April 29, 1997

Consciousness Studies: From Stream to Flood


NEW YORK -- At a small restaurant on West 70th Street in Manhattan, Dr. Piet Hut, an astrophysicist at the Institute for Advanced Studies in Princeton, N.J., has pushed aside his French toast to draw a quick sketch of objective and subjective reality. His drawing, on a yellow pad, shows a stick figure, a chair, the stick figure's experience of the chair, the stick figure's experience of itself and the stick figure's understanding of its experience of the chair and itself.

This is not an unusual moment in the current state of the scientific study of consciousness. Everybody from neuroscientists to philosophers to physicists is in the game. And the arena of investigation ranges from high-tech brain imaging centers to breakfast brainstorms, from monkey experiments to thought experiments.

The debate is still open as to whether the problem of consciousness -- how felt experience is connected to the physical brain -- is purely philosophical, an illusory difficulty that will be swept away by progress in neuroscience, or one that requires a revamping of all of science, starting with physics, which is what Hut is suggesting.

Whatever the approach, the stream of consciousness studies, rising for more than a decade, seems to be reaching flood stage. Dr. Daniel Dennett, a philosopher and director of the Center for Cognitive Studies at Tufts University, was asked by The Quarterly Review of Biology to review some recent books on the subject. He counted 34 in the last six years, "not including the awful ones, or those by journalists" (or those by Dennett himself), and decided there were just too many. He put the project off.

Two scientific journals on consciousness have been started in recent years. A 1995 Massachusetts Institute of Technology Press book, a 1,447-page compilation of articles titled "The Cognitive Neurosciences," is in its fourth printing and has sold 9,000 copies. The book weighs eight pounds and costs $95. This spring and summer there are major conferences on consciousness in Montreal and California. "The scientific race for consciousness is on," writes Bernard Baars, a psychologist at the Wright Institute in Berkeley, Calif., in one of those new books, "The Theater of Consciousness" (Oxford University Press). If it is a race, it is an unconventional one in which neither the starting line nor the finish have been agreed on. The arguments are not only over answers to questions, they are over what the questions should be, and what the terms of the discussion mean. Neuroscientists, psychologists and philosophers, along with the odd physicists and anesthesiologist all have opinions and a stake in finding out what exactly goes on in that elusive, internal space where a person thinks, feels and wonders about everything from what kind of pizza to order for dinner to what exactly it means to "wonder."

The result is a field, or rather an effort to create a field, which is "boiling" with activity, says Dennett, the author of several books on consciousness, including the recent "Kinds of Minds" (Basic Books) and one of the main figures in debates about the mind. The intensity of current interest is "almost ridiculous," he said. And the disagreements are so large that the pursuers of consciousness sometimes dismiss each other with a wave of the hand.

David Chalmers, a philosopher at the University of California at Santa Cruz, and author of another new book, "The Conscious Mind: In Search of a Fundamental Theory" (Oxford University Press), says the situation reminds him of "physics 500 years before Newton" at a point when the intellectual vocabulary was not available to talk about things like gravity. Of course, even on that point there is disagreement. Baars says the situation is now like that right at the time of Newton, when gravity was beginning to be isolated and understood.

The players do agree that they disagree. Dr. John Searle, a philosopher at the University of California at Berkeley, who panned Chalmers's new book recently in The New York Review of Books, a traditional jousting ground for academics, said that in the attempt to study how the physical brain and conscious mind are related, "there's no unifying principle," adding, "We're just thrashing around in the dark."

Dr. Michael Gazzaniga, a neuroscientist who started Dartmouth College's Program in Cognitive Neuroscience, said the most outrageous ideas were now reasonably discussed (he mentioned some offered by physicists), and suggested, "The reason they can get away with it is that nobody has a clue."

And among those physicists who have decided to join the fray, both Dr. Roger Penrose at Oxford and Hut say that all of science needs to be shaken up. Of course, they differ slightly in how it should be shaken up, but they both agree that modern science, as constituted, is not prepared to grapple with the conscious mind.

There are two levels of problems being solved in the pursuit of consciousness. On one level, where there is much less sound and fury, the wiring of the brain is being studied, the activity of the brain is being glimpsed in new kinds of imaging techniques and experiments are being done on animals to separate conscious from unconscious activity in the brain.

Scans of the brain, for instance, enable scientists to watch people talk to themselves, silently. Both the center for control of vocal activity and the center for analyzing speech are active while the subject says, silently, something like: "Why am I getting my brain scanned? I could be getting my hair done. What if they don't see anything happening?"

No one doubts that over the next 10 or 20 years, a much clearer picture will emerge of what happens in the brain when people, and presumably animals, have conscious experiences. But that still leaves the old, big questions that have troubled philosophers and undergraduates since there have been philosophers and undergraduates, questions like: When you talk to yourself, who talks and who listens?

And on this level, whether there is a difference between mental experience and brain activity, for instance, disagreements are dismayingly large, and on occasion blunt beyond the normal bounds of scientific discourse. In an interview, Searle said that Dennett and Chalmers were both making the "same dumb mistake" in assuming that the terms of this question were valid. (They come up with different answers; Chalmers finds a distinction and Dennett does not.) And although his physics is respected and his books attract popular attention, almost everyone else who has a stake in consciousness dismisses Penrose out of hand. Steven Pinker at MIT, who has a much anticipated book coming out this fall from W.W. Norton, "How the Mind Works," says, "Penrose is not even in the ball park."

Penrose, on the other hand, can dismiss most of what passes for activity in neuroscience as hopeless. His contention is that something other than the computer model must be used. And he says, "The trouble with John Searle is, I don't think, although I've talked to him quite a bit, I never felt that he really grasped what a noncomputational system is. I don't think he's really got that on board yet."

Sometimes it seems like a free-for-all. Dennett said in an interview, chuckling, that "one of the really refreshing discoveries of the last few years was the advent of physics getting into the act," because it proved that "there's a discipline that is even more ignorant about the brain and even more arrogant than philosophy."

Among the several positions held about consciousness and the self, Dennett and many others believe consciousness is simply what the brain does, a process, like life or growth, not a great philosophical problem. Gazzaniga believes that it is indeed something the brain does, but he offers a location for the self, an "interpreter module" in the left cerebral cortex. Some philosophers say the whole notion that activity in the brain can account for subjective experience is naive and unacceptable.

The headier discussions are worrisome to some more traditional neuroscientists. Dr. Francis Crick, who won the Nobel Prize for his discovery with Dr. James Watson of the structure of DNA, has attracted many neuroscientists to the field with his forays into the subject of the mind. But he said at a recent talk that he wished journalists would stop writing about consciousness.

Dr. Christof Koch, a neuroscientist at the California Institute of Technology, said the interest in consciousness "might be too much of a good thing." He and others say that there is essentially no progress on the more difficult philosophical problems of self-awareness, and that the concentration should be in hard experimental studies on subjects like visual perception.

"We're going to be called to the table in 5 or 10 years," said Koch, and the current fascination with the mind could well fade, as it has in the past, and research support with it. Chalmers said, "If the results aren't delivered in a few years someone might say, well, there was this consciousness craze in the 1990's and look what came of it."

If all goes well, said Chalmers, himself a philosopher, scientific interest in consciousness will continue to increase, and the problem will move further and further away from philosophy as it gets closer to being solved.

Chalmers remarked, "I'd hate for it to go the other way."

Copyright 1997 The New York Times Company