The Mind and the Brain (37 page)

Applying quantum theory to the brain means recognizing that the behaviors of atoms and subatomic particles that constitute the brain, in particular the behavior of ions whose movements create electrical signals along axons and of neurotransmitters that are released into synapses, are all described by Schródinger wave equations. Thanks to superpositions of possibilities, calcium ions might or might not diffuse to sites that trigger the emptying of synaptic vesicles, and thus a drop of neurotransmitter might or might not be released. The result is a whole slew of quantum superpositions of possible brain events. When such superpositions describe whether a radioactive atom has disintegrated, we say that those superpositions of possibilities collapse into a single actuality at the moment we observe the state of that previously ambiguous atom. The resulting increment in the observer’s knowledge of the quantum system (the newly acquired knowledge that the atom has decayed or not) entails a collapse of the wave functions describing his brain. This point is key: once the brains of observers are included in the
quantum system, the wave function describing the state of the brain of any observer collapses to the form corresponding to his new knowledge. The quantum state of the brain must collapse when an observer experiences the outcome of a measurement. The collapse occurs in conjunction with the conscious act of experiencing the outcome of the observation. And it occurs in the brain of the observer—the observer who has learned something about the system.

What do we mean by collapsing the quantum state of the brain? Like the atom threatening Schrödinger’s cat, the entire brain of an observer can be described by a quantum state that represents all of the various possibilities of all of its material constituents. That brain state evolves deterministically until a conscious observation occurs. Just before an observation, both the observed quantum system (let’s stick with the radioactive atom) and the brain that observes it exist as a profusion of possible states. Think of each possible state as a branch on a tree. Each branch corresponds to some possible state of knowledge, or course of action. But when an observation registers in the mind of the observer, the branches are brutally pruned: only the branches compatible with the observer’s experience remain. If, say, the observation is that the sun is shining, then the associated physical event is the updating of the brain’s representation of the weather. Branches corresponding to “the sky is overcast” are chopped off. An increase in knowledge is accompanied by an associated reduction of the quantum state of the brain. And with that, the quantum brain changes, too.

Because the observer’s only freedom is the choice of which question to pose (Shall I look up at the sky?), it is here that the mind of the observer has a chance to affect the dynamics of the brain. An examination of the mathematics, Stapp argued, shows that “the conscious intentions of a human being [reflected in the choices he makes about what question to put to nature] can influence the activities of his brain…. Each conscious event picks out from the multitude
of…possibilities that comprise the quantum brain the subensem-ble that is compatible with the conscious experience.” The physical event reduces the state of the brain to that branch of it that is compatible with the particular experience or observation.

Each of the principal interpretations of quantum theory—hidden variables, many-worlds, the dynamical role of consciousness, von Neumann’s application of quantum rules to the brain—has its passionate partisans. For many physicists, unfortunately, which interpretation they subscribe to seems to be more a matter of intellectual fashion and personal taste than rigorous analysis. So is whether they bother with interpretation at all. Just as many neuroscientists are perfectly happy to sweep the question of consciousness under the rug and stick to something they can measure and manipulate—the brain—so a similar attitude prevails among physicists (though physicists may not be quite so oblivious as neuroscientists. “It is surprising,” Wigner dryly noted, “that biologists are more prone to succumb to the error of disregarding the obvious than are physicists”). Engineers who design or use transistors, which exploit quantum phenomena, rarely think about the ontological implications of quantum mechanics and whether the mind shapes reality; neither do high-energy physicists, as they work out the chain of reactions in a particle accelerator. For every hundred scientists who use quantum mechanics, applying the standard equations like recipes, probably no more than one ponders the philosophy of it. They don’t have to. You can do perfectly good physics if you just “shut up and calculate,” as the physicist Max Tegmark puts it. Physicists can safely continue to believe in classical epistemology and ontology, whether consciously or not, and stash the epistemology and ontology demanded by quantum mechanics in a rarely opened room of their mind like an ugly lamp exiled to Grandma’s attic. “The reason I went into physics was my fascination with the fundamental issues raised by quantum mechanics, but I quickly realized the subject was taboo,” recalls Tegmark.
“Real physicists just didn’t spend time on these questions, and you realize pretty quickly that you can’t get a job doing this. So what I would do is write quantum papers secretly, when no one knew what I was doing. When I was a grad student at Berkeley, I would make sure my adviser was far away from the printer when I printed them out.”

