Well, I just did the dumbest thing. His research papers include models of, and experimental constraints on, violations of Lorentz invariance; the appearance of closed timelike curves in general relativity; varieties of topological defects in field theory; and cosmological dynamics of extra spacetime dimensions. When I applied for my first postdoc, like I said, I was a hot property. I did not get into Harvard, and I sweet talked my way into the astronomy department at Harvard. There was, but it was kind of splintered because of this large number of people. Who knows? So, I used it for my own purposes. I think the departments -- the physics department, the English department, whatever -- they serve an obvious purpose in universities, but they also have obvious disadvantages. As it turned out, CERN surprised us by discovering the Higgs boson early. Fred Adams, Katie Freese, Larry Widrow, Terry Walker, a bunch of people who were really very helpful to me in learning things. So, it was very tempting, but Chicago was much more like a long-term dream. Honestly, I still think the really good book about the accelerating universe has yet to be written. [20] In 2014, he was awarded the Andrew Gemant Award by the American Institute of Physics for "significant contributions to the cultural, artistic or humanistic dimension of physics". You know, every one [of them] is different, like every child -- they all have their own stories and their own personalities. He has written extensively on models of dark energy and its interactions with ordinary matter and dark matter, as well as modifications of general relativity in cosmology. Like I said, we had hired great postdocs there. Well, how would you know? So, you can apply, and they'll consider you at any time. We both took general relativity at MIT from Nick Warner. I'll say it if you don't want to, but it's regarded as a very difficult textbook. So, my thought process was, both dark matter and dark energy are things we haven't touched. For many interviews, the AIP retains substantial files with further information about the interviewee and the interview itself. I like teaching a lot. Oh, there aren't any? I think there have been people for many, many years who have been excellent at all three of these things individually. The answers are: you can make the universe accelerate with such a theory. Something that very hard to get cosmologists even to care about, but the people who care about it are philosophers of physics, and people who do foundations of physics. I asked him, "In graduate school, the Sean Carroll that we know today, is that the same person?" They don't frame it in exactly those terms, but when I email David Krakauer, president of SFI, and said, "I'm starting this book project. [10] Carroll thinks that over four centuries of scientific progress have convinced most professional philosophers and scientists of the validity of naturalism. Absolutely brilliant course. When it came time to choose postdocs, when I was a grad student, because, like I said, both particle physics and cosmology were in sort of fallowed times; there were no hot topics that you had to be an expert in to get a postdoc. Everyone sort of nods along and puts up with it and waits for the next equation to come on. You're still faced with this enormous challenge of understanding consciousness on the basis of this physical stuff, and I completely am sympathetic with the difficulty of that problem. I can just do what I want. I've only lived my life once, and who knows? During this migration, the following fields associated with interviews may be incomplete: Institutions, Additional Persons, and Subjects. Honestly, I only got that because Jim Hartle was temporarily the director. I'm crystal clear that this other stuff that I do hurts me in terms of being employable elsewhere. His research focuses on foundational questions in quantum mechanics, spacetime, cosmology, emergence, entropy, and complexity, occasionally touching on issues of dark matter, dark energy, symmetry, and the origin of the universe. They did not hire me, because they were different people than were on the faculty hiring committee and they didn't talk to each other. Do you see this as all one big enterprise with different media, or are they essentially different activities with different goals in mind? Had I made a wrong choice by going into academia? It worked for them, and they like it. It's not just a platitude. It was really the blackholes and the quarks that really got me going. He used that to offer me a job, to pay my salary. So, even though the specialists should always be the majority, we non-specialists need to make an effort to push back to be included more than we are. Several of these people had written textbooks themselves, but they'd done it after they got tenure. I started blogging in 2004, and I was rejected in 2005 from Chicago. My only chance to become famous is if they discovered cosmological birefringence. Carroll is the author of Spacetime And Geometry, a graduate-level textbook in general relativity, and has also recorded lectures for The Great Courses on cosmology, the physics of time and the Higgs boson. There's a sense in which the humanities and social sciences are more interchangeable. So, I'm surrounded by friends who are supported by the Templeton Foundation, and that's fine. I'm not discounting me. A defense of philosophical naturalism, a brand of naturalism, like a poetic naturalism. Yeah, absolutely. But there were postdocs. So, biologists think that I'm the boss, because in biology, the lab leader goes last in the author list. There's a certain gravitational pull that different beliefs have that they fit together nicely. I thought that given what I knew and what I was an expert in, the obvious thing to write a popular book about would be the accelerating universe. To me, the book is still the most profound way for one person to say ideas that are communicated to another one. People were very unclear about what you could learn from the microwave background and what you couldn't. But there's plenty of smart people working on that. WRITER E Jean Carroll filed a defamation lawsuit against former President Donald Trump in 2019 claiming he tarnished her reputation in his response to her sexual assault allegations against him . My biggest contribution early on was to renovate the room we all had lunch in in the particle theory group. So, it's not an easy hill to climb on. I'm enough of a particle physicist. Like I said, I wrote many papers that George was not a coauthor on. I'm just thrilled we were able to do this. We can't justify theoretical cosmology on the basis that it's going to cure diseases. The cosmologists couldn't care, but the philosophers think this paper I wrote is really important. Basically Jon Rosner, who's a very senior person, was the only theorist who was a particle physicist, which is just weird. And of course, it just helps you in thinking and logic, right? From the outside looking in, you're on record saying that your natural environment for working in theoretical physics is a pen and a pad, and your career as a podcaster, your comfort zone in the digital medium, from the outside looking in, I've been thinking, is there somebody who was better positioned than you to weather the past ten months of social distancing, right? 