Ian Stewart

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 30:09

The programme was originally broadcast in nineteen ninety eight and the presenter was Sue Lawley.

Presenter0:31

My castaway this week is a mathematician. For nearly thirty years he's taught at the University of Warwick, which has one of the best mathematics departments in the country. But his reputation stretches far beyond his academic home, thanks to his unique ability to popularise his subject. Maths, he believes, only becomes interesting once you leave school, when there's no longer a right answer. He's written sixty books, the most popular one is called Does God Play Dice, and writes a column for a monthly American magazine. Last year he became only the second mathematician for more than 150 years to deliver the Royal Institution's Christmas lectures. The pattern of stripes on a tiger, the formation of a snowflake, the spirals on the shell of a snail, all these, he says, are part of the magical maze of the mathematician's search. According to him, mathematics is the closest humans get to true magic. He is Ian Stewart. You make the search for explanations to these things, Ian, sound exciting, a kind of dangerous journey with talk of magic and mazes. But the truth is surely that a mathematician takes a logical progression through these things. It's fairly sort of solid stuff, isn't it?

Ian Stewart1:40

It's a mixture of lots of solid stuff most of the time, but th th this inspiration, this feeling that you're in touch with the the universe in certain respects. Every so often you you get that and that's that I think is certainly for me is what keeps me at it.

Presenter1:52

Can you allow inspiration in?

Ian Stewart1:53

Oh, absolutely. But that the mathematician's job in a sense is to start from the inspiration and then you have to turn it into this logical progression. The logical progression is a framework that you impose upon your ideas, partly while you're creating them, but very much rationalizing them afterwards.

Presenter2:10

So you would look for the broad picture as it were and say it would be very interesting if I could prove that big concept.

Ian Stewart2:16

That's right. It's a bit like looking at a landscape and seeing that there's a distant hill or a jungle that you've got to get your way through. And you can kind of see that and you've got some idea of where to go. But then when you get tangled up in the jungle, suddenly you're fighting with the vines and you're hacking your way through the thorn bushes and you didn't realize there were going to be thorn bushes.

Presenter2:34

So you get bewildered and you stumble.

Ian Stewart2:35

That's right. And you stumble. Yes, and then and a large part of the mathematician's existence consists of in effect banging your head against a brick wall. And it's nice when you leave off and the brick wall's not there and you you get this amazing feel hey, wow, now we've cracked it. That's what you're after. That's what you're for. Yes.

Presenter2:49

That's what you're after. That's joy. There is joy in wonder.

Ian Stewart2:52

1% of the time you get this wonderful joy which compensates for the other 99.

Presenter2:57

Why then, if there is joy in it, does mathematics have such a dull image? I mean, I'm sure if you're on holiday or at a party or something, somebody says to you, What do you do? and you say, I'm a mathematician, they kind of cough and look the other way, or get away as fast as they can, you know?

Ian Stewart3:11

Nearly always. The one occasion this didn't happen to me was a lady at immigration in Houston, Texas, who said, Oh, I love math when I was at school.

Ian Stewart3:20

And that's the only time I've ever got that kind of response to announcing to somebody that I'm a mathematician.

Presenter3:25

But I was very encouraged to uh to read that you'd said that if you can pack the boot of a car to go on holiday, then you're probably very good at maths.

Ian Stewart3:33

Well, see, this is people are doing maths or maths like activities. They're doing the fun bit of maths in a sense, the thing that drives the real mathematicians. Packing objects into the boot of a car, this is a sort of three-dimensional jigsaw puzzle. And this is really difficult frontier mathematics to understand

Ian Stewart3:50

good ways of packing things. There's an awful lot about packings we do not know.

Presenter3:53

And there are a lot of people who are very bad at it and others who are very good at it. It's a kind of instinctive thing.

Ian Stewart3:57

Yeah, some people can get twice as much into the car boot as others.

Presenter4:00

Boom.

Ian Stewart4:01

And they somehow better mathematicians.

Presenter4:01

Yeah.

Presenter4:04

Okay. Yeah.

Ian Stewart4:04

Uh

Presenter4:04

Yeah.

Ian Stewart4:05

Yeah.

