Chapter 1: The Thinking Machine
The truth is that a supercomputer is too good to behave like a human brain. A computer could never answer or even imagine the purple cow question. It is too precise, too correct, too predictable, too Miss Goody Two-Shoes. The computer is like the ticking of a Swiss watch, and the human brain is more like a blues note on a bender.
To behave like the human brain, a computer would have to behave like this: start searching for an item with fierce concentration, then back off a little, then jump back in, then find itself staring blankly out the window (assuming there is a window), then off to a warm reverie—shafts of sunlight bouncing off the green grass or something like that—and then suddenly, bang, back to reality with an abrupt epiphany: “Got to put Puppy Chow on the grocery list!”
Now that’s more like a human brain.
Even logical thinking—the kind you might expect from a rocket scientist or a McKinsey strategist—is more like a swallow wafting in the evening air, doing loop-de-loops and acrobatic tumbles, than an arrow sent shivering into a tree. We can’t help it.
That’s the way the brain works.
For that reason, the human brain is also a lousy computer. And it’s not one that you would probably care to employ. Can you imagine having a handheld calculator that begins humming “Strawberry Fields Forever” in the middle of a calculation? Or an ABS brake sensor that wonders, just as you are going into a skid, what it must be like to be an air bag deployer?
What characterizes human thought? “A period of mulling,” says University of Chicago professor Howard Margolis, “followed by periods of recapitulation, in which we describe to ourselves what seems to have gone on during the mulling.”1 In other words, just like a swallow, the human mind thinks in a series of loop-de-loops.
But we haven’t gathered here today to badmouth the brain. Quite the contrary. The brain is capable of doing marvelous things—things that computers couldn’t imagine doing (if they could imagine doing anything). The appreciation of beauty, creativity, contemplation, imagination, and, yes, purple cows—these are all in the realm of the human brain.
When we talk about the creation of a thinking machine, in fact, this is the kind of intelligence we mean: not merely a machine that can calculate a sum to the billionth decimal point but one that has a sense of reason, balance, and intuition. A machine that can learn from its mistakes, as humans sometimes can, and even move the ball of civilization forward. Can we really build something like this, ever?
This is an important question, but before we can answer it, we must ask ourselves, What do we mean by thinking? What do we mean by conscious thought? To answer those questions, I need to introduce you to Dan Dennett, my former philosophy professor and mentor.