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

It's become increasingly clear that the Turing Test -- determining whether human interlocutors can tell whether a conversation is being carried out by a human or a machine -- is not a good way to think about consciousness. Modern LLMs can mimic human conversation with extraordinary verisimilitude, but most people would not judge them to be conscious. What would it take? Is it even possible for a computer program to achieve consciousness, or must consciousness be fundamentally "meat-based"? Philosopher Ned Block has long argued that consciousness involves something more than simply the "functional" aspects of inputs and outputs.

Time for the holiday message! Rounding off the year with a brief and casual reflection on some issue that doesn't quite rise to the level of a full solo podcast. And hopefully something uplifting.

This year, I offer a short apologia for higher education in the liberal arts and sciences, focusing not on the down-to-earth economic/occupational benefits of a college degree, but on the very real ways in which such an education opens up possibilities for personal growth. I think all of us in academia should be loud and unapologetic about the more romantic, idealistic values...

Welcome to the December 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.

Blog post with transcript: https://www.preposterousuniverse.com/podcast/2025/12/15/ama-december-2025/

In the intro I give a plug for the Pods Fight Poverty eff...

The story goes that Wolfgang Pauli, who first proposed the existence of neutrinos, was embarrassed to have done so, as it was considered uncouth to hypothesize new particles that could not be detected. Modern physicists have no such scruples, of course, but more importantly neutrinos turn out to be very detectable, given sufficient resources and experimental technique. I talk with neutrino physicist Ryan Patterson about what current and upcoming experiments teach us about neutrinos themselves, as well as implications for dark matter and why there are more particles than antiparticles in the universe.

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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.

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.

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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...

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/

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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.c...

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.

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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/

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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/

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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...

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/p...

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/

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 H...

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/

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"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 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.

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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/

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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...

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/

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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/

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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 a...

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/

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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/

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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...

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...

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/

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Edward Miguel received his Ph.D. in economics from Harvard university. He is currently Distinguished Professor of E...

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/

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Nicole C. Rust received her Ph...

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/

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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.

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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/

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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.

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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...

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/

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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.

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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 n...

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 lin...

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...

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.p...

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/

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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...

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/

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Kevin Peterson received a...

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/

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Helen Czerski received h...

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...

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/

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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...

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.

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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...

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 ma...

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.

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 i...

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...

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.

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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 h...

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/

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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 a...

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.

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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, wi...

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!

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Blog post with AMA questions and transcript: https://www.preposterousuniverse.com/podcast/2024/11/04/ama-november-2024/

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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 o...

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.

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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 o...

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!

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Blog post with questions and transcript: https://www.preposterousuniverse.com/podcast/2024/10/07/ama-october-2024/

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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 o...

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 f...

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...

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.

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Welcome to the September 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/2024/09/02/ama-september-2024/

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One common feature of complex systems is sensitive dependence on initial conditions: a small change in how systems begin evolving can lead to large differences in their later behavior. In the social sphere, this is a way of saying that history matters. But it can be hard to quantify how much certain specific historical events have affected contemporary conditions, because the number of variables is so large and their impacts are so interdependent. Political economist Jean-Paul Faguet and collaborators have examined one case where we can closely measure the impact today of events from centuries ago: how Colombian communities...

Understanding how life began on Earth involves questions of chemistry, geology, planetary science, physics, and more. But the question of how random processes lead to organized, self-replicating, information-bearing systems is a more general one. That question can be addressed in an idealized world of computer code, initialized with random sequences and left to run. Starting with many such random systems, and allowing them to mutate and interact, will we end up with "lifelike," self-replicating programs? A new paper by Blaise Agüera y Arcas and collaborators suggests that the answer is yes. This raises interesting questions about whether computation is...