Presenter4:05

Yeah.

Ian Stewart4:05

Mathematician.

Presenter4:07

And where does ma mental arithmetic come into it? Because I've also read that you say that good mathematicians are ol uh are quite often very bad at mental arithmetic.

Ian Stewart4:16

They often are. There's definitely a difference between being able to do arithmetic fast in your head and thinking in this more intuitive mathematical way.

Ian Stewart4:25

One of the great mathematicians, Gauss, was able to do enormous calculations very fast in his head. He's almost the only one of the great mathematicians who had this facility. But most mathematicians are pretty hopeless at arithmetic. In fact, I mean if I have to do arithmetic, I Reach for my calculator.

Presenter4:42

So does it follow, then, that i i if you're good at mental arithmetic, you're probably no good at packing the boot of a car?

Ian Stewart4:48

I think that's a good idea. You're using different parts of your brain in those two activities. There's no reason why being good at one should make you good at the other, certainly.

Presenter4:48

I think that's a probability.

Presenter4:56

I want to talk to you about probabilities in a minute, but let's pause for your first record. What is it?

Ian Stewart5:01

This is the one that I play to myself in the car at the moment and sing along very badly to. I'm not a good singer, but I enjoy it anyway. As long as nobody else is in the car, this is great fun.

Ian Stewart5:12

It has very interesting lyrics. It's the only record I know that has Marconi in there as part of the lyrics, and it seems to me this is quite an intelligent sort of thing to do.

Presenter5:22

Sinking in your fight

Presenter5:26

Too many, run away.

Presenter5:29

Eating up the night

Presenter5:32

My colleague plays the bumble.

Presenter5:35

Listen to the radio, don't you remember We don't listen

Speaker 35:44

We built the city on our own

Presenter5:50

Starship and We Built This City. Just to show that uh mathematics and the law of probabilities can be fun, Ian Stewart, let me ask you to uh to pose the dilemma which you've often quoted of of of the three doors, door A, B and C. Behind one of them is a a new car, and behind the other two

Presenter6:07

But behind each of the other two is a goat. How does it go on from there? Because obviously what what we want, me the Chris show contestant, as it were, is the new car.

Ian Stewart6:15

That's right. The mathematical point here is to convince you that your intuition for probabilities is faulty. What happens here is you've got three doors, car behind one door, and the game show host says choose a door.

Ian Stewart6:29

And you choose a door.

Ian Stewart6:30

And you think, okay, one chance in three I'm getting the car.

Ian Stewart6:34

After you've done this, he says, Now I'm going to give you an opportunity to change your mind if you wish. What I'm going to do.

Ian Stewart6:40

is take one of the other doors that you haven't chosen.

Ian Stewart6:44

I know where the car is, I know where the goats are. I am going to open one of the other doors and show you a goat.

Ian Stewart6:49

So he does this.

Ian Stewart6:51

And he looks at you and says, Do you want to change your mind?

Ian Stewart6:55

And you're sitting there thinking, Okay, there's the door I originally chose.

Ian Stewart6:58

He's eliminated one door with the goat, so I've got two possibilities, my door or the other one that nobody's actually opened. I've got a fifty-fifty chance, haven't I?

Presenter7:06

I've got a 50-50 chance. I've got a 50-50 chance. There's two doors, there's a car behind one, a goat behind the other. What's the point of changing? What's the point of changing? I'm as likely to be right behind you.

Ian Stewart7:11

Yeah, what's the point of changing?

Ian Stewart7:15

And in fact, psychologically, people don't like to change their minds once they've made a choice.

Ian Stewart7:20

Now if you do the mathematics you find that you're twice as likely to win the car if you change.

Ian Stewart7:26

If you stick with the original choice, you've got one door out of the three. You chose that, that's all there is, that's a one in three chance, and nothing else that happens changes that one in three chance. It doesn't suddenly turn into fifty-fifty.

Ian Stewart7:38

The other two doors between them have twice as much chance as of containing the car.

Ian Stewart7:44

Somewhere.

Ian Stewart7:45

Now what the host does is say to you, if it's behind one of the other two doors, I can tell you which one. It's not the one I show you.

