Material Objections

In the two previous posts (here, and here) in our ongoing examination of mind-body dualism, we looked at the “interaction problem” — the question of how an entirely non-physical Mind might push the necessary neural buttons and levers to get the body to do anything.

We noted that philosopher William Valicella, in looking for a loophole, had suggested that there might be exotic interpretations of causality that let the dualist off the hook — a “regularity” model, in which no actual medium of interaction is on offer, but in which all that can be said is that A “causes” B if whenever an event A occurs, it is followed by an event B. In the last post we passed over in silence a serious objection to this view, namely that all of the examples of causal interaction we have yet observed require a transfer of energy, and that causation of the sort Dr. Vallicella imagines might in fact result in observable violations of conservation-of-energy principles. Nevertheless, this narrow philosophical ledge seems to him broad enough to stand upon, and he goes so far as to say that with this argument, causality objections have been “disposed of”. But as we saw in the last post, examples of such causation should leave empirically detectable clues, and to find violations of causal closure, and therefore of conservation principles, will be surprising, to say the least. We shall see.

Another area where the skeptic might request clarification is the question of origins. We know that there was a prebiotic era in Earth’s history, during which there were no creatures to embody minds. How, then, as organic life got underway, did immaterial Minds arrive on the scene to join us, and by what process did they attach themselves to the animals they are bound to? The same question applies to the ontogeny of the individual; where was my non-physical Mind prior to my physical existence? Should we imagine that the development in utero of our bodies somehow summons a Mind to join it? Also, if we are considering “substance” dualism, in which the Mind is, by the philosophical definition of “substance”, capable of independent existence, why is my mind attached to my body, instead of another?

This line of questioning leads us to another troublesome area: if the Mind is immaterial, then why is it so exquisitely vulnerable to the state of the body? Why do drugs, blows to the head, and other physical insults have the deleterious effect they do? An answer sometimes given to this question is that the physical body stands, somehow, in the same relationship to the Mind that a radio receiver does to the signal it amplifies; a damaged receiver will produce garbled audio. This won’t do, though, because in the case of physical meddling with the brain, it is the content itself that is affected. A damaged radio receiver won’t cause the newscaster to trail off in midsentence, for example, or burst into laughter for no apparent reason, but even tiny lesions in the brain can have enormous effects on the mind itself.

A more subtle response for the dualist is to acknowledge this objection, but to say that even though a Mind is by definition a metaphysically independent substance, once it is an embodied mind, it has entered into a two-way causal marriage with a physical system, and so is quite naturally going to be affected by changes in the brain. Though this is indeed a clever move, it comes at a high cost, because once we begin to consider the enormous effects that such physical changes can have, we seem to be forced to relegate the immaterial Mind to a decidedly subordinate position — and we must ask what, if anything, such a “substance” is actually bringing to the party. Is it the faculty of reason, as C.S. Lewis would have it? But our ability to reason can be swiftly destroyed by trauma or drugs. Is it our personality, then? There are countless examples of brain injuries causing radical personality changes; the most famous, perhaps, is the case of Phineas Gage, who had an iron bar driven through his skull, but case studies abound, and researchers now can even predict with confidence what sort of personality alterations will result from trauma to specific brain regions. Is it a temporal continuity of self, a binding of our experiences over time? All of that can be wiped away with a bullet or a scalpel. Is it the flow of our conscious thoughts and impressions in real time? Our “qualia”? Those, too, can be overridden by physical influences; electrical stimulation of tiny areas of the brain can produce smells, emotions, memories, sounds, and much more.

So what, then, is the “metaphysically independent” part? What is the special kernel of Mind that is held apart from the merely physical? Why cling to this model, when there are so many reasons to doubt it? If we are willing, instead, to adopt the materialist view — to imagine that the mental arises somehow from the activity of the physical — all of these problems melt away. The problems of origins and attachment vanishes at a stroke; we needn’t wonder where the minds were before the bodies arrived. The problems of causal interaction need trouble us no more; the neural activity that gives rise to our mental world proceeds in an ordinary causal sequence, with no worries about conservation violations. And of course if the brain is what generates the mind in the first place, it is entirely unsurprising that altering its functioning will affect our mental experiences, dispositions, and abilities.

So why does anyone defend interactionist mind-body dualism? We’ll talk about that next.

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  1. That theory of Dr. Vallicella as outlined by you sounds like the pre-established harmony of Leibniz, a type of psychophysical parallelism. It’s as though mind and body are running on parallel tracks or like two clocks in perfect sychronicity. Koan: “The sound of Ockham stropping”.

