Why great minds can't grasp consciousness

By Ker Than

updated 3:42 p.m. ET Aug. 8, 2005

At a physics meeting last October, Nobel laureate David Gross outlined 25 questions in science that he thought physics might help answer. Nestled among queries about black holes and the nature of dark matter and dark energy were questions that wandered beyond the traditional bounds of physics to venture into areas typically associated with the life sciences.

One of the Gross's questions involved human consciousness.

He wondered whether scientists would ever be able to measure the onset consciousness in infants and speculated that consciousness might be similar to what physicists call a "phase transition," an abrupt and sudden large-scale transformation resulting from several microscopic changes. The emergence of superconductivity in certain metals when cooled below a critical temperature is an example of a phase transition.

In a recent email interview, Gross said he figures there are probably many different levels of consciousness, but he believes that language is a crucial factor distinguishing the human variety from that of animals.

Gross isn't the only physicist with ideas about consciousness.

Beyond the mystics
Roger Penrose, a mathematical physicist at Oxford University, believes that if a "theory of everything" is ever developed in physics to explain all the known phenomena in the universe, it should at least partially account for consciousness.

Penrose also believes that quantum mechanics, the rules governing the physical world at the subatomic level, might play an important role in consciousness.

It wasn't that long ago that the study of consciousness was considered to be too abstract, too subjective or too difficult to study scientifically. But in recent years, it has emerged as one of the hottest new fields in biology, similar to string theory in physics or the search for extraterrestrial life in astronomy.

No longer the sole purview of philosophers and mystics, consciousness is now attracting the attention of scientists from across a variety of different fields, each, it seems, with their own theories about what consciousness is and how it arises from the brain.

In many religions, consciousness is closely tied to the ancient notion of the soul, the idea that in each of us, there exists an immaterial essence that survives death and perhaps even predates birth. It was believed that the soul was what allowed us to think and feel, remember and reason.

Our personality, our individuality and our humanity were all believed to originate from the soul.

Nowadays, these things are generally attributed to physical processes in the brain, but exactly how chemical and electrical signals between trillions of brain cells called neurons are transformed into thoughts, emotions and a sense of self is still unknown.

"Almost everyone agrees that there will be very strong correlations between what's in the brain and consciousness," says David Chalmers, a philosophy professor and Director of the Center for Consciousness at the Australian National University. "The question is what kind of explanation that will give you. We want more than correlation, we want explanation -- how and why do brain process give rise to consciousness? That's the big mystery."

Just accept it
Chalmers is best known for distinguishing between the 'easy' problems of consciousness and the 'hard' problem.

The easy problems are those that deal with functions and behaviors associated with consciousness and include questions such as these: How does perception occur? How does the brain bind different kinds of sensory information together to produce the illusion of a seamless experience?

"Those are what I call the easy problems, not because they're trivial, but because they fall within the standard methods of the cognitive sciences," Chalmers says.

The hard problem for Chalmers is that of subjective experience.

"You have a different kind of experience -- a different quality of experience -- when you see red, when you see green, when you hear middle C, when you taste chocolate," Chalmers told LiveScience. "Whenever you're conscious, whenever you have a subjective experience, it feels like something."

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