Presenter7:49

It's

Ian Stewart7:51

So it kind of compresses that two chances out of three into one door.

Presenter7:55

But you're right, instinctively we feel it's a 50-50 chance there ain't no point in changing the material I've chosen.

Ian Stewart8:01

That's right.

Presenter8:02

And just to be sure, because it's just difficult to believe you've run that on a computer, what, a hundred thousand runners?

Ian Stewart8:07

I ran it 100,000 times, 33,000 times your first ch sticking with your first choice wins and 67,000 times swapping to the other one.

Presenter8:15

So it it is a fiendishly counterintuitive problem. What do we deduce from that? That that human beings can be determinedly wrong?

Ian Stewart8:26

Our brains have evolved certain abilities for the obvious reason of survival. Really, what we've got is things that helped us survive out on the savannas hundreds of thousands of years ago. And we have, in a sense, subverted all of those to the activities of modern living. And our visual sense was great for survival on the savannah but probabilities don't really help you survive on the savannah very much. Because what are probabilities about? They're about doing the same thing many, many times. Now, if you approach problems like, do I run away from that lion or not? What's the chance he's going to eat me? Well, I will try 100 times not running away to see what happens. You don't survive. So you need a quick and dirty approach to chance. Is it very likely, not very likely, roughly 50-50?

Ian Stewart9:11

And most of our intuition about it, unless you refine it by mathematical calculations, is on this quick and dirty level.

Presenter9:19

But what's the application of this counter i intuitive problem? I mean i what what might we be doing wrong in life because we don't spot what we ought to be doing?

Ian Stewart9:29

A huge number of extremely important things. Our whole attitude to risk, our attitude to planning, to government policy on various things, things like BSE, as a you know, the whole probability of what is the probability of catching BSE if you eat beef? We don't actually know. It's clearly not enormously high, otherwise we'd all have caught it by now.

Ian Stewart9:49

And on the other hand, we're pretty sure it's not zero. But is it one in a million, one in ten million, one in a hundred million? What is it? Record number two.

Ian Stewart9:56

When I was at school in the sixth form I played in a guitar group and of course in those days if you play guitar the shadows were the people you copied. Everyone cut their teeth on shadows records. The Savage wasn't one of their earliest but it's the one I particularly remember because it's from a movie soundtrack and I remember sitting in the movies with a girlfriend at the age of about 15 and watching this thing and there are the shadows up on the stage playing this. I thought this was fantastic.

Presenter10:51

The Shadows and the Savage. History has it, Ian, that you built your career on a broken bone. I think a broken collarbone, to be precise. Can you explain?

Ian Stewart10:59

Yes, it was my mum that saved me for for mathematics and I guess inflicted everything else on the world. Uh when I was at primary school.

Ian Stewart11:07

I was doing quite badly at maths. It wasn't because I couldn't understand it. It was a combination of silly circumstances. On one of the tests, I had added all the sums when I should have subtracted, so I got them all wrong. And I was put down into a lower group. And then that group was split in half. And because my name begins with S, I was in the lower half. So I was in group 3. And although the teacher had split them alphabetically, he kind of forgot. And so the group 3 wasn't getting anything very interesting. It was stuff I knew backwards. And I was getting bored. At this point, a friend pushed me over in the playground. I broke my collarbone.

Ian Stewart11:42

And I was out for five weeks. And so my mother decided, Right, we're going to sort this child's maths out.

Ian Stewart11:48

So she went in and got the text book from the school.

Ian Stewart11:50

And of course I had to dictate to her all the answers, and she wrote them down. And after we'd done four hundred questions from the book and I'd got three hundred and ninety six of them right,

Ian Stewart12:01

She went marching into the school waving this exercise book and said, Why is this child in group three for his maths? And it turned out when I got back, I was about ten weeks ahead of the class.

Presenter12:09

But you also uh eventually had a very good maths teacher, didn't you? Because by the time you got to the sixth form you were really going great gun.

Ian Stewart12:16

That's right. This was a man called Gordon Radford who

Ian Stewart12:19

enjoyed having bright kids in his class who could do maths and would go to enormous lengths to encourage that, and so he gave up all of his free periods.