The reluctance of most physicists to face, let alone explore, the interpretation and philosophical implications of quantum mechanics has had an unfortunate consequence. Scientists in other fields, many of whom consider physics the most basic of all sciences and the one with whose tenets their own findings must accord (an attitude sometimes denigrated as “physics envy”), have remained, for the most part, painfully naïve about the revolutionary implications of quantum theory. For neuroscientists, this ignorance exacts a price: the view of reality demanded by quantum physics challenges the validity of the Cartesian separation of mind and material world, for in the quantum universe “there is no radical separation between mind and world.” As Wolfgang Pauli stated in a letter to Niels Bohr in 1955, “In quantum mechanics…an observation here and now changes in general the ‘state’ of the observed system…. I consider the unpredictable change of the state by a single observation…to be an abandonment of the idea of the isolation of the observer from the course of physical events outside himself.” This is the textbook position on quantum mechanics and the nature of reality: that the Cartesian separation of mind and matter into two intrinsically different “substances” is false.

Ignoring quantum physics thus deprives both philosophers and neuroscientists of an avenue into, if not a way out of, the mystery of mind’s relationship to matter. The unfortunate result, as we’re seeing, is the belief that interactions among large assemblies of neurons are causally sufficient to account for every aspect of mind. As the philosopher Daniel Dennett put it, “A brain was always going to do what it was caused to do by local mechanical disturbances.” In this view, mind is indeed nothing more than billions of interact
ing neurons—in short, nothing more than brain processes. There is no power we ascribe to mind—even what we experience as the power to choose, to exert the will in a way that has measurable consequences—that is not completely accounted for by electrochemistry. Most attempts to resolve the mind-matter problem, derived as they are from a Newtonian worldview, dismiss both consciousness and will as illusions, products of human fallibility or hubris. And yet such conclusions, built as they are on an outdated theory of the physical world, are built on a foundation of sand. The classical formulations are wrong “at the crucial point of the role of human consciousness in the dynamics of human brains,” Stapp argues. If the mind-brain problem has resisted resolution for three centuries, it is because the physical theory that scientists and philosophers have wielded is fundamentally incorrect. If we are foundering in our attempts to resolve the mind-matter problem, the fault lies with the physics more than with the philosophy or the neuroscience. In other words, we are not doing all that badly in our efforts to understand the mind side of the equation; it’s our understanding of the role of matter that is seriously off. For this, we can thank the materialist view that grew to predominance over the last three centuries.

The more I talked with Stapp throughout the summer of 1998, the more I became convinced that quantum physics would provide the underpinning for the nascent idea of mental force. The fact that the collapse of the wave function so elegantly allows an active role for consciousness—which is required for an intuitively meaningful understanding of the effects of effort on brain function—is itself strong support for using a collapse-based interpretation in any scientific analysis of mental influences on brain action. In my discussions with Stapp, it became clear that a genuine scientific synergy was possible. It would not be just my OCD patients and their PET scans, or any other data from neuroscience alone, that would drive the final nail in the coffin of materialism. It would be the integration of those data with physics. If there is to be a resolution to the mystery of how mind relates to matter, it will emerge from explaining
the data of the human brain in terms of these laws—laws capable of giving rise to a very different view of the causal efficacy of human consciousness. Quantum mechanics makes it feasible to describe a mind capable of exerting effects that neurons alone cannot.

Historically, the great advances in physics have occurred when scientists united two seemingly disparate entities into a coherent, logical whole. Newton connected celestial motions with terrestrial motion. Maxwell unified light and electromagnetism. Einstein did it for space and time. Quantum theory makes exactly this kind of connection, between the objective physical world and subjective experiences. It thus offers a way out of the morass that the mind-brain debate has become, because it departs most profoundly from classical physics at a crucial point: on the nature of the dynamical interplay between minds and physical states, between physical states and consciousness. It ushers the observer into the dynamics of the system in a powerful way. Following quantum theory into the thicket of the mind-matter problem actually leads to a clearing, to a theory of mind and brain that accords quite well with our intuitive sense of how our mind works. In Stapp’s formulation, quantum theory creates a causal opening for the mind, a point of entry by which mind can affect matter, a mechanism by which mind can shape brain. That opening arises because quantum theory allows intention, and attention, to exert real, physical effects on the brain, as we will now explore.

