Solving the Mind-Body Problem: Dualism vs. Searle, Part 2

[continued from yesterday]

John Searle, about the age I remember him.

3. The Problem of Interaction

For the sake of argument, let us accept that Searle’s view of the mind is correct, and then see whether he has really solved the problem that dualism allegedly founders upon: the problem of interaction. It seems to be an obvious fact that my mind can cause my body to do things (and vice versa), and Searle admits that this is so. He then claims that his view makes the causal efficacy of the mental easy to understand, and in Intentionality he even diagrams out the pattern of causation. If you glance at the diagrams (p.269, my diagram 2) you will see that for each simple “A causes B” relationship, Searle produces a four-cornered diagram with four causal arrows. The lower half of the diagram indicates the micro-level, and the higher half indicates the macro-level. In each case, the micro-level “causes and realizes” its correlative macro-level; and at the same time, A causes B at both levels of description. Searle applies this four-cornered diagram to the explosion in the cylinder of an internal combustion engine. On the macro-level, a rise in temperature causes the explosion in the cylinder; on the micro-level, the movement of individual electrons between electrodes causes the oxidation of individual hydrocarbon molecules. But these two levels are not independent. Rather, the movement of individual electrons between electrodes “causes and realizes” the rise in temperature, and the oxidation of individual hydrocarbon molecules “causes and realizes” the explosion in the cylinder.

And, says Searle, the mind and body interact in the same way. (See Intentionality, p.270, my diagram 3.) On the macro-level, an intention-in-action causes a bodily movement; on the micro-level, the individual neuron firings cause physiological changes. But these two levels are connected causally, too. The individual neuron firings cause and realize the intention-in-action, and the physiological changes cause and realize the bodily movement. What could be simpler? The upshot of this view, Searle explains, is that the mental is quite able to cause physical things; the mental makes a causal difference. Or, as Searle tells us, “on such a model, the mental phenomena are no more epiphenomenal than the rise in temperature of the firing of a spark plug.”[8]

I remain unconvinced. Return to Searle’s diagram and you will notice that the arrows from the micro- to the macro-levels move in only one direction. (Searle does mention that we could draw a diagonal from the macro-level of A to the micro-level of B, but at no point indicates that the macro-level of A or B could cause its correlative micro-level.) The causation always moves bottom-up, never top-down. In order for the macro-level mental cause, such as the intention-in-action, to even happen the micro-level has to initiate the cause. It is not merely the case that the mind needs to have a brain to exist; in order for any mental cause to happen, a neuronal cause must cause and realize that mental cause. The bottom line then, is that the mental (the macro-level phenomena) is always an effect of the neurons (the micro-level), but cannot itself cause the neurons to do something. In other words, I could at this moment use my mind to cause my arm to move. And if the explantion were that simple, there would be mental causation in the true sense. But according to Searle, my mental state was itself caused by the neurons of my brain. My intention-in-action is merely a higher-level perspective on the neurons, which originate the causal sequence. In what sense, then, is the mental causally efficacious on Searle’s view?

Notice the asymmetry between a Searlean account of the brain causing something in the mind and the mind causing something in the brain. If my neurons cause me to become drunk, for example, Searle could represent this with a single up-pointing arrow from the neurons to the drunken state. But if decide to raise my arm, Searle does not reverse the direction of the causal arrow. Instead, he says that my neurons first cause and realize my intention to raise my arm, and then the bodily movement occurs. When the brain causes the mind to do something, Searle draws an arrow from the neurons to the mind; but when the mind causes the brain to do something, Searle draws an arrow from the neurons to the mind to the neurons again. In no case does Searle begin the causal sequence with the mind. Given this, it is simply inconsistent for him say that the mind is causally efficacious.

