Sean Carroll's Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas

A typical human lifespan is approximately three billion heartbeats in duration. Lasting that long requires not only intrinsic stability, but an impressive capacity for self-repair. Nevertheless, things do occasionally break down, and cancer is one of the most dramatic examples of such breakdown. Given that the body is generally so good at protecting itself, can we harness our internal security patrol - the immune system - to fight cancer? This is the hope of Nobel Laureate James Allison, who works on studying the structure and behavior of immune cells, and ways to coax them into fighting cancer. This approach offers hope of a way to combat cancer effectively, lastingly, and in a relatively gentle way.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/01/27/303-james-p-allison-on-fighting-cancer-with-the-immune-system/James P. Allison received his Ph.D. in biology from the University of Texas at Austin. He is currently Regental Professor and Chair of the Department of Immunology, the Olga Keith Wiess Distinguished University Chair for Cancer Research, Director of the Parker Institute for Cancer Research, and Director of the James P. Allison Institute at MD Anderson Cancer Center. He is the subject of the documentary film Jim Allison: Breakthrough. Among his numerous awards are the Breakthrough Prize in Life Sciences and the Nobel Prize in Physiology or Medicine.Web pageNobel Prize citationGoogle Scholar publicationsWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Randomness plays an important role in the evolution of life (as my evil twin will tell you). But random doesn't mean arbitrary. Biological organisms are physical objects, after all, and subject to the same laws of physics as non-biological matter is. Those laws place constraints on how organisms can fulfill their basic functions of metabolism, reproduction, motility, and so on. Easy to say, but how can we turn this into quantitative understanding of actual organisms? Today I talk with physical biologist Chris Kempes about how physics can help us understand the size of organisms, their metabolisms, and features of major transitions in evolution.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/01/20/302-chris-kempes-on-the-biophysics-of-evolution/Chris Kempes received his Ph.D. in physical biology from the Massachusetts Institute of Technology. He is currently Professor and a member of the Science Steering Committee at the Santa Fe Institute. His research involves the origin of life and the constraints placed by physics on biological function and evolution.Web siteSanta Fe Institute web pageGoogle Scholar publicationsOrigins of Life online courseSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Big data is ruling, or at least deeply infiltrating, all of modern existence. Unprecedented capacity for collecting and analyzing large amounts of data have given us a new generation of artificial intelligence models, but also everything from medical procedures to recommendation systems that guide our purchases and romantic lives. I talk with computer scientist Tina Elassi-Rad about how we can sift through all this data, make sure it is deployed in ways that align with our values, and how to deal with the political and social dangers associated with systems that are not always guided by the truth.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/01/13/301-tina-eliassi-rad-on-al-networks-and-epistemic-instability/Tina Eliassi-Rad received her Ph.D. in computer science from the University of Wisconsin-Madison. She is currently Joseph E. Aoun Chair of Computer Sciences and Core Faculty of the Network Science Institute at Northeastern University, External Faculty at the Santa Fe Institute, and External Faculty at the Vermont Complex Systems Center. She is a fellow of the Network Science Society, recipient of the Lagrange Prize, and was named one of the 100 Brilliant Women in AI Ethics.Web siteNortheastern web pageGoogle Scholar publicationsWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

A new year, and a new centennial -- 300 (regularly-numbered) episodes of Mindscape! Our tradition is to have a solo episode, and what better topic than the nature of time? Physicists and philosophers have so frequently suggested that time is some kind of illusion that it's become almost passé to believe that it might be fundamental. This is an issue where, despite the form of the question, physics has important things to say that most philosophers haven't yet caught up to. I will talk about ideas from quantum mechanics and quantum gravity that bear on the question of whether time is emergent or fundamental, and the implications of each possibility.