PW: In your acknowledgements, you write that The Road to Reality was eight years in the making. What made you decide to start this project?

Roger Penrose: After The Emperor's New Mind had been out for a few years, it had been suggested to me by various sources that some people had quite liked the way that I'd described the science, but were unhappy, they wouldn't want to use it in a course (say a 'Physics for Poets' course or something like that) because of all the contentious stuff about the mind. They asked if it wouldn't be possible to take those chapters, remove all the contentious stuff about the mind, and then they could happily use it in their courses. I thought that didn't sound too bad; I'd just take my scissors and cut out all the bits about the mind, and leave in the physics.

This, however, didn't make much of a book, because when I removed the search to find out what on earth's going on in producing mentality, the motivation for the book somehow dropped away. I felt it needed a different thread of motivation, and the obvious one was the search for the laws that governed the world. So I kind of started all over again, thinking, "Well let's do it that way, instead." What happened, of course, is that as the book went on I realized that there were certain topics that I hadn't addressed, and they needed to go in somewhere. In trying to explain various different things, the book got a bit longer than I'd originally intended.

PW: Why did you choose to treat the mathematics underlying physics on its own terms, rather than drawing analogies that might seem more accessible?

RP: I'd read some reviews of the book where people had said, "Why do we need all these mathematics? So-and-so has written explaining physics without any mathematics, so why do we need all this stuff?" The answer to that seems to be that you can appreciate the plot of The Magic Flute by just simply reading about it, but if you don't hear the music, you've missed the point, [which is] to realize that there is beauty in there, it's not just a means to understanding the laws, it's something in itself which is worth trying to appreciate.

PW: As you were writing, whom did you imagine as your ideal reader?

RP: There really are different kinds of readers for the book, and I didn't have any particular one in mind when writing. On one hand, there's the reader who is familiar with the physics that I am describing, who can read for my particular views on the disputes between theories, while there's an entirely different sort of reader who might be learning these things for the first time. Both can find things of value here. Imagine the hardest case, a reader who might be intimidated by some of the more technical arguments.

PW: What would you like him to come away from your book having learned?

RP: What would please me the most would be if somebody who just had no feeling for mathematics beforehand came away and thought, "This is something I'd really like to follow." Just the idea that there's some beauty in mathematics that they might not have thought was there. More than any specific topic, just the general feeling that there's a whole area here that's opened up to them, that they hadn't appreciated prior to that.