Ian Stewart12:29

and taught us real maths, interesting things, extra things outside the syllabus.

Presenter12:31

It's anxious.

Presenter12:33

And you sailed through S level, therefore, I think.

Ian Stewart12:35

I sound through S levels. Yes, it was the last year of the state scholarship. I was in the first year of the sixth form and would not normally have been taking A levels, let alone S levels. But because it was the last year, Gordon Radford persuaded the headmaster to let three of us take the S levels and the A levels a year early. And the way he convinced him that this was the right thing to do.

Ian Stewart12:55

We arrived one morning at school and he grabbed three of us and said, Right, you're doing the Mach A levels today with the upper six.

Presenter13:01

With no preparation.

Ian Stewart13:01

No preparation, nothing.

Presenter13:02

Bush Q.

Ian Stewart13:03

Pushed us in. We came first, second and third in the list. He knew this was going to happen. He knew we could do this backwards.

Presenter13:08

Yes. But it's very interesting, isn't it? That that without an interventionist mother, without a very dedicated teacher, you might not be where you are today.

Ian Stewart13:17

That's right. I think this is this is so true.

Ian Stewart13:20

you get this horrible feeling that

Ian Stewart13:23

In in a sense, the way you succeed at these things is by not finding one of the many routes to failure that are sitting there waiting for you. If you're lucky enough to steer clear of this, or there are people around who will grab you and push you back onto the correct road,

Ian Stewart13:37

Then you do find.

Presenter13:38

Next record.

Ian Stewart13:40

Next record.

Ian Stewart13:41

The Beatles, you can't do that. When I was an undergraduate,

Ian Stewart13:45

I for two years made quite a lot of money, quite actually almost as much as my grant, by playing in a rock group with three friends. And then unlike most people who played in rock groups, I then went and spent all the money that I'd earned on mathematics books.

Speaker 313:58

Yeah.

Ian Stewart13:58

Oh, there it is.

Speaker 113:59

But it

Speaker 313:59

Let's see.

Speaker 314:03

You're talking that way, they laugh in my face. So please listen to me if you wanna say mine. I can't help my feelings, I go out of my mind. I'm gonna let you down.

Speaker 114:19

Ah Uh

Speaker 114:24

Oh, you can do that.

Presenter14:28

The Beatles and you can't do that. Now, apart from being lead guitarist and playing that kind of thing at at uh Cambridge, you were dedicated to to pure mathematics, which is, if I attempt to define it simply, maths for its own sake, is it maths which has no practical application.

Ian Stewart14:41

Let's

Ian Stewart14:44

No.

Ian Stewart14:45

When you're doing it, there's no emphasis on the application whatsoever. It's simply on the actual structure of the maths as maths. You're playing games with the maths. It may have an application, but you're not thinking about that. You're not interested in that.

Presenter14:56

And a good example is perhaps one that people will have heard of in recent times, which is Fermat's Last Theorem, which has been the best selling book and an award winning television program. A seventeenth century French lawyer who put forward this theorem theorem that, if I understand it correctly, was a negative. It said something was not possible.

Ian Stewart15:13

That's right, he said that certain kinds of numbers, if you combine them together to give more numbers of the same kind, you just can't do it.

Presenter15:19

But it's taken us or someone until 1994, Andrew Wiles, Cambridge mathematician, to prove that he was right about this negative.

Ian Stewart15:25

And furthermore, in this case, it's not one of these problems that just gets neglected and no one is throughout that entire three hundred and fifty year period, mathematicians are trying really hard to prove that you cannot solve this particular equation that Fermat was interested in.

Presenter15:40

But does it have any application at all, or is it simply a theorem?

Ian Stewart15:44

None. But the mathematics that you use to solve it, the mathematics Andrew Wiles invented to solve it, that is very beautiful mathematics with lots of potential uses, still at the moment within pure mathematics, but it's opening up all sorts of theories that you can imagine in fifty years' time might suddenly become rather important, let's say somewhere in mathematical physics. There are a few applications already to things like quantum theory.

