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

A characteristic of complex systems is that individual components combine to exhibit large-scale emergent behavior even when the components were not specifically designed for any particular purpose within the collective. Sometimes those individual components are us -- people interacting within societies or online communities. Studying the dynamics of such interactions is interesting both to better understand what is happening, and hopefully to designing better communities. I talk with Petter Törnberg about flows of information, how polarization develops, and how artificial agents can help steer things in better directions. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/09/29/330-petter-tornberg-on-the-dynamics-of-misinformation/ [https://www.preposterousuniverse.com/podcast/2025/09/29/330-petter-tornberg-on-the-dynamics-of-misinformation/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Petter Törnberg received a Ph.D. in complex systems from Chalmers University of Technology. He is now an Assistant Professor at the Institute for Language, Logic and Computation at the University of Amsterdam, Associate Professor in Complex Systems at Chalmers University of Technology, NWO VENI laurate, and senior researcher at the University of Neuchâtel. * Web site [https://www.pettertornberg.com/] * Univ. Amsterdam web page [https://www.uva.nl/en/profile/t/o/p.tornberg/k.p.tornberg.html] * Google Scholar publications [https://scholar.google.com/citations?user=KuJMuvIAAAAJ&hl=en] * Amazon author page [https://www.amazon.com/stores/Petter-T%C3%B6rnberg/author/B0DRJ8H2G9] * Bluesky [https://bsky.app/profile/pettertornberg.com] See Privacy Policy at https://art19.com/privacy [https://art19.com/privacy] and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info [https://art19.com/privacy#do-not-sell-my-info].

Getting along in society requires that we mostly adhere to certainly shared norms and customs. Often it's not enough that we all know what the rules are, but also that everyone else knows the rules, and that they know that we know the rules, and so on. Philosophers and game theorists refer to this as common knowledge [https://plato.stanford.edu/entries/common-knowledge/]. In Steven Pinker's new book, When Everyone Knows That Everyone Knows... [https://stevenpinker.com/publications/when-everyone-knows-everyone-knows-common-knowledge-and-mysteries-money-power-and], he explores how common knowledge (or its absence) explains money, power, and a wide variety of subtextual human interactions. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/09/22/329-steven-pinker-on-rationality-and-common-knowledge/ [https://www.preposterousuniverse.com/podcast/2025/09/22/329-steven-pinker-on-rationality-and-common-knowledge/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Steven Pinker received his Ph.D. in psychology from Harvard University. He is currently the Johnstone Family Professor of Psychology at Harvard University. He is the author of several best-selling books and recipient of several honorary doctoral degrees. Among his awards are Humanist of the Year (two different organizations) and the William James Lifetime Achievement Award from the Association for Psychological Science. * Web site [https://stevenpinker.com/] * Harvard web page [https://psychology.fas.harvard.edu/people/steven-pinker] * Google Scholar publications [https://scholar.google.com/citations?user=bUhVerAAAAAJ&hl=en] * Amazon author page [https://www.amazon.com/stores/Steven-Pinker/author/B000AQ3GGO] * Wikipedia [https://en.wikipedia.org/wiki/Steven_Pinker] See Privacy Policy at https://art19.com/privacy [https://art19.com/privacy] and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info [https://art19.com/privacy#do-not-sell-my-info].

Like any machine, bodies occasionally break down, and it's natural to go in search of a replacement part. Ancient societies featured simple prosthetics for teeth, noses, and limbs, while modern medicine pursues more advanced ways of replacing internal organs and microbiomes. But what is striking is not just the impressive ingenuity of our attempts to replicate human anatomy, but the surprising level of difficulty involved in doing it well. I talk with author Mary Roach about the many ways in which humans have chosen to replace bits of themselves, as told in her recent book Replaceable You: Adventures in Human Anatomy [https://www.maryroach.net/replaceable.html]. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/09/15/328-mary-roach-on-replacing-parts-of-our-bodies/ [https://www.preposterousuniverse.com/podcast/2025/09/15/328-mary-roach-on-replacing-parts-of-our-bodies/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Mary Roach received a bachelor's degree in psychology from Wesleyan University. Her books include multiple New York Times bestsellers and have appeared on numerous best-of lists. She was a guest editor in the Best American Science and Nature Writing series, and received the Rushdie Award from the Harvard Secular Society. * Web site [https://maryroach.net/] * Wikipedia [https://en.wikipedia.org/wiki/Mary_Roach] * Bluesky [https://bsky.app/profile/maryroach.bsky.social] * Goodreads profile [https://www.goodreads.com/author/show/7956.Mary_Roach] * Amazon author page [https://www.amazon.com/stores/Mary-Roach/author/B001H6MAHM] See Privacy Policy at https://art19.com/privacy [https://art19.com/privacy] and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info [https://art19.com/privacy#do-not-sell-my-info].

Welcome to the September 2025 Ask Me Anything episode of Mindscape! These monthly excursions are funded by Patreon supporters [https://www.patreon.com/seanmcarroll] (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/2025/09/08/ama-september-2025/ [https://www.preposterousuniverse.com/podcast/2025/09/08/ama-september-2025/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. See Privacy Policy at https://art19.com/privacy [https://art19.com/privacy] and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info [https://art19.com/privacy#do-not-sell-my-info].

"Liberalism," divorced from its particular connotations in this or that modern political context, refers broadly to a philosophy of individual rights, liberties, and responsibilities, coupled with respect for institutions and rule of law over personalized power. As Cass Sunstein construes the term, liberalism encompasses a broad tent, from Ronald Reagan and Margaret Thatcher to Martin Luther King and Franklin Roosevelt. But liberalism is being challenged both from the right and from the left, by those who think that individual liberties can go too far. We talk about the philosophical case for liberalism as well as the challenges to it in modern politics, as discussed in his new book On Liberalism: In Defense of Freedom [https://mitpress.mit.edu/9780262049771/on-liberalism/]. Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/09/01/327-cass-sunstein-on-liberalism/ [https://www.preposterousuniverse.com/podcast/2025/09/01/327-cass-sunstein-on-liberalism/] Support Mindscape on Patreon [https://www.patreon.com/seanmcarroll]. Cass Sunstein received a J.D. from Harvard Law School, and worked as a clerk for Supreme Court Justice Thurgood Marshall. He is currently Robert Walmsley University Professor at Harvard. He served in several government roles during the Obama administration. He is recognized [https://web.archive.org/web/20170801153300/http://holberg.uib.no/en/news/holberg-prize/holberg-prize-and-nils-klim-prize-laureates-2017-announced] as "by far the most cited legal scholar in the United States and probably the world." * Harvard web page [https://hls.harvard.edu/faculty/cass-r-sunstein/] * Google Scholar publications [https://scholar.google.com/citations?user=ddq2_gkAAAAJ&hl=en&oi=ao] * Substack [https://casssunstein.substack.com/] * Amazon author page [https://www.amazon.com/stores/author/B001ILMC6A?ccs_id=170570fa-d186-40d9-9492-00807245dcac] * Wikipedia [https://en.wikipedia.org/wiki/Cass_Sunstein] See Privacy Policy at https://art19.com/privacy [https://art19.com/privacy] and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info [https://art19.com/privacy#do-not-sell-my-info].