Mapping the millennium: Understanding consciousness

Consciousness - the undeniable presence, the centre of our being - has always been a puzzle to man. Scientists have been investigating the brain for more than a decade now, but all this research has only served to deepen the mystery. Marking the entry of the new millennium, GEORGE JOHNSON ponders on the patterns that fascinate us the most, the ones inside our heads in the land of the inner self.

I DON'T believe in ghosts. But standing inside the fallen stone walls of the ruins of Yapashi, I can almost feel the presence of the hundreds of souls who once inhabited this abandoned plateau. Their disappearance left the pueblo - isolated deep inside the Bandelier wilderness in northern New Mexico - one of the loneliest places on earth. About the only sound, other than wind blowing through ponderosa pines in the canyon below, is the ringing of blood rushing through the vessels in my eardrums, the buzzing of a brain contemplating the weird feeling of being alive.

Halfway through this millennium, Yapashi teemed with human life - a way station, archaeologists believe, for the Anasazi, ancestors of the Pueblo Indians who now live east of here along the Rio Grande. All around where I am walking, people once cooked rabbits, made pottery, danced to appease their invisible gods. Spirits seem to hover everywhere. Just beyond the edge of the pueblo, you can still see two stone mountain lions, crouching on the ground, symbols of an old religion in which everything - rocks, rivers, mountains, thunder and lightning - was aware and alive.

What were these people thinkings as they looked out at the distant mountains and up at the stars? What was it like to see the world through their eyes? These questions preoccupy me every time I take the six-mile hike to Yapashi, up and down the sides of the intervening canyons, across the pine-covered mesa tops. When I arrive, all that remains of the ancient ponderings are material clues, bits of inanimate matter carefully shaped by conscious minds.

Consciousness - the undeniable presence at the core of our being - may be more a mystery now than it was to the Yapashi. This year marks the end of what was grandiosely christened the Decade of the Brain. In the last 10 years, scientists have used new scanning techniques to see which parts of the brain light up when you listen to music, read a book or recall a buried memory. They have even uncovered neuronal circuits involved in mathematical computation. But all this has only served to deepen the mystery. The brain indeed appears to be a biological computer. So where in the neurological wiring is the source of consciousness? How does a three-pound glob of cerebral flesh exude thoughts and know that it is alive?

At the edge of a kiva, an underground ceremonial chamber whose rock walls collapsed long ago, I spot a broken shard of white- glazed pottery deliberately emblazoned with precise black lines. Turning it over with my fingers, I marvel at the pleasing geometric pattern. What made the potter decide to use this particular design? So little is known about the people of Yapashi or the meaning of their markings, but staring at the potsherd you immediately feel a sense of kinship, a connection across the centuries with a mind at play - the existence long ago of a contemplative individual. A self.

The potter's artistic inventiveness would seem, on the surface, to confer no real advantage in the Darwinian struggle for survival. Learning to make vessels to store food and carry water would give a tribe an edge in the game of life. But why expend the energy to decorate them? And what use was served by the spirals and zigzags the Anasazi carved into the sides of the volcanic cliffs throughout this region? What is it that drives us - both ancient artists and modern scientists - to dwell to intently on the abstract rhythms called patterns?

Turning my head eastward, I can barely see, on the horizon, a radio telescope pointing its white steel dish at the sky, a reminder that this isolated world is only a few miles from Los Alamos National Laboratory where cosmology and theoretical physics are now pursued as avidly as weapons research. From etching patterns on rocks, people have gone to contemplating patterns in the sky and in the particles that make up the universe. But the patterns that fascinate us most are the ones inside our heads, in the land of the inner self.

Throughout much of the century, speculating about the nature of consciousness was a sure way for a scientist to be labelled an eccentric or a crank. But as the picture we've drawn of the universe becomes more and more refined, this vacuum in our understanding only looms larger, begging to be filled. Since the mid-Nineties, psychologists, philosophers, neuroscientists, physicists, mathematicians and other academics have flocked to interdisciplinary jamborees with titles like "Toward a science of a consciousness," and have issued one book after another laying out their conflicting visions.