In fact, there is quite a bit of textual evidence that Searle admits precisely this point. In an especially revealing passage he informs us that, “Our basic explanatory mechanisms in physics work from the bottom up. Mental features are caused by, and realized in neurophysiological phenomena. But we get causation from the mind to the body, that is we get top-down causation over a passage of time; and we get top-down causation over time because the top level and the bottom level go together. But the top-down causation works only because the mental events are grounded in neurophysiology to start with.”[9] (emphasis added) Searle makes this point in his discussion of free will; but it also implies that even deterministic mental causation is impossible.

The truth of this follows from two premises, both of which Searle accepts. First, the mind is merely a higher-level feature of the brain. Second, valid causal explanations (excepting those through time) always work from the lower-levels to the higher-levels, never the other way around. From this it follows that the mind could never cause anything unless it were itself caused by the brain. And this is precisely what epiphenomenalism amounts to -- the denial that the mental genuinely makes a causal difference. Let me emphasize that this point has nothing to do with free will; Searle’s theory of the mind makes genuine mental causation impossible, even deterministic mental causation. Yet this is the very counter-intuitive proposition that Searle was trying to avoid when he came up with his theory of the mind; because it is absurd to say that my intentions-in-action make no causal difference. Even if Searle’s view were correct, then, it winds up denying the common-sense truths with which his theory is supposedly consistent.

To this we may compare my dualistic theory of the mind. On my view, it is just a brute fact that the mind can causally affect the brain and the brain can causally affect the mind. Mind- to-brain causation need not be reduced to something else; it is fully real. Searle, if you recall, has no problem with brain-to-mind causation; but he tries to show that mind-to-brain causation is actually neuron-to-mind-

to-neuron causation. Yet when he does this, he winds up unable to say that the mental makes a causal difference. I refuse to paint myself into that corner: the mind really causes changes in the brain, and this fact is irreducible to any other causal relationship. Rather than making mind-brain causation incoherent, as Searle accuses dualism of doing, only dualistic theories can naively embrace the common-sense truth that the mental makes a causal difference.

I illustrate this view in diagram 4. The mind can cause changes in both the mind and the brain; the brain can cause changes in both the mind and the brain. The brain “sustains” the mind, in the sense that humans need to have a brain to have a mind; but they are not identical. I diagram this relationship by drawing arrows marked “cause” from the mind to the mind and the brain, and from the brain to the mind and the brain. They illustrate the state relationship between the mind and the brain with the solid pillars, with arrows indicating that they are just two perspectives on one event. As in Searle’s diagram, my diagram has four arrows; but in my diagram all of the four arrows refer to one and the same causal instantiation. Since “rise in temperature”=”movement of individual electrons between electrodes” and “explosion in cylinder”=”oxidation of individual hydrocarbon molecules,” if one of the former terms causes one of the latter terms, we could, with equal validity, diagram the causal change in any of four possible ways. To wit: “rise in temperature” causes “explosion in cylinder” could, with equal validity, be diagramed as “rise in temperature” causes “oxidation of individual hydrocarbon molecules”; “movement of individual electrons between electrodes” causes explosion in cylinder”; or finally, “movement of individual electrons between electrodes” causes oxidation of individual hydrocarbon molecules.”

The reader will notice how my account of a spark plug firing differs from my account of the mind-brain relationship. In the first place, the relationship between the micro-level and macro-level of the spark plug firing is identity, whereas the relationship between the mind and the brain is that the mind is causally dependent on the brain, but not identical with it. Secondly, (and following from the first point) all four descriptions of the spark plug firing (see above) are equally valid descriptions of one and the same event. But since the mind is not identical with the brain, the four possible types of causation (i.e., mind-brain, mind-mind, brain-mind, and brain-brain) are not identical. Indeed, they are mutually exclusive. It might be, for example, that when the brain causes a change in the brain, the brain also causes a change in the mind; but there would be two distinct causal instantiations here, not two views on one and the same causal event.

