Duke University Alumni Magazine

he fleshy half-brain floats languidly in a sealed plastic box. Its pale, corrugated mass slashes gently back and forth in the clear liquid as neurobiologist Gillian Einstein holds it aloft before two dozen attentive students. At one time, the inert object of their scrutiny harbored a living human consciousness -- one that loved, feared, and contemplated its own death. But now, cleaved to show its labyrinthine interior, the half-brain serves only as a teaching guide to illustrate the brain's intricate structures.

     The half-brain has found its useful employment in an unusual interdisciplinary senior course, "Mind and Brain," taught by Einstein and her colleague, philosopher Owen Flanagan. Designed to be a culminating intellectual experience of the students' years at Duke, the course spans the intellectual landscape of mind and brain studies -- including lectures on vision, memory, emotions, sex, dreams, and language.

     But the course also offers the students les- sons about another critically important conceptual geography -- that of collaboration among disciplines. They learn not only how the brain's tangle of wire-like neurons signal one another with explosive bursts of chemical neurotransmitters, but they also come to understand lecting machine that makes some kind of decision about information. I think about it in a shorthand way -- perhaps a little too simply -- as a fundamental unit of mind."

     What's more, the conglomeration of such "units of mind" into the cerebral cortex might be called "the organ of the mind," says Einstein,"because people who have portions of it removed seem to lose certain aspects of mind." She notes that if a pinched artery starves a cortical region, called the temporal lobe, of oxygen, the person loses language function. And if a nearby region is similarly oxygen-starved, the person loses the ability to recognize faces.

     After Einstein's anatomy lesson, Flanagan rises to voice the great puzzlement of the philosopher facing the hard physical reality of the brain. "Jill talks about all this stuff, this soggy gray stuff, or pink stuff It has blood going through it, all kind of ventricles. There's electricity, there are chemicals. How the heck does all that taken together account for the rich, subjective mental life a person has! You might say to yourself, 'Holy mackerel, after she starts to tell this story about the brain and neurochemicals and all that kind of stuff, then what role is there any longer for what I users to think I have -- namely this free will, say, to raise my left arm or right arm as I wish to?' "

     Then there's the problem of how the ghostly phenomenon of human consciousness could arise from a brain that is but a tangle at living wires. Flanagan tells the students, "We know you can knock out the visual areas or the linguistic areas, modality by modality in the brain. But when do you get to knock out consciousness? And the answer seems to me is when people are dead. That's the only clear case where there's no consciousness left."

     Even though consciousness is a terrifically slippery concept, it hasn't stopped philosophers from trying to wrestle with it, Flanagan says. "The traditional view [of consciousness] is what's called Cartesian dualism...that the body and the mind are in some sense distinct, and that the mind can rule the body. And that the mind is not completely reducible to a physical system." Still other philosophers treat consciousness as an "epiphenomenon," a side-effect, "the way the sizzling of the frying pan is a side effect when you're frying eggs -- not interestingly involved in the overall thing that's happening as you're frying up the eggs," Flanagan says. Such thinkers hold that the brain does, indeed, give risc to consciousness, "but that the consciousness itself doesn't do anything interesting. It's just a side effect, the way the toot of a steam engine is a noise that the steam engine gives off, but it doesn't affect the steam engine very much."

     There's also the "parallelism" theory of con- sciousness, in which mental states are correlated with brain state -- the way rain is correlated with wet earth -- but are iwt equivalent to brain states. "When Shakespeare decides to write Hamlet, something distinctive happens to his brain. But tlat. 'decision' to write Hamlet is not some event in Shakespeare's brain -- the decision is an event in Shakespeare's mental or spiritual life."

     Then there is "identity theory," explains Flanagan, "Just as we discovered that salt is NaCl and water is H₂O, so too we should expect neuroscience to reveal that such things as the decision to write a play just is a complex neural event, nothing more, The mind is the brain!" Once Einstein and Flanagan finish their talks, they open the floor for a discussion about everything under the cerebral sun. The evening ends, with the students departing to contemplate how their own brains will cope with the course's challenging collaborative writing assignments.

     But besides teaching students, Einstein and Flanagan also teach each other. "I've been interested in the philosophical issues of what makes a person the same individual over time -- what makes a person's identity," says Flanagan. "Do we say somebody is the same person if their body remains the same? So, Jill taught me a huge amount about the nature of Alzheimer's disease, which is her research specialty. That disease clearly raises questions of identtity, as a person with the disease is 'no longer there.' And because Jill's a biologist, she showed me how to observe as a scientist such things as the way a person moves, to give clues to the nature of their identity, of what's going on physiologically."

