THE QUANTUM BRAIN: THE SEARCH FOR FREEDOM AND THE NEXT GENERATION OF MAN. By JEFFREY SATINOVER. Wiley. 276 pp. $24.95.
JEFFREY SATINOVER HAS written an audacious book. He believes that he has found, in two great breakthrough ideas, the keys to understanding the human mind. He is not the originator of these ideas, which are the result of the work of many researchers in neuroscience, computer science, and physics; he is their herald. Although a psychoanalyst by profession, he writes with an impressive level of knowledge and sophistication about all of these highly technical disciplines.
The first of the two key ideas of The Quantum Brain is "bottom-up computation." In the book's first half, Satinover guides the reader through the penetralia of that field: neural networks, spin glasses, Hopfield nets, cellular automata, Belousov-Zhabotinsky reactions, and much, much more. The nontechnically inclined should be prepared for some hard spelunking; but these are fascinating ideas, and worth the effort.
Satinover believes that in this part of the book he has succeeded in exposing the general principles on which the human brain is built. He is convinced that artificial thinking machines based on these principles are just around the corner and will far outstrip human mental powers. He likes to think, he says, that these artificial superbrains will "in their kindness ... be willing to keep us [around]--flawed racehorses turned out to pasture." With this view, of course, goes the idea that we ourselves are machines. "Looking back at the territory we've covered," he says near the end of the book's first part, "we ... arrive at the following conclusion: Man is a machine." And yet he finds this idea disquieting. He doesn't mind being a machine, even an obsolete machine, but he does not want to be just a machine. He wants to have some semblance of free will. He wants at least to keep that shred of dignity. This is where the second key idea of the book, "quantum indeterminacy," comes into play. Quantum theory, Satinover suggests, will rescue us from mere mechanism.
As he is aware, the problem of mechanism did not begin with the modern computer. It began with Newton. The great problem that Newton left philosophers was to reconcile human freedom with the rigid determinism of physical law. With the advent of quantum theory--which showed that the laws of physics predict only the probabilities of future events--many philosophers and physicists have come to think that such a reconciliation might be possible. I am inclined to believe that they are right.
However, there are several difficulties with the idea that quantum indeterminacy provides an opening for free will. The most formidable is the fact that quantum indeterminacy usually only plays a significant role in events at the atomic scale, whereas neurons, generally thought to be the basic building blocks of the brain, are a great deal larger. Consequently, neurons should behave...
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