Roughly speaking, my mom and my stepfather told me, "We have zero money to pay for you to go to college." So, no, it is not a perfect situation, and no I'm not going to be there long-term. Sean Carroll, a physicist, was denied tenure by his department this year. I'm very pleasantly surprised that the podcast gets over a hundred thousand listeners ever episode, because we talk about pretty academic stuff. No one gets a PhD in biology and ends up doing particle physics. What you should do is, if you're a new faculty member in a department, within the first month of being there, you should have had coffee or lunch with every faculty member. Of all the things that you were working on, what topic did you settle on? The space of possibilities is the biggest space that we human beings can contemplate. We learned Fortran, the programming language back then. That's just not my thing. We never wrote any research papers together, but that was a very influential paper, and it was fun to work with Bill. As I look from a galaxy to a cluster to large-scale structure, it goes up, and it goes up to .3, and it kind of stays at .3, even as I look at larger and larger things. I learned general relativity from Nick Warner, which later grew into the book that I wrote. What's interesting is something which is in complete violation of your expectation from everything you know about field theory, that in both the case of dark matter and dark energy, if you want to get rid of them in modified gravity, you're modifying them when the curvature of space time becomes small rather than when it becomes large. As a result, it did pretty well sales-wise, and it won a big award. So, string theory was definitely an option, and I could easily have done it if circumstances had been different, but I never really regretted not doing it. Well, I was in the physics department, so my desk was -- again, to their credit, they let me choose where I wanted to have my desk. Apply for that, we'll hire you for that. She never ever discouraged me from doing it, but she had no way of knowing what it meant to encourage me either -- what college to go to, what to study, or anything like that. I don't want to say anything against them. But exactly because the Standard Model and general relativity are so successful, we have exactly the equation -- they're not just good ideas. At the time, . I'm curious, in your relatively newer career as an interviewer -- for me, I'm a historian. We did not give them nearly enough time to catch their breath and synthesize things. Philosophical reflections on the nature of reality, and the origin of the universe, and things like that. Alright, Sean. Sean, if mathematical and scientific ability has a genetic component to it -- I'm not asserting one way or the other, but if it does, is there anyone in your family that you can look to say this is maybe where you get some of this from? It's funny that you mention law school. There aren't that many people who, sort of, have as their primary job, professor at the Santa Fe Institute. Very, very important. Or are you comfortable with that idea, as so many other physicists who reinvent themselves over the course of a career are? Phew, this is a tough position to be in. No, no, I kind of like it here. A lot of theoretical physics is working within what we know to predict the growth of structure, or whatever. And my response to them is what we do, those of us who are interested in the deepest questions about the nature of reality, whether they're physicists, or philosophers, or whoever, like I said before, we're not going to cure cancer. We're not developing a better smart phone. It doesn't need to be confined to a region. And I was amused to find that he had trouble getting a job, George Gamow. He didn't know me from the MIT physics department. No one expects that small curvatures of space time, anything interesting should happen at all. So, my thought process was, both dark matter and dark energy are things we haven't touched. Graduate departments of physics or astronomy or whatever are actually much more similar to each other than undergraduate departments are, because they bring people from all these undergraduate departments. If I'm going to spend my time writing popular books, like I said before, I want my outreach to be advancing in intellectual argument. People still do it. And who knows, it all worked out okay, but this sort of background, floating, invisible knowledge is really, really important, and was never there for me. There's a certain gravitational pull that different beliefs have that they fit together nicely. Like, literally, right now, I'm interested in why we live in position space, not in momentum space. But no, they did not tie together in some grand theme, and I think that was a mistake. The Santa Fe Institute is this unique place. First year seminars to sort of explore big ideas in different ways. Well, most people got tenure. A coalition of graduate students and scholars sent a letter to the university condemning the decision at the time. Sorry, I forgot the specific question I'm supposed to be answering here. And I didn't. But I wanted to come back to the question of class -- working class, middle class. One is, it was completely unclear whether we would ever make any progress in observational cosmology. 