Being rational necessarily involves engagement with probability. Given two possible courses of action, it can be rational to prefer the one that could possibly result in a worse outcome, if there's also a substantial probability for an even better outcome. But one's attitude toward risk -- averse, tolerant, or even seeking -- also matters. Do we work to avoid the worse possible outcome, even if there is potential for enormous reward? Nate Silver has long thought about probability and prediction, from sports to politics to professional poker. In his his new book On The Edge: The Art of Risking E...

Welcome to the August 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 transcript: https://www.preposterousuniverse.com/podcast/2024/08/05/ama-august-2024/

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The human brain does a pretty amazing job of taking in a huge amount of data from multiple sensory modalities -- vision, hearing, smell, etc. -- and constructing a coherent picture of the world, constantly being updated in real time. (Although perhaps in discrete moments, rather than continuously, as we learn in this podcast...) We're a long way from completely understanding how that works, but amazing progress has been made in identifying specific parts of the brain with specific functions in this process. Today we talk to leading neuroscientist Doris Tsao about the specific workings of vision, from how...

Change is scary. But sometimes it can all work out for the best. There's no guarantee of that, however, even when the change in question involves the introduction of a powerful new technology. Today's guest, Daron Acemoglu, is a political economist who has long thought about the relationship between economics and political institutions. In his most recent book (with Simon Johnson), Power and Progress: Our Thousand-Year Struggle Over Technology and Prosperity, he looks at how technological innovations affect the economic lives of ordinary people. We talk about how such effects are often for the worse, at least to start o...

The philosophy of mathematics would be so much easier if it weren't for infinity. The concept seems natural, but taking it seriously opens the door to counterintuitive results. As mathematician and philosopher Joel David Hamkins says in this conversation, when we say that the natural numbers are "0, 1, 2, 3, and so on," that "and so on" is hopelessly vague. We talk about different ways to think about the puzzles of infinity, how they might be resolved, and implications for mathematical realism.

Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/07/15/282-joel-david-hamkins-on-puzzles-of-reality-and-infinity/

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Welcome to the July 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 questions and transcript: https://www.preposterousuniverse.com/podcast/2024/07/08/ama-july-2024/

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Just like with physics, in biology it is perfectly possible to do most respectable work without thinking much about philosophy, but there are unmistakably foundational questions where philosophy becomes crucial. When do we say that a collection of matter (or bits) is alive? When does it become an agent, capable of making decisions? What are the origins of morality and altruistic behavior? We talk with one of the world's leading experts, Samir Okasha, about the biggest issues in modern philosophy of biology.

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Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/07/01/281...

Which is more intelligent, ChatGPT or a 3-year old? Of course this depends on what we mean by "intelligence." A modern LLM is certainly able to answer all sorts of questions that require knowledge far past the capacity of a 3-year old, and even to perform synthetic tasks that seem remarkable to many human grown-ups. But is that really intelligence? François Chollet argues that it is not, and that LLMs are not ever going to be truly "intelligent" in the usual sense -- although other approaches to AI might get there.

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For those of us who are not dualists, the mind arises from our physical bodies -- mostly the brain, but the rest of the body has a role to play. And yet it remains tempting to treat the mind as a thing in itself, disconnected from how the body is doing. Ellen Langer is a psychologist who is one of the foremost researchers on the idea of mindfulness -- the cognitive skill of paying to one's thoughts, as well as to one's external environment. Her most recent book is The Mindful Body: Thinking Our Way to Chronic Health. We t...

Wow in the World is the #1 science podcast for kids and their grown-ups. Hosts Mindy Thomas and Guy Raz share stories about the latest news in science, technology, and innovation. Stories that give kids hope, agency and make us all say "WOW"!

New episodes come out every Monday. Listen to Wow in the World: http://wondery.fm/wowintheworld.

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We claim to love all of our children, friends, and students equally. But perhaps deep down you assign a ranking to them, from favorite to not-so-favorite. Ranking and quantifying people is an irresistible human tendency, and modern technology has made it ubiquitous. In this episode I talk with sociologist Kieran Healy, who has co-authored (with Marion Fourcade) the new book The Ordinal Society, about how our lives are measured and processed by the technological ecosystem around us. We discuss how this has changed how relate to ourselves and the wider world.