Ian Stewart16:09

So it's not completely useless, but mathematics departments tend to split into two halves, the pure half and the applied half.

Presenter16:16

But you have said at at Warwick that what you like to do and I'm right in saying, aren't I, that you don't offer a a pure course and an applied course. It you just offer a mathematics course. That's right. But you've said that you like to paper over the crack, which of course acknowledges that there is a crack.

Ian Stewart16:25

That's right.

Ian Stewart16:31

There is a crack in terms of the formal organisation of mathematics, particularly in this country.

Ian Stewart16:36

But I think in terms of the actual structure of the subject, there really isn't a crack. The the formal structure tends to create a crack that should not be there.

Presenter16:43

But if you didn't specialize in, let's say, the pure mathematics, then you wouldn't throw up an Andrew Wiles and you wouldn't be able to prove Femme's last theory.

Ian Stewart16:49

That's right. What happens is individuals specialise at some point on the spectrum. I specialise somewhere in the middle, with a foot in each camp.

Presenter16:58

Right. We'll talk about the gap in the middle and what you do in it in a minute, but let's have your next record.

Ian Stewart17:03

This is a record that my wife who was then not my wife, was wife to be, bought me as a birthday present.

Ian Stewart17:10

And we played this record so many times because it was the only one we had. We we nearly wore the grooves out.

Speaker 317:20

Are you going to Scarborough Fair?

Speaker 317:27

Yeah.

Ian Stewart17:27

Parsley Sage Rose Mary and Tom

Speaker 317:36

Remember me to one who lives there.

Presenter17:43

Scarborough Fair by Simon and Garfunkel. So it's the gaps, Ian Stewart, the gaps between pure and applied mathematics that you're interested in. And in your case that that they seem quite often to involve the natural world. I think you have a a mathematical formula for the pattern of seeds on the head of a sunflower.

Ian Stewart17:59

That's right. I'm getting more and more interested in the fact that in biology you see lots and lots of mathematical patterns. It it's not currently what biologists tend to focus on, but I think it's actually very interesting. There are certain numbers that tend to come up in association with plants and flowers. These are called Fibonacci numbers. They were invented in 1202 by an Italian, and he was actually it was in a problem about rabbits. But anyway, the way they come up in flowers is if you count the petals or you look at various things in the geometry of the plant, you will see these numbers and certain patterns. The sunflower seeds, if you look at the head of a sunflower,

Ian Stewart18:34

You find spirals of seeds, two intersecting families, interlocking families of spirals. One goes clockwise, one goes anticlockwise. And the typical sorts of numbers of spirals you see are 34 one way, 55 the other. And if you count the petals, you find you've got 34 petals. And these Fibonacci numbers are enormously common. And the question is, why?

Ian Stewart18:54

And there's a whole mathematical theory which goes through several stages.

Ian Stewart19:00

If you're going to pack the seeds together efficiently so they don't leave gaps into a nice circular sort of shape like you get on a plant.

Presenter19:07

And there are no gaps.

Ian Stewart19:08

These numbers fall out of the mathematics as in a sense the only way you can do this.

Ian Stewart19:13

So hidden in the maths is a kind of secret pa if the universe is going to play that game, it's got to get that kind of answer.

Presenter19:20

And those seeds, as I understand it, also are are occur at a at a given angle, so that they can get the right amount of light, otherwise each petal would die because it would be submerged by the next one.

Ian Stewart19:32

That's right. In order to spread them out nicely, when the plant's growing, they they th these things get put in one by one at the tip of the growing plant, and the angle from one to the next is always one hundred and thirty seven and a half degrees.

Presenter19:45

And you call it a golden

Ian Stewart19:46

The golden angle is very significant mathematically. It sounds completely bizarre number.

Presenter19:51

Where else does it occur?

Ian Stewart19:52

It occurs in things like spirals of shells.

Ian Stewart19:56

These same funny angles and these these growth patterns are there in the shape of snail shells and sea shells, pineapples or pine cones or anything of that kind. You start to see these numbers if you count the right things.

Presenter20:08

Although it's wondrous what you describe, it's also vaguely depressing, I think, isn't it? That that that you know, nature, despite her her beauty and her seeming unpredictability,

Presenter20:19

Obviously has a kind of complete mathematical mathematical logic behind her.

