Sean Carroll's Mindscape

Game theory is a way of quantitatively describing what happens any time one thing interacts with another thing, when both things have goals and potential rewards. That's a pretty broad class of interesting events, so it is unsurprising that game theory is a useful way of thinking about everything from international relations to the evolution of peacock feathers. I talk with philosopher Kevin Zollman about what game theory is and how it gets used in biology and human interactions. We discuss how thinking in game-theoretic terms can help understand the origin of meaning and intentionality in human language.Blog post...

Machine learning using neural networks has led to a remarkable leap forward in artificial intelligence, and the technological and social ramifications have been discussed at great length. To understand the origin and nature of this progress, it is useful to dig at least a little bit into the mathematical and algorithmic structures underlying these techniques. Anil Ananthaswamy takes up this challenge in his book Why Machines Learn: The Elegant Math Behind Modern AI. In this conversation we give a brief overview of some of the basic ideas, including the curse of dimensionality, backpropagation, transformer architectures, and more.Blog post with t...

Welcome to the November 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 AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2025/11/17/ama-november-2025/In the intro I mentioned a couple of my favorite TV shows of th...

Science has an incredibly impressive track record of uncovering nonintuitive ideas about the universe that turn out to be surprisingly accurate. It can be tempting to think of scientific discoveries as being carefully constructed atop a rock-solid foundation. In reality, scientific progress is tentative and fallible. Scientists propose models, assign them probabilities, and run tests to see whether they succeed or fail. In cosmologist Andrew Jaffe's new book, The Random Universe, he illustrates how models and probability help us make sense of the cosmos.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/11/10/335-andrew-jaffe-on-models-probability-and-the-universe/Support Mindscape on Patreon.Andrew Jaffe re...

The universe as revealed by physics is objective: it's out there, existing and behaving in ways that are completely independent of human thought. But the process by which we learn about the universe, and the language with which we talk about it, is extremely human-dependent. Does that mean that aliens would do science differently, and even think differently about physics, even if we all live in the same universe? Physicist Daniel Whiteson has teamed with cartoonist Andy Warner to investigate these questions in their new book Do Aliens Speak Physics?Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/11/03/334-daniel-whiteson-on-the-physics-of-and-by-aliens/S...

Why are people wrong all the time, anyway? Is it because we human beings are too good at being irrational, using our biases and motivated reasoning to convince ourselves of something that isn't quite accurate? Or is it something different -- unmotivated reasoning, or "unthinkingness," an unwillingness to do the cognitive work that most of us are actually up to if we try? Gordon Pennycook wants to argue for the latter, and this simple shift has important consequences, including for strategies for getting people to be less susceptible to misinformation and conspiracies.Blog post with transcript: https://www.preposterousuniverse.com...

Music is math that you can dance to. The fact that certain notes sound good when played together, or in succession, is related to the mathematical properties of the frequencies to which they correspond, an idea that goes back as far as Pythagoras himself. These days we have a much more intricate understanding of these relationships and how to manipulate them. I talk to composer and music theorist Dmitri Tymoczko about how different musical scales are constructed and the math underlying what sounds good.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/10/20/332-dmitri-tymoczko-on-the-mathematics-behind-music/Support Mindscape on Patreon.Dmitri Tymoczko r...

Welcome to the October 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 AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2025/10/13/ama-october-2025/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and Cal...

Certain features of our universe seem unnatural to us. These include "constants of nature" such as the cosmological constant and the mass of the Higgs boson, as well as features of the initial conditions like the curvature of space and the initial entropy. But they can't truly be "unnatural" -- they are literally features of Nature itself. Some have turned to the anthropic principle and the multiverse, while others look to theism for an explanation. I talk here about my views on the various attitudes one might take toward these apparent fine-tunings, and why it is important to think about...

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/Support M...

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. In Steven Pinker's new book, When Everyone Knows That Everyone Knows..., 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/Support Mindscape on Pat...

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 A...

Welcome to the September 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 AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2025/09/08/ama-september-2025/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and Cal...

"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...

In a relatively short period of time, exoplanets (planets around stars other than our Sun) have gone from an intriguing conjecture to an active field of scientific study, with over 5,000 confirmed discoveries. The task now is to move beyond merely accumulating new examples, and embarking on systematic studies of their properties. What fraction of stars have planets, how are they distributed in size and distance, what kinds of atmospheres do they have, are any promising homes for life? I talk with Natalie Batalha about what we've learned so far, and prospects for future discoveries.Blog post with transcript: https://www...

The world is becoming pixelated. As computers and other digital devices become ubiquitous, human knowledge and communication and information is gradually being converted into, and manipulated as, strings of bits. What does that really mean, and what are the ramifications going forward? Alvy Ray Smith is a computer scientist, co-founder of Pixar, and author of A Biography of the Pixel. We go through the journey of how he helped make computer animation a reality, and the implications of what he calls the "Great Digital Convergence."Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/08/18/325-alvy-ray-smith-on-pixar-pixels-and-the-great-digital-convergence/Support Mindscape on Patreon.Alvy Ray...

