One of the standard objections to substance dualism in the philosophy of mind is that the substance dualist cannot account for mind-body and body-mind causal interaction. I have already quoted Dennett and Searle to this effect. Here is Paul M. Churchland:
Churchland apparently thinks that a substance, to be 'substantial,' must be material. Churchland thereby betrays his inability to conceive of (which is not the same as to imagine) an immaterial substance. (Note that this expression is not an oxymoron like 'immaterial matter.') But let that pass. The issue for now is simply this: How can two things belonging to radically disjoint ontological categories be in causal contact? But here again, Churchland seems to be laboring under a false assumption, namely, that causation must involve contact between cause and effect. But why should we think that this 'billiards ball' model of causation fits every type of causation? Why must we think of causation as itself a physical process whereby a physical magnitude such as energy is transferred from one physical object to another? I discussed this briefly in a previous post and suggested that on a regularity or counterfactual theory of causation there is no difficulty in principle with the notion of a causal relation obtaining between two events that do not make physical contact.
But today I have different fish to fry. I want to see if the materialist's conception of mind-body interaction is free of difficulty. If the materialist view of mind were without diffuclty I would be a materialist, on grounds of parsimony.
Suppose that every token mental state is identical to some token brain state. (Token as opposed to type: If you don't undersdtand this distinction, I will explain it.) This token-token identity will be held both by type-type identity theorists as well as by functionalists who reject type-type identity. Accordingly, my pain sensation after touching a hot stove is strictly identical to (not merely correlated with) a state of my brain. If so, there would seem to be no difficulty in principle with this state's being brought about by other physical states. For then physical-mental causation would just be a special case of physical-physical causation — which we assume to be unproblematic. At first glance, then, it appears that physicalism does not face the sort of interaction objection that substance dualism faces. To put it graphically, there is no 'ontological chasm' to 'jump over.' The mind-body problem gets traded in for the brain-body problem which presents no special philosophical difficulties, as difficult as it may be to work out the scientific details.
But why does the brain state which is (identically!) my pain sensation cause aversive behavior such as the withdrawal of my hand from the stove? Because it has the property of being painful. It is the painfullness of the sensation that is causally relevant. Why did I remove my hand from the stove? Because touching the stove hurt. A causal explanation of my aversive behavior (the yanking back of the hand) cannot merely invoke a brain state such as the firing of C-fibers (or whatever a completed neuoscience would specify): it must make reference to a brain state that has the property of being painful. This is a qualitative property or a quale to use a piece of phlosophical jargon. It is the peculiar first-person feel of the experience, the what-it-is-like of it. This raw feel (to us an old expression of Herbert Feigl) has what Searle calls a "first person ontology": its esse is its percipi. One cannot distinguish its appearing from its being.
Now here is the problem: if the pain sensation is identical to a brain event, then there is no place for the felt painfulness. For the brain event has a third person mode of existence and among the properties of this brain event you will not find anything that has a first person mode of existence. A brain event is purely physical and has only physical properties.
But even if you insist that the phenomenal property of painfulness -- the sensory quale -- is a property of the brain state, this phenomenal property surely plays no causal role in bringing about the aversive behavior. For it is only the physical aspects of the brain state that play a causal role in bringing about the the other physical states that comprise aversive behavior.
The materialist seems to be no better off than the substance dualist. Both face the problem of interaction since common sense strongly suggests that mind acts on body, and body acts on mind. (Parallelists and occasionalists deny this, but they move quite a distance from common sense.) The problem for the dualist is the problem of bridging the gap between two disjoint ontological categories, while the problem for the materialist is explaining the causal relevance of a pain sensation, say, to other physical events when the very painfulness which accounts for the aversive behavior cannot play any causal role if the pain sensation is identical to a brain state.
Although the materialist avoids the dualists' gap problem, he faces a different problem which is just as bad: the problem of explaining how a brain state can bring about aversive behavior when the property of this brain state that ought to be causally relevant, namely,
the phenomenal painfulness of it, cannot be causally relevant.
In sum, the materialist solves the gap problem by construing mental-physical interaction as physical-physical interaction, but he can do this only by rendering the very phenomenal properties that first give rise to the mind-body problem causally inefficacious.
Why then the double standard? Why is the substance dualist taxed with a problem of interaction, when the materialist faces an equally difficult problem? My conjecture is that there is an ideological bias in favor of materialism that is at the root of this double standard.
Recommended Reading: Kenneth Einar Himma, "What is a Problem for All is a Problem for None: Substance Dualism, Physicalism, and the Mind-Body Problem," Amer. Phil. Quart. (April 2005), 81-92.
[emphasis added]
My own arguments will likely proceed along these lines. I'll also be noting that, as our mastery of the manipulation of qualia increases, this mastery will stand as evidence of the tight association between-- indeed, inseparability of-- mind and matter.