On one side are materialists of various stripes, sure that the inner light can, like everything else, be explained scientifically - in terms of matter, energy and information. On the other side are the "New Mysterians," named by their opponents in honour of the Sixties rock band "Question Mark and the Mysterians". They believe that consciousness is so far outside the domain of conventional science that it maybe the one pattern we never understand.

For those who hope that, in time, science will answer every question, the ralling cry of the materialists is reassuring: the mind is what the brain does. As the trillion brain cells called neurons communicate with electrochemical signals, intelligence, awareness and all the mysterious inner feelings emerge like a simulation run on a biological computer. In The Astonishing Hypothesis, Francis Crick, co-discoverer of the double-helical structure of DNA, starkly described this view: " 'You,' your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will are, in fact, no more than the behaviour of a vast assembly of nerve cells and their associated molecules."

In fact, to many neuroscientists, there is nothing astonishing about the hypothesis at all. Explaining consciousness, they assume, will turn out to be no more of a philosophical problem than explaining life - as interlocking whorls of chemistry. What really would floor them would be to find that the mind could not be entirely explained in terms of neuronal circuitry.

It is not too difficult to imagine how billions of brain cells trading signals process the information people need to survive. There are circuits for detecting patterns in the light that falls on the retina, circuits for teasing the phonemes of language from vibrations of sound. From this information, the brain builds models of the world. So why not models of one's own behaviour? Could this crude sense of self-awareness be what we mean by consciousness?

In his tour de force, Consciousness Explained, the philosopher Daniel Dennett showed how neuronal machinery might even give rise to the stream of consciousness, the inner voice that plays constantly in our heads. The brain, in this view, is a sense- making machine, engaged in a constant internal debate. Is that a herd of elk grazing over in the valley or a cluster of pinyon trees? And over there: is that a huge snowcapped mountain or a low-hanging cumulus cloud? In Dennett's theory, competing teams of neurons silently weigh and discard the possibilities: can't be a mountain because the whole thing just moved.

From the pandemonium, bubbling just below the surface of awareness, a single narrative emerges - the voice of the inner "I" conducting its running story about what seems to be going on in the world. Consciousness, then, is a tale-spinning computer, what Dennett calls "the Joycean machine." The implication is that there is no reason a properly programmed digital computer couldn't be made equally aware. And that is where Dennett's opponents rise up with their objections. One can imagine a robot that is aware of its surroundings and even aware of its place in its surroundings. But could these rudimentary cogitations ever be accompanied by the profound feeling of inhabiting vast mental spaces?

Of course, the robot could operate perfectly well without agonising and enthralling over its own existence. But so, it seems, could we. Philosophers call this "zombie problem." If the point of life were simple survival, creatures could conceivably have evolved that performed all the functions people do - building houses, villages, civilisations - but without the sensation of being alive. What purpose does the feeling of consciousness, of inner experience, really serve?

In the mid-Seventies, the psychologist Julian Jaynes created a sensation with his intimidatingly titled book, The Origin of Consciousness in the Breakdown of the Bicameral Mind. People, he declared, indeed used to be zombies, with no more feeling of I- ness than the living dead. For centuries, they were steered through life by persistent inner voices, as controlling circuits in the right side of the brain sent signals to the left side. Modern people experience these thoughts as the sound of the inner self. But, in the beginning, Jaynes says they were interpreted as the voices of gods. "There were no private ambitions, no private grudges, no private frustrations, no private anything," Jaynes wrote. As the world grew more complicated, this "bicameral mind" broke down. The two sides of the brain became more closely intertwined and consciousness, the sense of being a self, was born. The spirits were replaced by the ego, the I.

From studying ancient texts like the Iliad and the Odyssey, Jaynes concluded that, in Europe and Asia, consciousness arose around 3,000 years ago. When the Asiatic tribes believed to be the ancestors of all Native Americans crossed the Bering land bridge at least 12,000 years ago, could they still have been Jaynesian robots haunted by inner voices? Had consciousness dawned by the late 13th Century when the Anasazi abandoned their empire on the Colorado Plateau, dispersing to places like Yapashi, and eventually settling in the pueblos along the Rio Grande?

