Solving the Mind-Body Problem: Dualism vs. Searle, Part 1

Written for the late great John Searle's Philosophy of Mind class in Fall, 1992

My teacher, famed philosopher John Searle, died last week. I took his Philosophy of Language class in Spring, 1991, and his much-better Philosophy of Mind class in Fall, 1992. He was brilliant and hilarious. He also had a distinctive speaking style that his students found easy to imitate. Here’s one monologue from memory:

These guys, they go from the preposterous to the platitudinous, then back to the preposterous. Like this one time, I’m debatin’ Jacques Derrida. He says, “No one understands anyone else.” And I say, “That’s ridiculous, I talk to my wife all the time.” So Derrida comes back with, “I’m just sayin’ that people sometimes misunderstand each other.” I reply, “That’s obvious. Everybody knows that. So what?” And then he goes, “See, you’ve admitted that no one understands anyone else.” Thinking about this makes me sick to my stomach, and I lie awake at night wondering about the future of philosophy.”

Searle was publicly reviled for sexual harassment in his later days. But I never saw him do or say anything objectionable, even by the hypersensitive standards of today. Furthermore, all of my ten generic objections to MeToo apply. Even if the worst accusations were true, I’m baffled by a society (or perhaps a mere academic subculture) that prioritizes sexual harassment over dozens of greater sins. If John Searle had once been in a bar fight, lost his license for drunk driving, or praised Fidel Castro — all of which are worse than sexual harassment — his obituaries probably wouldn’t mention these failings. So why not stick to his accomplishments?

In that spirit: The John Searle that I remember would not have wanted a pity party. He would have wanted a philosophy party. Here’s my term paper for his Philosophy of Mind class, split into two posts, very lightly edited.

John Searle, younger than I remember him.

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Solving the Mind-Body Problem: Dualism vs. Searle

“It is startling to realize how much unbelief is necessary to make belief possible.”

--Eric Hoffer, The True Believer

Bryan Caplan

Phil 132

Fall, 1992

1. Introduction

When John Searle exposes the errors of materialists, dualists can only be delighted. Searle and dualists, both minorities in academic philosophy of mind, have something crucial in common: Namely, they agree that mental states as standardly conceived exist; they are not “really” illusions, behavior, functions, or computer programs. Denial of the reality of the mental, rather than being the necessary implication of science, is in fact a profoundly unscientific attempt to say that reality can only contain what our theories adequately account for. Despite these points of agreement, Searle’s solution to the mind-body problem is avowedly anti-dualistic; and even if he requested admission to the dualist camp, it is likely that they should be uneasy to receive him. This paper compares and contrasts the Searlean and dualistic solutions to the mind-body problem; it then argues that dualism is a perfectly adequate theory of the mind and Searle’s view is not.

2. The Mind-Body Problem

In his works in the philosophy of mind, John Searle claims to solve the subject’s central problem: how the mind relates to the rest of the world. His solution to this problem, in turn, leads him to his positions on the other main questions about the mind -- most importantly, the problems of interaction and free will.

What exactly is Searle’s solution? It consists in two simple propositions:

1. The mind is caused by the brain.

AND

2. The mind is a feature of the brain.

As Searle puts it, “Mental phenomena are caused by neurophysiological processes in the brain and are themselves features of the brain.”[1] There is nothing radical about this claim, he insists, because it aptly parallels a host of non-controversial relationships that modern science has exhaustively studied. Searle’s favorite example is the liquidity-H20 relationship. The feature of liquidity that we observe in water, says Searle, is caused by the underlying molecular features of water. At the same time, liquidity is not some extra property that floats on top of the H2O molecules; it is the molecules, or rather one feature of the molecules. The crucial notion here, Searle explains, it that of levels of description. Frequently, we can describe something either at the micro- or the macro-level. In all of these cases, the macro-level is caused by the micro-level, and is at the same time identical with the micro-level (or a feature thereof). On this model, the mind is a macro-level property of the brain, and the neurons are the micro-level of the brain; it is therefore true, says Searle, that the mind is both caused by the neurons and at the same time simply is a feature of the neurons. One explicit implication of this view is that the mental is also physical. It is a mistake, says Searle, to divide the world up into physical and mental; everything is physical; there simply happen to be mental physical things and non-mental physical things.

