ETFRC Featured Reading on This Topic:
The Character of Mind: An Introduction To The Philosophy of Mind
by Colin McGinn
Perhaps the most beautifully written, meticulously
thought-out intoduction
to the subject to be found anywhere.
What is the Mind?
Why is There a "Mind-Body" Problem?
A Personal Introduction To The Philosophy of Mind for Non-Philosophers
For some people, the mystery of the mind-body problem is self-evident; others cannot see what the problem is despite one’s best efforts at explaining it to them (I once had a friend sarcastically suggest that perhaps such people don’t see the mind-body problem because it doesn’t apply to them). As with many philosophical problems, stating clearly what the question is is a challenge in itself. In this short essay, I will try to make the nature of the problem clear to any intelligent reader, without employing any of the technical jargon of philosophy.
I can clearly remember when I first became aware that there was something about the relationship between my mind and my body that seemed as though it couldn’t possibly be understood. I was perhaps eight or nine years old. My father was a doctor, and on the desk in his consulting room he had a model of the human brain. He explained to me that all of my thoughts and feelings, and all of my behavior, were the product of activity in my brain. He explained that the brain was made up of an enormous number of individual cells, called neurons, and that chains of neurons led out of the brain and into the rest of my body, ultimately ending up in my muscles and thereby causing my body to move about and exhibit behavior. Every time I spoke, for example, signals from my brain were causing the muscles of my mouth and tongue to move so as to form words.
I immediately had the sense that there was something strange about the idea that physical events in my brain were the source of my feelings, but I couldn’t quite place my finger on what was troubling about that idea. Then I considered the idea of volitional action – of course, since I was only a young boy, I thought of it as "doing something" rather than as "volitional action." According to my father’s explanation, the huge number of neurons in my brain were constantly sending signals to one another. I thought about what happened when I made a conscious decision to, say, raise my arm. I supposed that a whole, vast sequence of neural events were set in motion, which culminated in the muscles in my arm contracting. Then a thought struck me. That thought filled me with a dizzying awe – the kind of awe one experiences when one first realizes the sheer size of the universe – which has never left me to this day. The thought was this: what was the first neuron to send a signal when I decided to raise my arm, and what caused it to send that signal? I asked my father about this, and he laughed and said, "Well, that's really the question, isn't it? No one has any idea."
I was old enough to know that things didn’t happen by magic; events in the world always had causes. But how could something you couldn’t touch, like a thought, cause something to happen? My thoughts certainly did not cause events in the world outside of my body (although, as a child, naturally, I wished that they did). So how did my mind, which was not a physical "thing" like my brain, manage to cause a physical event in my brain? Yet it was a plain fact of experience that thoughts did cause physical events. If I decided to raise my arm, my arm did in fact go up. If a thought had a physical result in the world outside of my body, that would plainly be magic. But magic wasn’t real. How, then, could mental events cause physical results inside of my body? Philosophers call this question "the problem of mental causation."
Of course, I was a little boy then, and I’ve since gone to graduate school, studied neurophysiology, and become, hopefully, a bit more sophisticated in my understanding of these matters. I know now that there isn’t any one neuron that is the "first" one in the chain of events that leads to my raising my arm. But that knowledge doesn’t remove the mystery of how my will – my thoughts – can result in physical actions. And there is a converse side to this problem: why should physical events – for example, light striking my eyes – result in thoughts, feelings, and perceptions? After all, most physical events – like, say, knocking something over – don’t result in any such thing. A book knocked off of a desk (presumably) doesn’t have any awareness of hitting the floor. So why doesn’t light simply enter the eyes, travel to the brain, go through all kinds of complex processing, and emerge as behavior, without there being any experience, awareness, or consciousness accompanying these events? Why is there awareness, consciousness, experience, subjectivity in the world, rather than merely behavior? Subjectivity seems oddly gratuitous. It certainly seems that, if physics is a complete description of reality, as scientists believe, behavior alone would be the expected result of physical causes. Yet behavior alone does not fully describe us. There is an inwardness to our existence, which is consciousness. In the philosopher Thomas Nagel’s famous formulation, there is something it is like to be a person, whereas there is nothing it is like to be, for example, a cinderblock. The question as to how consciousness arises from the activity of the brain is one part of our question. The other part is whether consciousness can really cause things to happen – and this question is really identical to the question as to whether we have what is commonly called "free will" – and, if it does, how does it contrive to produce effects in physical things like neurons? Taken together, these two questions constitute the mind-body problem. The causal connection between consciousness and neurophysiology is sometimes referred to as the "psychophysical link." Consciousness seems like literal magic in a world that science describes as devoid of magic. How are we to account for it in a way that is consistent with what we know about the world? To solve the mind-body problem would be to render the psychophysical link as transparent to our intellects as, say, the fluidity of water is clear to us from our understanding of the chemical properties of water molecules.