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/01/06/300-solo-does-time-exist/Some of the papers discussed herein:Carroll (2008), "What If Time Really Exists?"Dyson, Kleban, and Susskind (2002), "Disturbing Implications of a Cosmological Constant."Albrecht and Sorbo (2004), "Can the Universe Afford Inflation?"Boddy, Carroll, and Pollack (2014), "De Sitter Space Without Dynamical Quantum Fluctuations."Lloyd (2016), "Decoherent Histories Approach to the Cosmological Measure Problem."Page and Wootters (1983), "Evolution Without Evolution: Dynamics Described by Stationary Observables."Albrecht (1994), "The Theory of Everything vs the Theory of Anything."Albrecht and Iglesias (2007), "The Clock Ambiguity and the Emergence of Physical Laws."See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It's the end of the year, and time for our annual holiday break here at Mindscape. But as usual, we wrap up with a Holiday Message. This year, inspired by Joni Mitchell's "Hits" and "Misses" albums, I go through my scientific papers and talk about some of my favorites -- some of which were hits, in terms of making an impact on subsequent research, and some of which were misses by that standard. But I love them all! It's an excuse to talk about process -- how papers come to be, from the initial informal idea to sitting down and doing the work.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/12/23/holiday-message-hits-and-misses/Here are links to the papers I discuss in the episode.S.M. Carroll, G.B. Field and R. Jackiw, 1990, "Limits on A Lorentz and Parity-Violating Modification of Electrodynamics,'' Phys. Rev. D 41, 1231. [pdf file; inSPIRE]S.M. Carroll, E. Farhi and A.H. Guth, 1992, "An Obstacle to Building a Time Machine,'' Phys. Rev. Lett. 68, 263; Erratum: 68, 3368. [pdf file; inSPIRE]S.M. Carroll, E. Farhi, A.H. Guth and K.D. Olum, 1994, "Energy-Momentum Restrictions on the Creation of Gott Time Machines,'' Phys. Rev. D 50, 6190; gr-qc/9404065. [arXiv; pdf; inSPIRE]S.M. Carroll, 1998, "Quintessence and the Rest of the World,'' Phys. Rev. Lett. 81, 3067; astro-ph/9806099. [arXiv; pdf; inSPIRE]S.M. Carroll, V. Duvvuri, M. Trodden, and M.S. Turner, 2003, "Is Cosmic Speed-Up Due to New Gravitational Physics?'' astro-ph/0306438. [arXiv; pdf; inSPIRE]S.M. Carroll and J. Chen, 2004, "Spontaneous Inflation and the Origin of the Arrow of Time'', hep-th/0410270. [arXiv, inSPIRE]L. Ackerman, M.R. Buckley, S.M. Carroll, and M. Kamionkowski, 2008, "Dark Matter and Dark Radiation," arxiv:0807.5126. [arXiv; pdf; inSPIRE]S.M. Carroll, M.C. Johnson, and L. Randall, 2009, "Dynamical Compactification," arxiv:0904.3115. [arXiv; pdf; inSPIRE]C. Cao, S.M. Carroll, and S. Michalakis, 2016, "Space from Hilbert Space: Recovering Geometry from Bulk Entanglement," arxiv:1606.08444. [arXiv, inSPIRE]C. Cao and S.M. Carroll, 2018, "Bulk Entanglement Gravity without a Boundary: Towards Finding Einstein's Equation in Hilbert Space," arxiv:1712.02803. [arXiv, inSPIRE]N. Bao, S.M. Carroll, A. Chatwin-Davies, J. Pollack, and G. Remmen, 2017, “Branches of the Black Hole Wave Function Need Not Contain Firewalls," arxiv:1712.04955. [arXiv, inSPIRE]See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Living organisms seem exquisitely organized and complex, with features clearly adapted to serving certain functions needed to survive and procreate. Natural selection provides a compelling explanation for why that is so. But is there a bigger picture, a more general framework that explains the origin and evolution of functions and complexity in a world governed by uncaring laws of physics? I talk with planetary scientist and astrobiologist Michael Wong about how we can define what "functions" are and the role they play in the evolution of the universe.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/12/16/299-michael-wong-on-information-function-and-the-origin-of-life/Michael Wong received his Ph.D. in planetary science from Caltech. He is currently a Sagan Postdoctoral Fellow at the Carnegie Institution for Scienceʼs Earth & Planets Laboratory. He is in the process of co-authoring two books: A Missing Law: Evolution, Information, and the Inevitability of Cosmic Complexity with Robert M. Hazen, and a revised edition of Astrobiology: A Multidisciplinary Approach with Jonathan Lunine.Web siteCarnegie web pageStrange New Worlds podcastWong et al. (2023), "On the Roles of Function and Selection in Evolving Systems."Wong and Prabhu (2023), "Cells as the First Data Scientists."See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