It is not manifestly obvious that universities should be where most scholarly research is performed. One could imagine systems that separated out the tasks of "teaching students" and "generating new knowledge." But it turns out that combining them yields spectacular synergies, both from letting students experience cutting-edge research and from keeping researchers inspired by interacting with bright young minds. Today we talk to Elizabeth Mynatt, Dean of Computer Sciences at Northeastern, both about her own research in "human-centered computing," and about the bigger-picture issues of why basic research is important, and why universities are such good places to do it...

Welcome to the August 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/2025/08/04/ama-august-2025/Support Mindscape on Patreon.

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The search for a foundational theory of quantum mechanics that all physicists can agree on remains active. Over the last century a number of contenders have emerged, including Many-Worlds, pilot-wave theories, and others, but all of them have aspects that many people object to. Jacob Barandes has taken up the challenge, proposing a new formulation of quantum theory in which there is no wave function, only real degrees of freedom with fundamentally stochastic dynamics. We talk about this new theory and the challenges facing it.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/07/28/323-jacob-barandes-on-indivisible-stochastic-quantum-mechanics/Support Mindscape on Patreon.Jacob Bar...

When we think of the capacities that distinguish humans from other species, we generally turn to intelligence and its byproducts, including our technological prowess. But our intelligence is highly connected to our ability to use language, which is in turn closely related to our capacities as social creatures. Philosopher Philip Pettit would encourage us to think of those social capacities, as enabled by language, as the primary locus of what makes humans different, as discussed in his new book When Minds Converse: A Social Genealogy of the Human Soul. And that linguistic aptitude helps us understand the nature of agency, r...

Quantum field theory is the basis for our most successful theories of fundamental physics. And yet, there are things we don't understand about it. Some of these puzzles are relatively well-known, while others are less celebrated. David Tong joins us to talk about some of the more interesting and perplexing aspects of quantum field theory. He also discusses his new project to write a series of textbooks covering (all?) important topics in theoretical physics. To date, these include Classical Mechanics, Quantum Mechanics, Fluid Mechanics, and Electromagnetism.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/07/14/321-david-tong-on-open-questions-in-quantum-field-theory/Support Mindscape on Patreon.David...

Welcome to the July 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/2025/07/07/ama-july-2025/See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://ar...

Our universe started out looking very simple: hot, dense, smooth, rapidly expanding. According to our best current model, it will end up looking simple once again: cold, dark, empty. It's in between -- now, roughly speaking -- that things look complex. I have been working to understand the stages by which complexity comes into existence, thrives, and eventually disappears. Without going into technical details, in this solo episode I give an overview of the general picture and the clues we are looking at to better understand the process of complexogenesis.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/06/30/320-solo-complexity-and-the-universe...

It is common to refer to philosophy as "a series of footnotes to Plato." But in the original quote, Alfred North Whitehead was more careful: he limited his characterization to "the European philosophical tradition." There are other traditions, both ancient and ongoing: Chinese philosophy, Indian philosophy, Africana philosophy, and various indigenous philosophies. For the most part, these do not get nearly as much attention in European and American schools as the European tradition does. Bryan Van Norden argues for expanding philosophy's geographical scope, to the benefit of philosophy in general.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/06/23/319-bryan-van-norden-on-philosophy-from-the-rest-of-the-world...

Economics is seeing an upsurge in the importance of controlled, reproducible empirical studies. One area where this has had a great impact is on development economics, which studies the economies of low- and middle-income societies. Edward Miguel has been at the forefront of both the revolution in empirical methods, and in applying those techniques to alleviating poverty in sub-Saharan Africa and elsewhere.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/06/16/318-edward-miguel-on-the-developing-practice-of-development-economics/Support Mindscape on Patreon.Edward Miguel received his Ph.D. in economics from Harvard university. He is currently Distinguished Professor of Economics and Oxfam Professor in Environmental and R...

The human brain is extremely complicated, but decades of careful neuroscientific research have revealed quite a bit about how it works, including how certain genes affect particular brain behaviors. Nevertheless, this progress has not led to quite as much improvement in the treatment of brain disorders as we might expect. I talk with neuroscientist Nicole Rust about why this is and how to improve the situation, as discussed in her new book Elusive Cures.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/06/09/317-nicole-rust-on-why-neuroscience-hasnt-solved-brain-disorders/Support Mindscape on Patreon.Nicole C. Rust received her Ph.D. in neuroscience from New York Un...

Welcome to the June 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 AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2025/06/02/ama-june-2025/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and Cal...

