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Roger Penrose's previous book, The Emperor's New Mind,
was a marvelous survey of modern physics as well as a provocative reflection on
the human mind, offering a new perspective on the scientific landscape and a visionary
glimpse of the possible future of science. Now, in Shadows
of the Mind, Penrose offers another exhilarating look at modern science as
he mounts an even more powerful attack on artificial intelligence. But, perhaps
more importantly, he points the way to a new science, one that may eventually
explain the physical basis of the mind. Penrose provides
powerful arguments to support his conclusion that there is something in the conscious
activity of the brain that transcends computation -- and for which there is no
explanation in terms of present-day science. To illuminate what he believes this
"something" might be, and to suggest where a new physics must proceed
so that we may understand it, Penrose cuts a wide swathe through modern science,
providing penetrating looks at everything from Turing computability and Godel's
theorem, via Schrodinger's cat and the Elitzur-Valdman bomb-testing problem, to
detailed cell biology. Of particular interest is Penrose's examination of quantum
mechanics, which introduces some new ideas that differ markedly from those in
The Emperor's New Mind, especially concerning quantum entanglement, the
mysterious interface where classical and quantum physics meet. No prior knowledge
of quantum theory on the part of the reader is assumed.
In the author's consideration of microbiology
he examines cytoskeletons and microtubules, minute substructures
lying deep within the brain's neurons. He argues that microtubules
rather than neurons may be the basic units of the brain,
and that it is within them that the collective quantum effects
necessary for consciousness reside.
For physics to accommodate something that is as foreign to our
current physical picture as the phenomenon of consciousness, we must expect a
profound change -- one that alters the very underpinnings of our philosophical
viewpoint as to the nature of reality. Shadows of the Mind provides an
illuminating look at where these changes may take place and what our future understanding
of the world may be. |