    Posted March 27, 2007 at 8:21 am | Permalink
  2. Malcolm says

    Hi Michael,

    Well, I hope I have characterized Bill’s position accurately; his original post is here. I don’t think it’s right to say that he is endorsing parallelism or occasionalism; what he proposes is real, directional causality, with mental events causing the physical in some unspecified way. He argues that since there is no rock-bottom account of “ordinary” causality on offer anyway, why can’t we imagine a different model? This is a bit disingenuous, as we can still have a coherent picture of causal chains without drilling all the way down to the bottom, and one thing we have noticed is that every example of causality we can observe involves a transfer of energy. So either “ordinary” causal closure will be appear to be violated in his model (as well as conservation of energy), or else the interactionist will have to maintain that the mental “overdetermines” the physical causal chain. Such overdetermination must be far from a satisfying result for the dualistic view, though, as it makes the mind’s causal input seem wholly unnecessary. Ockham stropping, indeed!

    I do wish I had ever managed to get a response from Dr. V. to these critiques; instead, I was asked to leave! Bill, if you are reading this, how about a comment, or a post?

    Posted March 27, 2007 at 11:12 am | Permalink
  3. bob koepp says

    Malcolm – The “regularity theory” of causality is hardly “exotic.” It’s standard fare among empiricists in the humean tradition, who would also dispute your claims about causation involving transfers of energy. I don’t, BTW, think a regularity theory of causation supports the thesis of interactive dualism. But it does, indeed, deflate certain objections to that thesis — just as Bill claimed.

    Posted March 27, 2007 at 12:30 pm | Permalink
  4. Malcolm says

    Hi Bob,

    Well, perhaps “exotic” was too strong a word (though not, I would imagine, to most scientists), and of course we all nod respectfully to Hume; his arch-skepticism regarding natural laws and confirmability of theory keeps us all honest. But the fact remains that when we examine the natural world, all examples of causality appear to involve a transfer of energy, and such an account would be perfectly satisfactory even to Bill, I imagine, were it not for the difficulty it presents for interactionist dualism.

    And as I’ve pointed out here and (ahem) elsewhere, a regularity-causation account of mind-body interaction may well find itself subject to empirical tests before long; if “ordinary” causal closure is not violated, then the dualists will be in a bit of a cleft stick, I think. But, of course, such a “wait-and-see” approach, in which we actually try, as technique permits, to test our philosophical models against the actual world, is not particularly palatable to some temperaments.

    Posted March 27, 2007 at 12:48 pm | Permalink
  5. galileo says

    Hi Malcolm,
    I think we would say that the sun causes the earth to orbit in a near-circular path but no transfer of energy takes place between the two. I put this forward not to undermine your argument but to point up the morass of confused ideas that we call ‘causation’. For example, I can’t see how to translate the sun/earth interaction into the ‘event A causes event B’ language of the regularity theory. It’s interesting that physics describes the regularities of the material world without recourse to causes, so it’s rather strange to bring them in to handle mind/brain interactions. Indeed, it looks as if the notion of ’cause’ is something that needs explaining rather than treated as a fundamental feature of the world, as BV does.

    Posted March 28, 2007 at 8:51 pm | Permalink
  6. Malcolm says

    Hello again, and thanks for visiting.

    Actually, as you know, the Earth is just coasting inertially along a geodesic path, in a region of spacetime that has the geometry it does due to the massive Sun’s proximity. There’s no transfer of energy, because there are no forces involved. To deflect the Earth from its orbit would require a large transfer of energy indeed, however; that would be a sizable dose of “causation” by any measure.

    The point as regards neural “causation” is not abstruse or difficult; we can trace the pattern of stimulation from cell to cell in any region of the brain where we look closely enough, and when neurons fire we can explain why in electrochemical terms. For muscles to move, nerves must transmit signals; the causal-closure violations I’m talking about would be such a signal train being launched without an antecedent stimulus.

    Posted March 28, 2007 at 10:43 pm | Permalink
  7. galileo says


    I’m very sympathetic to your line of thought but to play devil’s advocate for a minute I think BV’s response would be to say that you are working with a strong notion of causation that simply begs the question against the duallist. A weaker notion of cause such as a regularity theory lets us say that mental events can cause physical events just by virtue of their constant conjunctions, and vice versa. It seems to me that to address this philosophically we must either argue directly against the mental/physical split in the way, say, that Dennett tries to undermine our attachment to qualia, or we must show that this weak notion of causation is inadequate in some way as a theory of causation. The latter strategy moves us away from the philosophy of mind and into a new domain, of course.

    As an example of causation without energy transfer but with forces, how about the circular motion of charged particles in a uniform magnetic field?