To Searle may be contrasted the dualistic approach. I am not aware that any other philosopher holds precisely the same theory of the mind that I do; but it should be clear that I fall in the dualist camp. In any case, it is my own version and only that version of dualism that I am presenting and defending. With that caveat aside, let me explain what I think the truth about the relationship between the mind and the brain is. Contra Searle, the mind is caused by the brain, but the mind and the brain are two separate entities. The mind is a mental entity, and the brain is a physical one. You cannot have a mind without a brain, but nevertheless they are not one and the same thing. Both exist and are fully real; but they are different things. Since Searle gives some analogies to explain his view, so will I. The relationship between the mind and the brain is like that of a building to its foundation: you cannot have a building without a foundation to support it, but nevertheless a building and its foundation are two distinct entities. Here is second analogy: the relationship between the mind and the brain is like that of an astronaut to his spaceship: the astronaut cannot survive without his spaceship, but nevertheless the astronaut and the spaceship are two distinct entities.

The reader familiar with the usual flavors of dualism, substance dualism and property dualism, will note that my view does not neatly fall into either category. It is not substance dualism because, according to normal philosophic usage, a “substance” is something able to exist all by itself. But according to me the mind depends upon the brain causally; the mind could not exist all by itself; hence it is not a substance. Neither is my view property dualism; for the essence of a property is that it could not even be conceived as existing apart from something else. For example, “whiteness” could not even be imagined to exist all by itself; the reason is that it is a property, not an independent thing. But we can conceive of the mind all by itself; hence it is not a property. A even stronger argument against property dualism is that if there are mental properties but no mental entities, it would be unclear what made all of my mental states mine, how they could be experienced as the mental states of a single, unified subject. But the unity of the mind, the impossibility of analyzing it into a disconnected succession of discrete mental states without leaving out something essential, is one of its central features which simply must be accounted for.

What then is the mind? It is an entity; we learn empirically that it requires the brain to exist, so it is not a substance; but it is not a property because it can be conceived of as an independent existent, and because the mind is a unity. We are already overloaded in philosophic jargon; but if I had to give my view a name, it would be “entity-dualism.” The content of this view is simple: the mind and the brain are two different things; the mind could not exist without the brain; and the mind is not merely a property of the brain but an entity.

Whatever other dualists have said, on my view the mental and the physical are not “two separate realms.” They are very different, but they all exist in one “realm.” How are the mental and the physical different? They are different in many ways, but we all understand the important ones. The physical things are matter and energy; they are both indestructible and can transform into one another; and they are unconscious. Matter has extension and mass, and energy at least could potential have these attributes since it can transform into matter. The mental, in contrast, is destructible and cannot change into either matter or energy; it lacks and could never acquire extension or mass; and most distinctively, the mental is conscious.[2] Since this view overlaps closely with common sense, it should be easy to understand.

Searle has said that it is simultaneously true that the brain causes the mind and that the mind is a higher-level feature of the brain. That appears almost incoherent. It seems that something can be identical with something else, or be caused by something else, but not both. I am not the first person to make this criticism, and Searle has a carefully prepared reply: “Place [a critic of Searle] is thinking of cases such as ‘These footprints can be causally dependent on the shoes of the burglar, but they can’t also be identical with those shoes.’ But how about ‘The liquid state of this water can be causally dependent on the behavior of the molecules, and can also be a feature of the system made up of the molecules’?”[3]

The very essence of Searle’s solution, he explains, is to deny both that (1) The mind is a different thing than the brain, (2) The mind can’t cause anything. As Searle puts the apparent dilemma, “Either you have dualism and an unintelligible account of causation or you have an intelligible account of causation and abandon the idea of the causal efficacy of the mental in favor of some version of the identity thesis with an attendant epiphenomenalism of the mental aspects of psycho-physical events.”[4] He thinks that he solves this problem by saying that the mind is a higher-level aspect of the brain; hence, since the mind is itself physical, causation is conceivable, and since it is a higher-level feature, causation is possible and indeed real. Just as an explosion is caused by movements of molecules and is at the same time identical with the movements of molecules, so too the mind is caused by the brain and is a feature of the brain.

If Searle’s H20-liquidity and molecular movement-explosion examples were genuine instances of causation and identity at one and the same time, his case might be strong. However, he is simply wrong to think that there are any examples of simultaneous causation and identity. The explosion isn’t caused by molecular movement; it is molecular movement; liquidity isn’t caused by H20; it simply is a feature of H20.