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 think it's perfectly rational in that sense. I said, "I thought about it, but the world has enough cosmology books. Yes. But then, the thing is, I did. The argument I make in the paper is if you are a physicalist, if you exclude by assumption the possibility of non-physical stuff -- that's a separate argument, but first let's be physicalists -- then, we know the laws of physics governing the stuff out of which we are made at the quantum field theory level. For me, it's one big continuum, but not for anybody else. Be proud of it, rather than be sort of slightly embarrassed by it. Like, you can be an economist talking about history or politics, or whatever, in a way that physicists just are not listened to in the same way. So, that's when The Big Picture came along, which was sort of my slightly pretentious -- entirely pretentious, what am I saying? I'm not someone who thinks there's a lone eccentric genius who's going to be idiosyncratic and overthrow the field. And I said, "But I did do that." I looked at the list and I said, "Well, honestly, the one thing I would like is for my desk to be made out of wood rather than metal. They had these cheap metal desks. Would I be interested in working on it with him? These were not the exciting go-go days that you might -- well, we had some both before and after. I thought and think -- I think it's true that they and I had a similar picture of who I would be namely bringing those groups together, serving as a bridge between all those groups. But clearly it is interesting since everyone -- yeah. Here is the promised follow-up to put my tenure denial ordeal, now more than seven years ago, in some deeper context. So, you have to be hired as a senior person, as a person with tenure in a regular faculty position. I think there are plenty of physicists. Carroll, S.B. Yeah. This is really what made Cosmos, for example, very, very special at the time. She could pinpoint it there. The paper was on what we called the cosmological constant, which is this idea that empty space itself can have energy and push the universe apart. We wrote a paper that did the particle physics and quantum field theory of this model, and said, "Is it really okay, or is this cheating? It's difficult, yes. He is also a very prolific public speaker, holding regular talk-show series like Mindscape,[23] which he describes as "Sean Carroll hosts conversations with the world's most interesting thinkers", and The Biggest Ideas in the Universe. At least, I didn't when I was a graduate student. Maybe going back to Plato. We did some extra numerical simulations, and we said some things, and Vikram did some good things, and Mark did too, but I could have done it myself. At least one person, ex post facto, said, "Well, you know, I think some people got an impression during that midterm evaluation that they didn't let go of that you don't write any papers," even though it wasn't true. I think it's bad in the following way. No one told you that, or they did, and you rebelled against it. I still do it sometimes, but mostly it's been professionalized and turned into journalism, or it's just become Twitter or Facebook. Please give us a bit of background on your life and professional experience. So, then, I could just go wherever I wanted. The South Pole telescope is his baby. [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. You're not going to get tenure. You didn't have to be Catholic, but over 90% of the students were, I think. Like I said, it just didn't even occur to me. Three, tell people about it. So, this was my second year at Santa Barbara, and I was only a two-year postdoc at Santa Barbara, so I thought, okay, I'll do that. And, a university department is really one of the most exclusive clubs, in which a single dissent is enough to put the kibosh on an appointment! Sean, I'm sorry to interrupt, but in the way that you described the discovery of accelerating universe as unparalleled in terms of its significance, would you put the discovery of the Higgs at a lower tier? It just came out of the blue. Actually, this is completely unrelated but let me say something else before I forget, because it's in the general area of high school and classes and things like that. No one goes into academia for fame and fortune. He worked as a postdoctoral researcher at the Massachusetts Institute of Technology (MIT) and Kavli Institute for Theoretical Physics at the University of California, Santa Barbara[16] and as an assistant professor at the University of Chicago until 2006 when he was denied tenure. At Caltech, as much as I love it, I'm on the fourth floor in the particle theory group, and I almost never visit the astronomers. It was a tough decision, but I made it. I didn't listen to him as much as I should have. It just so happened, I could afford going to Villanova, and it was just easy and painless, so I did it. The bad news is that I've been denied tenure at Chicago. When I got there, we wrote a couple of papers tighter. This transcript may not be quoted, reproduced or redistributed in whole or in part by any means except with the written permission of the American Institute of Physics. No, not really. So, it was explicable that neither Harvard nor MIT, when I was there, were deep into string theory. Let's pick people who are doing exciting research. We'd be having a very different conversation if you did. Michael Nielsen, who is a brilliant guy and a friend of mine, has been trying, not very successfully, but trying to push the idea of open science. I wrote a paper with Lottie Ackerman and Mark Wise on anisotropies. Payton announced he was leaving the Saints on Jan. 25, 2022; Schneider and Broncos GM George Paton began discussing . Harvard is not the most bookish place in the world. 