Sir Roger Penrose

Speaker 30:00

Hello, I'm Kirsty Young, and this is a podcast from the Desert Island Discs archive. For rights reasons, we've had to shorten the music.

Speaker 30:08

The programme was originally broadcast in the year two thousand, and the presenter was Sue Lawley.

Presenter0:30

My castaway this week is a mathematician. His love of puzzles helped him to discover how tiles of certain shapes can be laid out in a pattern which never repeats itself, a profound achievement of mathematical thought, as well as a useful concept, it turns out, for the manufacture of non-stick frying pans. As a follower of Einstein, he believes that the universe is unbounded and will grow forever. And with this comes his firm conviction that the human mind operates in such a way that it can never be outsmarted by a computer, an argument he put forward in his most famous book, The Emperor's New Mind. Science and fun can never be separated, he says. You've got to enjoy it. He is the Emeritus Rouse Ball Professor of Mathematics at Oxford University, Sir Roger Penrose OM. Does it go on being fun, Professor, even at your distinguished heights?

Sir Roger Penrose1:20

Good heavens, yes. I mean, it's something.

Sir Roger Penrose1:22

One never loses the enjoyment of, I think.

Presenter1:25

But it's something you began doing. Play you've played puzzles of one kind or another all your life.

Sir Roger Penrose1:29

Well, this goes back to my family and upbringing. My father was professor of human genetics, but uh he had an interest in mathematics and uh puzzles and there was no dividing line between his serious work and what he did for fun. He used to make things for his children and for his grandchildren and

Presenter1:47

So you had two brothers and together you and your father played played human chess, I think.

Sir Roger Penrose1:47

So you

Sir Roger Penrose1:52

My father and I and my two brothers used sometimes to go for long walks and uh one of my brothers was way back at the back, my father was in the middle and my other brother way off at in the front. And they would be playing this game Kriegspiel in their heads. That's a game where each player doesn't know where his opponent's pieces are. He only knows where his own pieces are. And my job was to be the runner. I would I would carry the move from one player back to the to my father and then to the other player and so on.

Presenter2:20

And what about at school? Because I understand you also questioned even things like times tables. You never accepted took anything for granted, as it were.

Sir Roger Penrose2:29

I was always somebody who had to sort of work things out for myself, I think. I mean, I was always very slow. You might think being a mathematician I was good at doing sums and all that. But I once actually got moved down a class because I couldn't do mental arithmetic. And later on at the same school, there was a a much more enlightened teacher, I think, who realized that even though I didn't get necessarily get very good marks in my maths exams, it was because I was just too slow. And so he allowed anybody to take as long as they liked on the tests. And finally, I used I used extremely well then.

Presenter3:02

But was that because you were not accepting that s six sevens are forty two?

Sir Roger Penrose3:06

I don't think it was I didn't sec accept it. I probably had to work it out each time. That's a problem, you see.

Presenter3:11

And did you lie in bed as a boy thinking about numbers?

Sir Roger Penrose3:14

Well, there was one particular occasion I remember

Sir Roger Penrose3:17

I can't remember how old it was, about young, probably about ten or so. When I

Sir Roger Penrose3:21

One knows that two plus two is equal to two times two, you see. And I happened to notice that three and a half times one half was equal to three and a half plus one half. And I mentioned this to my brother Oliver, and he then went away and worked out some formula, you see. And I was so amazed by this that you could actually encapsulate all these different instances of some property in a in a in a formula. And it was one of the things that that set me on my course as a mathematician.

Presenter3:48

Well, you say it set you on your course, but you didn't intend to do it as a job, did you? You didn't intend mathematics to be your life. You just thought it was fun, as we say.

Sir Roger Penrose3:55

Secretly I was going to be a brain surgeon. I was going to discover the secret of consciousness or something by opening up people's brains. And it was at a certain stage when I was at school and each of us had to go up and see the headmaster one after the other. And I was going up to the headmaster believing I was going to be a doctor. And he said, well, what do you want to do in your final two years? And I said, well, I'd like to do biology, chemistry, and mathematics. And he said, no, you can't do that. If you're going to do biology, you can't do mathematics. Mathematics, you can't do biology.

Presenter4:24

One one of those school conundrums.