Searle’s reply is not too difficult to anticipate: “But how does it work?” Yet as the last section showed, Searle himself admits that there are many brute facts in the world, such as gravity, which we accept as real even though we have no explanation of how they work; and even if we cannot see the mechanism, it still might be there. This demand for an explanation of “how” before we will accept the “what”, made by Searle and materialists alike, is confused. Normally, the “what” is what we know for sure, while the “how” is accepted only tentatively, only so long as its predictions match up with our observations. Observations trump explanations; if an observation is inconsistent with an explanation, it is the explanation that must go, not the observations.

There is another reason why the unconditional demand for a mechanism is mistaken. Imagine that we get an explanation of any observation. At this point, it is still open to us to request a deeper explanation, an explanation of the explanation. And if we find that, we can look for an explanation of the explanation of the explanation -- and so on. But eventually we must come down to the brute fact: This is the way that it works, and there is no additional reason. In the end we bottom out in brute facts, facts for which we have no further explanation. Does this show that all of our observations are invalid? I doubt it; what I think it shows is that we do not always require an explanation in order to have knowledge. In many cases we do; but if something is a brute fact, such that no further explanation is possible, then it isn’t necessary either. Explanations have but limited utility; they are useful so long as we deal with facts for which a further explanation exists. But when we reach the brute facts, explanation is neither possible nor necessary.

It may very well be that the causal interaction of the mind and the brain is one of these brute facts. Since no one has come up with a remotely plausible scientific theory about their interaction, and since it is logically impossible to deduce a mental statement from a non-mental statement, the mind-brain interaction is a likely candidate. This doesn’t mean that I am sure that no explanation is possible; maybe one day someone will show that this “brute fact” is not a brute fact at all, but one capable of a simple explanation. The point is that we don’t need to wait for this explanation before we can accept my view. We can gather all of the needed evidence for that if we merely turn inwards and observe.

4. The Problem of Free Will

There is no need to show that Searle’s view leads to the denial of free will; he freely admits it. “In order for us to have radical freedom, it looks as if we would have to postulate that inside each of us was a self that was capable of interfering with the causal order of nature. That is, it looks as if we would have to contain some entity that was capable of making molecules swerve from their paths. I don’t if such a view is even intelligible, but it’s certainly not consistent with what we know about how the world works from physics. And there is not the slightest evidence to suppose that we should abandon physical theory in favor of such a view.”[10] Since Searle has said that the mind is merely a higher-level feature of the brain, and the brain is made up of neurons, and neurons certainly don’t have any free will, the mind has no free will. Searle’s doubts about free will stem from his whole bottom-up model of explanation; to him it just seems incoherent to think that the higher-level could in turn cause the lower-level. With evident skepticism, Searle remarks: “The naive idea here is that consciousness gets squirted out by the behavior of the neurons in the brain, but once it has been squirted out, it then has a life of its own.”[11] Such a thing would, he says, violate the weakest principle of the transitivity of causation.

Unlike other philosophers who intellectually accept determinism, Searle admits that free will seems to be an obvious fact. After all of his philosophizing, he continues to act on the assumption of free will. In a rather disheartened admission Searle tells us, “the experience of the sense of alternative possibilities is built into the very structure of conscious, voluntary, intentional human behavior. For that reason, I believe, neither this discussion nor any other will ever convince us that our behavior is unfree.”[12] At the end of his reflections, Searle finds himself driven to pragmatism: he cannot see how free will is consistent with everything he knows, but he continues to believe that he is free all the same.

When we reach a view that so manifestly contradicts experience, such as the denial of free will, it is time to check our basic premises. Searle’s basic premise, as explained earlier, is that the mind is a higher-order feature of the brain. But it doesn’t take much insight to see that this leads to determinism: for if the brain is deterministic, and the mind is a feature of the brain, then the mind must be deterministic as well.

