Science Across the Sean

The Two Sean Carrolls

This is the tale of two Sean Carrolls. Nautilus brought the two scientists together for the fun reason that they share a name. And their conversation is filled with humor and camaraderie. And brilliance. The Sean Carrolls bring their perspectives from physics and evolutionary biology to bear on timeless questions about the origin of life, the possibilities of life on other planets, the tension between science and religion, the fate of Earth, and how they first got enchanted by science as kids.

Sean Carroll, the evolutionary biologist, is the former vice president for science education at the Howard Hughes Medical Institute, where he championed research and the role of science as a human endeavor rich with drama and beauty. His books include A Series of Fortunate Events about the chance occurrences that shaped life on Earth and The Serengeti Rules, which traces the invisible rules that govern ecosystems. His writing is rich in personal narratives that uncover the mechanisms of biological order and collapse.

Sean Carroll, the physicist, is a distinguished theoretical physicist celebrated for his contributions to quantum mechanics, cosmology, and the philosophy of science. He holds the position of Homewood Professor of Natural Philosophy at Johns Hopkins University. His most recent books are part of a series, The Biggest Ideas in the Universe, in which he brings readers “up to speed with exactly what professional physicists are talking about, with an emphasis on established knowledge rather than speculation.” His other books include From Eternity to Here, which explores the concept of time; The Big Picture, discussing the origins of life and the universe; and Something Deeply Hidden, focusing on quantum mechanics.

As the two Sean Carrolls sat down together in a conference room at the Howard Hughes Medical Institute in Maryland, the first thing they had to talk about was mistaken identity.

The Case of the Mistaken Identity

Sean Carroll, physicist It’s so good to talk to you in person. I’ll start with my little story. When I was in graduate school, still in that early stage of your scientific career—who knows where you’re going?—I was walking down Harvard Square by the magazines, and Time magazine was coming out with an issue with 40 scientists under 40 who are going to change the world. And jokingly I said to myself, “Oh, I bet I’m in there.” So I pick it up and I’m in there! There’s my name. But I realized they made a terrible mistake. They had the wrong Sean Carroll. This guy was doing evolutionary biology, not cosmology at all. And that’s when I realized there was another Sean Carroll lurking out there in nature.

Sean Carroll, evolutionary biologist And the confusion persists. The most common is when I’m giving a talk on a campus and the poster for the talk is illustrated with your books. People bring me your books to sign and I explain the confusion and they’re like, “Will you sign it anyway?” I say, “Maybe you can get both of us to sign it.”

Sean Carroll, physicist The only one that hurt was when I was invited to a ritzy conference in the hills of Tuscany at a villa. I accepted and they said, “Actually, we don’t want you. We’re looking for the other one.”

Sean Carroll, evolutionary biologist They didn’t find me, because I would have gone!

Origins and Inspirations

Sean Carroll, physicist So, what happened to make you do biology? It’s so messy and hard.

Sean Carroll, evolutionary biologist It’s funny. I had decent math ability as a kid. But my math ardor waned as I got into high school. That probably had something to do with how things were being taught. It just got less interesting, less fun. At the same time, friends in my neighborhood introduced me to flipping over logs and things like that, up by Lake Erie. Catching snakes and salamanders and frogs was something I did nearly every day. I thought “maybe I’ll be a herpetologist.” How did you stay on your path? How old were you when you knew you were interested?

I’m a super-duper atheist, but I don’t think we can figure out our purpose just from doing science.

Sean Carroll, physicist I was 10. I was reading books about black holes and the Big Bang. I was never a go-out-there-and-touch-things-in-nature kind of guy. Even when I became interested in cosmology, my parents would get me a telescope or take me to the observatory and I’m like, “Why are we here? What is this? I can just read about this in a book.” It’s the simplicity and profoundness, the fact that the world that physics explains to us is so different than our expectations, and yet our minds can wrap around it a little bit. That’s what really got me excited.

Sean Carroll, evolutionary biologist So, were you explaining things around the dinner table?

Sean Carroll, physicist I was excited but I grew up in a resolutely non-excited family. No academic background, no bookshelves in our house. My parents were very supportive, but they had no idea what I was interested in or what I was doing, even in my science classes. I remember very vividly my high school teacher asking us all what we wanted to do, and I said I wanted to be a theoretical astrophysicist. He was so aghast that he wrote the words “theoretical astrophysicist” on the board, just to show everyone how weird that was. What was your background? Did you know you wanted to do this for a living?

Sean Carroll, evolutionary biologist I had no clue. I’m sure you and I get asked this all the time, especially by younger people, “What’s the path?” You don’t really know what the path is. You just hope you’re lucky enough that a few mentors recognize that you’ve got the passion, and they’ll channel it, tell you where to steer it. That happened for me as an undergrad.

Sean Carroll, physicist For me too. I’m continually impressed by how crucial it is to have some older person say, “You can do this.”

Sean Carroll, evolutionary biologist So, my dad grew up on a farm, but he ended up being a scholar in Gregorian chant—the lucrative field of Gregorian chant. The example he set was that he followed his passion.

Sean Carroll, physicist Were you religious in that sense? Or was it more about the songs?

Sean Carroll, evolutionary biologist My dad was scholarly and knew a lot of languages. He read widely and his ideas didn’t conform to the party line, although he was a very observant Catholic. When the time came and I didn’t have those feelings and thoughts and sentiments, all he asked of me was that I would watch his choirs perform at Christmas. I said, “Dad, I’d be happy to come listen to the choirs at Christmas.” I was then released from my religious duties at age 12. I still appreciate that my dad was open-minded to say, “OK, if you think differently …”

Sean Carroll, physicist It’s a complicated relationship between science and religion. I have good friends in cosmology and biology who are also deep believers. Do you think they’re fooling themselves? Do you think there is really a controversy there?

Science and Faith

Sean Carroll, evolutionary biologist The evolutionary biologists I know are predominantly nonbelievers. We like science as an explanation of things, and those other explanations that we may have grown up with don’t carry much power. My dad was pro-science, but he was also strongly a person of faith, so clearly those ideas can coexist in people and