Friday, October 15, 2004

The Remarkable Mind of Roger Penrose

It's been a while since I read Roger Penrose's Shadows of the Mind, an exploration of consciousness and the possibility of replicating it in computers. Penrose is a scientist with his head screwed on right, as I am reminded by an article by Martin Gardner in The New Criterion, "Theory of everything." There, Gardner reviews Penrose's new book, The Road to Reality: A Complete Guide to the Laws of the Universe.

First, Gardner summarizes Penrose's views on the replicability of consciousness:
...Penrose’s two best sellers, The Emperor’s New Mind and its sequel, Shadows of the Mind, were slashing attacks on the opinions of a few artificial intelligence mavens that in just a few decades computers made with wires and switches will be able to do everything a human mind can do. Advanced computers, it was said, will some day replace the human race and colonize the cosmos! Penrose disagrees. Not until we know more about laws below the level of quantum mechanics, he argues, can computers cross that mysterious threshold separating our self-awareness from the unconscious networks of computers. Maybe the threshold will never be crossed. Computers of the sort we know how to build obviously are no more aware of what they do than a typewriter knows it is typing....

Now, on to physics:
Penrose is frank in admitting that he has “prejudices” which other physicists reject. For another instance, he is not impressed by the “many-worlds interpretation” of quantum phenomena. According to this eccentric view, every time a quantum event takes place the entire universe splits into two or more parallel universes, each containing a possible outcome of the event!

Take the notorious case known as “Schrödinger’s cat.” Imagine a cat inside a closed box along with a Geiger counter that emits random clicks. The first click triggers a device that kills the cat. Some quantum experts, notably Eugene Wigner, believed that no quantum event is real until it is observed by a conscious mind. Until someone opens the box and looks, the poor cat is a “superposition” of two quantum states, dead and alive. In the many-worlds interpretation the cat remains alive in one world, dies in the other. This proliferation of new universes, like the forking branches of a rapidly growing tree, naturally must include duplicates of you and me!

If these billions upon billions of sprouting universes are not “real” in the same way our universe is real, but only imaginary artifacts, then the many-worlds interpretation is just another way of talking about quantum events. Yes, the talk erases some of the bizarre concepts of quantum theory, but with such an enormous violation of Occam’s razor....
And that's just a taste of the nuggets to be mined in Gardner's review. Makes me want to buy the book.