that (P3) => ¬(R) does not depend on any properties of reduction that are not stated in (P3). In other words, the proof is valid for every relation that preserves all the properties of the relata. The only logical choice is to reject either (P3) or (R). (R) is as you rightly say essential to the notion of reduction. Therefore, (P3) needs to go. Do you agree?

[David Brightly]

Bill, in your para (5) you see reduction as a relation between particulars and this seems to lead to a radical incoherence. I have always thought of reduction as a relation between concepts. For example, earlier in the post you remark that 'the gene got reduced' (presumably to snippets of DNA). What this means to me is that talk of genes, their properties and behaviours was found to be translatable into talk about DNA molecules and their properties and behaviours. This was all very well because genes were previously hypothetical entities put forward to account for the observed facts of inheritance. For all we knew they might be some exotic entity outside the domain of physics and chemistry. But no, they turn out to be molecules of a large and complicated kind but with some interesting symmetries. But there is no sense in which genes are no longer thought to exist. Indeed a gene is now identified with a DNA molecule consisting of a certain sequence of nucleotides. But this is an identity, or better, an equivalence, between concepts, not between particulars, concepts F and G being equivalent when everything that falls under F also falls under G, and vice versa. The asymmetry occurs when one concept is more established as a theoretical posit, or more general, than the other, and the reduction is from the less established/general to the more. But this is a relation between concepts.

[godddinpotty]

Well, if you can show that simpler physical mechanisms than the brain exhibit intentionality, that should go a long way to convincing you that brains can as well.

Or to put it another way: I claim that using a drastically simplified model system is a good way to understand how the mind's intentionality can work. The mind's intentionality may seem like something that couldn't possibly be reduced to a physical machinery. But if you understand how machinery can produce meaning in a simple case, maybe it will seem less magical.

[Bill Vallicella]

Hi David,

Excellent comment. Kim would like it. In fact, he speaks of reduction in terms of properties which is equivalent to your talk of concepts.

One can of course speak of the reduction of properties to properties. Temperature to mean molecular kinetic motion, etc. But it seems to me that the action is at the level of individuals or particulars. Not only cayusal action but mental 'action.' A mind is a particular, and so is a state of a mind, e.g., my present feeling sleepy, or my present desiring of a cup of coffee.

So it seems that ultimately the physicalist needs a reduction of individuals, e.g., my act of desire to a brain state. After all, properties and concepts are not conscious of anything, are not subjects of experience. By the same token temperature in general is not hot or cold.