But these conflicting observations are actually a great point in favor of dualism. For if the brain is determined and the mind is not, they can’t be the same. Now it should be stressed that one could easily be a dualist and a determinist at the same time; one could say that every mental event was necessitated by prior mental events, so that they are deterministic even though they are not physical. However, the reality of free will is a central feature of my theory of the mind. Let me first explain its content and then give the most convincing arguments in its favor.

My view is that the mind is causally dependent on the brain. All that this means is that minds don’t float around by themselves; they aren’t ghosts in the machine; they are simply another development of evolution, not visitors from another dimension. But that is the limit of the causal dependence; once the mind exists, it can both be influenced by and influence the brain (and thereby the rest of the body). One basic feature of this mind is that it has freedom. This does not mean the freedom to do anything -- for example, I don’t think that my memory, emotions, or intelligence do what I want automatically. But I do at least have freedom over my beliefs, the course of my thoughts, my effort, and some bodily movements.

Now I suspect that if a neurophysiologist were looking at my brain while I made free choices, he would observe changes. This is no problem for my view, because correlations between mental and physical states is precisely what interactionism requires. Nor would it be an objection to my view that the doctor might inject me with a drug that makes me hallucinate helplessly; for brain-mind causation is real, too. All that my view says is that the mind can cause things to happen in the brain, and at least in some cases there was more than one thing that my mind really could have done.

How is this possible? As I explained in the previous sections, we don’t need an explanation of, say, free will before we can accept its reality. From the fact that it is real, it follows that it is possible. The pressing question, then, is this: Is free will real? I have five arguments to this effect.

First, there is the simple fact of observation. I observe that I choose freely, at least sometimes; and if you introspect, you will see it too. There is no reason to assume that these observations are illusory, any more than there is reason to assume that vision or hearing is illusory. I frequently hear scientists declare that real science (as opposed to bogus Aristotelian science) rests on observation; that is, they take the observed facts as a given, and work from there. The insistence that free will does not exist has more in common with the worst a priori scholasticism than with modern science. The latter demanded that the facts fit the theory, while the essence of science is supposed to be that we make our theories fit the observed facts. I would like to see a single argument for rejecting introspective evidence in favor of the other senses, because any argument against the validity of introspection might be applied, ipso facto, to sight, hearing, touch, taste, and smell.

Second, determinism leads to skepticism, a self-contradictory position. It is a fact that people disagree on many questions; this leads us to wonder if on any given issue we are correct. But if the content of my mind is determined entirely on the level of micro-particles, how would I ever double-check my views? I would be determined to believe them; and if arguments convinced me, then they would be determined to convince me. But all of the wrong people were determined to be convinced too -- so how could I know that I’m right? Of course, I might be correct by coincidence. But knowledge is justified true belief; and when we are pre-determined to believe whatever we happen to believe no matter what, it is hard to see what the justification of our beliefs is. Put succinctly, if we have knowledge we must accept beliefs only because we understand them to be true; but if determinism is correct, then we automatically accept whatever beliefs that our constituent micro-particles impose on us, since as Searle says, scientific explanation works from the bottom up. It might be the case that those micro-particles coincidentally make me believe true things, but the truth would not be the ultimate causal agent acting upon me.

Determinism, then, leads to skepticism. This is a controversial issue, but I hold that skepticism is necessarily false. For suppose we affirm skepticism. Then we may wonder if we know that skepticism is true. If we do know it, then at least one item of objective knowledge exists, which contradicts the premise. But if we don’t know that skepticism is true either, why should we accept it? To recap: Determinism implies skepticism; Skepticism is necessarily false; Hence determinism is false.

Third, I bring G.E. Moore to my defense. In his “Proof of the External World,” Moore refuted skepticism about physical objects merely by saying, “Here is a hand, and here is another hand.” Critics accused Moore of begging the question; and the critical reader of this paper might object that I am merely repeating my first argument. Both of these complaints simply miss Moore’s point, which was this: In order for any argument to work, it is necessary that the initial plausibility of its premises have greater initial plausibility than those of any other argument. Since no premise has greater initial plausibility than “This is a hand,” said Moore, it is in principle impossible for that claim to be overturned. I think that the same is true of the existence of free will. Nothing has greater initial plausibility than the premise “I have free will”; no scientific or philosophical argument will ever have greater initial plausibility. So how is it even coherent to argue against free will?