Sir Roger Penrose4:25

Exactly. And at that stage, I just didn't want to lose the maths. I said mathematics, physics, and chemistry.

Presenter4:31

Not surprisingly, it has to be said, you're taking a lot of bach to your desert island. You want to tell us about the first one?

Sir Roger Penrose4:36

Yes. Well, I I had this sort of image that I'd probably take entirely Bach, but that might be boring to people, I suppose. But music, there is this relation to mathematics, which I think you find particularly with Bach. But you you sort of use the mathematical things like subtle key changes and things like that in a way which creates incredible emotion. And I think uh one of the places you find this to an enormous extent is in Bach's B minor Mass.

Presenter6:00

Part of the Crucifixion from Bach's B minor Mass performed by the Taverner Consort and Players, directed by Andrew Parrott.

Presenter6:07

Some people might argue, Roger Penrose, that uh a piece of music, a Bach fugue, for example, is so mathematical that a a a computer could compose it. From what you said just now in the introduction to that piece of music, you don't believe that's possible.

Sir Roger Penrose6:21

Music has an emotional content, but the important thing is you have to be aware of it.

Sir Roger Penrose6:25

And what a computer is not is aware, in it certainly in my view of what things how things work, that computers can compute, that's what they're there for, but they don't actually know what they're doing, if you like. They're not conscious.

Presenter6:39

They only know the rules that have been input into it.

Sir Roger Penrose6:42

Yes, well some people might argue that whatever consciousness is, it has to be a result of some kind of computation. But I think there's something quite different going on as well. And uh we don't know yet what it is.

Presenter6:51

But that's of course where those who champion the creation of artificial intelligence have parted company with you, isn't it? They accuse you of being a romantic, of looking for dramatic proof of the specialness of the mind and they're saying, look, look, we can we can imitate this

Sir Roger Penrose7:07

If you think that's all that's going on, then okay, they will get devices which will exceed human capabilities of a purely computational nature. But I think there's something else which goes to the roots of what's actually the universe is made of, if you like. There are things we don't deep things we don't know about the universe and what the constituents of the universe are. And one of these, I'm sure, relates directly to our awareness and our consciousness. And it's completely absent from a purely computational activity. And to appreciate a piece of music, you have to hear it, you have to form judgments, you have to.

Presenter7:44

You have to react to it.

Sir Roger Penrose7:45

You have to react. There has to be an emotion, if you like. F feeling is a good word, because it means you actually feel it. And that's what the computers don't have. They don't have feeling.

Presenter7:53

L let me just get this straight, because you're agreeing that a computer can play chess because there are rules and although there are billions of mo possible moves, there's a finite number and a computer can chug through and eliminate it's a process of elimination and it can arrive at the best one.

Sir Roger Penrose8:09

Nation

Sir Roger Penrose8:11

But there are good examples even in chess. I mean, we know with Deep Blue that that that they it can play extraordinarily well, but um there are chess positions that are specifically constructed.

Sir Roger Penrose8:22

to distinguish between human beings and computers because they they're

Sir Roger Penrose8:26

If you just do it by computation, which you can do, they're just too complicated, and even too complicated for Deep Blue. It just takes too long. Whereas you present it to a human player and it's completely obvious what you should do.

Presenter8:37

But isn't he isn't he taking a gamble in that moment? And and of course computers don't take gambles, they only do something that is totally logical and by the rules.

Sir Roger Penrose8:45

You can build in the gambles, you see. These are are not quite the reasons, you see. And and certainly AI people, artificial intelligence people will will say, yes, well, we can build in gambles, we can all do all that kind of thing. But what they can't build in is the judgment and the understanding and the feeling.

Sir Roger Penrose9:02

Record number two. Well, I think an important part of upbringing.

Sir Roger Penrose9:06

In my family was my father's interest also in music. He had a great appreciation of music. He also wrote music and and i in a sort of amateur way and and even pieces where you had to turn the page upside down to finish the piece and so on. One of his great interests was was Mozart, so I I'd like to have part of the concerto number twenty-one.

Speaker 19:16

And and

Presenter10:28

Part of the second movement of Mozart's piano concerto, number twenty one, in C major, played by Alfred Brendel with the Academy of St. Martin in the Fields, conducted by Sir Neville Mariner.