For those who might be interested: Mark Salzman wrote a novella titled Lying Awake, which is the story of a Carmelite nun, Sister John of the Cross, who experiences ecstatic visions and becomes famous for her vision-inspired writings. Her visions are accompanied by debilitating side effects, however, and this necessitates a trip to the hospital, where she discovers (I don't think I'm spoiling the plot here) she has a low-grade form of temporal lobe epilepsy. The novel recounts, among other things, the nun's internal struggle as she decides whether to undergo minor surgery to remove the tumor causing the problem. Does she get the surgery? I'll leave you in suspense at that point, but will note that the novella explores the issue of "the ultimate quale"-- i.e., "direct" experience of the divine-- in a deep and compassionate way.
Kevin
I'd simply point out that neither most interpretations of Quantum Mechanics nor General Relativity adopt the traditional sense of substances. (David Bohm tried to salvage substances for QM, although people disagree to what degree he was successful in this) I think a case could be made that the solution is either to move, as Einstein did, towards a more Spinoza idea of a single substance which is the universe or to move more towards something not quite absolute mind and not quite absolute substance, much like I think Peirce's semiotic realism does.
What you say in your first paragraph is worked out in detail in an excellent book by Arthur W. Collins, The Nature of Mental Things (Notre Dame, 1987).
Kevin + Clark,
Do either of you accept the argument I gave?
I should add that I've long thought that traditional materialism simply pushed the assumption "like affects like" without explaining how that is possible. (Outside of Spinoza or Leibniz) I never saw traditional mechanics really grappling with the underlying ontology. (I should add that I don't think this was a problem for Newton with his more neoPlatonic ontology)
It would be interesting to look at your Peirce post. You might give us the link. Off the top of my head, I can't see how continuity would do the trick. If space and time are continuous, that still won't get one beyond space and time.
One could argue that qualia naturally evolved. Organisms that were unreactive to important environmental stimuli would have been weeded out. Hard to imagine any present-day land mammal that would willingly expose itself to flesh-charringly high temperatures, and the same would go for most sea creatures, except for those tiny beasties that live near undersea volcanic fumaroles.
While my above paragraph doesn't explain what qualia are, it might be helpful in understanding how qualia come to be present in a sentient being without resorting to a non-materialistic/anti-naturalistic theory.
What, according to anti-naturalists, are the origins of qualia?
Regarding this:
I'd respectfully disagree. Assume the materialists are correct and that something like tasting an orange can be explained in terms of biological, chemical, and other physical processes. Taste still happens. If the materialist is correct, then we simply know that the experience of tasting is perfectly natural. I don't think it's a question of "room"-- taste is a brute fact, albeit a subjective one.
[Well, not a brute fact if one wants to take the solipsistic route, I suppose... but then one has to explain how a company like Coca-Cola markets a single formula that has appeal to billions of people. To assume that all people taste Coke in radically different ways will make the Coca-Cola marketer laugh in your face. He knows the truth even if we don't: his sales figures reflect people's reactions to that single formula.
There's an objective component to all this that needs to be discussed. We accurately and reliably manipulate the senses all the time. Not in ways that affect all people exactly the same way, but well enough to make large groups of people react in the same manner, even though they hail from different genetic and cultural backgrounds.]
I do think the anti-naturalist needs to check with biologists re: the question of "lower" mammals and qualia. If the anti-naturalist agrees that humans evolved, and further agrees that mammals like monkeys, dogs, cats, etc. have a certain low-grade level of subjectivity, that they experience (is that the right verb?) qualia, etc., then s/he might want to think about how it is that these other forms of life come to possess their own types of consciousness.
I haven't done enough reading to know whether the substance dualist position makes human beings a special case. If it does, I think the position is doomed because once again we're back to pseudo-theological questions of "ensoulment."
Sorry-- way past my bedtime, and this comment isn't particularly coherent. I'll regret it later in the day.
Kevin
If you don't mind slightly muddled prose and a lack of terseness here is one of the posts I developed the ideas in.
Davidson, Peirce and Mind
The basic argument is the following.
1. (Premise) Anomalous Monism
2. (Premise) Peirce's notion of continuity.
3. From (1) mental talk (representation) can't be causally linked to physical talk under a law-like relation. That is within representation we can't causally explain the relation of the two
4. From (1) physical events cause mental events and vice versa
5. We can't explain (4) because of (3) That is the restrictions on mental talk and physical talk being translated prevent us from explaining the causality (which is what Bill demands)
6. By (2) we can gradually move from mental talk to physical talk. That is with an infinite number of moves we can slowly describe events from purely physical talk into talk that is more and more mental.
7. By (6) we know that causality between the mental and the physical can be explained, we just can't explain it because we are finite beings.
Now clearly (2) is the controversial premise. One has to buy the Peircean sense of holism and continuity. Thus for Peirce language is infinite and there is a full continuity of gradation of mental talk to physical talk which is possible.
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