4. They saw that they were not getting to the critical density. I got to reveal that we had discovered the anisotropies in the microwave background. Sean Carroll is a theoretical physicist at Caltech, specializing in cosmology and quantum mechanics. Unlike oral histories, for the podcast, the audio quality, noise level, things like that, are hugely important. And he's like, "Sure." Also, with the graduate students, it's not as bad as Caltech, but Chicago is also not as user friendly for the students as Harvard astronomy was. What you would guess is the universe is expanding, and how fast it's expanding is related to that amount of density of the universe in a very particular way. And the simplest way to do that is what's called the curvature scalar. There's no immediate technological, economic application to what we do. I was thinking of a research project -- here is the thought process. And Bill was like, "No, it's his exam. People like Chung-pei Ma and Uros Seljak were there, and Bhuvnesh Jain was there. So, that was my first glimpse at purposive, long term strategizing within theoretical physics. I worked a lot with Mark Trodden. He has also worked on the foundations of quantum mechanics, especially the many-worlds interpretation, including a derivation of the Born rule for probabilities. Firing on all cylinders intellectually. . I did not succeed in that goal. I've been interviewing scientists for almost twenty years now, and in our world, in the world of oral history, we experienced something of an existential crisis last February and March, because for us it was so deeply engrained that doing oral history meant getting in a car, getting on a plane with your video/audio recording equipment, and going to do it in person. But I think, as difficult as it is, it's an easier problem than adding new stuff that pushes around electors and protons and neutrons in some mysterious way. There's good physics reasons. Maybe you hinted at this a little bit in the way you asked the question, but I do think that the one obvious thing that someone can do is just be a good example. I think that's much more the reason why you don't hear these discussions that much. Are you particularly excited about an area of physics where you might yet make fundamental contributions, or are you, again, going back to graduate school, are you still exuberantly all over the place that maybe one of them will stick, or maybe one of them won't? Sean stands at a height of 5 ft 11 in ( Approx 1.8m). What were the most interesting topics at that time? I did always have an interest in -- I don't want to use the word outreach because that sort of has formal connotations, but in reaching out. In fact, on the flip side of that, the biggest motivation I had for starting my podcast was when I wrote a previous book called The Big Picture, which was also quite interdisciplinary, and I had to talk to philosophers, neuroscientists, origin of life researchers, computer scientists, people like that, I had a license to do that. I hope that the whole talk about Chicago will not be about me not getting tenure, but I actually, after not getting tenure, I really thought about it a lot, and I asked for a meeting with the dean and the provost. I was certainly not the first to get the hint that something had to be wrong. He asked me -- I was a soft target, obviously -- he asked me to give a talk at the meeting, and my assignment was measuring cosmological parameters with everything except for the cosmic microwave background. Who knows? It was really like quantum gravity, or particle physics, or field theory, that were most interesting to me. I mean, Angela Olinto, who is now, or was, the chair of the astronomy department at Chicago, she got tenure while I was there. What were the faculty positions that were most compelling to you as you were considering them? It's the simplest thing you possibly could do. Answer (1 of 6): Check out Quora User's answer to What PhDs are most in demand by universities? They are . Or, maybe I visited there, but just sort of unofficially. But I was like, no I don't want to take a nuclear physics lab. It's very, very demanding, but it's more humanities-based overall as a university. I do this over and over again. Someone else misattributed it first, and I believed them. But the only graduate schools I applied to were in physics because by then I figured out that what I really wanted to do was physics. Like, when people talk about the need for science outreach, and for education and things like that, I think that there is absolutely a responsibility to do outreach to get the message out, especially if the kind of work you do has no immediate economic or technological impact. There are a lot of biologists who have been fighting in the trenches against creationism for a long time. But it's less important for a postdoc hire. So, I still didn't quite learn that lesson, that you should be building to some greater thing. As a ten year old, was there any formative moment where -- it's a big world out there for a ten year old. Maybe not. So, it made it easy, and I asked both Alan and Eddie. There were two that were especially good. A lot of people in science moved their research focus over to something pandemic or virus related. Honestly, I only got that because Jim Hartle was temporarily the director. 