Penrose, Roger

Jan 19, 2010 3:05 PM  (note this is from 1995)

This quote is taken from Dennett's essay on intuition pumps here

http://www.edge.org/documents/ThirdCulture/r-Ch.10.html

Roger Penrose: Dan Dennett is obviously somebody who'll listen to arguments. The title of his book Consciousness Explained is overstated, however. I certainly don't believe that those ideas explain consciousness.

He's exploring what I call "point of view A," in the list of four viewpoints I discuss in Shadows of the Mind, which I call A, B, C, and D.

A is the strong artificial- intelligence viewpoint: that is, that mentality is to be understood in terms of computation. It doesn't matter what's doing the computation; a computer or a biological structure would be equally good.

Point of view B — which is more the philosopher John Searle's viewpoint, as I understand it — is that you could simulate the action of the brain, but the simulation wouldn't have mental attributes, so there's something other than computation involved in conscious thinking.

That differs from point of view C, which is my own point of view and asserts that you can't even simulate conscious activity. What's going on in conscious thinking is something you couldn't properly imitate at all by computer, according to C.

Point of view D asserts that you can't understand mentality in terms of science at all. So I'm saying, "Yes, it's science, but it's science of a kind that eludes computation." Dennett belongs to the A point of view, of which he's one of the best exponents. Another person representing this point of view is Hans Moravec, who's written an interesting book, where he takes this point of view to its extreme and argues that within thirty-five years or so the computer will achieve our level and then race beyond us.

There are at least two different kinds of arguments you can use against A. One is the John Searle type of argument, which is that just because something carries out computations, that doesn't make it capable of being aware of anything. That argument has quite a lot of power to it. But my argument is different, because it argues against both A and B. It's a stronger argument, because it says that you can't even properly simulate conscious actions. If something behaves as though it's conscious, do you say it is conscious? People argue endlessly about that. Some people would say, "Well, you've got to take the operational viewpoint; we don't know what consciousness is. How do you judge whether a person is conscious or not? Only by the way they act. You apply the same criterion to a computer or a computer- controlled robot." Other people would say, "No, you can't say it feels something merely because it behaves as though it feels something." My view is different from both those views. The robot wouldn't even behave convincingly as though it was conscious unless it really was — which I say it couldn't be, if it's entirely computationally controlled.

Penrose, Roger

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