     For Einstein, who studies how neurons atrophy in Alzheimer's disease,"It's very interesting for me to learn the perspective of a philosopher on identity itself. Owen's viewpoint makes it clear to me that there are aspects of self that are not affected by Alzheimer's disease. And to me as a neurobiologist, those aspects are represented by a population of neurons. As a scientist, I want to know what that population of neurons is, And I don't think I would have been thinking exactly that way if I hadn't been having these conversations with him."

     Einstein and Flanagan are perhaps unusual in that their broad backgrounds made them highly suited for reaching out to other disciplines. Einstein the neurobiologist began her college career as an art history major. "I've always been kind of a visually driven person. I've always been interested in composition and color and how things look, [the] visual and textures of things," she says. Oddly, it was an art course in Indian miniature paintings that started her on the road to neurobiology. "I was analyzing a painting that the Shahs would have painted, and I began wondering about how the composition really affects my physiology. How it really affects my brain." Sitting on the steps of a Harvard museum, she shared her frustration with a friend. "And she said, you know, there's this field called neurobiology." From that spark came Einstein's first interest in anatomy, which led to a doctorate in the field at the University of Pennsylvania, and on to a career in neurobiology, now as an assistant research professor in the Duke medical school's department of neurobiology.

     Flanagan, conversely, is a philosopher who began with a leaning toward science. "Right after the end of undergraduate school, I didn't know whether I'd go on to graduate work in experimental psychology or philosophy. It was a toss-up. I ended up in philosophy because I didn't like rats very much," he says, laughing. He earned his Ph.D. in philosophy at Boston University, ultimately joining the Duke faculty as professor and chairman of Trinity College's department of philosophy, Perhaps the most illuminating aspect of the Einstein-Flanagan collaboration is what it reveals about the nature of the disciplines themselves -- in particular, philosophy. Nobody would be surprised to learn that neurobiologists seek to understand how brain circuits spawn the mind. But many might be surprised to learn that philosophers do. To Flanagan, this surprise reflects a misapprehension of philosophy, which he emphasizes is no cloistered ivory-tower discipline. Rather, he says, philosophy reaches out to a broad range of human endeavor, including science. It was thus from the very beginning, he notes. "If one looks closely at the history of philosophy, at one time everything was philosophy. Aristotle remains one of the greatest philosophers, but he also did important work in biology, physics, political science, and logic. A sign over the entrance to Plato's academy said, 'Let no one who does not know geometry enter here.' So, there's always been this love affair that philosophy has with mathematics and the sciences. In fact, I've heard of philosophy called the queen of the disciplines -- maybe like the queen bee that gives rise to the special disciplines."

     To Flanagan, philosophy's mission in exploring such puzzles as the mind-brain prob- lem is to survey the broad reaches of neuroscience and psychology and attempt to create a theoretical structure. He first realized philosophy's unique role after he published his first book, The Science of Mind, while a professor at Wellesley. "I came to understand that if you took a science like physics or chemistry and went to different textbooks, you'd see close agreement on the theories behind them. But if you study psychology, you get ten different theories on how something works. That kind of debate over theories is usually a sign that there's something interesting for philosophers to do -- to get to the bottom of all the different assumptions and experiments."

     Philosophers are neatly positioned to help advance the theory of such contentious fields, he says. "Philosophy gives you the luxury of figuring out the intellectual landscape in an area, without having to do experiments within the constraints of a research program, or trying to get grants because you're convinced that this is the way to go." To aid such ecumenical explorations, Flanagan holds appointments not only in philosophy, but also in psychology and neurobiology. Similarly, he points out, many of his colleagues in the philosophy department hold joint appointments that signal productive links with other disciplines -- Robert Brandon with zoology, Greg Cooper with ecology, Lynn Joy with history, and Alastair MacIntyre with political science. Philosophers' engagement with science is wholehearted, says Flanagan. "You won't find the best philosophers shying away from reading scientific papers or working through difficult mathematics. As often as there is a story like mine -- where I almost went into psychology except for the rats -- many philosophers are people who were almost ready to become computer scientists or mathematicians." And the colleagues in other disciplines that philosophers reach out to welcome them as contributors. "Those of us doing this kind of work are being invited to all the scientific conferences. All the important books on consciousness were written by philosophers, with the exception of the one by Nobelist Francis Crick. Of course, there are those who see us basically as harmless people who get paid to spin out theories. But I think the dominant trend is for there to be lots of respect for philosophers doing this work."