    Posted March 29, 2007 at 8:05 am | Permalink
  8. Malcolm says

    Hi again galileo, and thanks as always for your thoughful comments, and for playing the Devil’s advocate — a role I relish myself, even though it gets me in trouble on occasion.

    Well, Bill does indeed say that this begs the question against the dualist, and of course he’s within his rights to do so, just as I am to say he is begging the question against the materialist. This is why I suggest, instead of getting into such a stalemate, that the interactionist interpretation may be open to some empirical testing.

    As I said above, we have already in hand a parsimonious account of what excites neurons, and in round-trip examples of stimulus and response, such as: 1) I see a falling flowerpot, 2) I decide to move (this is the purely “mental” part, according to Bill), and 3) I move out of the way — we would, if Bill is right, expect to see the neural sequence of part 3 begin without apparent electrochemical cause. The only other option is that the mental overdetermines the physical, which seems quite pointless, explains nothing, and is utterly unfalsifiable.

    I do agree that a complete account of causation is an open question, but the account we have in hand is sufficient to account for macroscopic biological processes, I think. And regarding your second example, charged particle behavior is mediated by the exchange of messenger photons, and when moving charged particles are deflected by magnetic fields there is energy exchanged between whatever is generating the field and the particles themselves.

    Posted March 29, 2007 at 10:53 am | Permalink
  9. galileo says

    Hello again, Malcolm,

    Carrying on the devil’s advocacy for a bit, allow for a minute the idea that charged particles are caused to orbit in a uniform magnetic field without transfer of energy (I’ll try to justify this later). How are we to explain this? It doesn’t fit the usual ‘event A causes event B’ picture of interacting billiard balls or bricks and windows. It seems to me that we just have to give up and say that it’s part and parcel of what we mean by magnetic fields and charged particles that this is what they do. To paraphrase commenter Tim McGrew over at BV’s, at some point the causal explanations just give out. It’s as if the field’s just being there is the cause of the circular motion. Perhaps the substance dualist is saying something similar: somehow it’s the very presence of mind that causes the brain’s physical behaviour (apologies for the pun). Now I don’t see this as a very fruitful starting point for a scientific investigation but it does seem to hold philosophical water.

    Returning now to the business of causation without energy transfer. Your claim is that energy transfer really is going on because our picture of electromagnetic force is one of point interactions between charged particles and ‘particles’ of field, viz, messenger photons, very much on the lines of ‘event A causes event B’. But is this conceptualisation sustainable? The rules of QED tell us to draw up a family of Feynman diagrams showing all possible histories by which a system starting in state S1 at time t1 could get to state S2 at time t2. Each diagram involves zero or more point interactions between particle and photons. For each diagram we calculate a complex number, add them all up, and the modulus of the result is the probability of the transition. To my mind this takes us far beyond the kind of causal notions we are accustomed to in classical physics. It’s as if causation starts to give out at roughly the scale where classical physics has to give way to quantum physics. I think this entitles me to look at my charged particle and magnetic field in a purely classical light in which neither field or particle gains or loses energy, and ask questions about causation. In a way, the gradual fading away of causation as scale decreases is a nice solution to Tim’s problem of causal explanations ‘bottoming out’, and has connections elsewhere in philosophy of mind that have come up at BV’s.

    By the way, I’m no expert in quantum field theory. Most of this comes from Feynman’s marvelous little book QED: The Strange Theory of Light and Matter.

    Posted April 10, 2007 at 4:13 pm | Permalink
  10. Malcolm says

    Hi once again galileo, and may I say that you do a bang-up job on behalf of Old Nick. And I too, have Feynman’s books; they are outstanding. In particular, the collection “The Feynman Lectures On Physics” is probably the best introduction to modern physics ever.

    But to deflect (i.e. accelerate) charged particles does require energy; if you do it vigorously enough, they give you the energy back in dramatic fashion, by emitting the potently energetic glow known as synchrotron radiation.

    I will cheerily admit, however, that at bottom there are still philosophical mysteries surrounding causation, as well as just about every other aspect of low-level physics. I think, however, that dualistic mind-body philosophers are simply scurrying out of the light, rather than producing any, when they seek out such pools of shadow in the hope of finding somewhere to stand. We don’t worry about causal processes at the Planck scale to hit a golf ball, and I rather doubt that we need invoke such arcana in trying to follow the path of causality in the brain, either (Penrose and Hameroff might disagree, of course).

    Neurons are macroscopic things; smaller and more complex than dominos, of course, but I think that in time, and with the right tools, we shall be able to follow the causal dance right the way round. A causal-closure failure, which would be startling and convincing evidence of dualistic causation in, say, my flowerpot example, would be like having a large gap in a chain of dominos, but with the second half of the chain toppling nevertheless, without apparent cause.