Presenter10:38

So let's go back to Penrose, the boy who wanted to be a brain surgeon. I I get the impression that mathematics it wasn't just that they were fun, that puzzles were fun, but also that somehow and you've said this they were a kind of refuge. A refuge from what?

Sir Roger Penrose10:54

It was sort of curious because my parents quite often had arguments, and I always felt somehow that my father's arguments were totally ridiculous, and my mother was right. But on the other hand, I had this kind of emotional feeling with some of the things he was saying, and I couldn't quite figure out what it was. But it's the sort of thing I couldn't face in a way. There were these conflicts.

Sir Roger Penrose11:16

Doing mathematics is a way of retreating from the world, in the world of people.

Sir Roger Penrose11:21

There's no answer about what's right and what's wrong. Whereas in mathematics you have this rock-solid base, and it's somewhere you can stand and you can build a world around that. And later on you can somehow break out from this world and relate to the outside world. But it's a way of sounding.

Presenter11:36

Can you break out?

Sir Roger Penrose11:38

Well, I hope so.

Presenter11:39

Uh

Sir Roger Penrose11:39

I certainly try and do that.

Presenter11:41

Your father was obviously a very dominant man.

Sir Roger Penrose11:43

He was very dominant. He didn't allow my mother to to practise medicine. She was uh she was uh medically trained. It was it was somehow he found it embarrassing if she if she was doing serious things out in the world. I don't quite know what it was.

Presenter11:56

But did you feel

Presenter11:58

you and your brothers sort of driven by him, that you had you obviously have all been high achievers. Your your brothers have been chess champions and mathematical physicists and so on. You you know, you all went on to do amazing things.

Presenter12:09

Was he

Presenter12:10

driving you to that, do you feel?

Sir Roger Penrose12:12

I don't think it was quite like that. I think it was more

Sir Roger Penrose12:15

That he had a tremendous excitement in science, which he shared with us.

Sir Roger Penrose12:22

A good example of this is when at school I happened to mention to my father that the next day we were going to learn calculus at school, and he immediately took me away and did his best to teach me calculus.

Sir Roger Penrose12:34

Not because he wanted me to go head or anything like that, but just because he wanted the pleasure of showing me the beauties of calculus.

Presenter12:41

Tell me about your third record.

Sir Roger Penrose12:43

My wife always accuses me of choosing gloomy pieces of music, so this is a a nice antidote to that. It's also something where where I went with my wife in Vienna to to the ballet and we heard Procofiev's Romeo and Juliet, and I just want to choose part of that, which is very uplifting.

Presenter13:59

Dance of the Nights from Act One of Prokofieff's Romeo and Juliet, performed by the Boston Symphony Orchestra conducted by Seiji Ozawa. Before we leave the um the part that your father played in your story, Roger, we have to mention the Penrose Staircase. Now, I'm not sure whether he or you invented that.

Sir Roger Penrose14:16

I was, I think, in my second year as a graduate student at Cambridge, and I went to the International Congress of Mathematicians in Amsterdam, where they had an exhibition of the work of M. C. Escher. And I was stunned by the various sort of impossible structures that he constructed. And when I got back, I decided I would try something of that nature myself.

Presenter14:36

They're rather surreal kind of paintings where strange things happen that you couldn't possibly build. I'm trying to give a picture of the

Sir Roger Penrose14:37

Yes.

Sir Roger Penrose14:40

Yes, buildings which are which you couldn't imagine with gravity directions going in different directions at once. And I thought I would do something like this and produce, after various attempts, a thing which is now referred to as a tri-bar. It's a triangle consisting of four rods at right angles to each other.

Presenter14:58

You couldn't possibly make it because the right angles wouldn't sit.

Sir Roger Penrose14:59

You couldn't make it.

Sir Roger Penrose15:02

And I showed this to my father, and then he he became fascinated and produced all sorts of impossible buildings and so on, and then produced the w the impossible staircase, which is n now sometimes referred to as the Penrose Staircase. Then we sent a copy to Escher, who then incorporated the staircase in his lithograph Ascending and Descending.

Presenter15:23

But what is it?

Sir Roger Penrose15:25

It goes round and round and round and and you seem to be going up all the time and you're back where you are.

