Isaac Asimov - The Difference between a Brain and a Computer 汉译

The difference between a brain and a computer can be expressed in a single word: complexity.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

The large mammalian brain is the most complicated thing, for its size, known to us. The human brain weighs three pounds, but in that three pounds are ten billion neurons and a hundred billion smaller cells. These many billions of cells are interconnected in a vastly complicated network that we can’t begin to unravel as yet. Even the most complicated computer man has yet built can’t compare in intricacy with the brain. Computer switches and components number in the thousands rather than in the billions. What’s more, the computer switch is just an on-off device, whereas the brain cell is itself possessed of a tremendously complex structure.

Can a computer think? That depends on what you mean by “think.” If solving a mathematical problem is “thinking”, then a computer can “think” and do so much faster than a man. Of course, most mathematical problems can be solved quite mechanically by repeating certain straight forward processes over and over again. Even the simple computers of today can be geared for that.

It is frequently said that computers solve problems only because they are “programmed” to do so. They can only do what men have them do. One must remember that human beings also can only do what they are “programmed” to do. Our genes “program” us the instant the fertilized ovum is formed ,and our potentialities are limited by that “program”.

Our “program” is so much more enormously complex, though, that we might like to define “thinking” in terms of the creativity that goes into writing a great play or composing a great symphony, in conceiving a brilliant scientific theory or a profound ethical judgment. In that sense, computers certainly can’t think and neither can most humans.

Surely, though, if a computer can be made complex enough, it can be as creative as we. If it could be made as complex as a human brain, it could be the equivalent of a human brain and do whatever a human brain can do.

To suppose anything else is to suppose that there is more to the human brain than the matter that composes it. The brain is made up of cells in a certain arrangement and the cells are made up of atoms and molecules in certain arrangements. If anything else is there, no signs of it have ever been detected. To duplicate the material complexity of the brain is therefore to duplicate everything about it.

But how long will it take to build a computer complex enough to duplicate the human brain? Perhaps not as long as some think. Long before we approach a computer as complex as our brain, we will perhaps build a computer that is at least complex enough to design another computer more complex than itself. This more complex computer could design one still more complex and so on and so on and so on.

In other words, once we pass a certain critical point, the computers take over and there is “complexity explosion”. In a very short time thereafter, computers may exist that not only duplicate the human brain – but far surpass it. Then what? Well, mankind is not doing a very good job of running the earth right now. Maybe, when the time comes, we ought to step gracefully aside and hand over the job to someone who can do it better. And if we don’t step aside, perhaps Supercomputer will simply move in and push us aside.