Books: Between Angel & Machine

THE DIFFERENCE OF MAN AND THE DIFFERENCE IT MAKES by Mortimer J. Adler. 395 pages. Holt, Rinehart & Winston. $7.95.

It is 108 years since Charles Darwin's The Origin of Species exploded in the midst of the square Victorian scene. Man's thoughts about man have not been the same since. Is he in truth just a little lower than the angels? Or did he evolve as just another species of animal? It seems like an old-fashioned question, but it still preoccupies poets, theologians, scientists and—emphatically—naturalists, whose books on primates seem to be crowding each other to get on the publishers' lists.*

Mortimer Adler, the philosopher and dialectician who heads Chicago's Institute for Philosophical Research, argues that the matter is far from merely academic. If man is not basically different from the animals, that would undermine "those who now oppose injurious discrimination on the moral ground that all human beings, being equal in their humanity, should be treated equally." Inferior types might be looked upon as man now looks on inferior animals. A large measure of truth could be read into one of Hitler's Nürnberg decrees that held "there is a greater difference between the lowest forms still called human and our superior races than between the lowest man and monkeys of the highest order." Yet Adler gives the subject a new twist by asserting that man's nature is defined not only by his difference from the beasts but by his difference from machines.

Computer Talk. He goes back to Descartes to test what he calls "the immaterialist hypothesis," the theory that at some point in man's evolution, a supernatural factor entered and set man forever above lower orders of creation. This hypothesis, once generally held, and still held by orthodox Christians, is now challenged by widespread acceptance of the "materialist hypothesis"—the notion that man is merely a more complicated organism in a hierarchy of natural history extending down to the smallest bacterium.

Against this assumption, Adler poses a contemporary version of the "Cartesian challenge." Show me an animal or a machine that can speak in sentences, said Descartes, in effect, and I will believe that man is not unique in his possession of an immaterial power that gives him reason. Even idiots can arrange words to make known their thoughts, Descartes explained, but "no animal can do the same." To him that was satisfactory proof that "the brutes" have no reason at all. Adler demands more before he will abandon man's uniqueness. Show me a neurologist who can "give an adequate explanation of conceptual thought in terms of brain action," he says; a zoologist who can "discover a non-human species of animal the members of which engage in conversation with one another"; and, most important of all, a technologist who can "produce a machine, specifically not a computer but an artifact that, without being programmed to do so, can engage in conversation with human beings."