Presenter15:30

Or down and out.

Sir Roger Penrose15:31

Or down, that's right. And in Escher's picture they there are monks which go up one way around, they go up and up and up all the time. The other way around, they go down and down and down all the time.

Presenter15:39

So this is art meeting science. Science meeting art. So i it's not at all surprising that that therefore as a student you know you you were interested in in patterns.

Sir Roger Penrose15:40

In sense, yes.

Presenter15:47

And in patterns that have repeats, because as we know, all patterns do, rather like when you're hanging wallpaper or material on a bale or whatever, at some point there is a repeat.

Presenter15:57

Was it a given that there was no such thing as a pattern that did not repeat itself?

Sir Roger Penrose16:02

Well, there's no problem in making a pattern not repeating itself. You could just s do something randomly. But there are many patterns things like a jigsaw puzzle. You can have a number of pieces, but many copies of each piece. And the question is can you put them together to form a a completed jigsaw? Well, you only say you have three or four different pieces.

Presenter16:20

So you've got no gaps, no overlaps.

Sir Roger Penrose16:20

No gaps, no.

Sir Roger Penrose16:23

That's right.

Presenter16:24

It's got to be flat and it's got to go on and on and on.

Sir Roger Penrose16:26

On and on. But the normal way you'd think of making that uh happen with a finite number of pieces would be to have a pan pattern which like wallpaper, which repeats itself.

Sir Roger Penrose16:35

But there are certain sets of carefully designed shapes which will only fit together in a way which never repeats itself.

Sir Roger Penrose16:45

And I I was really just playing around and producing designs which I thought were attractive in one way or another.

Sir Roger Penrose16:53

But then I found that there was a pair of two shapes which the only way you can fit them together is in such a non-repeating pattern. And it didn't take long to realize I could find six pieces which did this. And I then somebody mentioned it that an a mathematician by the name of Rafael Robinson had another set of six pieces which did the same thing. So I thought, well, I can do better than that. I knew I could glue two of my bits together and do it with five, you see. And then I thought for a bit. It took it only a day or so. And then I realized you could do it with two.

Presenter17:21

What are the two shapes?

Sir Roger Penrose17:23

Well, there are different versions. There's one the easiest to to

Presenter17:26

Um

Sir Roger Penrose17:27

Play whether really things were kites and darts.

Presenter17:29

We'll find out what happened to the pattern in a minute, but let's pause there for another piece of music. Number four.

Sir Roger Penrose17:34

Well, I wanted to have something by Roslyn Turek. I heard her play Bach when I was a graduate student in Cambridge, and and I find it it's really wonderful to hear it first hand. And I've just chosen a piece which I think illustrates um this, the Bach fantasy in C minor.

Presenter18:34

Rosalind Turek playing part of Bach's Fantasia in C minor. So when when did you spot, or or indeed was it you who spotted, uh, that that this incredibly special pattern of yours appeared to be being used on on a leading brand of lavender paper?

Sir Roger Penrose18:51

I wasn't the one who first spotted it, was my wife, because somebody who had previously inhabited the house we just moved into had been using.

Sir Roger Penrose18:58

Uh this particular brand of loop paper.

Sir Roger Penrose19:01

And it appeared that the patterns of mine were.

Sir Roger Penrose19:04

Perhaps being used on this.

Presenter19:05

Too clever of her to spot it.

Sir Roger Penrose19:07

Yes. Oh no, she's she's good at these things. We've also got better eyesight for close close things.

Presenter19:13

We should explain that you have to be careful on this because uh there there was in the end a court case about it, about the fact that that a non-repeating pattern w w was used on on this paper and there was an outer court settlement. But but the you can explain the fundamental issue, can't you?

Sir Roger Penrose19:27

I should make clear that that the issue is not so much that I was worried about people using the pattern, but there is a company that uh uses my designs called Pentaplex, and uh it was more of a concern for them.

Presenter19:40

Can we explain this then? Why would it have been good to to use such a pattern on lavatory paper?

Sir Roger Penrose19:45

Well, the issue, I think, was the nesting problem. If you have patterned lavatory paper, then there are certain places where the pattern will kind of

Presenter19:53

Mm-hmm.