Einstein's general theory of relativity, plus some reasonable assumptions about the universe and what it's made of, has a remarkable implication: that as we trace cosmic evolution into the far past, we ultimately hit a singularity of infinite density and curvature, the Big Bang. Did that really happen? Einstein's theory is classical, after all, and the world is quantum. And whose to say what assumptions are reasonable? Niayesh Afshordi and Phil Halper have written a new book, Battle of the Big Bang: The New Tales of Our Cosmic Origins, that surveys all of the mind-bending possibilities.Blog post with transcript: h...

Every time you see an apple spontaneously break away from a tree, it falls downward. You therefore claim that there is a law of physics: apples fall downward from trees. But how can you really know? After all, tomorrow you might see an apple that falls upward. How is science possible at all? Philosophers, as you might expect, have thought hard about this. Branden Fitelson explains how a better understanding of probability can help us decide when new evidence is actually confirming our beliefs.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/05/19/315-branden-fitelson-on-the-logic-and-use-of-probability/Support Mindscape on Patreon.Branden Fitelson re...

There are living creatures dwelling deep below the surface of the Earth, as deep as we are able to drill. These hearty microorganisms are related to more familiar life forms on land and under water, but the operate and survive in ways that are quite different from what we're familiar with. They live off of nutrients that have penetrated from the surface, or sometimes off of pure electrons. Karen Lloyd is a scientist who has traveled around the world studying these organisms, as she explains in her new book Intraterrestrials: Discovering the Strangest Life on Earth.Blog post with transcript: h...

Medical science is advancing at an astonishing rate. Today we talk with leading expert Eric Topol about two aspects of this story. First, the use of artificial intelligence in medicine, especially in diagnostics. This is an area that is a perfect match between an important question and the capabilities of machine learning, to the point where AI can out-perform human doctors. And second, our understanding of aging and what to do about it. Eric even gives some actionable advice on how to live more healthily into our golden years.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/05/05/episode-313-eric-topol-on-the-changing-face-of-medicine-and-aging...

Welcome to the May 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 AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2025/04/28/ama-may-2025/Support Mindscape on Patreon.See Privacy Policy at https://art19.com/privacy and Cal...

The germ theory of disease is a crowning achievement of science, up there with modern physics, continental drift, and evolution via natural selection. (Even if there will always be cranky skeptics.) But the road to widespread acceptance isn't always an easy one. Why did it take so long between Anton van Leeuwenhoek seeing "animalcules" in a microscope (1670s) to Louis Pasteur's work on pasteurization and vaccination (1860's)? Thomas Levenson is the author of a new book exploring this fascinating history: So Very Small: How Humans Discovered the Microcosmos, Defeated Germs--and May Still Lose the War Against Infectious Disease.Blog post wi...

Questions about consciousness range from the precise and empirical -- what neurons fire when I have some particular experience -- to the deeply profound -- does consciousness emerge from matter, or does matter emerge from consciousness? While it might be straightforward to think that consciousness arises from the collective behavior of atoms in the brain, Annaka Harris and others argue that consciousness could be the fundamental stuff from which matter arises. She talks with a variety of experts in her new audio series, Lights On: How Understanding Consciousness Helps Us Understand the Universe.Blog post with show notes and transcript: h...

Welcome to the April 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/2025/04/07/ama-april-2025/Support Mindscape on Patreon.A couple of links relevant to the intro:Tariff formula (Snop...

Cosmologists were, let us be honest, pretty stunned in 1998 when observations revealed that the universe is accelerating. There was an obvious plausible explanation, the cosmological constant proposed by Einstein, which is equivalent to a constant vacuum energy pervading space. But the cosmological constant was known to be enormously smaller than its "natural" value, and it seems fine-tuned for it to be so small but not yet zero. Once burned, twice shy, and since then we have been looking for evidence that the dark energy might not be strictly constant, even though that's even more fine-tuned. We talk to cosmologist Marc Kami...

Consciousness is easier to possess than to define. One thing we can do is to look into the brain and see what lights up when conscious awareness is taking place. A complete understanding of this would be known as the "neural correlates of consciousness." Once we have that, we could hopefully make progress on developing a theoretical picture of what consciousness is and why it happens. Today's guest, Christof Koch, is a leader in the search for neural correlates and an advocate of a particular approach to consciousness, Integrated Information Theory.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/03/24/309...

We often study cognition in other species, in part to learn about modes of thinking that are different from our own. Today's guest, psychologist/philosopher Alison Gopnik, argues that we needn't look that far: human children aren't simply undeveloped adults, they have a way of thinking that is importantly distinct from that of grownups. Children are explorers with ever-expanding neural connections; adults are exploiters who (they think) know how the world works. These studies have important implications for the training and use of artificial intelligence.Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/03/17/308-alison-gopnik-on-children-ai-and-modes-of-thinking/Support Mindscape on Patreon.Alison G...

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 P...

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 t...