    Of course, as I have said emphatically and often, I have no illusions about mind-body dualism having been conclusively refuted. It’s just that certain dualists I could name seem to feel the opposite is true, and I think that is entirely unwarranted. Hence this series of posts.

    Posted April 10, 2007 at 10:56 pm | Permalink
  11. The issue of causal interaction does not disappear if you claim that the mind is caused by the brain, unless you assume that the mind is nothing more than an abstract term for certain specific neurophysiological process!
    The brain must be causally affected by subjective experiences, because otherwise we could not claim to be talking or writing meaningfully (and specifically) about them. So, unless one denies either the irreducible existence of consciousness or of the physical world, it is logically necessary to accept (two-way) causal interactionism between consciousness and the brain.

    There is simply no escape for anyone who accepts the existence of both subjective experiences and a non-subjective, physical brain.

    Titus Rivas

    Posted April 11, 2007 at 2:06 am | Permalink
  12. Click my name to read an article by Dr. Van Dongen and myself entitled Exit Epiphenomenalism: The Demolition of a Refuge.

    Titus Rivas

    Posted April 11, 2007 at 2:10 am | Permalink
  13. Malcolm says

    Welcome, Titus, and thanks for stopping by. We’ll all take a look. I agree that the very point you mention is the key difficulty with epiphenomenalism. How can we create physical utterances about subjective experiences unless that subjective experience can have a causal influence? I think there is a way past this objection for the epiphenomenalist, but I won’t presume to comment on your position until I’ve read the article. (I’m swamped at work just now, so it might be a few days.)

    Comments by other readers will be welcome, as always, of course.

    Posted April 11, 2007 at 10:07 am | Permalink
  14. Hello Malcolm,

    Thanks for welcoming me to your discussion. You might also want to read my paper The Causally Efficacious Psyche, just click on my name again.

    Please note that in Exit Epiphenomenalism we claim to have formulated an analytical argument against epiphenomenalism, parallellism (both in a local and in a general, panpsychist sense), and the identity theory. Which leaves us with either reductive (or eliminative) materialism – i.e. the denial of the irreducible reality of subjective, qualitative experiences as defended by scholars like Dennett or Churchland -, interactionist dualism – defended by people like Karl Popper, John C. Eccles, and Howard Robinson- and ontological idealism -i.e. the denial of the irreducible reality of the brain as a physical system, defended by e.g. Peter B. Lloyd.

    Of these a priori three logically tenable positions, only interactionist dualism accepts the irreducible reality of subjective awareness AND of a physical brain. Unless we choose to deny the irreducible reality of one (or both ;-)) of these, we simply must accept that dualist interactionism is true. It does not matter how magical this would seem, because it is a matter of logical analysis. Any resistance against this, is simply irrational and must therefore be inspired by non-rational factors such as cultural prejudices.

    Anyway, that’s how I view it. Take your time!

    Titus Rivas

    Posted April 12, 2007 at 2:04 am | Permalink
  15. Malcolm says

    Titus, you are welcome indeed; I thank you for joining the conversation.

    While my intuitions (not that intuitions carry any philosophical weight, of course, but there they are), my scientific upbringing, and all the objections listed in this series of posts impel me strongly to resist dualism generally, and interactionist dualism in particular, I have also had long exposure to exposed to other influences, in particular certain non-Western systems of inner work, and it has become an overarching goal of what remains of my life to arrive at as coherent an understanding of these matters as I can. As I say, I am deeply skeptical of interactionist dualism, but what I really want is the truth.

    I agree that the issue you raise presents serious difficulties for the epiphenomenalist; I have considered epihenomenalism an attractive view for some time, and have been grappling with this very objection myself. I am not convinced that it is insurmountable.

    My strongest suspicion is that the problem is that the categories themselves (the various “isms” we are discussing), the underlying assumptions that undergird them, and the notion of “matter” and “reducibility” may themselves be insufficient, and that this deadlock will be broken only by a major, Kuhnian, “paradigm shift”. But that will only come about by pressing as hard as we can upon the framework that we have at present, in tandem, of course, with the accelerating pace of scientific research.

    This post, unfortunately, is quite old by now, and I imagine few readers have seen this late series of comments (one of the drawbacks of blogging’s journalistic format). I will post a new article shortly for the purpose of carrying on this discussion, once I have digested your paper. I read it over late last night, and it deserves more careful consideration than I have had time to give it just yet.

    Posted April 12, 2007 at 10:36 am | Permalink
  16. Hello Malcolm,

    I’m looking forward to your more extensive comments. Please alert me when you post them.

    Best wishes,

    Titus Rivas

    Posted April 13, 2007 at 2:21 am | Permalink