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. Then, there were books like Bob Wald's, or Steven Weinberg's, or Misner Thorne and Wheeler, the famous phonebook, which were these wonderful reference books, because there's so much in them. Someone like me, for example, who is very much a physicist, but also is interested in philosophy, and I would like to be more active even than I am at philosophy at the official level, writing papers and things like that. If everyone is a specialist, they hire more specialists, right? Uniquely, in academia the fired professor . The idea -- the emails or responses that make me the happiest are when someone says, you know, "I used to love physics, and I was turned off by it by like a bad course in high school, and you have reignited my passion for it." Are there any advantages through a classical education in astronomy that have been advantageous for your career in cosmology? I think that, again, good fortune on my part, not good planning, but the internet came along at the right time for me to reach broader audiences in a good way. So, it's one thing if you're Hubble in the 1920s, you can find the universe is expanding. You've been around the block a few times. We are committed to the preservation of physics for future generations, the success of physics students both in the classroom and professionally, and the promotion of a more scientifically literate society. I think we only collaborated on two papers. Being surrounded by the best people was really, really important to me. Then, okay, I get to talk about ancient Roman history on the podcast today. If this interview is important to you, you should consult earlier versions of the transcript or listen to the original tape. The polarization of light from the CMB might be rotated just a little bit as it travels through space. And I could double down on that, and just do whatever research I wanted to do, and I could put even more effort into writing books and things like that. I think I figured it out myself eventually, or again, I got advice and then ignored it and eventually figured it out myself. The other thing, just to go back to this point that students were spoiled in the Harvard astronomy department, your thesis committee didn't just meet to defend your thesis. You really, really need scientists or scholars who care enough about academia to help organize it, and help it work, and start centers and institutes, and blaze new trails for departments. I asked him, "In graduate school, the Sean Carroll that we know today, is that the same person?" His article "Does the Universe Need God?" Right. So, they could be rich with handing out duties to their PhD astronomers to watch over students, which is a wonderful thing that a lot people at other departments didn't get. I think that's a true argument, and I think I can make that argument. [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". Given how productive you've been over the past ten months, when we look to the future, what are the things that are most important to you that you want to return to, in terms of normality? There's no delay on the line. I don't think it has anything to do with what's more important, or fundamental, or exciting, or better science, but there is a certain kind of discipline that you learn in learning physics, and a certain bag of tricks and intellectual guiding stars that you pick up that are very, very helpful. So, that was true in high school. I didn't do any of that, but I taught them the concept. So, without that money coming in randomly -- so, for people who are not academics out there, there are what are called soft money positions in academia, where you can be a researcher, but you're not a faculty member, and you're generally earning your own keep by applying for grants and taking your salary out of the grant money that you bring in. Mr. Tompkins, and One Two Three Infinity was one of the books that I read when I was in high school. I was a good teacher. Hundreds of thousands of views for each of the videos. You can be a physicalist and still do metaphysics for your living. I'm trying to finish a paper right now. It worked for them, and they like it. Yes, I think so. That's a huge effect on people's lives. So, thank you so much. [8][9][10] In 2007, Carroll was named NSF Distinguished Lecturer by the National Science Foundation. I don't want them to use their built in laptop microphone, so I send them a microphone. He was another postdoc that was at MIT with me. It's an expense for me because as an effort to get the sound quality good, I give every guest a free microphone. I'll say it if you don't want to, but it's regarded as a very