Attending the Tucson III conference, “Toward a Science of Consciousness,” in April 1998 was both a great learning experience and a lot of fun. Dave Chalmers had encouraged me to present a talk on how my OCD work provided evidence for the power of the mind over the physical stuff of the brain. That alone would have made the meeting worthwhile, but the gathering also turned out to be a great place to make friends and (at least to some degree) influence people. At the very first session, I attended a presentation that immediately made me realize I wasn’t alone in denying that the mind is a mere appendage of the brain. The paper was by someone who was about to have a significant impact on my life: Jonathan Shear. A professor of philosophy at Virginia Commonwealth University and managing editor of the
Journal of Consciousness Stud
ies
, Shear is also a serious student (and practitioner) of Transcendental Meditation. He was an early adopter, as they say in the world of technology: by 1963 he was already deeply involved in the study of where meditation meets science, and he knew about the maharishi before he was The Maharishi (that is, before the Beatles worked with him in India). Fittingly, Shear’s talk was on Eastern philosophies and their views of consciousness—and he attracted quite a crowd.

The next day Shear and I ran into each other outside one of the meeting rooms and started talking. We quickly realized we had important interests in common, especially the use of meditation to investigate consciousness. After about fifteen minutes, we slipped out for a long lunch at the hotel restaurant. There, over the buffet (he seemed relieved that I wasn’t one of those “tofu-and-veggies-ordie” meditators), Shear peppered me with questions about Buddhism. My answers were long and technical, and so were his replies. We vowed to keep in touch, and after returning to Virginia, Shear asked whether I might contribute a long theoretical article to a single-topic issue being planned by the
Journal of Consciousness Studies
(
JCS
) to be called “The Volitional Brain.” The guest editor would be the renowned neurophysiologist Benjamin Libet of the University of California, San Francisco. I was eager to take it on, since it offered a chance to develop further my ideas on the philosophical implications of the OCD work.

On May 31, 1998, I sent Shear the abstract of the paper I had presented the month before in Tucson. In it, as I’ve mentioned, I first used the term
mental force
in a scientific sense, as I explored the importance of volition to my OCD patients in changing their neural activity. As my title posed the question, “A Causal Role for Consciousness in the Brain?” I described how PET studies of patients with obsessive-compulsive disorder had demonstrated systematic alterations in cerebral activity in those who were successfully treated with a drug-free cognitive-behavioral therapy. I outlined the Four Step method and explained how it teaches patients
to regard the intrusion of OCD symptoms into consciousness as the manifestation of a “false brain message,” training them to willfully select alternative actions when experiencing obsessions and compulsions. Although such willful behavioral change is difficult, I went on, it both relieves OCD symptoms and brings about systematic changes in metabolic activity in the OCD circuit. It turns out that the key predictor of whether the Four Steps will help an OCD patient is whether he learns to recognize that a pathological urge to perform a compulsive behavior reflects a faulty brain message—in other words, to Revalue it.

This work seemed appropriate for an issue on the volitional brain because it flew in the face of the widespread notion, dating back to at least the time of Descartes, that mind is incapable of acting on and changing matter. As noted in Chapter 1, this philosophical position, known nowadays as
epiphenomenalism
, views conscious experience as nothing more special than the result of physical activity in the brain, as rain is the result of air pressure, wind, and cloud conditions in the atmosphere. Epiphenomenalism is a perfectly respectable, mainstream neurobiological stance. But it denies that the awareness of a conscious experience can alter the physical brain activity that gives rise to it. As a result, it seemed to me, epiphenomenalism fails woefully to account for the results I was getting: namely, that a change in the valuation a person ascribes to a bunch of those electrochemical signals can not only alter them in the moment but lead to such enduring changes in cerebral metabolic activity that the brain’s circuits are essentially remodeled. That, of course, is what PET scans of OCD patients showed.