Note further that Searle says that he continues to believe in free will no matter how many arguments against it that he hears. This shows quite well that Searle finds the initial plausibility of “Searle has free will” to be greater than that of his arguments against free will; for if the arguments against free will were really that powerful, Searle would do what we usually do when overwhelmed by convincing arguments: Namely, change his mind. Since he can’t change his mind, the initial plausibility of his free will must exceed the plausibility of the apparently conflicting scientific arguments. Given this, he should re-examine the propositions of science and his philosophy of mind and see if they are really harder to doubt than the existence of free will.

Fourth, try the following thought experiment. Our brilliant neurophysiologists come up with an equation that they claim will predict all of our behavior. The equation is so good that it even incorporates our reaction to the equation, our reaction to knowing that it incorporates our reaction, and so on indefinitely. Suppose that the equation says that the next thing that you will do is raise your arm. Do you seriously believe that you couldn’t falsify this prediction by failing to raise your arm? But if you can falsify any prediction about your arm, and if the prediction is derived perfectly from a comprehensive knowledge of your body’s constituent micro-particles, then your mind must be free.

Fifth, let me answer the “argument from illusion” that Searle alludes to. On this view, we appear to be free, but aren’t. Science has shown that freedom is an illusion, along with sunsets and the apparent solidity of tables. We now accept that the sun does not set and that “solid” objects are mainly empty space. Why not accept that free will is equally illusory?

The answer, I think, is that the scientific explanation of sunsets and tables does not contradict our observations of sunsets and tables. Once we hear the scientific explanation, we learn that the explanation is perfectly compatible with our common-sense observations; indeed, our common-sense observations follow with necessity from the scientific explanation. It is easy to see how the sunsets that we observe are consistent with a heliocentric model of the solar system; it is equally easy to see how the observation of solidity is consistent with the presence of empty space. The macro and the micro explanations fit together. They cohere. But how could the observation of free will ever be compatible with determinism? Our other examples of scientific debunking of naive folk beliefs wound up reconciling the views of the vulgar and the wise, as Aristotle might say. But there is no way to reconcile the observation of free will with the theory of determinism because they are mutually exclusive. Until the critics of free will come up with a single example in the history of science of a situation in which observations inconsistent with our theory led to the rejection of the observations rather than the theory, I will be unable take this line of argument seriously.

5. Conclusion: Dualism and Science

Searle repeatedly invokes the name of science in order to get us to limit the theories of the mind to which we will even listen. The primary challenge of the philosophy of mind, as he sees it, is to show how our common-sense picture of the mind can be reconciled with modern science, which tells us that nothing exists except micro-particles in fields of force. Materialists agree with him, but conclude that our naive views of the mind cannot be reconciled with science, so they reject the mental altogether. Searle thinks that he does attain a fairly successfully reconciliation; but I suspect that if he came to agree with my counter-arguments against his theory, he might drift away into the materialist camp.

I think that there is a serious misunderstanding of the nature of “science” going on here. Searle and the materialists both seem to think that science=”nothing but atoms and the void.” Yet they err; they confuse a particular conclusion of science with the essence of science. The true essence of science is the use of observation and reason to objectively understand the world. If what we know about the mental contradicts the findings of “science”, then our science must be revised. If we observe mental states, apparently inexplicable by atomic theory, then we discover that either atomic theory has its limitations or we are misinterpreting our science. We cast no doubt on the existence of mental states; for any argument for doubting our observations of our mental states would ipso facto be an argument to doubt the observations that confirmed atomic theory. Searle is correct that our culture suffers from deeply-rooted prejudices about the mind; but these prejudices do not come from Descartes, whatever his errors. The chief prejudices come from people who assume that everything about the mind must either be illusory or consistent with theories derived from the study of inanimate matter.

