April 16, 1996

Arizona Conference Grapples With Mysteries of Human Consciousness

By SANDRA BLAKESLEE

UCSON, Ariz. -- Like the proverbial blind men trying to identify by sense of touch a large, thick-hided animal with a trunk at one end and a tail at the other, some of the world's top scientists, philosophers and far-out thinkers gathered here last week to contribute their different perspectives on the elephant of consciousness.

A good time was had by all, even when the fur -- or maybe it was elephant hide -- began to fly.

Can machines be conscious? The question elicited a spirited debate between those who said, Of course, it's just a matter of time and clever engineering, and others who replied: Never! It's bad enough that you think consciousness can arise from gray lumps of tissue. It is inconceivable that sentience could ever emerge from wholly insentient matter.

Then there were less contentious questions. Does free will exist? Can consciousness exist without emotions? Are animals conscious? What happens to your conscious mind when you fall into a deep sleep?

And the most debated question of all: is consciousness something very special and unique or is it just the natural byproduct of a complex brain, emerging like wind from intricate weather patterns?

The conference, "Toward a Science of Consciousness," was sponsored by the University of Arizona with support from the Fetzer Institute and the Institute of Noetic Sciences, two organizations dedicated to exploring the metaphysical foundations of Western science. A similar but smaller conference was held two years ago in Tucson.

"We were deliberately eclectic in choosing speakers," said Dr. Stuart Hameroff, an anesthesiologist at the Arizona Health Sciences Center who was a principal organizer of the event. Experts in various disciplines can always talk among themselves, he said, "but there needs to be an arena where everyone can mix their ideas about consciousness together."

Thus the conference drew neuroscientists, philosophers, mathematicians, computer scientists, physicists, dream researchers, pharmacologists, doctors, ethnologists, psychologists, parapsychologists, scholars of religion and a variety of prophets who claim to have solved the mystery of consciousness.

The meeting was unusual from the start. Dr. Jaron Lanier, a computer scientist from Columbia University who is a pioneer in virtual reality, opened the plenary session on Monday by playing a brief piano recital. His blond dredlocks flew apace with the music. The audience was delighted.

The goal of the meeting was simple, Hameroff said. What is the nature of consciousness? Can we hope to understand it scientifically?

It is remarkable that such a diverse gathering could discuss the question of consciousness in a coherent manner. But this kind of cross pollination of ideas, where everything goes, is exactly what is needed, said Dr. Christof Koch, a neuroscientist at the California Institute of Technology who helped organize the event. One hundred years ago, people could not understand how life could arise out of mere chemicals, he said. But when DNA was explained, theories of vitalism -- that a magical force was needed to explain life -- disappeared.

The study of consciousness is like the study of physics before Newton, said Dr. Piet Hut, a theoretical physicist at the Institute for Advanced Studies in Princeton, N.J. In fact, he said, if people had organized a conference about physics in the Middle Ages, they would have dismissed Copernicus and Galileo as crackpots. "We shouldn't make that mistake today," Hut said.

But before progress can be made on the question, some definitions are in order. Consciousness has many guises.

In Tucson, the tone of discourse was set by a young philosopher from the University of California at Santa Cruz, Dr. David Chalmers. He is widely credited for posing the so-called hard problem of consciousness.

To explain this concept, Chalmers first described the so-called easy problems of consciousness, the sorts of questions being tackled in neuroscience laboratories around the world: How does sensory information get integrated in the brain? How do we see and reach out for an object? How are we able to verbalize our internal states and report what we are doing or feeling?

"These problems are not trivial," Chalmers said. "They may take 100 years or more to solve, but progress is being made."

The hard problem is this: What is the nature of subjective experience? Why do we have vividly felt experiences of the world? Why is there someone home inside our heads?

Thus far, nothing in physics or chemistry or biology can explain these subjective feelings, Chalmers said. "What really happens when you see the deep red of a sunset or hear the haunting sound of a distant oboe, feel the agony of intense pain, the sparkle of happiness or meditative quality of a moment lost in thought?" he asked. "It is these phenomena, often called qualia, that pose the deep mystery of consciousness."

In Tucson, people mounted four responses to the hard problem: it doesn't exist, it will be answered soon enough by conventional science, there must be something else in the universe that we do not yet understand, and hey guys, forget it, we can never understand consciousness.

