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

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.