     Flanagan recognizes the limits of his ability to understand neuroscience and the value of collaborations such as his with Einstein. "There's no way that I could remotely keep up with neuroscience in general. I need to trust certain people, such as Jill, to know 'who's on first' within neuroscience. You depend on the intellectual division of labor that has worked out in a reasonable way."

     Flanagan says philosophers can bring to brain studies benefits ranging from the semantic to the psychological. In his work with neurobiologists, he discovered that they tend to use words such as "determinism" and "reductionism" in ways that were misleading by a philosopher's standards. "When neuroscientists say something is not determined, they mean only that its laws are complicated, not that it can never be determined. And, when they talk about reductionism, they mean taking large objects and breaking them down into components." In contrast, philosophers define the word as the attempt to explain complex phenomena by relatively simple principles. Beyond semantics, Flanagan hopes he and his colleagues can offer reassurances to those who fear science's impact on our sense of self-worth. "I understand why people worry that the more we explain things scientifically, the less room there is for thinking of ourselves as creative, ethical makers of our own destiny. I want to explain that the scientific image is not an enemy of meaning for our lives." And Flanagan says he hopes his work on the nature of consciousness will help bring a necessary sense of optimism to the field, one that will help inspire continued efforts to understand consciousness.

     Such optimism arises primarily from his belief in a "naturalistic theory of consciousness." That is, he believes that the physical brain harbors consciousness, and that this three-pound mass of some 100 billion cells represents a crowning achievement of Darwinian evolution. In contrast, some philosp phers have theorized that consciousness is some nonnatural or supernatural phenomenon that may never be understood in natu- ralistic terms. Still others believe in the "new mysterianism" -- that consciousness is "terminally mysterious to our minds but possibly not to minds of greater intelligence," he explains in his book Consciousness Reconsidered. Then there are the "eliminativist naturalists," who believe that "consciousness is a concept that is simultaneously too simplistic, too vague, and too historically embedded in false and confused theory to...denote...phenomena in need of explanation." Flanagan emphasizes that he is a constructivist: "There are some people who say we will never understand how consciousness works. But given that there haven't yet been any scientific hurdles we've faced that haven't given way, I feel on grounds of induction that there's no reason in principle that we can't understand consciousness."

     He warns, however, that consciousness might be incredibly complex, with quite different theories needed to explain, say, dreaming consciousness or visual consciousness. Nevertheless, he insists, such multiple theories don't mean consciousness is inexplicable. "In physics, we need one theory for bodies moving at astronomically high velocities at Such optimism arises primarily from his belief in a "naturalistic theory of consciousness." That is, he believes that the physical brain harbors consciousness, and that this three-pound mass of some 100 billion cells represents a crowning achievement of Darwinian evolution. In contrast, some philosophers have theorized that consciousness is some nonnatural or supernatural phenomenon that may never be understood in natu- ralistic terms. Still others believe in the "new mysterianism" -- that consciousness is "terminally mysterious to our minds but possibly not to minds of greater intelligence," he explains in his book Consciousness Reconsidered. Then there are the "eliminativist naturalists," who believe that "consciousness is a concept that is simultaneously too simplistic, too vague, and too historically embedded in false and confused theory to...denote...phenomena in need of explanation."

     Flanagan emphasizes that he is a constructivist: "There are some people who say we will never understand how consciousness works. But given that there haven't yet been any scientific hurdles we've faced that haven't given way, I feel on grounds of induction that there's no reason in principle that we can't understand consciousness."

     He warns, however, that consciousness might be incredibly complex, with quite different theories needed to explain, say, dreaming consciousness or visual consciousness. Nevertheless, he insists, such multiple theories don't mean consciousness is inexplicable. "In physics, we need one theory for bodies moving at astronomically high velocities at great distances that are different from the kind of physics we use to get people to the moon, for example. And nobody says that theories of physics are invalid."

     And even though consciousness theories might not be comprehensive, they will still be useful, he insists. "There's a big difference between finding something satisfying and finding it satisfactory. Also, we have to understand that there's a difference between explanation and prediction. For example, we have theories that explain the weather very well, but we can't predict it because of the massive numbers of variables involved. Similarly, we want a good theory of how the brain works, not to predict it, but to help us especially in case of breakdowns. I want to know what's wrong with my brain if my right arm suddenly starts acting funny. But I don't want to predict what my right arm's going to do on a normal day-to-day basis."

     Neither Flanagan nor Einstein will pretend that their respective fields have come anywhere close to an ultimate understanding of the brain. Neurobiologists haven't yet decoded the brain's wiring strategies, nor have philosophers deduced how mind emerges from that wiring. But the two are certain that the kinds of collaborations theirs represents are the best chance for progressing toward an ultimate understanding of the most complex organ on Earth.