SCIENCE / MEDICINE : Beauty Is in the Eye of the Beholder, Along With Everything Else
Everyone knows how the eye works. Light passes through the lens and strikes the retina behind it, which tickles the optic nerve and sends an electrical signal to the brain. Presto, we see.
I don’t know about you, but I don’t see electrical signals or anything like that when I look out through my eyes. I see a scene--a picture--before me, peopleand furniture and cars and buildings and trees and whatnot. A constantly changing scene.
Where--and how--does that scene get put together?
Somewhere in the brain, the physical sensation is turned into a mental sensation. But how it happens is a mystery. One thing is certain: Vision is not a replication of the image on the retina.
The question of where vision comes from is an example of a larger philosophical question that has concerned thinkers and scientists for centuries: the mind-body problem. What is the relationship between our thoughts, which are “mind,” and our brains, which are “body?”
In the example of vision, the eye, the retina, the optic nerve and its complex electrochemical activity are body. The scene we see is mind.
Asking where vision comes from is like asking where consciousness comes from. The little voice in your head that talks to you--what is its source? The brain is not like other organs of the body, whose outputs are physical substances. It would be a mistake to say, for example, that the brain is like the pancreas: One secretes insulin and the other secretes thoughts. You can collect insulin and measure it. But where are the thoughts?
To simplify, there are basically two approaches to the problem of understanding the relationship between mind and brain, neither of which is altogether satisfying. On the one hand, there is the reductionist position, which says that mind and brain are the same, that every thought, emotion, memory and nuance of experience corresponds to a physical state of the brain. We are far from understanding what that correspondence is, of course, but someday it will all be worked out.
Or, on the other hand, one could say that mind represents something else, something left over, the soul perhaps. The gray matter is not all there is. The trouble with this explanation, which is favored by many researchers, is that all it does is give a name to what we don’t know. What is the something else and, more important, where is it?
I favor the reductionist position, which collapses mind to brain, though I admit that it seems that there is something else involved. But much of what neuroscientists discover points in this direction.
Consider, for example, one famous experiment in which electrodes were placed on the heads of human subjects so their brain activity could be monitored. They were then told, “When you feel like it, bend your finger.”
Sooner or later, the subjects bent their fingers. But in each case, there was activity in their brains before they were aware of any conscious decisions to move.
Brain activity comes first. Consciousness comes second. It is simply how we experience the electrochemical activity in our brains.
This finding casts doubt on our cherished notions of free will. We may simply be deceived in thinking that we are free agents. If thoughts follow brain activity, and brain activity is a matter of physics and chemistry, we have much less freedom than we imagined.
This is no idle philosophical issue. If mind and brain are the same, then people who are smart shouldn’t be praised or rewarded for it. They can’t help themselves.
Similarly, if free will is in question, our notions of punishment are on shaky ground. Is it proper to punish people for doing things for which they are not responsible?
The predominance of the brain over our mental life seems overwhelming. In some experiments, certain patients who are awake have had parts of their brains electrically stimulated. They report feeling sensations in various parts of their bodies. Not in their brains, mind you, but in their hands, for example. Stimulate the brain, and the patient feels it elsewhere.
Or take various studies of the perception of color. It turns out that there is no physical quality that enables you to determine what color is. Color is not a physical property. It is a property of brain. “The world is very much a matter of our own creation,” says Richard Cytowic, a neurologist in Washington.
However, there is something out there. We don’t just make up the world out of whole cloth. But it is fair to conclude that most of what we say about the world says more about us than it does about the world.
But as to how the brain works, our knowledge is, to be generous, rudimentary. In neuroscience, “We don’t have a feeling for much at all,” says Jack D. Cowan of the University of Chicago. “Physics is easy compared to biology.”
Perhaps the 20th-Century philosopher Ludwig Wittgenstein said it best: All the interesting things can’t be written down and described.