Ian Stewart20:23

Nature is working under constraints. Nature is working under the constraints of what the laws of physics are. The laws of physics are actually mathematically rather beautiful, the ones that we currently understand. I mean, whether these are the base, the fundamental laws, I don't think they are actually. I think there's probably something even deeper. But we've understood a certain amount about how nature ticks on a a very deep level, and it's very mathematical, and it's actually rather beautiful. And everything else that we see somehow has to

Ian Stewart20:53

It has to live within the constraints imposed by those laws, by those rules. And so in that sense, nature can't do anything that it wants to.

Ian Stewart21:02

So you can think of that as depressing or you can think of that as uh part of the beauty of the whole thing. I if there isn't some sort of constraint on what you do then

Ian Stewart21:11

Anything's possible and somehow that's not so interesting.

Ian Stewart21:14

Next piece of music.

Presenter21:15

Yeah.

Ian Stewart21:16

This is a band called Sky. This is the the the the great classic jazz rock fusion band.

Ian Stewart21:22

It was started by John Williams, and the particular piece is Genophody number one.

Ian Stewart21:30

My son was learning to play a recorder when he was quite young, and this is one of the tunes that he played on it.

Ian Stewart21:37

And we went along he went along to recorder classes and we went along to one of these classes in rugby one morning for the the kind of end of the term concert.

Ian Stewart21:46

And we suddenly discovered that he was playing solo in this. He hadn't told us.

Ian Stewart21:52

He hadn't told us anything about it. We turned up and discovered our son was the soloist.

Presenter22:54

Skye and Eric Sarti's Geomenopidi number one, there's a kind of mathematical

Presenter23:00

rhythm to that tune and

Ian Stewart23:02

Isn't there?

Ian Stewart23:06

There's a basic rhythm which is the obvious pattern. And then when

Ian Stewart23:10

the instrument comes in and starts playing, it's playing a different pattern.

Ian Stewart23:13

But it fits together. It's doing something different from what you're expecting, yet there is a logic to it.

Presenter23:18

Do you find yourself? Stop analyzing music in that

Ian Stewart23:20

Mathematical way? A little bit. I I try not to too much. I think if you analyze these things you you can you can spoil it a bit by by um not actually just sitting there and reacting and you should react emotionally to music.

Presenter23:30

But people talk about the the great mathematical quality of Bach, of course.

Ian Stewart23:35

Yes, there is Bach particularly played mathematical games with music. He played games with the geometry of the notes on the page. He had pieces where you could turn the whole thing upside down and then play it again and it still made sense and it still worked. You could even play it alongside in harmony with the version the right way up.

Ian Stewart23:52

I think that this is'cause Bach is just so good. It's it's a little intellectual puzzle he's setting himself.

Presenter23:57

But do you think there is a a a link between a mathematician and and a musician in the general sense?

Ian Stewart24:02

I think there is. It's it's often said that mathematicians are very musical, and I think that's true, although I I've never done any kind of analysis to find out whether they're more musical than the rest of the population. But there's something in the mathematician's intuitive sense of pattern which is very similar to the way that people appreciate music.

Presenter24:20

Mm.

Presenter24:21

Let's just pause one moment and tell me about because I mentioned in the introduction uh stripes on tigers and spots on leopards. Apparently they too can be accounted for by by mathematics. That maths has has framed their fearful symmetry.

Ian Stewart24:35

That's right. The if you look at animals, you get these very striking patterns and and while the stripes on a tiger are not completely regular stripes like stripes on a zebra crossing, they are very stripy, there's no question. And you wonder where they come from.

Ian Stewart24:48

And there's a whole mathematical theory about pattern formation of that kind, in which in a sense stripes turn out to be the primary pattern you would expect. Spots are what happen when stripes become unstable and break up. And it's all classified by and analyzed within the framework of symmetries, which is a very, very beautiful area of mathematics. This is the area I really work in myself, is the application of symmetry principles to pattern formation.

Presenter25:13

But a but a biologist would say that that you know the stripes of the tiger spots of the liberty are are in his genes.

