This engaging, non(too)technical book offers a new and plausible theory of how the brain, or more specifically the neocortex, works.
When I learned about the existence of this book, I was drawn to it for a number of reasons. For one thing, I’m intrigued by the faculty we call intelligence: what is it, exactly? For another, I, like the author Jeff Hawkins, have long been fascinated by the brain and how it works. And finally I was eager to read a book on neuroscience by a nonscientist, for Hawkins, inventor of the Palm Pilot and other things, is a technologist who has long pursued brain science as a hobby. I love the idea of contributions to knowledge being made by amateurs, for they seem best able to think outside the box.
And thinking outside the box is what Hawkins has done here. His point of attack was to discover whether it is possible to build an “intelligent machine,” and how this might be done. He noted the relative unsatisfactoriness of the results achieved by “artificial intelligence” in the computing world, and wondered why this was. How was it that a computer, with processors executing millions of instructions per second, could not seem to remotely approach the prowess of the human brain at most tasks requiring “intelligence,” when the cells in that brain could only execute a few tens of “instructions” per second? Even relatively simple perceptual tasks, like recognizing faces and chairs, are done effortlessly and almost instantly by humans, while machines toil to achieve a success rate well below 100%. What have humans got that computers don’t got?
Humans have a way of processing information that is completely different from the way computers process it. The brain, unlike a computer, does not run on the instructions of a single master program controlled from the top. The brain, says Hawkins, operates as a vast array of small, localized processing systems. In particular, the neocortexthat sheet of neurons that covers the upper frontal part of our brain, and is responsible for all of our human intelligenceis set up as an intricate, interconnected feedback system that can be boiled down to performing two functions: memory and prediction. He’s saying that what we call intelligence is the interplay of memory and prediction.
To defend and illustrate this thesis, he goes into some detail on exactly how he thinks the neocortex is wired up. It is known to consist of 6 layers of neurons, which are all interconnected in certain characteristic ways. Hawkins shows why they are so interconnected, and how this results in the formation of memories at increasingly high levels of abstraction. What we call intelligence is the recognition of a current sensory input as belonging to an abstract category already in memory. According to this view, animals that also possess neocortexes have this same intelligence, but in lower degree than humans, who have the most sophisticated neocortex (one interesting fact in the book was that dolphins, which are intelligent and also possess large brains, have a neocortex with only 3 layers, as opposed to the humans’ 6).
Hawkins makes his case very well; I found it persuasive. Where I found myself less persuaded was in what I would call the philosophical side of the book, where the author addresses questions such as, What is creativity? What is imagination? What is consciousness? And of course the basic question: what is intelligence itself? I think that Hawkins, an extremely able technologist and even scientist, overplays his hand as a philosopher.
Along the way, for example, he talks about Plato’s theory of forms as an explanation of how we are able to recognize sameness in the hurly-burly of our ever-shifting sensations. Hawkins notes offhand, “His system of explanation was wildly off the mark.” Well, maybe it was and maybe it wasn’t, but what makes Hawkins so sure? I recall that Roger Penrose, in chapter 1 of his Road To Reality, treats the world of mathematical truth as one part of a Platonic world of forms, seemingly real but also different from the worlds of mental experience and of physical things. My point here is just that Plato’s ideas live on; they’ll keep climbing back out of the dustbin of history.
I had similar feelings about Hawkins’s take on the other philosophical questions. He contends that the difference between the intelligence of, say, a rat and of a human is purely one of degree. But Mortimer J. Adler, in his book Intellect: Mind over Matter, contends the opposite. According to him, intellectwhich was the word formerly used to label the faculties that we now point to with the word intelligenceis something more than the rudimentary power of abstraction used by brutes. In this view, animals are able to respond to individually differing things in the same way, as when a rat is able to press different triangular buttons to get food, but this is not the same thing as
cognizing what is common to them or knowing them in their universal aspects. . . . By means of concepts, and only by means of concepts, we understand kinds or classes as such entirely apart from perceived particulars and even though no particular instances exist.
Adler argues that the brain is a necessary but not a sufficient condition of the human intellect. The existence of the intellect, he thinks, is a sign that a human being is something more than just a body.
Is Adler right in this? I don’t know. And I don’t think Jeff Hawkins knows either, no matter how confident he is in his assertions. But for someone who wants to build intelligent machines, I think a cautious outlook would be fitting. Hawkins dismisses people’s worries that superintelligent machines might become our overlords or our executioners, like HAL in 2001: A Space Odyssey or the Skynet computers in the Terminator movies. He thinks that such behavior would require the presence of the equivalent of the emotional centers of the brain in addition to the neocortex, and he’s only planning to build an analog of the neocortex. So don’t worry, folks.
I recall reading a comment from the Dalai Lama, apparently changing his mind about whether robots or machines could become sentient. He said that if some being had the necessary karma to take birth or manifestation in a machine, then that would happen. I note that karma is not a word that occurs in the index of Hawkins’ book.
But this is a good, clear, strongly argued, plainspoken, provocative, and, yes, intelligent book. Hawkins has persuaded me that “intelligent” machines are very likely in our near future. And even though we’ll be their intellectual inferiors, I’m sure they will be very helpful and will have no reason to do anything mean.
If they do turn on us, then, well, maybe God will help us.