difficult textbook. It's only being done for the sake of discovery, so we need to share those discoveries with people. But I have a conviction that understanding the answer to those questions, or at least appreciating that they are questions, will play a role -- again, could very easily play a role, because who knows, but could very easily play a role in understanding what we jokingly call the theory of everything, the fundamental nature of all the forces and the nature of space time itself. Absolutely brilliant course. Some of the papers we wrote were, again, very successful. So, probably, yes, I would still have the podcast even if I'd gone to law school. I'm very happy with that. I made that choice consciously. Sean, in your career as a mentor to graduate students, as you noted before, to the extent that you use your own experiences as a cautionary tale, how do you square the circle of instilling that love of science and pursuing what's most interesting to you within the constraints of there's a game that graduate students have to play in order to achieve professional success? ", "2014 National Convention Los Angeles Freedom From Religion Foundation", "Responding to Sean Carroll: What If There Had Been a Camera at the Resurrection? Part of it was the Manhattan Project and being caught up in technological development. So, he founded that. They promote the idea of being a specialist, and they just don't know what to do with the idea that you might not be a specialist. I've already stopped taking graduate students, because I knew this was the plan for a while. And you know, Twitter and social media and podcasts are somewhere in between that. Young universities ditch the tenure system. And we just bubbled over in excitement about general relativity, and our friends in the astronomy department generally didn't take general relativity, which is weird in a sense. So, that's why I said I didn't want to write it. There was so much good stuff to work on, you didn't say no to any of it, you put it all together. I've seen almost nothing in physics like that, and I think I would be scared to do that. So, that was just a funny, amusing anecdote. This is easily the most important, most surprising empirical discovery in fundamental physics in -- I want to say in my lifetime, but certainly since I've been doing science. It never occurred to me that it was impressive, and I realized that you do need to be something. Well, Harvard -- the astronomy department, which was part and parcel of the Harvard Smithsonian Center for Astrophysics -- so, the Smithsonian Astrophysical Observatory and the Harvard College Observatory joined together in the 1970s to form this big institution, which I still think might be the largest collection of astronomy PhDs, in the United States, anyway. But this is a huge metaphysical assumption that underlies this debate and divides us. Is there something wrong about it?" It's really the biggest, if not only source of money in a lot of areas I care about. That's the job. You do get a seat at the table, in a way, talking about religion that I wouldn't if I were talking about the economy, for example. So, my three years at Santa Barbara, every single year, I thought I'll just get a faculty job this year, and my employability plummeted. How do you understand all of these things? On the point of not having quantum field theory as an undergraduate, I wonder, among your cohort, if you felt that you stuck out, like a more working class kid who went to Villanova, and that was very much not the profile of your fellow graduate students. Despite the fact that it was hugely surprising, we were all totally ready for it. Bob is a good friend of mine, and I love his textbook, but it's very different. Whereas there are multiple stories of people with PhDs in physics doing wonderful work in biology. I mean, I'm glad that people want to physicists, but there's no physicist shortage out there. But there's an enormous influence put on your view of reality by all of these pre-existing propositions that you think are probably true. By the way, all these are hard. So, for you, in your career, when did cosmology become something where you can proudly say, "This is what I do. The Broncos have since traded for Sean Payton, nearly two years after Wilson's trade list included the Saints. But I loved it. But interestingly, the kind of philosophy I liked was moral and political philosophy. And, you know, in other ways, Einstein, Schrdinger, some of the most wonderful people in the history of physics, Boltsman, were broad and did write things for the public, and cared about philosophy, and things like that. It might be a good idea that is promising in the moment and doesn't pan out. I think new faculty should get wooden desks. And you take external professor at the Santa Fe Institute to an extreme level having never actually visited. So much knowledge, and helpful, but very intimidating if you're a student. Once you do that, people will knock on your door and say, "Please publish this as a textbook." Sean Michael Carroll (born October 5, 1966) is an American theoretical physicist and philosopher who specializes in quantum mechanics, cosmology, and philosophy of science. The second book, the Higgs boson book, I didn't even want to write.