1 Physics Ellipse Not just that they should be allowed out of principle, but in different historical circumstances, progress has been made from very different approaches. Maybe it was that there was some mixture of hot dark matter and cold dark matter, or maybe it was that there was a cosmological constant. So, what they found, first Adam and Brian announced in February 1998, and then Saul's group a few months later, that the universe is accelerating. Like, ugh. He's a JASON as well, so he has lots of experience in policy and strategizing, and things like that. But I do do educational things, pedagogical things. Fast forward to 2011. So, I made the point that he should judge me not on my absolute amount of knowledge, but by how far I had come since the days he taught me quantum field theory. I didn't stress about that. So, if you've given them any excuse to think that you will do things other than top-flight research by their lights, they're afraid to keep you on. And I did reflect on that option, and I decided on option B, that it was just not worth it to me to sacrifice five years of my life, even if I were doing good research, which hopefully I would do. Is your sense that your academic scholarly vantage point of cosmology allows for some kind of a privileged or effective position within public debate because so much of the basis of religion is based on the assumption that there must be a God because a universe couldn't have created itself? We don't understand economics or politics. If you actually take a scientific attitude toward the promotion of science, you can study what kinds of things work, and what kinds of approaches are most effective. So, I did eventually get a postdoc. Not to put you on the psychologists couch, but there were no experiences early in life that sparked an interest in you to take this stand as a scientist in your debates on religion. Let's put it that way. Usually the professor has a year to look for another job. It was clearly for her benefit that we were going. "The University of Georgia has been . Rather than telling other people they're stupid, be friendly, be likable, be openminded. So, a lot of the reasons why my path has been sort of zig-zaggy and back and forth is because -- I guess, the two reasons are: number one, I didn't have great sources of advice, and number two, I wasn't very good at taking the advice when I got it. To his great credit, Eddie Farhi, taught me this particle physics class, and he just noticed that I was asking good questions, and asked me who I was. Eventually I figured it out, and honestly, I didn't even really appreciate that going to Villanova would be any different than going to Harvard. The obvious choices were -- the theoretical cosmology effort was mostly split between Fermilab and the astronomy department at Chicago, less so in the physics department. Everyone knew that was real. They didn't even realize that I did these things, and they probably wouldn't care if they did. They can't convince their deans to hire you anymore, now that you're damaged goods. I can't get a story out in a week, or whatever. I do try my best to be objective. I think, now, as wonderful as Villanova was, and I can rhapsodize about what a great experience I had there, but it's nothing like going to a major, top notch university, again, just because of the other students who are around you. It's a messy thing. To second approximation, I care a lot about the public image of science. The polarization of light from the CMB might be rotated just a little bit as it travels through space. MIT was a weird place in various ways. I think it was like $800 million. There's no immediate technological, economic application to what we do. The two advantages I can think of are, number one, at that time, it's a very specific time, late '80s, early '90s -- specific in the sense that both particle physics and astronomy were in a lull. So, many of my best classes when I was a graduate student I took at MIT. So, literally, Brian's group named themselves the High Redshift Supernova Project: Measuring the Deceleration of the Universe. But I did overcome that, and I think that I would not necessarily have overcome it if I hadn't gone through it, like forced myself to being on that team and trying to get better at it. She never went to college. He knew exactly what the point of this was, but he would say, "Why are you asking me that? That's not all of it. It doesn't sound very inspired, so I think we'll pass." It's not just you can do them, so you get the publication, and that individual idea is interesting, but it has to build to something greater than the individual paper itself. But it was a great experience for me, too, teaching a humanities course for the first time. I had some great teachers along the way, but I wouldn't say I was inspired to do science, or anything like that, by my teachers. It is interesting stuff, but it's not the most interesting stuff. Well, you could measure the rate at which the universe was accelerating, and compare that at different eras, and you can parameterize it by what's now called the equation of state parameter w. So, w equaling minus one, for various reasons, means the density of the dark energy is absolutely constant. Given the way that you rank the accelerating universe way above LIGO or the Higgs boson, because it was a surprise, what are the other surprises out there, that if they were discovered, might rank on that level of an accelerating universe? I did not succeed in that goal. It's way easier to be on this side, answering questions rather than asking them. I'm definitely not going to be at Caltech, even two years from now. But the astronomers went out and measured the matter density of the universe, and they always found it was about .25 or .3 of what you needed. That's not data. What was your thesis research on? I'm curious, is there a straight line between being a ten year old and making a beeline to the physics and astronomy department? In other words, if you were an experimental condensed matter physicist, is there any planet where it would be feasible that you would be talking about democracy and atheism and all the other things you've talked about? So, then, you can go out and measure the mass density of the universe and compare that with what is called the critical density, what you need to make the universe flat. But I'm classified as a physicist. So, I do think that my education as a physicist has been useful in my caring about other fields in a way that other choices would not have been. Then, the other transparency was literally like -- I had five or six papers in my thesis, and I picked out one figure from every paper, and I put them in one piece of paper, Xeroxed it, made a slide out of it, put it on the projector, and said, "Are there any questions?" So, it was a very -- it was a big book. Being surrounded by the best people was really, really important to me. But research professor is a faculty member. So, again, I'm going to -- Zoom, etc., podcasts are great. [3][4] He has been a contributor to the physics blog Cosmic Variance, and has published in scientific journals such as Nature as well as other publications, including The New York Times, Sky & Telescope and New Scientist. I say this as someone who has another Sean Carroll, who is a famous biologist, and I get emails for him. I do long podcasts, between an hour and two hours for every episode. So, for the last part of our talk, I want to ask a few broadly retrospective questions about your career, and then a few looking forward.