Cogito Ergo Sum

I think therefore I am. These words, written by French philosopher and mathematician Rene' Descartes (1596-1650), remind us that it is our mind that makes us what we are. It is the "human" part of a human being. Of all the mysteries confronting our race, the enigma of our own minds is among the most perplexing. How strange that something so intimately known to us is also so enigmatic. Basic questions remain unanswered: How do we learn? Where is memory stored and how is it retrieved? What are emotions? How does the mind control the body? What are dreams? What is consciousness?

Part of the problem has been that we can't simply poke around inside someone's live brain to see how it works. And for good reason! As a consequence, cognitive scientists are forced to theorize in a vacuum, or extrapolate from animal tests, seldom benefiting from direct human experimentation. What we do know for certain is that the human mind consists of two basic components: the brain, in which all cognitive neuronal processes take place, and conscious awareness, which comprises our sense of self, our free will. The means by which the brain gives rise to consciousness is where the topic becomes sticky. From the very beginning it seems, philosophers and scientists have not been able to provide an adequate solution to this "mind-body" problem.

That may be about to change, however. A fascinating new theory—proposed independently by Johnjoe McFadden, professor of Molecular Genetics at the University of Surrey, England, and Susan Pockett, visiting professor, Department of Physics, University of Auckland, New Zealand—puts forth a novel and controversial solution to the question: What is consciousness? But before taking a look, we need to understand a little brain physiology.

It has long been known that neurons firing in the brain generate tiny oscillating electrical voltages along and between nerve fibers, each just a few millionths of a volt. All electrical circuits (and that's basically what neurons are) generate an associated electromagnetic (em) field. However, unlike neuronal information, which is localized in a single neuron or groups of neurons, the brain's em field binds information into a single, integrated whole. Em fields are waves that tend to cancel out when the peaks and valleys from many unsynchronized waves combine. But if neurons fire together, the peaks and valleys of their em fields reinforce each other to generate a large disturbance to the overall em field. Recent experiments have shown that neuron firing alone does not correlate with conscious awareness, but—and this is where it gets exciting—the em field disturbance generated by synchronous firing does. The most likely explanation is that the brain's em field and consciousness are the same thing. Our consciousness is an electromagnetic field.

If this is indeed true, one might wonder: How then can our conscious em field control our body's movements, and thereby carry out our intentions? Here McFadden and Pockett differ in their beliefs. McFadden feels that just as radio and TV sets are designed to be sensitive to transmitted em waves, so are the "circuits" of the brain. Neurons are fired by specific structures known as voltage-gated ion channels that respond to the external em field. For the most part, they are gated in such a way that only massive changes to the brain's em field are likely to influence neuron firing. But in a normal, active brain there are many neurons teetering on the brink of firing. These "undecided" neurons are the ones sensitive to the em field. This field—our consciousness—thus comes into play precisely when the brain is poised to make delicate decisions. We decide to move our arm, and it does.

Pockett agrees with McFadden that consciousness is an electromagnetic field. Where she differs is on the point of whether or not consciousness can effect behavior. Pockett believes that our conscious minds can in no way "will" our body to move. This sounds impossible, but it really isn't. Counter-intuitive though it seems, numerous experiments have shown that conscious awareness appears to be an epiphenomenon, a derivative of preconscious neuronal processes, and is manifest after neuronal processes have occurred. Think about it: in an emergency (a child jumps in front of your car, for instance), you hit the brake immediately and without awareness. Only after the fact do you realize what you have done. Your reaction came before your conscious awareness. Pockett believes that the brain decides what to do in all instances, then informs consciousness only as a kind of courtesy. The feeling that we are consciously controlling our actions is, she believes, an illusion.

Perhaps Descartes had it all wrong. Maybe he should have said: "I think...because my brain told me to."