THE FOURTH DISCONTINUITY

An often interesting and provocative—though sometimes obvious and, finally, unconvincing—historical exploration of humanity's relationship to machines. Mazlish (History/MIT; The Meaning of Karl Marx, 1984, etc.) says that the three great shocks to our conception of ourselves- -with each shock forcing us to relinquish another claim to uniqueness—have been the Copernican Revolution, removing Earth from its centrality; Darwin's placement of humanity within the animal kingdom; and Freud's excavation of the unconscious. Now, claims the author, ``we are now coming to realize that humans are not as privileged in regard to machines as has been unthinkingly assumed''—and thus the ``fourth discontinuity,'' between ourselves and machines, is eliminated. That people and machines have coevolved, each shaping the other, is demonstrable; that they are of the same essential nature is an idea that seems, at least as treated here, destined to remain a metaphor. To support his claim, Mazlish surveys an eclectic intellectual history, including a chronicle of automata, from the Jewish golem to Vaucanson's duck (once the talk of 18th-century Paris, said to have ``drank, ate, digested, cackled and swam'') to Blade Runner; the intellectual response to the Industrial Revolution; the work of Linnaeus and Darwin; the research of Freud and Pavlov, revealing mechanistic aspects of behavior; Babbage's Difference Engine, turning the power of machines to intellectual tasks, as well as Samuel Butler's Erewhon, which depicted machines in revolt; and the two revolutions of our own age—the coming of computers and of biogenetic technology. Too flat and meandering to germinate something as vital as a reassessment of the humanity/machine symbiosis. (For a more expansive and engaging treatment of a similar theme, see Gregory Stock's Metaman, reviewed below.) (Twelve illustrations)