Dialogue : Roger PENROSE and SATO Humitaka
Molecular Physics and Consciousness
SH: Now, shall we talk more about your work, such as "tiling" or your interest in the mind ?
RP: Well, people seem surprised that I became interested in questions about the mind when I have been doing physics and mathematics. But in a sense, questions of the mind have interested me for a long time anyway. The viewpoint expressed in my books is one I've held for many years, since I was a research student and first learned about GOEL's theorem and TURING machines.
When I was in my first year as a graduate student in Cambridge, I went to lectures on GOEL's theorem, which was mathematical logic, and on TURING machines. These were not what I was supposed to be doing, as my research was in pure mathematics. On the one hand, GOEL's theorem seemed to me to make it clear that the way we understand mathematics is not just by means of given axioms-because they are never going to be sufficient-one always has ways of transcending the system of axioms. Even if one believes the axioms, one can also believe something that is not the consequence of axioms. This question of axioms is basically a question of computations: any logical system or mathematically formal system is something one could put on a computer, a TURING machine.
This view that some mathematical understanding lies outside what can be achieved by computation I must have formulated when I was in my first year as a research student. But it was just a point of view. I didn't think much about it-we all have our different ways of thinking about philosophical questions. Then I also learned about quantum mechanics from DIRAC, which was a great experience-they were a wonderful set of lectures-and about relativity from BONDI-also brilliant lectures, though in quite a different way. These were not my subjects at all at the time, but they had a great influence on what I did later.
The reason for my actually writing up my views about the mind not being a computational process was basically that I saw a television program where various people were taking a rather extreme computational position. Marvin MINSKY in particular. What they were saying was perfectly logical if one believed that all we do is computation. But I had my reasons for not believing that and since I had an earlier idea to write something at a popular or semi-popular level about science expressing my own very different view, this gave the proposed work a particular focus. So I decided to present my viewpoint in The Emperor's New Mind [Oxford University Press, 1989], which I hadn't seen anywhere else, but which seemed important. And one thing led to another. I hadn't anticipated the reactions I got from certain quarters-of course, I wasn't expecting people to get so angry. So the second book Shadows of the Mind [Oxford University Press, 1994] was meant to address what I thought were misunderstandings on their part. But then people still misunderstood things, because people still want to get angry. It really takes up too much time and it's not what I want to do. I'm much more interested in physics.
I would take the view that we're not going to make much progress on understanding what mentality is, what the mind is, until we know much more about what physicality is. Our picture of the physical world still has a long way to go. A lot of very important things are completely outside our present understanding. Particularly, the question of quantum mechanical state reduction, or if you like, how small-scale of quantum phenomena relate to large-scale phenomena.
SH: Usually, people in quantum mechanics do not consider the mind-this seems a peculiar combination. If I understand you correctly, you're saying that the mind suddenly appeared? This seems to be a bit strange!
RP: Suddenly? I don't think that it was sudden, just like that. It's making use of things that are out there in nature, and must have taken a long time to evolve. And I don't think of consciousness as an on-or-off thing: it's something that evolved gradually and it has a selective advantage. So creatures possessing this quality of understanding, which requires some awareness, had an advantage over creatures that did not. But I don't think this was a sudden process. I think it was something that took a long long time, much more primitive aspects of which must be present in other creatures quite far down in the animal kingdom. I don't think of it as a specifically human quality.
SH: All right, not a uniquely human quality, but anyway, do you think that the mechanics of consciousness is created through interaction with the outside ?
RP: Well, that certainly is important, but I don't think it's the crucial thing. Some people regard interaction with external realities as being an essential part of consciousness, but I don't see that necessarily. Certainly in mathematics, one does an awful lot of internal thinking, which has little relation to the outside world. There's a lot to get on with completely internally. Of course, to get started, one picks up some stimuli from the outside world, and all the time one uses analogies to the outside world, but interaction with the outside is not essential.
SH: Sort of internal observation ? Some processes are internal, but consciousness itself is not outside the system.
RP: One can't have a clear dividing-line, but I don't think of it as outside. It's funny. It's something in the outside world-I mean, it is out there, potentially out there, in the sense that our brains are organized to take advantage of certain potentials in the outside world. No, I don't think of consciousness as something entirely internal. It's potentially in nature, it's potentially in the way the world operates, and beings that somehow can take advantage of this potential have advantage over those who don't.