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

Welcome to the March 2025 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!Link to the 2012 Moving Naturalism Forward workshop, mentioned in the episode.Blog post with questions and full transcript: https://www.preposterousuniverse.com/podcast/2025/03/10/ama-march-2025/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.

A lot of science goes into crafting the perfect cocktail. Balancing sweet and bitter notes, providing the right amount of aeration and dilution, getting it to just the right temperature and keeping it that way. And even if you have no interest in cocktails as such, the general principles extend to other activities in art and in life. I talk to scientist-turned-mixologist Kevin Peterson about how to think about the simple magic of a perfect drink.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/03/03/307-kevin-peterson-on-the-theory-of-cocktails/Support Mindscape on Patreon.Kevin Peterson received a Ph.D. in Mechanical Engineering from the University of Michigan. He is currently co-owner of both Castalia (an experimental craft cocktail bar) and Sfumato Fragrances in Detroit, Michigan. He is the author of Cocktail Theory: A Sensory Approach to Transcendent Cocktails.Mindscape Petrichor Negroni (from the episode)1 part gin distilled from vetiver(alternative: herbaceous gin such as Moletto)1 part St. George Bruto Americano1 part Antica Formula vermouthStir over an ice cube, express with orange peel (not shown).See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It is commonplace to refer to the Earth's oceans as vast and largely unexplored. But we do understand some aspects, and improving that understanding is crucial to ensuring the continued viability and success of life on this planet. The oceans are a paradigmatic complex system: there are many components, distinct but mutually interacting, that add up to a nuanced whole. We talk with ocean physicist Helen Czerski about what the ocean is and how it's changing.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/02/24/306-helen-czerski-on-our-energetic-oceans/Support Mindscape on Patreon.Helen Czerski received her Ph.D. in physics from the University of Cambridge. She is currently an Associate Professor at the Department of Mechanical Engineering at University College London. She is the author of several books, most recently The Blue Machine: How the Ocean Works. She is a frequent television presenter for the BBC and elsewhere.Web siteUCL web pageGoogle Scholar publicationsWikipediaAmazon author pageBlueskySee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Political outcomes would be relatively simple to predict and understand if only people were well-informed, entirely rational, and perfectly self-interested. Alas, real human beings are messy, emotional, imperfect creatures, so a successful theory of politics has to account for these features. One phenomenon that has grown in recent years is an alignment of cultural differences with political ones, so that polarization becomes more entrenched and even violent. I talk with political scientist Lilliana Mason about how this has come to pass, and how democracy can deal with it.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/02/17/305-lilliana-mason-on-polarization-and-political-psychology/Support Mindscape on Patreon.Lilliana Hall Mason received her Ph.D. in political psychology from Stony Brook University. She is currently an SNF Agora Institute Associate Professor of Political Science at Johns Hopkins University. She is the author of Uncivil Agreement: How Politics Became Our Identity and co-author (with Nathan Kalmoe) of Radical American Partisanship: Mapping Violent Hostility, Its Causes, and the Consequences for Democracy.Web SiteHopkins web pageGoogle Scholar publicationsBlueskySee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

The Trump administration, led by Elon Musk and his Department of Government Efficiency, has proposed sweeping cuts to spending on science research here in the US, in particular at the National Institutes of Health and the National Science Foundation. I explain a little about what is being cut and why these funds are important to scientific progress. I try, for what it's worth, to provide these explanations in a way that would be informative to those who generally favor cutting government waste in dramatic fashion.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/02/12/bonus-cuts-to-science-funding-and-why-they-matter/Support Mindscape on Patreon.Indirect costs primerCuts to NIH indirect costsAppropriated funds are mandated by statuteProposed NSF cutsElon Musk doesn't understand indirect costsShrimp treadmill storyBribing foreign officialsDeleting NSA web pagesExecutive Orders are not lawsHistory of impoundmentsSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

It is a feature of many human activities - sports, cooking, music, interpersonal relations - that being able to do them well doesn't necessarily mean you can accurately describe how to do them well. Science is no different. Many successful scientists are not very good at explaining what goes into successful scientific practice. To understand that, it's necessary to study science in a scientific fashion. What kinds of scientists, in what kinds of collaborations, using what kinds of techniques, do well? I talk with James Evans, an expert on collective intelligence and the construction of knowledge, about how science really works.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/02/10/304-james-evans-on-innovation-consolidation-and-the-science-of-science/Support Mindscape on Patreon.James Evans received his Ph.D. in Sociology from Stanford University. He is currently the Max Palevsky Professor of History and Civilizations, Director of Knowledge Lab, and Faculty Director of Computational Social Science at the University of Chicago; External Professor at the Santa Fe Institute; External Faculty at the Complexity Science Hub, Vienna; and Visiting Faculty Researcher at Google.Knowledge Lab web siteUniversity of Chicago web pageGoogle scholar publicationsSee Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Welcome to the February 2025 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 questions and transcript: https://www.preposterousuniverse.com/podcast/2025/02/03/ama-february-2025/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.

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.