Excerpts from “The Little Man In the Brain”
During a recent television show entitled “Inside
Information,” neuroscientist V. S. Ramachandran of the University of California
at San Diego made some interesting points about how we see. He said that
if you ask the man in the street how vision works, he will say there is
an image on the retina of the eye. The optic nerve faithfully transmits
this image to a screen in the brain, in what we call the visual cortex.
And that image is what you see.
Ramachandran pointed out that this explanation leads
to a logical fallacy. If you create an image inside the head, then you
need another person in the head—a little man in the brain—who looks at
that image. Then you have to postulate an even smaller person inside his
head to explain how he sees, and so on, ad infinitum. This is obvious nonsense,
and Ramachandran said that inside the brain there really is no replica
of the external world. Rather, there is an abstract, symbolic description
of that world. Brain scientists are like cryptographers trying to crack
the code the brain uses in perceiving its environment. . . .
One idea is that consciousness may arise at the level
where the brain organizes information from separate systems, like those
for shape, color, and motion, and integrates it into one unified gestalt.
One problem with this proposal: Does such unification actually occur? To
write down a lot of information you need many letters, and if you code
the information in patterns of nerve impulses, you need a lot of neurons
to store it. No matter how much you try to compress it by careful coding,
it remains spread out and not truly unified. The idea of a unified “gestalt”
simply takes us back to the original little man who looks at the information
and is conscious of it.
The basic fallacy of the little man in the brain argument
is that it assumes implicitly that consciousness can be understood in physical
terms. One tries to explain consciousness by describing a machine that
creates a certain display of information. Then one recognizes that the
mere presence of displayed information fails to account for consciousness
of that information. Then one proposes another mechanism to interpret the
information and finally generate consciousness. When that attempt also
fails, one takes refuge in the overwhelming complexity of the brain and
says that a consciousness-producing mechanism must be hidden in there somewhere.
All we have to do is find it. . . .
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Copyright © 2004 by Richard L. Thompson