Ian Stewart25:14

Goodbye.

Ian Stewart25:18

That's right. And that's another way of looking at it. Now, it seems to me.

Ian Stewart25:23

The truth is both of these things and neither. It's the combination. The genes are establishing, are perhaps controlling the release of certain kinds of chemical pigments and so on, that realize the pattern. But the pattern is already implicitly available in the laws of nature, in the mathematics of the universe. The reason there is a pattern there is nothing to do with the genes. The genes are accessing a pattern that in some sense is already there in the catalogue of things that biology can use.

Speaker 125:41

The reason

Ian Stewart25:53

Record number six.

Ian Stewart25:55

Jeff Wayne's War of the Worlds.

Ian Stewart25:57

Which I was introduced to this. I'm a science fiction fan and of course H. G. Wells's War of the Worlds is a great science fiction classic. And I was introduced to this piece of music by a friend of mine who was in advertising. We went up to stay with them and he played it. I thought this was great and I got a tape of it. And then I bored the pants off everybody by playing it for months on end in the car whenever I got the chance.

Speaker 126:20

No one would have believed in the last years of the nineteenth century.

Speaker 126:24

that human affairs were being watched from the timeless worlds of space.

Speaker 126:29

No one could have dreamed we were being scrutinized as someone with a microscope studies creatures that swarm and multiply in a drop of water.

Speaker 126:38

Few men even considered the possibility of life on other planets.

Speaker 126:42

And yet

Speaker 126:43

Across the gulf of space.

Speaker 126:45

Minds immeasurably superior to ours regarded this earth with envious eyes.

Speaker 126:51

And slowly and surely

Speaker 126:54

They drew their plans against us.

Presenter27:11

Part of Jeff Wayne's musical version of The War of the Worlds introduced there by Richard Burton. You're not just a a fan of uh science fiction, Ian Stewart. You you've published lots of short stories and you've got a novel with your co-author biologist Jack Cohen in the planning. Surely it's a it's a hindrance to have a trained scientific brain if you're trying to write science fiction. Shouldn't you just have an imagination that can run riot?

Ian Stewart27:34

Well in a sense that's true. And it's what uh writing science fiction did for me was to to open up that way of thinking about things. It's uh you've got to tell a story in science fiction.

Ian Stewart27:45

Whereas if I'm writing some sort of mathematical research paper, I've just got to put down the facts in a reasonable order.

Ian Stewart27:50

And if you write your books that way and um

Ian Stewart27:54

A lot of academics do. They're actually rather boring books. They're great for the other academics who are already interested, and nobody else would ever want to read them.

Ian Stewart28:02

Having to getting practice at writing science fiction stories completely changed the way I thought about writing the books.

Speaker 328:09

Mm-hmm.

Ian Stewart28:10

And

Ian Stewart28:11

Focus me on the point that you're telling a story. And it's it was such a different style of writing from what I'd done before.

Presenter28:17

But I would have thought that that there must be a a body of mathematicians who thoroughly disapprove of you, who are kind of quite disdainful of one of their number who wants to write for the general public, and worse, wants to write science fiction.

Ian Stewart28:31

To some extent that's true. It's not as bad as it used to be. My immediate colleagues at Warwick, in fact, are very supportive of all these strange activities, but Warwick's always been a bit like that. And over the years, I've found less and less of this attitude.

Ian Stewart28:45

But it is this.

Presenter28:45

But it is this whole business, isn't it, of trying to increase the public understanding of science in all of its forms. There will always be the old diehards who believe that even in the process of doing that you are somehow bringing this very pure discipline into disrepute.

Ian Stewart29:00

Yeah.

Presenter29:00

Uh

Ian Stewart29:01

That's right. In a sense though, that focuses attention on what I think is the real problem. There's a lot of talk about the public understanding of science, but in a way that's the wrong way round.

Ian Stewart29:09

A lot of the problem is not with the public.

Ian Stewart29:12

It's with the scientists. And these surveys that you know, oh, it's terrible, the public still don't know the earth goes round the sun, whatever. Well, I suspect you could do a survey like that on almost anything and find that all of us are incredibly ignorant about almost anything you care to name.