The proof of this is quite simple. Searle places all of the weight of his argument on the so-called “different levels of description.” But -- as Searle has pointed out in his critique of cognitivism -- we must be careful to distinguish those attributes that are intrinsic from those that are observer-relative. As he explains the distinction, “The expressions ‘mass,’ gravitational attraction,’ and ‘molecule’ name features of the world that are intrinsic. If all observers and users ceased to exist, the world still contains mass, gravitational attraction, and molecules. But expressions such as ‘nice day for a picnic,’ ‘bathtub,’ and ‘chair’ do not name intrinsic features of reality. Rather, they name objects by specifying some feature that has been assigned to them, some feature relative to observers and users.”[5] What kind of attribute are these “levels of description”? Well, there aren’t any “levels” in a thing apart from observers -- the thing just exists. There are as many “levels” as there are ways to observe something; and if there were no observers, there could be no “levels.” Therefore, the levels are observer-relative. Now, it makes no sense to say that observer-relative attributes cause anything; these attributes aren’t in the things observed at all, but are rather assigned to the world by observers. So how could the levels be causally inter-acting when they aren’t intrinsic to the world at all? We can’t create new causal relations just by looking at one and the same object from different perspectives.

At first glance my position appears to lead to a strange conclusion. Wouldn’t this mean that, for example, liquidity couldn’t really cause anything? Wouldn’t that be an observer-relative feature (along, presumably, with the rest of the world we directly experience)? This initially puzzling objection misunderstands what part of the world I claim is observer-relative. All of the features that we perceive, at higher and lower levels alike, are intrinsic and have causal powers. The point is just that these things don’t acquire or lose intrinsic attributes when we look at them on different levels (though it may be easier to discern certain properties on a particular level). This is because there is no intrinsic feature of a thing that demands that it be “split up” into any particular levels; instead, the levels get attributed by observers, i.e., they are observer-relative. And these observer-relative features, virtually by definition, cannot have any causal powers -- since in a fundamental sense they aren’t in the thing at all.

Water exists; we can look at it on the micro-level and on the macro-level. But that doesn’t mean that the levels are causing anything; it means we have two different perspectives on one and the same event. Now we may loosely talk about H20 molecules “causing” the behavior of water, but they do nothing of the kind. Learning about the molecules helps us understand why the behavior of the macro-level is the way that it is; but the relationship is identity and only identity. To deny this is to accept the absurd view that we can create new causal relations in the world simply by observing them from additional perspectives. And the same goes a fortiori for the mind and the brain. If the mind is merely a feature of the brain, the two can’t causally relate; if they two causally relate, they can’t be identical. Searle’s dilemma remains unscathed.

This is the first criticism of Searle’s view. Second, we may bring up the objections of Thomas Nagel, which, though not specifically directed at Searle, nevertheless apply. What is interesting about these objections is not so much the objections themselves but Searle’s reply to them; for as I shall show Searle’s defense of himself could just as easily be used by me to defend my theory against Searle.

Nagel’s central criticism of any solution to the mind-body problem is that we lack the requisite conceptual apparatus to even begin to resolve the difficulty. Causal explanations in science are necessary. Given the theory, the observed effects must follow. Given the molecular composition of H20, for example, its solidity, liquidity, etc. is strictly deducible. But no necessary connection exists between the physical and the mental. No matter how much we know about the brain, we could never deduce a single mental predicate.

We might state Nagel’s objection even more strongly. As Michael Huemer has pointed out, it is logically impossible to deduce any mental statement from any non-

mental statement.[6] Just as Hume said that we can never deduce any “ought” statement from any “is” statement, or just as we will never deduce anything about geometry from non-geometrical statements, so too will we never deduce mental facts from physical ones. Even if we knew everything about the physical world of molecules, forces, spins, etc., we would not be able to predict the most trivial mental fact unless we smuggled a mental premise into the argument.

Searle has three responses to Nagel; they are quite revealing. First, says Searle, not all scientific explanations demand necessity; for example, gravity appears to be just a brute fact, not a necessary implication of anything more basic. Second, there is a kind of necessity in mental-

physical causation even now: witness a man screaming with his hand caught in a punch- press, says Searle in effect, and tell him that he is not necessarily in pain. Third, this lack of perceived necessity may merely be epistemic. It might very well exist, but we are too dense to see it.

As usual, Searle gives a comprehensive reply to his critics. Alas, this reply proves far too much. We have to reject dualism, Searle has repeated again and again, because the dualists could never explain how the mind and brain interact. With evident skepticism, Searle asks, “Are we supposed to think that our thoughts and feelings can somehow produce chemical effects on our brains and the rest of our nervous system? How could such a thing occur? Are we supposed to think that the thoughts can wrap themselves around the axons or shake the dendrites or sneak inside the cell wall and attack the cell nucleus?”[7] Apparently, dualism can only be true if we can describe the mechanism. But if Searle’s reply to Nagel is valid (and I think it is), then it is open to me to say to Searle just what Searle said to Nagel. Namely:

1. It could just be a brute fact that when you get a working brain a mind appears, and these two causally interact. Just as we don’t need a transcendental deduction to conclude that gravity exists, neither do we need to describe the mechanism of mind-brain causation before we can conclude that it is real.