The number of neurons in the human brain is comparable to the number of stars in the Milky Way galaxy. Unlike the stars, however, in the case of neurons the real action is in how they are directly connected to each other: receiving signals over synapses via their dendrites, and when appropriately triggered, sending signals down the axon to other neurons (glossing over some complications). So a major step in understanding the brain is to map its wiring diagram, or connectome: the complete map of those connections. For a human brain that's an intimidatingly complex challenge, but important advances have been made on tinier brains. We talk with Jeff Lichtman, a leader in brain mapping, to gauge the current state of progress and what it implies.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/12/09/298-jeff-lichtman-on-the-wiring-diagram-of-the-brain/Jeff Lichtman received an MD/PhD from Washington University in St. Louis. He is currently the Jeremy R. Knowles Professor of Molecular and Cellular Biology and Santiago Ramón y Cajal Professor of Arts and Sciences at Harvard University. He is co-inventor of the Brainbow system for imaging neurons. He is a member of the National Academy of Sciences.Web pageLab web siteGoogle Scholar publicationsWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to the December 2024 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters (who are also the ones asking the questions). We take questions asked by Patreons, whittle them down to a more manageable number -- based primarily on whether I have anything interesting to say about them, not whether the questions themselves are good -- and sometimes group them together if they are about a similar topic. Enjoy!Blog post with AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2024/12/02/ama-december-2024/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Not too long ago, Brad Pitt and Eric Bana starred in a (loose) adaptation of Homer's epic poem The Iliad; next month, Ralph Fiennes and Juliette Binoche will headline a film based on The Odyssey. Given that the originals were written (or at least written down) in the 8th century BCE, that is some impressive staying power. But they were also written in a very different time than ours, with different cultural context and narrative expectations. We talk about the issues of translation in general, and these Greek classics in particular, with Emily Wilson, whose recent translations of The Iliad and The Odyssey have garnered worldwide acclaim.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/11/25/297-emily-wilson-on-homer-poetry-and-translation/Emily Wilson received her Ph.D. in classical and comparative literature from Yale. She is currently Professor of Classical Studies at the University of Pennsylvania. Among her awards are the Charles Berheimer Prize from the American Comparative Literature Association, a Rome Prize fellowship from the American Academy in Rome, and Guggenheim and MacArthur fellowships.Web siteUPenn web pageWikipediaAmazon.com author pageYouTubeSubstackBlueSkySee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Biological evolution via natural selection is a simple idea that becomes enormously complicated in its realization. Populations of organisms are driven toward increased "fitness," a measure of how successfully we reproduce our genetic information. But fitness is a subtle concept, changing with time and environment and interactions with other organisms around us. We talk with biologist Brandon Ogbunu about the best mathematical and conceptual tools for thinking about the messy complexities of evolution, and how modern technology is changing our way of thinking about it.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/11/18/296-brandon-ogbunu-on-fitness-seascapes-and-the-course-of-evolution/Brandon Ogbunu received his Ph.D. in Genetics and Microbiology from Yale University. He is currently Assistant Professor of Ecology and Evolutionary Biology at Yale, and External Faculty at the Santa Fe Institute. He has been awarded a Fullbright Fellowship and was the Martin Luther King Jr. Visiting Professor at MIT. He has contributed to a number of publications, including Wired, Undark, and Quanta.Lab web siteYale web pageGoogle Scholar publicationsWikipediaPublic talk: What is Lyfe? Towards a Biology of Context & ComplexitySee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Emergence is a centrally important concept in science and philosophy. Indeed, the existence of higher-level emergent properties helps render the world intelligible to us -- we can sensibly understand the macroscopic world around us without a complete microscopic picture. But there are various different ways in which emergence might happen, and a tendency for definitions of emergence to rely on vague or subjective criteria. Recently Achyuth Parola and I wrote a paper trying to clear up some of these issues: What Emergence Can Possibly Mean. In this solo podcast I discuss the way we suggest to think about emergence, with examples from physics and elsewhere.