“Dogma” is a harsh term, but an appropriate one for such belief-systems. For what is the essence of dogmatism but the acceptance of a belief in the absence of or in contradiction to one’s immediate observations? Materialism is not science; it is a dogmatic perversion of science that blindly demands that the mental be just like the physical when it plainly isn’t. As Eric Hoffer observes in The True Believer, “It is the true believer’s ability to ‘shut his eyes and stop his ears’ to facts that do not deserve to be either seen or heard which is the source of his unequaled fortitude and constancy. Strength of faith, as Bergson pointed out, manifests itself not in moving mountains but in not seeing mountains to move.”[13] Materialists refuse to look at something even more evident than moving mountains -- their own minds.

Unfortunately, for all of his skillful critiques of materialism, Searle falls into the same errors that they do, only in a less obvious form. While he affirms such aspects of the mind as consciousness and subjectivity, he denies some equally essential and obvious facts about the mind. In particular, he says that the mind is merely a “higher-level” feature of the brain rather than a separate mental entity, and that free will is incoherent; yet both of these are vital facts about the mind that any unbiased person can see if they observe their own minds with care.

Dualism wears the mantle of science properly understood. Unlike materialists and Searle, dualists trust their own observations of the mind more than theories developed to explain completely different phenomena. As a dualist, I am happy to open up my theory to empirical falsification, unlike a priori theories such as those of materialists and Searle. Dualism, as I said, would be false if (a) There were no mental states, or (b) There were yet another type of existent, like angels or God. If these conditionals empirically fail (and I think they do), then dualism is true. Like all good scientific (and philosophical) theories, dualism is internally consistent, intuitive, and, above all else, consistent with our observations.

Notes

1: John Searle, The Rediscovery of the Mind (Cambridge, MA: MIT Press, 1992), p.1.

2: I am indebted to Steve Blatt for the observation that matter and energy can transform into each other and are indestructible, whereas mental things are extinguishable and cannot turn into either matter or energy. This considerably clarifies and renders more plausible the distinction between the physical and the mental.

3: The Rediscovery of the Mind, op. cit., p.252n4.

4: John Searle, Intentionality: An Essay in the Philosophy of Mind (Cambridge: Cambridge University Press, 1983), pp.264-265.

5: The Rediscovery of the Mind, op. cit., p.211. The criticism has been made by Jennifer Hudin that causality is itself observer-relative. It is clear that Searle could not make this objection because he mentions “gravitational attraction” as an intrinsic feature of the world, which is a specifically causal property that matter has. This view of causality as observer-relative would incidentally also undermine almost all science, the chief function of which is the discovery of causal properties. I find the notion that causality could be an observer-relative feature to be almost incoherent. A strange tribe might have objects that look just like our bathtubs, except that they use them to store pet chickens. The tribe could change a bathtub into a chicken cage merely by commonly using it for that purpose. But could that strange tribe take gravitational attraction away from the bathtub and give it some other attractive or repulsive feature merely by changing their conventions? To sum up, if a feature is really observer-relative we would be able to change it merely by changing the nature of the subject; but causal properties work just the same no matter who the observer is. Hence they are not observer-relative.

6: See Michael Huemer, “What is the Mind-Body Problem?”, unpub. ms., available on request.

7: John Searle, Minds, Brains, and Science (Cambridge, MA: Harvard University Press, 1984), p.17.

8: Intentionality, op. cit., p.270.

9: Minds, Brains, and Science, op. cit., p.93.

10: ibid, p.92.

11: The Rediscovery of the Mind, op. cit., p.112.

12: Minds, Brains, and Science, op. cit., p.98.

13: Eric Hoffer, The True Believer (New York: Harper and Row, 1951), pp.78-79.