We have no way of knowing. Science can study the signs of self- awareness: drawings on rock walls and pottery, written words, facial expressions. But the only consciousness anyone has access to is the private world inside oneself. In trying to map this unique geography, the scientific method of separating subject and object breaks down. The subject is the object and, in thinking about thinking, we get caught in dizzying regresses of introspection.

No wonder archaeologists have habitually regarded ancient peoples as automatons, moved around like pawns by geographical forces. Why did the southwest pueblo cultures so often build on mesa tops, like Yapashi, when the source of water and the best farmland was down below on the canyon floors? The common textbook explanation is that the villagers were defending themselves against enemies. But maybe they were just enjoying the view.

One can always find a reductive answer. When the Anasazi scratched their patterns on the rocks, maybe they were just instinctively marking territory like ancient gangs. Even the curiosity that drives modern astronomers to explore the night sky could be no more than an outgrowth of the primitive need to watch for invaders.

It all seems so logical, and so unsatisfying. I pick up a shard of glassy black obsidian, wondering if it is a flake left by the maker of an arrowhead or by the insentient weathering of nature. My visual sensors register black and shiny. My tactile sensors register the sharpness of the edge. But I also experience the feeling, both subtle and intense, of seeing and holding the rock: the sharpness of the sharp, the blackness of the black.

The immediacy of subjective experience is so overwhelming that the New Mysterians believe conventional science will never explain it. Their predecessors, the Old Mysterians, were dualists who saw mind as a spiritual essence separate from matter. Members of the new wave assume that consciousness is a natural feature of brain matter.

The problem, as Colin McGinn argues in his new book, The Mysterious Flame, is that people simply haven't evolved enough to understand it, and probably never will. The most provocative of these sceptics, David Chalmers, offers a strange kind of hope: he believes that the impenetrability of consciousness is a clue that science needs to start over gain from scratch and carve up the world in a whole new way. "The physical structure of the world - the exact distribution of particles, fields and forces in space- time - is logically consistent with the absence of consciousness," he recently wrote, "so the presence of consciousness is a further fact about our world." Science has been treating consciousness as something secondary, to be explained in terms of existing concepts. Chalmers believes it will be necessary to admit consciousness into science as an irreducible thing-in-itself, along with matter, energy, space and time. Then perhaps, we will truly understand the universe.

It seems absurd to think that this newfound quality would happen to reside only in human heads. So Chalmers has joined a handful of philosophers who reluctantly entertain the possibility that what we call consciousness might somehow pervade the material world. This notion, panpsychism ("mind everywhere"), is not so different from what Anasazi believed - that everything is full of spirits. And so we return, full circle, to the philosophy of Yapashi.

The idea seems crazy. But so, a century ago, did the notion that a lump of seemingly inert matter holds vast amounts of energy - the discovery that put Los Alamos on the map and almost erased Hiroshima.

The modern Pueblo Indians, who trace their ancestry to Yapashi and other nearby ruins, teach that northern New Mexico is the centre of the universe. Four sacred mountains, one for each direction, mark the boundaries of this mythological world. But the cosmologists, at Los Alamos and elsewhere, say there is no centre. The universe, as Freeman Dyson put it, is infinite in all directions.

As I look one last time at the mountainous panorama, it is easy to understand the pueblo view. The centre is right here where I am standing, at the focus of my awareness. In trying to make sense of the world, we fight to overcome such parochial feelings. But future archaeologists - if they are able to decipher the scratchings we leave in our books and on our computer disks - will probably understand, and maybe even improve upon our confusion.

(c)The New York Times Magazine

George Johnson is the author of "Fire in the Mind: Science, Faith and the Search for Order." His book "Strange Beauty Murray Gell- Mann and the Revolution in 20th century Physics "will be published this month by Knopf.

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