One summer I was finishing up a book, coming out of my thesis on a very abstract subject — algebraic combinatorics, for goodness sakes! — and I didn’t know what to do, so I spoke to my brother. My brother was a development neurobiologist and was going through graduate school, and Arthur suggested to me, “You’re a mathematician. You know all about information theory. You should learn about the brain. The brain is a really great place to apply it.” So being hopelessly naive, I said, “Okay, I’ll learn neurobiology this summer.” I got a couple of books and papers and things on mathematical aspects of neurobiology. They were interesting, but they didn’t ring very true, and I, in any case, decided I had to learn more neurobiology. So I started learning about neurobiology, wet lab neurobiology. I decided in order to do that I needed to know more biology, so I decided, okay, next semester I’d learn biology.