Dr. Ian Stewart is an emeritus professor of mathematics at Warwick University in Great Britain, math communicator, and the author of more than a hundred scholarly and popular books, including *Does God Play Dice?: The New Mathematics of Chaos *(1989), *Flatterland *(2001), and *The Science of Discworld *books [co-authored with Terry Pratchett and Jack Cohen] (1999-2013). At this June’s convocation the University of Waterloo will be awarding him an honorary doctorate, and on June 13 he will also be delivering a free public lecture online: “Synchronisation in Feedforward Networks.”

Ahead of these events, we had the chance to sit down with him and chat about his prolific career, his creative pursuits, and the secret to effectively sharing math with the public. The following interview has been edited for length and clarity.

## How did you fall in love with math?

I was always pretty good at math, even in primary school – it came naturally to me. But what clinched it for me was a combination of two people’s influence. The first was my math teacher in high school, Gordon Radford. He was a lovely man, so interested in mathematics that when he got some students in the class who were pretty good, he would take us aside and teach us something from outside the syllabus, like set theory, so he could learn the material himself. He took a couple hours a week teaching five of us just because he was excited about math. It gave me the message that there’s a lot of stuff out there beyond what you learn in school.

The other big influence was Martin Gardner, an American mathematician who ran a “Mathematical Games” column for twenty-five years in *Scientific American. *Gardner was very good at taking a new mathematical idea that had some kind of amusement value and using it to teach you something deeper while you were having fun. By a series of coincidences, I inherited his column years later!

This pattern of influence has continued. About 8-10 times in my life, I’ve met someone, we’ve gotten on very well, and we’ve started working together and big changes occurred. I can trace my research career that way – it changes direction because I met somebody.

## How have you seen the field of mathematics change throughout your career?

I studied math as an undergraduate at Cambridge University in 1963, and I got my PhD in 1969, working as in an obscure branch of algebra. Around ten years later I changed to studying dynamical systems, and wrote *Catastrophe Theory and its Applications *(1978) with Tim Poston.

Math has become a much bigger subject than it used to be, touching lots of new issues. When I started, it was very abstract, and now we’re seeing all kinds of applications: in politics, in biology, and of course, in computing. I’ve been doing work recently on mathematical biology, especially involving animal movement. That’s what my talk will be about: modeling the nerve cells of animals that may control their movement.

One of the most interesting applications for math I encountered during my career was when a very nice engineer at The Institute of Spring Technology called me because he had read my book and thought I might be able to help with a problem he had making springs. I ended up working with him in quality control, and we invented a quality control machine based on chaos theory! It saved the industry about $25 million a year, so I reckon that I have more than repaid the government grant that allowed me to go to university and follow my pure mathematical nose for as long as I wanted.

## How did you start writing fiction? What connections do you see between mathematics and fiction?

I started writing science fiction while I was in Connecticut for a year and my wife brought home a box from the flea market with all the disassembled parts of a typewriter. Ninety inches of snow fell that that winter, and she’d bought it to give me something to do. I reassembled that typewriter and then I wrote a science fiction story on it, which I sold to *Analog Science Fact and Fiction *magazine.

Obviously, there are major differences between mathematics and science fiction: in fiction you have the freedom to invent stuff, and you can’t just invent an answer if you’re struggling with a math problem. But some areas of math are full of wild and wacky ideas, places for your imagination to run riot. Topologists, for example, spend their whole lives working in alien worlds.

I’ve always felt that there is so much overlap between a mathematical proof and a well-structured story. In some ways, a good mathematical proof is a story told by mathematicians to mathematicians. But you have to bear in mind that mathematicians are a very critical audience, so you’d better be a good storyteller.

## What led to your collaboration with legendary British fantasy author Terry Pratchett?

I was friends first with the biologist Jack Cohen, who reached out after reading one of my books. He introduced me to Terry at a science conviction convention, and then I read one of Terry’s books and I was hooked.

Terry had a stable of scientists and folklorists and such, and I was his math person. He would call and say “Terry here! Tell me sixteen things about X that most people don’t know!” and then years later you would be reading one of his books and suddenly see something and say “hey, that’s what he was on about!” The three of us got the idea to write about the science of Discworld once while having dinner at a Mongolian restaurant. We didn’t think we would write more than one book, but we just had so much fun.

## What advice would you give to math educators and communicators?

The difficulty with communicating math to the general public is their resistance that they actually want to think about math at all. So, one tactic is to help them understand all the ways they use math every day, especially in technology, and all the math behind that.

But it doesn’t have to be practical. Many people are very interested in deep philosophical questions of “life, the universe, and everything.” Mainly, I just follow my nose and write about things that interest me. Sometimes I say that my main audience is me at 16, when I was fascinated by mathematics but didn’t know very much. I try to understand the reader or listener as someone who has zero knowledge, but infinite intelligence.

I do think that if you are welcoming, and you convey your enthusiasm, then people will get hooked, and you can teach them about all kinds of things. And it can all be such, such fun.

*You can learn more about Ian Stewart by visiting his website. *