Many people feel offended when their minds are likened to computer programs or machines. We've seen how a simple tower-building skill can be composed of smaller parts. But could anything like a real mind be made of stuff so trivial?
Ridiculous, most people say. I certainly don't feel like a machine!
But if you're not a machine, what makes you an authority on what it feels like to be a machine? A person might reply, I think, therefore I know how the mind works. But that would be suspiciously like saying, I drive my car, therefore I know how its engine works. Knowing how to use something is not the same as knowing how it works.
But everyone knows that machines can behave only in lifeless, mechanical ways.
This objection seems more reasonable: indeed, a person ought to feel offended at being likened to any trivial machine. But it seems to me that the word machine is getting to be out of date. For centuries, words like mechanical made us think of simple devices like pulleys, levers, locomotives, and typewriters. (The word computerlike inherited a similar sense of pettiness, of doing dull arithmetic by little steps.) But we ought to recognize that we're still in an early era of machines, with virtually no idea of what they may become. What if some visitor from Mars had come a billion years ago to judge the fate of earthly life from watching clumps of cells that hadn't even learned to crawl? In the same way, we cannot grasp the range of what machines may do in the future from seeing what's on view right now.
Our first intuitions about computers came from experiences with machines of the 1940s, which contained only thousands of parts. But a human brain contains billions of cells, each one complicated by itself and connected to many thousands of others. Present-day computers represent an intermediate degree of complexity; they now have millions of parts, and people already are building billion-part computers for research on Artificial Intelligence. And yet, in spite of what is happening, we continue to use old words as though there had been no change at all. We need to adapt our attitudes to phenomena that work on scales never before conceived. The term machine no longer takes us far enough.
But rhetoric won't settle anything. Let's put these arguments aside and try instead to understand what the vast, unknown mechanisms of the brain may do. Then we'll find more self-respect in knowing what wonderful machines we are.