Human beings didn’t just start wondering about this problem recently. We have been perplexed by it for thousands of years. Prior to our time, the mind-body problem was answered by a doctrine called dualism, which held that we had souls, and that our souls could evoke effects in our bodies – a doctrine sometimes called "the ghost in the machine." Today, for the most part, we no longer believe in souls – if, by souls, we mean consciousness that is detachable from the nervous system – but even if we did, dualism does not explain how the mysterious interaction between the soul and the body would take place. The idea of the soul is, perhaps, roughly analogous to the idea of consciousness – but souls did not require brains to give rise to them, and in fact, could survive the death of the body. It is now beyond any reasonable dispute that consciousness does not persist following the cessation of brain activity. Anyone who has undergone general anesthesia has experienced this first-hand: when the brain is shut down by pharmacological means, consciousness disappears. Further, selective parts of consciousness disappear as specific parts of the brain are disabled. In short, consciousness depends upon the brain. It is the brain that creates and sustains consciousness.
Modern analytic philosophy (with a few exceptions) doesn’t take dualism seriously, but it does offer a set of other proposals with which to either explain the link between the mental and the physical, or else make the problem go away by attempting to show that there is no real problem – that the only problem is that we are using words incorrectly, asking nonsensical or meaningless questions, or some variation of these ideas. The philosopher Colin McGinn has parsed the current set of proposed answers into four types, which he calls the DIME shape – "D" for "domestication," the claim that consciousness is really no big deal, that a sufficient understanding of neurophysiology (or perhaps computer science) will explain it, much as digestion and other physiological processes have been explained; "I" for "irreducibility," the idea that consciousness is just a basic feature of reality, like space and time, and can’t be explained in terms of anything simpler; "M" for mysticism, the idea that consciousness is literal magic (an idea McGinn and in fact all analytic philosophers reject almost by definition, but one which I don’t believe can be tossed aside so easily), and finally "E," for "elimination," which is the claim that consciousness does not actually exist, so there isn’t any problem to be addressed. This last position may strike readers as incredible, and they may be excused if they believe that no one could possibly take it seriously, but, in fact, it is currently one of the most popular views in philosophy of mind – a fact which demonstrates just how badly modern philosophy of mind, in its desperate desire to emulate science, has gone astray. McGinn also proposes his own idea for getting rid of the mind-body problem. McGinn’s view will be considered, along with the other four views, in subsequent essays.
There is some overlap between McGinn’s four positions in the actual thinking of specific philosophers on this subject, and, for the most part, no one individual represents any of the DIME positions in a totally pure form (although there are exceptions). But McGinn has done an admirable job of outlining the general shape of the contemporary debate. It should be noted that McGinn believes that his DIME shape applies, not just to the mind-body problem, but to most other philosophical problems as well. We will be considering only the mind-body problem, however.
Exemplifying the "domestication" approach is Daniel Dennett, professor of philosophy at Tufts University, and the author of the popular book Consciousness Explained. Dennett, who is usually described as a "functionalist," actually straddles McGinn’s "domestication" and "elimination" positions. Functionalism is a derivative and more sophisticated form of behaviorism, a view which virtually no one takes seriously any more. Functionalism, essentially, is the very popular idea that the mind is a kind of software running on the hardware of the brain. I won't detail the differences between functionalism and old-fashioned behaviorism here, other than to note that John Searle (see below) has commented, with his characteristic bluntness, "If you are tempted to functionalism, you don’t need refutation, you need help." Dennett is the leading proponent of this currently popular view: that we are essentially computer programs, and that any system whatsoever, if it implemented the correct algorithm, would be conscious in exactly the same sense that we are. Even if Dennett’s thesis – that our minds are software running on the massively parallel computing architecture of the brain – were stipulated, no explanation of the mechanism by which all of this results in subjective awareness is offered by functionalists. Dennett, of course, can offer no such explanation, so he instead he tries to intimidate the reader by suggesting that only an intellectual weakness prevents one from seeing the necessity of consciousness as the outcome of a high enough level of computing complexity. In terms of its use of misdirection, sleight-of-hand, and mountains of impressive-seeming data to prop up a dubious premise, Consciousness Explained ranks right up there with The Bell Curve, another work in which clear thinking takes a back seat to rhetorical pyrotechnics.