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/11/11/295-solo-emergence-and-layers-of-reality/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to the November 2024 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters (who are also the ones asking the questions). We take questions asked by Patreons, whittle them down to a more manageable number -- based primarily on whether I have anything interesting to say about them, not whether the questions themselves are good -- and sometimes group them together if they are about a similar topic. Enjoy!Support Mindscape on Patreon.Blog post with AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2024/11/04/ama-november-2024/See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Erwin Schrödinger said that the important characteristic of life is that it "goes on doing something... for a much longer period than we would expect an inanimate piece of matter to keep going under similar circumstances." Living organisms are in constant motion inside; so where does this stability and persistence come from? Addy Pross points to a novel kind of chemical phenomenon -- "dynamic kinetic stability" (DKS), a feature that enables a chemical "fountain" to persist in the presence of an energy source. This suggests an interesting perspective on the question of life's origin, and perhaps on the origin of consciousness.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/10/28/294-addy-pross-on-dynamics-stability-and-life/Addy Pross received his Ph.D. in chemistry from the University of Sydney. He is currently Professor Emeritus of Chemistry at Ben-Gurion University. He has held visiting positions in the University of Lund, Stanford University, Rutgers University, University of California at Irvine, University of Padova, the Australian National University Canberra, and the University of Sydney. He is the author of What Is Life? How Chemistry Becomes Biology.Web pageAmazon author pageGoogle Scholar publicationsSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

A large economy is one of the best examples we have of complex dynamics. There are multiple components arranged in complicated overlapping hierarchies, out-of-equilibrium dynamics, nonlinear coupling and feedback between different levels, and ubiquitous unpredictable and chaotic behavior. Nevertheless, many economic models are based on relatively simple equilibrium principles. Doyne Farmer is among a group who think that economists need to start taking the tools of complexity theory seriously, as he argues in his recent book Making Sense of Chaos: A Better Economics for a Better World.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/10/21/293-doyne-farmer-on-chaos-crashes-and-economic-complexity/J. Doyne Farmer received his Ph.D. in physics from the University of California, Santa Cruz. He is currently Director of the Complexity Economics program and Baillie Gifford Professor of Complex Systems Science at the University of Oxford, External Professor at the Santa Fe Institute, and Chief Scientist at Macrocosm. He was the founder of the Complex Systems Group in the Theoretical Division at Los Alamos National Laboratory, and co-founder of The Prediction Company.Web siteOxford web pageGoogle Scholar publicationsAmazon author pageWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It's not immoral to kick a rock; it is immoral to kick a baby. At what point do we start saying that it is wrong to cause pain to something? This question has less to do with "consciousness" and more to do with "sentience" -- the ability to perceive feelings and sensations. Philosopher Jonathan Birch has embarked on a careful study of the meaning of sentience and how it can be identified in different kinds of organisms, as he discusses in his new open-access book The Edge of Sentience. This is an example of a question at the boundary of philosophy and biology with potentially important implications for real-world policies.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/10/14/292-jonathan-birch-on-animal-sentience/Jonathan Birch received his Ph.D. in the philosophy of science from the University of Cambridge. He is currently a Professor in the Department of Philosophy Logic and Scientific Method at the London School of Economics and Political Science (LSE). He is one of the authors of the New York Declaration on Animal Consciousness, and has advised the British government on matters of animal cruelty and sentience.Web siteLSE web pageGoogle scholar publicationsPhilPeople profileWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to the October 2024 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters (who are also the ones asking the questions). We take questions asked by Patreons, whittle them down to a more manageable number -- based primarily on whether I have anything interesting to say about them, not whether the questions themselves are good -- and sometimes group them together if they are about a similar topic. Enjoy!Support Mindscape on Patreon.Blog post with questions and transcript: https://www.preposterousuniverse.com/podcast/2024/10/07/ama-october-2024/See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Aging and death happen to the best of us, but there are increasing efforts to do something about it. That effort requires that we have some reasonable understanding of why aging happens, and what processes are involved. You will be unsurprised to learn that it's complicated. Venki Ramakrishnan, who won the Nobel Prize for his work on the ribosome, investigates what we know about aging in his book Why We Die: The New Science of Aging and the Quest for Immortality. We talk about aging and death, and manage to get some thoughts in about ribosomes. Venki and many other great communicators will be speaking at New Scientist Live, which takes place at ExCeL London between 12 - 14 October 2024, and is also streamed live as well as on-demand.