Dr. Daniel Dennett, a philosopher at Tufts University, is a forceful proponent of the idea that consciousness is no big deal. "It's like fame," Dennett said. "It doesn't exist except in the eye of the beholder." When does fame happen, he asked? Is it when 10 people know your name? A hundred people? A thousand?

Scientists have shown that information coming into the brain is broken down into separate processing streams, Dennett said. But no one has yet found any "place" where all the information comes together, presenting a whole picture of what is being felt or seen or experienced. The temptation, he said, is to believe that the information is transduced by consciousness. But it is entirely possible that the brain's networks can assume all the roles of an inner boss. Mental contents become conscious by winning a competition against other mental contents, Dennett said. No more is needed. Consciousness is an epiphenomenon.

A second group of scientists agreed with Dennett but took a softer line. When all the "easy" problems are solved, the hard problem will disappear -- but consciousness certainly exists. "It's silly to deny it," said Dr. Pat Churchland, a philosopher at the University of California at San Diego.

Awareness and subjectivity are network effects involving many millions of nerve cells in the cortex and thalamus, Dr. Churchland said. And while the exact nature of the phenomenon cannot yet be explained, the call for a "new physics" or some mysterious forces in nature are not needed.

Dr. Rodolfo Llinas, a neuroscientist at New York University, agreed, suggesting that timing effects inside the brain produce conscious experience.

Those who believe machines can someday be conscious tended to fall into this camp. The trick will be to make computers that are sufficiently complex, said Dr. Danny Hillis, vice president of research and development at Walt Disney Imagineering in Glendale, Calif. Then, like human brains, they should give rise to the emergent properties of consciousness.

Others tried to answer a few of the easy questions. Dr. Allan Hobson, a sleep expert at Harvard Medical School, described a neurobiological theory of dreaming. It does not explain where consciousness "goes" when people are asleep, he said, but finds that different chemical states in the brain seem to produce different sorts of consciousness.

The next major group of consciousness seekers might be called modern dualists. Agreeing with the hard problem, they feel that something else is needed to explain people's subjective experiences. And they have lots of ideas about what this might be.

According to Chalmers, scientists need to come up with new fundamental laws of nature. Physicists postulate that certain properties -- gravity, space-time, electromagnetism -- are basic to any understanding of the universe, he said.

"My approach is to think of conscious experience itself as a fundamental property of the universe," he said. Thus the world has two kinds of information, one physical, one experiential. The challenge is to make theoretical connections between physical processes and conscious experience, Chalmers said.

Another form of dualism involves the mysteries of quantum mechanics. Dr. Roger Penrose from the University of Oxford in England argued that consciousness is the link between the quantum world, in which a single object can exist in two places at the same time, and the so-called classical world of familiar objects where this cannot happen.

Moreover, with Hameroff, he has proposed a theory that the switch from quantum to classical states occurs inside certain proteins call microtubules. The brain's microtubules, they argue, are ideally situated to perform this transformation, producing "occasions of experience" that with the flow of time give rise to stream of consciousness thought.

The notion came under vigorous attack. "Pixie dust in the synapses is about as explanatorily powerful as quantum mechanics in the microtubles," Churchland said. Their logic is, consciousness is deeply mysterious, quantum mechanics is deeply mysterious, ergo the two are the same mystery, she said.

Penrose's ideas are popular, Churchland said, because many people have dualist hankerings. They want to believe in a soul, life after death and the specialness of humans and their inner thoughts. They have a negative gut reaction to the idea that neurons -- cells that can be probed under a microscope -- are the source of the "me-ness of me," she said.

Finally, there are those who argued that people can never understand consciousness. The mystery is too deep. Dr. Colin McGinn, a philosopher from Rutgers University, said that for humans to grasp how subjective experience arises from matter "is like slugs trying to do Freudian psychoanalysis -- they just don't have the conceptual equipment."

But this did not deter many from trying. During the week, presentations were made on animal consciousness (featuring apes, dolphins and gray parrots), free will and the spiritual nature of consciousness.

Dr. Robert Forman, a professor of religion at Hunter College in New York, said mystical experience had something to tell people about consciousness. "To understand genes," he said, "we look at bacteria like E. coli. To study memory, we analyze the memory of a sea slug. But to probe consciousness, we need to examine the experience of mystics, who experience their own consciousness in its simplest form."

Millions of people regard these types of experiences, feeling a oneness with the universe, as the highest experience that the conscious brain has to offer, Forman said.