The Hard and Easy Problems in the Mind-Brain Question

Michael Egnor

jar.jpgIn the debate between dualists and materialists over the relationship between the mind and the brain, materialists often invoke neuroscience to buttress their assertion that the brain causes the mind entirely, without need for an immaterial mind or soul. Indeed neuroscience has demonstrated many examples of correlation between physical brain processes and mind states. Do examples of correlation between brain states and mind states genuinely provide evidence for the materialist claim that mind states are merely brain states?
The wild claims of neuroscientists, such as the astonishing claim by atheist Yale neurologist Steven Novella that “the materialist hypothesis– that the brain causes consciousness — has made a number of predictions, and every single prediction has been validated,” suggest that some materialists, such as Dr. Novella, don’t even understand the core issues in the mind-brain debate.
David Chalmers, a leading philosopher of the mind and a particularly lucid thinker on the matter of consciousness, published a paper in the Journal of Consciousness Studies in 1995 entitled “Facing Up to the Problem of Consciousness.” The seminal paper has given rise to much debate, and I believe that Chalmers clarifies the important issues in the mind-brain debate in a very important way.

Chalmers, who is probably best described as a property dualist, notes:

Consciousness poses the most baffling problems in the science of the mind. There is nothing that we know more intimately than conscious experience, but there is nothing that is harder to explain. All sorts of mental phenomena have yielded to scientific investigation in recent years, but consciousness has stubbornly resisted. Many have tried to explain it, but the explanations always seem to fall short of the target. Some have been led to suppose that the problem is intractable, and that no good explanation can be given.

He continues:

To make progress on the problem of consciousness, we have to confront it directly. In this paper, I first isolate the truly hard part of the problem, separating it from more tractable parts and giving an account of why it is so difficult to explain.

Chalmers notes:

There is not just one problem of consciousness. “Consciousness” is an ambiguous term, referring to many different phenomena. Each of these phenomena needs to be explained, but some are easier to explain than others. At the start, it is useful to divide the associated problems of consciousness into “hard” and “easy” problems. The easy problems of consciousness are those that seem directly susceptible to the standard methods of cognitive science, whereby a phenomenon is explained in terms of computational or neural mechanisms. The hard problems are those that seem to resist those methods.

Chalmers characterizes the easy problems:

There is no real issue about whether these [neurophysiological] phenomena can be explained scientifically. All of them are straightforwardly vulnerable to explanation in terms of computational or neural mechanisms. To explain access and reportability, for example, we need only specify the mechanism by which information about internal states is retrieved and made available for verbal report. To explain the integration of information, we need only exhibit mechanisms by which information is brought together and exploited by later processes. For an account of sleep and wakefulness, an appropriate neurophysiological account of the processes responsible for organisms’ contrasting behavior in those states will suffice. In each case, an appropriate cognitive or neurophysiological model can clearly do the explanatory work….If these phenomena were all there was to consciousness, then consciousness would not be much of a problem. Although we do not yet have anything close to a complete explanation of these phenomena, we have a clear idea of how we might go about explaining them. This is why I call these problems the easy problems. Of course, “easy” is a relative term. Getting the details right will probably take a century or two of difficult empirical work. Still, there is every reason to believe that the methods of cognitive science and neuroscience will succeed.

Chalmers describes the hard problem of consciousness:

