ARE WE UNIQUE?

An attempt to explain the ``problem of consciousness'' scientifically, by the prolific popular science writer (A Scientist in the City, 1994, etc.) and NPR commentator. Consciousness is a problem because it is difficult to define scientifically and yet would seem to be the one entity rendering humankind distinct from animals—and from the imminent artificial- intelligence capabilities of computers. Trefil (Physics/George Mason Univ.) easily dispenses with arguments that the DNA of some animals hardly differs from our own, and with the supposedly intelligent behavior of, say, chimpanzees and octopi, since, in the end, the gap between animal and human intelligence is impressively large. Computers prove harder to deal with, however. First, in his most brilliant chapters, Trefil lays out everything science knows about the workings of the human brain: how synapses fire to cause actions such as the resolution of sight, and the tracking of where individual functions, such as muscle control or the perception of motion, are born. With his model established, Trefil then tries to demolish the notion of a computer as a mechanical brain. The brain is not an electrical apparatus, but a chemical one, he points out, and therefore the parallel commonly drawn between the firing of a synapse and the connections between semiconductors is false. And what to do about that sturdy yet poorly understood mechanism known as intuition? Could a machine, no matter how sophisticated, ever manage such a leap? Even so, Trefil acknowledges that science will shortly be able to map every function of the brain and that eventually enough semiconductors, mimicking those functions, might be strung together to equal the brain's huge capacity. Once he does so, only a mystical approach to consciousness can rescue him, but Trefil is at pains to avoid any but strictly empirical arguments. A gallant, moving, but in the end unconvincing argument.