On June 3, Shear responded to the abstract I had sent him. Two of the
JCS
editors he had shown it to, he said, had reacted “quite positively.” One of them, Keith Sutherland, answered Shear’s query about whether to include something along those lines in the
JCS
volume with a succinct “Yes—go for it!” Sutherland remembered an article on my work that appeared in
New Scientist
, a pop
ular British science weekly, the previous summer, and asked, “Does he touch on any similarities between cognitive therapy and Buddhist practice?” This was the first time a fellow scientist had independently suggested tying the OCD results, and implicitly my Four Step therapy, to Buddhist philosophy and meditation. Another editor, Bob Forman, called it “a counter punch, long overdue, to the meaning-ignoring epiphenomenalist types.”

Working that summer to refine my theory of mental force, I spent many long nights sweating bullets over the paper. I also spent hours discussing the details with Stapp, who, as it happened, had also been invited to contribute a paper to the
JCS
issue. As soon as I learned this, it struck me that this would be a great opportunity to integrate the OCD work with Stapp’s interpretation of quantum mechanics to create something like a grand synthesis. He and I discussed the possibility of writing back-to-back papers and decided to give it a shot. So one Sunday in late July, when I had to be in Berkeley for the opening of a film a friend had just produced, I drove up early that morning and took the opportunity to visit Stapp at home. Sitting beside the pool in his backyard, with its breathtaking view of San Francisco Bay, we started talking about quantum physics, and how the philosophy that it supports seems quite Jamesian in implying that the willful expression of consciousness has causal efficacy in the material realm. What struck us both was how close William James had come to formulating a persuasive, scientifically based theory of how attention reifies intention. He lacked only a mechanism, but that was because only quantum physics, and not the classical physics of his day, provided one. We talked, too, about how both quantum physics and classical Buddhism give volition and choice a central role in the workings of the cosmos. For quantum physics, until and unless a choice is made about what aspect of nature to investigate, nothing definite occurs; the superposition of possibilities described by the Schrödinger wave equation never collapses into a single actuality, as discussed in the previous chapter. As Stapp puts it, “For the quantum process
to operate, a question must be addressed to Nature.” Formulating that question requires a choice about which aspect of nature is to be probed, about what sort of information one wishes to know. Critically, in quantum physics, this choice is free: in other words, no physical law prescribes which facet of nature is to be observed. The situation in Buddhist philosophy is quite analogous. Volition, or Karma, is the force that provides the causal efficacy that keeps the cosmos running. According to the Buddha’s timeless law of Dependent Origination, it is because of volition that consciousness keeps arising throughout endless world cycles. And it is certainly true that in Buddhist philosophy one’s choice is not determined by anything in the physical, material world. Volition is, instead, determined by such ineffable qualia as the state of one’s mind and the quality of one’s attention: wise or unwise, mindful or unmindful. So in both quantum physics and Buddhist philosophy, volition plays a special, unique role.

In neuroscience, on the other hand, to take an interest in the role of volition and the mental effort behind it, and further to wonder whether volition plays a critical role in brain function, is virtually unheard of. Piles of brain imaging studies have shown that volitional processes are associated with increases in energy use in the frontal lobes: “right here,” you can say while pointing to the bright spots on the PET scan, volition originates. But the research is mute on the chicken-and-egg question of what’s causing what. Does activity in the frontal lobes cause volition, or does volition trigger activity in the frontal lobes? If the former, does the activity occur unbidden, as a mere mechanical resultant, or is it in any sense free? Generally, neuroscientists assume that the brain causes everything in the mind, period—further inquiry into causality is most unwelcome.

