The Matter of Mind (3)

Dateline: December 14, 1997

DESPITE pessimism from such quarters as Steven Pinker (see How the Mind Works), it looks as though we may be on the road to a full scientific understanding of the complex, emergent, self-organizing properties and behavior of the mind and brain. Ian Stewart and Jack Cohen (see The Matter of Mind (1)) show why we need to go beyond reductionist methods to get there, and Ilya Progigine (see The Matter of Mind (2)) proposes one such new method, based on the mathematics of complexity.

John McCrone wrote recently in New Scientist of a new movement in neuroscience toward dynamicism (used here I think synonymously with complexity). But "convincing mainstream neurobiologists to stop looking for machine-like order in a biological organ that thrives on the creative energy of chaos and feedback is going to take more than a few experiments and lots of enthusiasm." McCrone quotes Scott Kelso, a brain/behavior dynamicist: "If we are serious about the brain as a self-organising system, then we need new tools, new concepts, a new language. Even the way we measure the brain has to be different."

Re-enter Roger Penrose (The Large, the Small and the Human Mind, Cambridge University Press, 1997), who points to the interface between classical and quantum physics as being the problem area where the new tools and concepts are to be found. He looks upon this area as being "non-computable," by which he means (p. 126) you could not model it on a computer. He recognizes, however, that this interface is the area we inhabit--it's where our sentience operates--in the sense that we experience it directly whereas we cannot directly perceive the very large structures and effects of classical physics (including relativity) nor the very small structures and effects of quantum physics.

In short, it is the area that encompasses the phenomena of mind and consciousness--let's call these phenomena "mentality" collectively. Penrose sees (p.94) "a fundamental problem with the idea that mentality arises out of physicality," and considers it "a mystery" not currently explainable by physics and not computable that we can feel happy and perceive the color red. Nevertheless, he thinks there is a scientific explanation. We just don't have the right theory yet.

Kurt Gödel interpreted his Incompleteness Theorem as admitting the possibility of AI. Penrose seems to interpret the theorem as admitting the opposite. But Gödel admitted his theory cannot prove the possibility of AI, in which case there could be no test to determine whether anything is truly a free-willed conscious self. And that must include you and me. So if a face appears on your computer screen one day and says: "Hi. I'm a machine, but I'm just as free-willed, intelligent, and conscious of myself as you are" you can never be sure if that's the truth. Stephen Hawking agrees: "If a little green man were to appear on our door step tomorrow, we do not have a way of telling if he was conscious and self-aware or was just a robot." (p. 171) Essentially, he believes you have to take someone else's consciousness on faith. The only consciousness you can be sure about is your own.

If there were an algorithm that could lead to such a being, Penrose thinks the algorithm would "presumably" have been shaped by natural selection for human beings but "would have to be created by deliberate AI construction" for non-human (i.e., non-biological) beings. I think he's right about the human beings but wrong about the non-human beings. He's right also in thinking that "understanding"--a hallmark of intelligent beings--is dependent on the "ability to be aware of things"; in other words, a mind must be able to experience the world, and the only way to do that is through a body and its sensory and motor assemblages. (That's an old argument for why God needs us, and can be used quite logically to defend the not un-Christian, process theology notion that we are both God and part of God.)

But he's wrong in thinking that understanding is "not a computational quality," unless you declare heuristics to be non-computational, which is OK if you want to be semantic about it, except that modern AI makes extensive use of computational heuristics! Hawking disagrees flatly with Penrose's view that intelligence cannot be simulated on a computer.

My, what a mess.

Penrose is not without suggestions, however, for sorting it out. At the theoretical level, he has an inkling that a quantum theory of gravity would clear things up, and at the experimental level, he'd like the neurobiologists to look for signs of quantum communications in the brain (he specifically suggests looking inside the microtubules of nerve cells, that seem to function like wave guides). Let's hope someone takes him up on the challenge.

P.S.: Apropos of nothing other than my penchant for ribbing philosophy, in a chapter contributed to Penrose's The Large, the Small and the Human Mind, philosopher Nancy Cartwright mentioned a recent seminar series conducted jointly by the prestigious London School of Economics and King's College, London. The series was called "Philosophy: Science or Religion." Apparently, they still don't know. :)

NEXT WEEK: Moravec Mulls Mind (4): Hans Moravec believes so strongly in mind as computer (program) that he foresees a day when you'll be able to store your "self" on floppy disk and have yourself replicated in machines.

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