Sir Roger Penrose19:53

nest into itself.

Presenter19:54

Sit in sit inside.

Sir Roger Penrose19:55

Yeah.

Presenter20:01

But you can see that in marketing terms, that if it if it didn't repeat and if it curls round and round on itself, then it remains big and bouncy and soft. It's bigger actually, isn't it?

Sir Roger Penrose20:10

Testing. That was the idea. But I think, as I say, one has to be careful about this. And the issue always was whether a pattern had been copied from something covered by my copyright or whether it was

Presenter20:24

Hmm.

Sir Roger Penrose20:24

Generated independently by a mathematical prescription, which is public property.

Presenter20:28

What is interesting though, of course, is that

Presenter20:32

Surely as as a pure mathematician you would say that all patterns exist, it's merely in that they're possible, it's simply that no one has found them, no one has come across them like you did that one?

Sir Roger Penrose20:43

Yes, but I think you uh I mean, you might say the same of art or music. You see, all combination of notes exists in a sense, but certain combinations have properties of of carrying emotional content and so on.

Presenter20:56

And why is this pattern then let's get on to less sticky ground as it were appropriate for non-stick frying pans?

Sir Roger Penrose21:03

This is quite an interesting story because initially I was just playing around, you see. And then about ten years later it was discovered that there are substances that can be produced artificially which seem to be of the same nature as my own patterns. And it's now believed that these materials known as now known as quasi-crystals turn out to be very hard because you can't in ordinary crystals has planes of cleavage where you can slip things along these planes. But these things, because they never quite repeat themselves, don't have those things. They don't have planes of cleavage. And it was discovered that these materials made out of quasicrystals were really excellent for frying pans. They form non-stick frying pans which you can scratch with your knife and it doesn't hurt them at all. There's one thing you mustn't do with them, that's fry eggs with them, apparently.

Speaker 121:50

Yeah.

Sir Roger Penrose21:50

I don't know, but there's something the eggs seem to react with them in some way.

Presenter21:55

Well, there we are. So so there we see all the applications that this pure mathematician has come across in his working w with this subject. But they're detours for you all of those, aren't they?

Sir Roger Penrose22:06

Well, it's part of this this fact that there's no dividing line between what you do for fun and what what's serious science that that I got from my father.

Presenter22:13

Record number five.

Sir Roger Penrose22:15

I want to have something of Schubert, uh, because I really have a a soft f spot for Schubert, and I d I I finally settled on the string quintet in C major.

Presenter23:20

The end of the second movement of Schubert's string quintet in C major, played by the Emerson string quartet and Rostropovich. So we come to your largest project, Roger, one which has held your attention for the last thirty years or more, I think, the twister theory. Is it is it possible to describe it in simple terms?

Sir Roger Penrose23:38

I think the shortest.

Presenter23:38

Yeah.

Sir Roger Penrose23:39

The short answer to that is no, but I can say what it's trying to do, if you like.

Sir Roger Penrose23:46

It's trying to form a bridge between the physics of space time and that means really Einstein's general theory of relativity, that's space and time and gravity and the physics of the small, which is quantum mechanics. Describes how atoms and molecules and things behave in a very mysterious way.

Sir Roger Penrose24:05

And it's a way of trying to unify these two ends of the spectrum. I think the only thing I can really say here is that the physics of the small, that's quantum mechanics, uses numbers which are to the non-mathematician strange, called complex numbers or imaginary numbers.

Sir Roger Penrose24:24

There is a certain use for these numbers also in relativity theory. Let me just explain. If you imagine you're out in space and you look out at the sky, you see a sphere out there.

Sir Roger Penrose24:35

and some colleague comes whizzing by at nearly the speed of light, and just as this colleague passes you, looks out at the same sky, and this sky will be slightly deformed from your own sky.

Sir Roger Penrose24:47

The the stars will be in slightly different positions and so on. And the transformation that from your sky to your colleague's sky is one which can be best described in terms of these strange complex numbers. And twister theory sort of builds on that as a fundamental fact, because I think usually people have the view that the physics of the small, which is quantum mechanics, really governs everything. That if you know how small things behave, then you in principle you know how everything behaves.

Presenter25:13

So that's conventional for the future.

