Q&A with Eugenia Cheng

Eugenia Cheng is the author of the new book How to Bake Pi: An Edible Exploration of the Mathematics of Mathematics. She teaches at the School of Mathematics and Statistics in the University of Sheffield in the U.K., and is the scientist in residence at the School of the Art Institute of Chicago. She lives in Chicago.

Q: Your book combines mathematics and food. What do you see as the relationship between the two?

A: I love food and I love math, but unfortunately most people love food more than math. I have always liked telling unexpected stories to give more character and "flavor" to math, and I realised that the ones involving food were particularly popular with my students, especially when it involved a demonstration.

I enjoyed it too as I secretly always wanted to be on a cooking show. And if I enjoy my explanations that's a good start - if I find my own explanations boring then I have no hope of interesting anyone else. Math is a lot more like food than people realise. Both are really about putting some ingredients together in funny ways and seeing if the result is delicious or not.

Q: You ask the question, "[I]f math is easy, why does anyone find it hard?" How do you answer that, and why do many people feel intimidated by math?

A: Spoiler alert: the answer is in my book! Basically math can seem hard if you're not given a reason to care about it, and if nobody helps you understand why it is the way it is. 

It can seem hard if you think you've got the right answer but you're then told it's the wrong answer. It can seem hard if it's presented as a bunch of rules you have to follow for no particular reason. 

I hate following rules. Actually I think a lot of research mathematicians hate following rules: we like making up our own rules that have good justification for existing, and that's what math is really about.  It's just often taught without the explanation and motivation.

I think many people feel intimidated by math because those who are good at math too often go round intimidating those who are not good. Making others feel stupid is one way that people use to feel better about themselves. I should add that I do not support this type of activity!

Q: For those of us who don't know much about category theory, how would you best describe it, and how does it relate to everyday life?

A: As in the subtitle of my book, it's the "Mathematics of Mathematics."  Mathematics is about understanding how things work, and so category theory is about understanding how mathematics works. 

I believe mathematics is the core of thinking: it's everything that is logical, which is the central nervous system of thought - or at least, it should be.  Unfortunately, it too often isn't! Not everything in life behaves according to logic, but I believe it's important to understand which parts do. 

This is the sense in which my work relates to everyday life. It's not about calculations or answering specific questions or solving specific problems.  It's about how to think.

Q: What surprised you most as you researched and wrote this book?

A: I was surprised that everyone wanted me to put more technical mathematical content into it!

Q: What are you working on now?

A: My next book is about infinity. This causes people to make jokes like, "How does it end?" I guess I'll have to get used to this!

Q: Anything else we should know?

A: I really like broccoli dipped in chocolate, but have not yet met anyone else who does. Anyone out there?

--Interview with Deborah Kalb