In the final version of my “Volitional Brain” paper, I was trying to do better than this glib dismissal. The feel of OCD symptoms and the feeling of mental effort that accompanies the Four Steps make this disease and its treatment a perfect fit for a volume exam
ining phenomena at the nexus of mind and brain, I argued to Stapp on that summer morning. The intrusive thoughts that plague patients feel like extraneous intrusions into consciousness, as if they were invaders from another brain. Experiencing OCD symptoms is a purely passive process. In contrast, Relabeling the OCD symptoms and Refocusing attention on healthy circuitry are wholly active processes. The difference between the two “feels” makes genuine choice and the causal efficacy of that choice possible. Going further, I argued that the undeniable role of effort and the possibility of an associated mental force to explain the observed changes in the OCD circuit suggest a mechanism by which the mind might affect—indeed, in a very real sense, reclaim—the brain. That mechanism would allow volition to be real and causally efficacious, not the “user illusion” that determinists call it; it would allow volition to act on the material brain by means of an active and purposeful choice about how to react to the conscious experience of OCD symptoms. As I laid all this out, Stapp expressed confidence that it was all consistent with quantum physics.

The mechanism that allows volition to be physically efficacious is the one I called mental force. Similarly to what has been called “mind as a force field,” mental force also echoes what Ben Libet, a pioneer in the study of the neurobiology of volition, has named the “conscious mental field.” I proposed in the final version of my
JCS
paper that mental force is a physical force generated by mental effort. It is the physical expression of will. And it is physically efficacious. At the moment an OCD patient actively changes how he responds to the obsessive thoughts and compulsions that besiege him, the volitional effort and refocusing of attention away from the passively experienced symptoms of OCD and toward alternative thoughts and behaviors generate mental force. Mental force acts on the physical brain by amplifying the newly emerging brain circuitry responsible for healthy behavior and quieting the OCD circuit. We know that directed mental effort causes measurable changes in brain function, the self-directed neuroplasticity dis
cussed earlier. And we know that mental effort is not reducible to brain action: hence the need for a new actor—mental force.

This notion of mental force fit an idea about free will that Libet had long propounded, one known as the “free won’t” version of volition. In a nutshell, “free won’t” refers to the mind’s veto power over brain-generated urges—exactly what happens when OCD patients follow the Four Steps. Since Libet served as a guest editor for the
JCS
volume, it didn’t hurt that I was able to acknowledge my intellectual debt to him. But it was hardly a stretch to make the connection to his work: OCD symptoms can be viewed as high-powered, painfully persistent versions of the desultory mental events that pop into consciousness countless times each day. Most of these thoughts do not insist on action, or demand attention, because the will can ignore them rather easily, Libet had argued. But in OCD patients the thoughts aren’t nearly this well mannered: they are as insistent and intrusive as a nagging toddler. The discomfort they cause demands attention. Making that attention mindful and wise requires effort of the highest degree. That effort, I suspected, becomes causally efficacious on brain action through the mechanism of mental force. At the 1999 Quantum Brain conference in Flagstaff, I had discussed this possibility with Libet, and now it became part of my argument.

The fact that willful refocusing of attention caused brain changes in patients with OCD had exciting implications for the physics of mind-brain. “Ideas that I had long been working on, but which seemed to have no practical application, tied in very well with Jeff’s discovery of the power of mental effort to keep attention focused,” Stapp recalled. “That gave me the impetus to pursue this.” In his own
JCS
paper, Stapp argued that neither scientists nor philosophers who adhered to the ideas of classical Newtonian physics would ever resolve the mind-brain mystery until they acknowledged that their underlying model of the physical world was fundamentally flawed. For three centuries classical physics has proved incapable of resolving the mind-body problem, Stapp
noted. And although quantum physics supplanted classical physics a century ago, the implications of the quantum revolution have yet to penetrate biology and, in particular, neuroscience. And that’s a problem, for the key difference between classical and quantum physics is the connection they make between physical states and consciousness. Quantum theory “allows for mind—pure conscious experience—to interact with the ‘physical’ aspect of nature…. [I]t is [therefore] completely in line with contemporary science to hold our thoughts to be causally efficacious,” Stapp argued. He ended his
JCS
paper with a discussion of my OCD therapy, calling it “in line with the quantum-mechanical understanding of mind-brain dynamics.” According to that understanding, mental events influence brain activity through effort and intentions that in turn affect attention. “The presumption about the mind-brain that is the basis of Schwartz’s successful clinical treatment,” Stapp concluded, “is that willful redirection of attention is efficacious. His success constitute[s] prima facie evidence” that “will is efficacious.”