Ian Stewart29:27

That to me is not what it's about. What it's about is very much the scientists realizing they've got to take their message out to the people. The people are willing to listen if you tell them the message in a form that makes sense to them.

Ian Stewart29:40

Number seven.

Ian Stewart29:42

Led Zeppelin and Kashmir. What I like about this is just that there is a a very clear mathematical pattern to the structure of this piece of music, and it's another one of these ones where there are several different patterns going on simultaneously.

Speaker 129:58

Sounds caressed my ears Not a word I heard could I relate

Ian Stewart30:11

You will squite clean

Presenter30:26

Led Zeppelin and Cashmere. How does a mathematician relax, Ian? I would think playing chess or bridge is a kind of bussman's holiday.

Ian Stewart30:34

I play guitar, I put headphones on so nobody else has to listen to it, and I hook it up to all sorts of weird gadgets that give you all sorts of strange sound effects, and then I play whatever whoever comes to mind.

Presenter30:44

And now you've invented a machine for testing wire for springs that could revolutionize the industry and make you a fortune, is that right?

Ian Stewart30:50

Along with various other people, as part of a yes, I'm part of a team which is based at Warwick, University of Manchester Institute of Science and Technology and the Institute of Spring Technology in Sheffield.

Ian Stewart31:03

We have invented a quality control machine for wire.

Ian Stewart31:06

which could save British industry about eighteen million pounds a year.

Presenter31:09

But this is really this is to do with your spirals and your

Ian Stewart31:11

This is

Ian Stewart31:13

What we do is we measure the coils in a big long test spring, and then extract certain mathematical patterns from that, which the engineers at IST discovered correlate very closely with whether or not that wire is good wire.

Presenter31:28

Last tree.

Ian Stewart31:28

Oh shit.

Ian Stewart31:29

Nirvana in bloom.

Ian Stewart31:32

I was driving along and I heard this record and I I thought, Oh, this is rather nice, I like that. So I bought it, and about three weeks later my younger son was cleaning out my car for me, and he came in and said,

Ian Stewart31:44

Is that your Nirvana C D in the car? and it turned out it was his favourite band.

Ian Stewart31:49

And I I had no idea who they were at this point. I didn't know about Grunge, I didn't know about Kirk Cobain. All I knew was most people probably don't like this kind of thing, but it appealed to me.

Presenter32:00

So it's in the genesis.

Ian Stewart32:01

So it's in the genes.

Ian Stewart32:07

One back, all of it sometimes, that's a single lunch, that's a shooting gun

Ian Stewart32:17

Uh

Presenter32:17

Uh

Ian Stewart32:18

Yeah.

Presenter32:18

Your

Presenter32:28

Nirvana and In Bloom. If you could only take one of those eight records, which one would it be?

Ian Stewart32:34

I'd take Scarborough Fair for sentimental reasons.

Presenter32:36

Hm. And what about your book as well as the Bible and Shakespeare?

Ian Stewart32:40

Douglas Hofstadter's Gödel Escher Bach. Oh, which.

Ian Stewart32:45

is is a wonderful it's a cult book in a sense, and it's full of it's lovely thing that it's got Lewis Carroll characters having conversations, Achilles and the Tortoise keep having conversations. But it's all about the Kurt Girdle is the man who showed that mathematics has limitations, that there are certain things you cannot answer.

Ian Stewart33:02

And there are certain, he did this by looking at self-referential structures in mathematics, things that talk about themselves, things like I am a liar.

Ian Stewart33:10

This is a lie, indeed. Is it a lie or not?

Ian Stewart33:13

And he found similar structures in Bach and in the Art of Msietche.

Ian Stewart33:18

And the book is about all of the analogies between these things, and in a sense using Bach and Escher as ways of understanding Gödel.

Presenter33:27

And what about your luxury?

Ian Stewart33:28

Great.

Ian Stewart33:29

I'd like a Damien Hearse sculpture of Margaret Thatcher, pickled in a tank.

Presenter33:35

Ian Stewart, thank you very much indeed for letting us hear your Desert Island discs.

Speaker 333:45

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