John Searle, author of two extraordinary books, Minds, Brains, and Science, and The Rediscovery of the Mind, is professor of philosophy at the University of California at Berkeley, and is perhaps Dennett’s primary nemesis (the two had a protracted and even acrimonious debate some time ago in The New York Review of Books.). Searle’s views straddle McGinn’s "domestication" and "irreducibility," as Searle ridicules the idea that an algorithm could give rise to consciousness. Unfortunately, Searle calls himself a "non-reductionist" while claiming that the mental is itself biological – a pair of claims whose coherence is, at best, unclear. In any event, Searle’s views are infinitely closer to reality than are Dennett’s. It seems that Searle believes that a sufficient grasp of neurophysiology, which he admits we are not even close to, would render the mechanism by which consciousness arises from the action of the brain comprehensible. Most importantly, Searle offers a straightforward and decisive rebuttal to Dennett. The rebuttal goes like this: computers are, by definition, formal symbol-manipulating machines, and any semantics (in other words, any meaning) attributed to the formal symbols the computer produces must come from outside – from a conscious human being (the programmer and/or the user) whose interpretation is necessary for computation to have any meaning at all. It is this person, and not the computer, who is the locus of whatever "meaning" the operation of the program has. As Searle puts it, there is no pathway available leading from syntax – the sole attribute of a formal system – to semantics, and this in one stroke undermines all of computer functionalism. Even if his own answer to the mind-body problem is flawed, Searle has done an enormous service by clearly and concisely disposing of decades worth of functionalist nonsense.
Patricia and Paul Churchland represent what is called "eliminative materialism," in other words, the "E" in McGinn’s DIME shape. Their views are so self-refuting that few bytes will be wasted here in describing them: after all, the denial of the reality of consciousness by conscious human beings surely must be the ultimate epistemological absurdity, for we know consciousness directly, and everything else only derivatively, by way of consciousness. As McGinn puts it, "Consciousness has the status of a primary datum, not a dispensable theoretical construct." The Churchlands are given an arguably deserved measure of derision by the estimable Thomas Szasz, a psychiatrist and social polemicist who steps into the mind-body problem fray in his The Meaning of Mind: Language, Morality, and Neuroscience. With the characteristic biting sarcasm Szasz reserves for the most astoundingly foolish views anyone advances, Szasz quotes Paul Churchland as saying, "All we can be sure of is the presumptively neurochemical nature of [unipoloar and bipolar illnesses.]" Szasz then comments, "How anyone can be sure of the presumptive cause of a putative illness, and what all this has to do with philosophy, are mysteries that further neurophilosophical research will no doubt dispel." Interested readers can find the Churchlands’ writings on "neurophilosophy" in any bookstore if they wish to investigate it. My own opinion is that the views of the Churchlands, and of Dennett, are examples of what philosopher Thomas Nagel calls views aimed at finding "a consistent set of things to say, rather than something to actually believe."
Nagel, author of the profound The View From Nowhere, is one of the very few contemporary philosophers who owns up to the staggering mystery presented by the mind-body problem. Nagel does not fit neatly anywhere on McGinn’s DIME spectrum. He is surprisingly unique in his rejection of the idea that an answer to the mind-body problem could win by default – that is, that an answer could be deemed correct simply because we were unable to think of any better possibilities. His willingness to commit to no view at all where no satisfactory one can be found is most unusual in modern philosophy, where philosophers typically stake out positions and defend them as though they were engaged in an intellectual game. Nagel's undiluted realism will be taken up in detail in other essays.
A fitting end to this brief essay would be one of my favorite quotes from Nagel, from his introduction to The View From Nowhere:
There is a persistent temptation to turn philosophy into something less difficult and more shallow than it is. It is an extremely difficult subject, and no exception to the general rule that creative efforts are rarely successful. I do not feel equal to the problems treated in this book. They seem to me to require an order of intelligence wholly different from mine. Others who have tried to address the central questions of philosophy will recognize the feeling.
Contrast this profound humility with the arrogance shown by Dennett in titling a book which does not even address, much less explain, consciousness Consciousness Explained. Dennett seems to believe that we are it – that we are, here and now, capable of understanding everything. Nagel is more cautious, understanding that evolution may have a long way to go beyond us, and that we may be no more capable of understanding the nature of the psychophysical link than a dog is capable of understanding quantum physics. In one of philosophy’s most humorous ironies, Dennett, who apparently takes physics as his model for the gold standard of knowledge, offers a mechanistic account of consciousness (really, behavior, but let it stand) of the type that physicists themselves have long since rejected.
The core of the mind-body problem is that there seems to be an unbridgeable gap between the psychological and the physical. We cannot comprehend how causality might leap across this gap. Not only do we not understand the nature of the psychophysical link, we do not even know what such an answer would look like – something which may be true of philosophical problems generally. Theories that substitute behavior for consciousness, explain behavior, and then claim to have explained consciousness (e.g., Dennett’s) abound, but they do us no good when it comes to unraveling the deep mystery of the mind-body problem. Explaining behavior is not philosophically problematic. It may be difficult indeed to explain the complex behavior exhibited by human beings, but we can see, in principle, what such an explanation would consist in. But such an explanation, however complete, would not in any way clarify the nature of the psychophysical link. Behavior is not experience.
It may be that the great problems of philosophy are questions which we simply lack the intellectual apparatus to grasp. This in fact is McGinn’s view, a position he calls "transcendental naturalism," to indicate his belief that nothing magical or mystical is going on, but that whatever is going on is beyond the reach of our intellects – in McGinn’s terminology, we are "cognitively closed" to any such understanding. But there are more optimistic possibilities.