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/09/30/291-venki-ramakrishnan-on-the-biology-of-death-and-aging/Venkatraman (Venki) Ramakrishnan received his Ph.D. in physics from Ohio University. He is currently Group Leader at the MRC Laboratory of Molecular Biology, Cambridge, England, and is a Fellow of Trinity College. He previously served as President of the Royal Society of London. He shared the Nobel Prize in Chemistry for his work uncovering the structure of the ribosome.Lab web pageNobel citationGoogle scholar publicationsWikipediaAmazon author pageSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It's a wonder democracy works at all -- a collection of people with potentially different interests have to agree to abide by majority vote even when it goes against their desires. But as we know, it doesn't always work, and racial and ethnic tensions are one of its biggest challenges. Hahrie Han studies the ground-up workings of democracy, how people can come together to successfully enact change. In her new book Undivided: The Quest for Racial Solidarity in an American Church, she investigates an example where democracy apparently has worked remarkably well, and asks what lessons we can draw from it.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/09/23/290-hahrie-han-on-making-multicultural-democracy-work/Hahrie Han recieved her Ph.D. in political science from Stanford University. She is currently the Director of the SNF Agora Institute, the Stavros Niarchos Foundation Professor of Political Science, and Faculty Director of the P3 Research Lab at Johns Hopkins University. She was named the Social Innovation Thought Leader of the Year by the World Economic Forum, is a Fellow of the American Academy of Arts and Sciences, and gave the 2024 Tanner Lectures on Human Values at Harvard University, among other awards.Web siteJohns Hopkins web pageGoogle Scholar publicationsAmazon author pageSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

As an experimental facility, the Large Hadron Collider at CERN in Geneva has been extraordinarily successful, discovering the Higgs boson and measuring multiple features of particle-physics interactions at unprecedented energies. But to theorists, the results have been somewhat frustrating, as we were hoping to find brand-new phenomena beyond the Standard Model. There is nothing to do but to keep looking, recognizing that we have to choose our methods judiciously. I talk with theoretical physicist Cari Cesarotti about what experimental results the modern particle physicist most looks forward to, and how we might eventually get there, especially through the prospect of a muon collider.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/09/16/289-cari-cesarotti-on-the-next-generation-of-particle-experiments/Cari Cesarotti received her Ph.D. in physics from Harvard University. She is currently a postdoctoral fellow at MIT. Her research is on particle phenomenology theory, with an eye toward experimental searches. Among her awards are the Sakurai Dissertation Award in Theoretical Physics from the American Physical Society and the Young Scientist Award at the 14th International Conference on the Identification of Dark Matter.Web siteMIT web pagePublications at inSpireSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It wasn't that long ago, historically speaking, that you might put on your tuxedo or floor-length evening gown to go out and hear a live opera or symphony. But today's world is faster, more technologically connected, and casual. Is there still a place for classical music in the contemporary environment? Max Richter, whose new album In a Landscape releases soon, proves that there is. We talk about what goes into making modern classical music, how musical styles evolve, and why every note should count.Support Mindscape on Patreon.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/09/09/288-max-richter-on-the-meaning-of-classical-music-today/Max Richter trained in composition and piano at Edinburgh University, at the Royal Academy of Music, and with Luciano Berio in Florence. He was a co-founder of the ensemble Piano Circus. His first solo album, "Memoryhouse," was released in 2002. He has since released numerous solo albums, as well as extensive work on soundtracks for film and television, ballet, opera, and collaborations with visual artists.Web siteYouTubeSpotifyWikipediaSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.