Sir Roger Penrose25:13

That's conventional.

Sir Roger Penrose25:15

But I don't think this is correct because quantum mechanics is is in a certain sense inconsistent and doesn't really make sense at a large scale. So what one is trying to do with twister theory

Sir Roger Penrose25:26

is to try to combine the physics of the small and physics of the large, if you like, space-time structure, in a more even-handed way, where each there's give on both sides.

Presenter25:36

And if you're right and I you know this may sound a a a very kind of literal question but if you're right will it be as important I'm just trying to get the scope of this will it be as important in time to come uh as, for example, Einstein's theory of relativity. Will there be generations of school children in time to come who might talk about the Penrose Twister theory?

Sir Roger Penrose25:55

Well there's a big if there. Well let me d say this thing, which is also a little bit unconventional. I would say that the physics of this century is going to involve some changes in the structure of quantum mechanics. I think that the physics of the large and the small will combine together in a way which will be a revolution at least as large as that of Einstein and of quantum mechanics. Now whether twister theory plays a big part in that or not is is a personal matter and I think I'd rather not venture an opinion.

Presenter26:25

But I suppose what you have to accept is, because of the nature of the kind of work you do, is that the result

Presenter26:31

Almost probably won't be achievable in your lifetime.

Sir Roger Penrose26:35

I think one of the things about doing

Sir Roger Penrose26:38

This kind of physics is to be incredibly over optimistic. You have to think that, you know, the just round the corner is the solution to all these problems and you will see the light. But the the altruism is there too. I mean, we don't really expect that.

Presenter26:51

Record number six.

Sir Roger Penrose26:53

I I I I think I s expressed at the begin beginning that I would like to have all Bach if I really had my choice. In fact, probably what I would have done would be to have all Bach cantat cantatas, and I've just selected one out of these, which I think is one of the more

Sir Roger Penrose27:06

Quite extraordinary pieces. It's really extraordinarily complicated and discordant in ways which I think it will take me all my time on the desert island to figure out what's going on.

Speaker 127:34

We turn on the spirit.

Presenter28:15

The opening of Bach's cantata number 101, Nymph von Unsher du Treuer Gott, performed by the Tolze Knaben Corps with the consentus Musicus Veen, conducted by Nicholas Arnenkor, and memories, um, Sir Roger Penrose, of your mother. You've just become a father again for the fourth time. You have three grown-up boys and now a brand new baby called Max. What's it like becoming a new father in your late sixties?

Sir Roger Penrose28:39

Very exhausting. I say wonderful on on the one hand, but ex totally exhausting on the other.

Presenter28:43

Are you more or less help than the first time around?

Sir Roger Penrose28:47

Probably less help, I would think, but but I do my best, yes.

Presenter28:50

Do you did you set your your big son's and will you set your small son, your new son, uh, puzzles in the way that your father did?

Sir Roger Penrose28:57

Curiously enough, you know, he's only um a month and a half now, but he he takes an interest in geometrical things, where there are sort of patterns that you're supposed to

Sir Roger Penrose29:06

you know, when they sit in the car, this car seat has to just face the back seat. And what I've noticed is that what he likes are these very intricate geometrical patterns rather than faces and things like that. He's he's much more interested in the geometry.

Presenter29:17

I wonder why.

Sir Roger Penrose29:18

Well I don't know yet.

Presenter29:18

And then we have a

Presenter29:20

C can I uh really sort of bridging through from that to your your your professional life. I mean, you obviously strike one as being a very gentle man who who who doesn't like upsetting people. And yet what you have done in your professional life is upset a lot of people because you've challenged

Presenter29:36

An awful lot of conventional thought. And it's interesting that it's a contradiction in you, isn't it?

Sir Roger Penrose29:41

Well, I'm not sure it's a contradiction. It certainly was disturbing. I I didn't expect people to react quite the way they did in the artificial intelligence community. I have nothing against them. I think what they do i is fine and they'll produce all sorts of wonderful gadgets and so on. It's just that that isn't the answer to the problem of what our consciousness is about. And I've got a different view, but sometimes they get very angry with this, which I find rather extraordinary.

Presenter30:07

But y isn't it that you find it more than extraordinary? You you actively don't like doing it, you find it uncomfortable, it's not the kind of person you are, that's not a problem.