The really hard problem of consciousness is the problem of experience. When we think and perceive, there is a whir of information-processing, but there is also a subjective aspect. As Nagel (1974) has put it, there is something it is like to be a conscious organism. This subjective aspect is experience. When we see, for example, we experience visual sensations: the felt quality of redness, the experience of dark and light, the quality of depth in a visual field. Other experiences go along with perception in different modalities: the sound of a clarinet, the smell of mothballs. Then there are bodily sensations, from pains to orgasms; mental images that are conjured up internally; the felt quality of emotion, and the experience of a stream of conscious thought. What unites all of these states is that there is something it is like to be in them. All of them are states of experience…It is undeniable that some organisms are subjects of experience. But the question of how it is that these systems are subjects of experience is perplexing. Why is it that when our cognitive systems engage in visual and auditory information-processing, we have visual or auditory experience: the quality of deep blue, the sensation of middle C? How can we explain why there is something it is like to entertain a mental image, or to experience an emotion? It is widely agreed that experience arises from a physical basis, but we have no good explanation of why and how it so arises. Why should physical processing give rise to a rich inner life at all? It seems objectively unreasonable that it should, and yet it does. If any problem qualifies as the problem of consciousness, it is this one.

So what is the materialist response to Chalmers’ observations? Materialists such as Dr. Steven Novella deny the relevance of the hard problem of consciousness to our understanding of the mind. Referring to an earlier reference of mine to the hard problem, Dr. Novella wrote:

Dr. Egnor…is referring to another common fallacy used to dismiss the undeniable evidence linking brain function to mental function – retreating to philosophy, or more specifically to a conceptual realm that is not empirical and which defies common language…[p]hilosophers have asked what is probably a meaningless question – why is it that we “feel” that we exist, that we experience ourselves and the world – a phenomenon they refer to as “qualia.” I say this is meaningless because it does not yield any specific predictions or distinctions from a purely materialistic world.

Dr. Novella’s description of the origin of our subjective experience as “a meaningless question” should leave the reader gasping. It’s hard to imagine an assertion more misguided. We are subjects, not merely objects. First-person ontogeny is the aspect of our minds with which we are most familiar. In fact, first-person ontogeny is the only aspect of ourselves with which we are familiar, in the tautological sense that it is the only thing that we actually experience. It is the indispensable quality of the mind. The origin of subjective experience is the fundamental question–the hard problem–in understanding the mind. Yet there is nothing in the material world that intrinsically refers to or explains subjective experience. There is nothing in third-person ontogeny from which one would infer first-person ontogeny. No theory in physics or chemistry invokes the emergence of first-person experience. A detailed scientific understanding of the physics and chemistry of the brain–from molecular structure to neurochemistry to electrophysiology to neuroanatomy–would not at any point provide a scientific explanation of why we are subjects and not just objects.
This hard question about subjective experience in the relationship between the mind and the brain has been at the core of the most active and contentious issue in analytic philosophy in later 20th century and early 21st century. As science is a branch of philosophy (natural philosophy), scientists must grapple with these profound philosophical issues. Contra Dr. Novella, it’s not a matter of applying or not applying philosophy to this scientific debate. It is a matter of applying good philosophy or bad philosophy to this debate.
The hard problem of consciousness is the most important problem in understanding the mind, and thus far materialism has provided no insight. It is unclear how it even could provide insight. Nothing about the scientific characterization of matter–and nothing about materialism–explains the emergence of subjective experience. The principal materialist response to this catastrophe for materialist ideology has been to deny the relevance of subjective experience to our understanding of the mind. Yet the retreat to science and the denial of the relevance of philosophy is no refuge. Science is natural philosophy.
Materialists, left with the choice of denying materialism or denying the reality of subjective mental experience, deny subjective mental experience. There is no fanaticism like materialist fanaticism.

Michael Egnor

Senior Fellow, Center for Natural & Artificial Intelligence
Michael R. Egnor, MD, is a Professor of Neurosurgery and Pediatrics at State University of New York, Stony Brook, has served as the Director of Pediatric Neurosurgery, and award-winning brain surgeon. He was named one of New York’s best doctors by the New York Magazine in 2005. He received his medical education at Columbia University College of Physicians and Surgeons and completed his residency at Jackson Memorial Hospital. His research on hydrocephalus has been published in journals including Journal of Neurosurgery, Pediatrics, and Cerebrospinal Fluid Research. He is on the Scientific Advisory Board of the Hydrocephalus Association in the United States and has lectured extensively throughout the United States and Europe.