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 Nuernberg 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."

Cartesian Games. Philosopher Descartes posed his challenge in full confidence that the science and technology of his day could never meet it. Philosopher Adler must deal with a vastly greater accumulation of scientific fact, with incredibly more sophisticated machines--some of them with nervous systems of electronic complexity that apes the mysterious labyrinths of the human brain. So today's philosopher is forced to lay down strict conditions for his Cartesian games. If it is to prove a replica of man, a machine must really "talk," says Adler; it must not only speak sentences but engage in reasoned dialogue. It must even be capable of committing "human error." Unless this condition is met, computers will always be evolutionary dropouts. For the possibility of free will to exist, it must also be true that man is not simply the sum of all the impulses he receives, as a computer is the sum of its man-made memory and its electronic input.

Adler cites the late British "mathematical genius," Alan M. Turing, who claimed "that it is mathematically possible to conceive a robot that will meet Descartes' challenge." That robot would be able to take part in an exercise known as "Turing's game." Two players, hidden behind screens, are being questioned by a third. All communication is by typewritten note, the questioner is allowed to ask anything at all, and the players are not required to tell the truth. Eventually, by reason and intuition, the questioner must determine the sex of the players. If a robot could be substituted for one of the players and engage in the necessary typewritten dialogue, it would have what Adler calls the "power of conceptual thought."

Open Question. Adler appears not to believe that the Turing robot will ever succeed. And he thinks that, a century hence, those who will be most shocked by this failure will be "those who are now united in a common disbelief--disbelief in the dogmas of traditional, orthodox Christianity." Ideas they now think are dead would come to life; issues considered closed would have to be faced once more.

For now, the question remains unsolved. No one has proved man's difference; no one has disproved it. But if an answer can be found, says Adler, it will make a difference indeed. "For the image that we hold of man cannot fail to affect attitudes that influence our behavior in the world of action, and beliefs that determine our commitments in the world of thought."

* Current entries: The Apes by Vernon Reynolds (TIME, Dec. 29), The Naked Ape by Desmond Morris.

This file is automatically generated by a robot program, so reader's discretion is required.