Sir Roger Penrose30:15

I don't like upsetting people, no. But on the other hand, I do feel strongly I need to say what I think.

Sir Roger Penrose30:22

uh if it's important to say it. And if that upsets people, I find that disturbing. But it's not that I'm doing something because I want to upset anybody.

Presenter30:32

Record number seven.

Sir Roger Penrose30:33

I've chosen a lot of Bach, but I want to say that there are a lot of other composers that I I feel for a lot, and uh one of these is is uh the Grosser Fuga from the string quartet number thirteen.

Speaker 131:04

Yeah.

Presenter31:37

Part of the Grosser Fuger from Beethoven's String Quartet No. thirteen in B flat major, performed by the Albenberg Quartet. Um so your desert island will be full of beautiful music, Roger, which is one advantage of being a castaway. Can you see any others?

Sir Roger Penrose31:52

Well, I do like to be by myself. This is certainly true. For certain lengths of time, and the point comes when I really want people. But the one real difficulty I would have is would be if I thought I had to catch animals to eat and survive. If there were lots of wonderful fruits and so on, that's great. I don't know whether I could manage to eat fish. That would be a even that would be a wrench.

Presenter32:12

And would you try to escape?

Presenter32:16

You got a plan.

Sir Roger Penrose32:17

I have a plan, yes. Well the plan would be, yes, to to construct objects which I'd drift out into sea. Nowadays, I mean there are lot lots of people looking down on the earth from the sky, and so I would try to build some absolutely enormous structure out of I hope that I hope I worry about the desert part of the desert island. I hope that there actually are trees and things which can u one can use to build structures. So I would do this so that they could be seen from from the sky.

Sir Roger Penrose32:42

Last record.

Sir Roger Penrose32:43

One of my problems is is that uh sort of thought about, you know, should I branch out and have some some popular piece of music or something. But my wife was very insistent, no, she doesn't like it when people do that, if you're really a classical person. But uh the thing of classical music she really loves, and it's something which I've loved almost from birth, I would say. I think it's one of the most perfect pieces of music ever written, the Bach double violin concerto.

Presenter34:00

The end of the third movement of Bach's double violin concerto in D minor, performed by the Academy of Ancient Music, conducted by Christopher Hogwood. And you're so confident, Roger Penrose, you tell me, about this escape plan working, that you're worried you're not going to have enough time on the island.

Sir Roger Penrose34:15

Well, that's overconfidence again that I I w I warned you about earlier.

Presenter34:19

Now, if you could only take one of those eight records, which one would you take?

Sir Roger Penrose34:23

Well, I think it has to be the the B minor map, especially if I get the whole lot of it. I'm never quite sure whether I just get one record or do I get the whole of it.

Presenter34:27

Never quite sure.

Presenter34:29

No, we'll end it up quite on.

Presenter34:31

Yeah.

Sir Roger Penrose34:32

It'll be minor masks, especially if I get the hold of it.

Presenter34:35

What about your your book?

Sir Roger Penrose34:37

Well, what I need is something to keep me cheerful, I think. What I really love to have is a nice collection of Michael Frayne's incredibly funny articles. I'm not quite sure which one, but that whichever is the fattest, I think.

Presenter34:50

And your luxury.

Sir Roger Penrose34:51

And from my luck to something a little bit odd, I think. What I would like to have is specially constructed for me, of course, because they know I'm going to be on this island, is a nineteen note piano. Normally one has twelve different notes in the octave, but it's the twelve is a wonderful fit to the main chords and the Pythagorean scale. This is mathematics again, you see. And the next number, which is a a beautiful fit, is nineteen. And f as far as I know, almost no music, very little music has been composed for the nineteen note octave. And what I would like to do in the few weeks that I have is to try and compose music on this wonderful piano which I'll have, nineteen note piano, for the nineteen note scale. And because I think one could do some wonderful things with it.

Presenter35:41

Sir Roger Penrose, thank you very much indeed for letting us hear your desert island discs.

Sir Roger Penrose35:44

Thank you.

Speaker 335:53

You've been listening to a podcast from the Desert Island Discs archive. For more podcasts, please visit bbc.co. uk slash radio four.