2. Anyway, there is a sort of necessity between the interaction of the mind and the brain. As Searle suggests, it might be a prima facie necessary truth that when a guy gets his hand stuck in a punch-press, he has to be in pain.

3. Just because we don’t (and maybe can’t) understand how the mind and brain interact doesn’t mean that they don’t.

When I presented this argument in lecture to Searle, he replied in the following way. Since on his view, the mental is also physical, it is obvious that mental things could causally interact with non-mental things, since they are both physical. It might be hard to understand how they relate, but it is not hard to understand that they could relate. In contrast, said Searle, dualism posits “two realms,” which makes it hard to envisage even the possibility of interaction, much less a mechanism for interaction.

I am not sure which dualists Searle is thinking of who use this “two realms” notion; I suspect that he lumps together dualists with a hidden religious agenda (e.g., Descartes) with dualists who see it as the best description of the way that the observed world works. In any case, as I specified, my dualism does not say that there are two realms. It says that there is one realm which contains two rather different types of things: mental things and physical things. If two very different types of physical things can interact (e.g., color and temperature), why couldn’t two very different types of existents interact (e.g., mental and physical)?

By now I have shown why Searle’s solution to the mind-body problem just doesn’t work. In particular, he gives insufficient heed to his own notion of intrinsic vs. observer-relative features; because if he did heed this distinction, he would realize that different levels of description are observer-relative, not intrinsic; hence different level features of one thing cannot “interact”; hence something cannot be both caused by X and be identical with X; hence Searle’s solution to the mind-body problem fails. I have also shown how Searle conveniently provides dualists with the proper response to his own criticisms. In particular, we don’t need to explain how mental-physical interactions happen before we can accept dualism. It is possible that their interaction is just a brute fact like gravity; or perhaps the limitation is merely epistemic.

With that out of the way, we may move to the crucial question: What is the evidence for my view? The best evidence is simply observation of our own minds. When I introspect (another Searlean no-no, but that is a topic for another paper), I observe thoughts, beliefs, pains, and so on. They are really there. Moroever, they are not floating randomly around, like Hume thought. Rather they are all predicates of one and the same thing; they are bound together, unified. But this thing to which they belong can also be observed by introspection; and like the thoughts, beliefs, and pains, it lacks all of the essential features of the physical: spatiality, mass, etc. It is not simply that I don’t see what its mass is; I see positively that it has none. And this entity of which individual mental states are predicated is the mind. If you doubt that there is a mental entity inside of you, please look again. Not only is there a mental entity “inside” me; but I essentially am that mental entity -- it is one and the same thing that I speak of when I speak of my “self.” The bottom line is this: My view should not be hard to accept, because intuitively this is what we all think. Only after people learn some philosophy do they begin to doubt this. But as I think Searle’s reply to Nagel shows, the doubts are illegitimate.

My view better explains the facts than Searle’s for two reasons. First, his notion that the mind can simultaneously be caused by the brain and be a feature of the brain is wrong; relationships like that just can’t exist. I accept the former and deny the latter: The mind is causally dependent on the brain, but is not identical with it. As for the allegedly attendant problem of explaining how the causal link works, Searle has solved the problem for me with his threefold reply to Nagel. In sum, my view is both internally consistent and intuitive, and Searle’s is neither.

Second, my view has genuine empirical content and Searle’s does not. Searle says that the mental is also physical; but I think that this stretches the meanings of mental and physical completely out of shape. When an eliminative materialist, for example, says that reality is all physical, he leaves his theory open to empirical falsification. To show that the eliminativist is wrong, we need merely find a single mental state, at which point he must say, “Reality isn’t all physical after all.” Searle, in contrast, will call anything that exists physical, even if it has no mass, extension, etc. I suppose that if we found some demonic spirits, he would say that they were also “physical.”

But what then, for Searle, is the meaning of “physical”? He apparently will re-define it to include anything that we discover to exist. But in that case, the previously meaningful (though false) identity statement “existence is physical” loses all of its content. Searle’s world, in effect, breaks down as follows: existents -- physical existents -- non-mental physical existents and mental physical existents. The dualistic categorization is simpler and more to the point: existents -- physical existents and mental existents. (See diagram 1.) Dualism is, moreover, falsifiable: it would be false if (a) There were no mental things, or (b) If a third type of thing, say angels or God, existed. Once again, the dualist’s breakdown of the world is both more internally consistent and more intuitive than Searle’s.

[continued tomorrow]