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Welcome to the June 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!

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Blog post with show notes, questions, and transcript: https://www.preposterousuniverse.com/podcast/2024/06/03/ama-jun-2024/

String theory, the current leading candidate for a theory of quantum gravity as well as other particles and forces, doesn't connect directly to the world we see. It's possible that there is a large landscape of possible states of theory, with the hope that one of them represents our universe. The existence of a landscape implies the existence of a corresponding swampland -- universes that are not compatible with string theory. I talk with Cumrun Vafa, a respected physicist and originator of the swampland program, about how we might use constraints on what kinds of physics are compatible with string...

The Earth's climate keeps changing, largely due to the effects of human activity, and we haven't been doing enough to slow things down. Indeed, over the past year, global temperatures have been higher than ever, and higher than most climate models have predicted. Many of you have probably seen plots like this. Today's guest, Gavin Schmidt, has been a leader in measuring the variations in Earth's climate, modeling its likely future trajectory, and working to get the word out. We talk about the current state of the art, and what to expect for the future.

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Publication week! Say hello to Quanta and Fields, the second volume of the planned three-volume series The Biggest Ideas in the Universe. This volume covers quantum physics generally, but focuses especially on the wonders of quantum field theory. To celebrate, this solo podcast talks about some of the big ideas that make QFT so compelling: how quantized fields produce particles, how gauge symmetries lead to forces of nature, and how those forces can manifest in different phases, including Higgs and confinement.

Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/05/13/275-solo-quantum-fields-particles-forces-and-symmetries/

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Welcome to the May 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 questions and transcript: https://www.preposterousuniverse.com/podcast/2024/05/06/ama-may-2024/

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Modern biology is advancing by leaps and bounds, not only in understanding how organisms work, but in learning how to modify them in interesting ways. One exciting frontier is the study of tiny "robots" created from living molecules and cells, rather than metal and plastic. Gizem Gumuskaya, who works with previous guest Michael Levin, has created anthrobots, a new kind of structure made from living human cells. We talk about how that works, what they can do, and what future developments might bring.

Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/04/29/274-gizem-gumuskaya-on-building-robots-from-human-cells/

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Humanity itself might be the hardest thing for scientists to study fairly and accurately. Not only do we come to the subject with certain inevitable preconceptions, but it's hard to resist the temptation to find scientific justifications for the stories we'd like to tell about ourselves. In his new book, The Invention of Prehistory, Stefanos Geroulanos looks at the ways that we have used -- and continue to use -- supposedly-scientific tales of prehistoric humanity to bolster whatever cultural, social, and political purposes we have at the moment.

Blog post with transcript: https://www.preposterousuniverse.com/podcast/2024/04/22/273...

Science is enabled by the fact that the natural world exhibits predictability and regularity, at least to some extent. Scientists collect data about what happens in the world, then try to suggest "laws" that capture many phenomena in simple rules. A small irony is that, while we are looking for nice compact rules, there aren't really nice compact rules about how to go about doing that. Today's guest, Leslie Valiant, has been a pioneer in understanding how computers can and do learn things about the world. And in his new book, The Importance of Being Educable, he pinpoints this a...

Welcome to the April 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 questions and transcript: https://www.preposterousuniverse.com/podcast/2024/04/08/ama-april-2024/

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Einstein's theory of general relativity has been our best understanding of gravity for over a century, withstanding a variety of experimental challenges of ever-increasing precision. But we have to be open to the possibility that general relativity -- even at the classical level, aside from any questions of quantum gravity -- isn't the right theory of gravity. Such speculation is motivated by cosmology, where we have a good model of the universe but one with a number of loose ends. Claudia de Rham has been a leader in exploring how gravity could be modified in cosmologically interesting ways, and...

Technology is changing the world, in good and bad ways. Artificial intelligence, internet connectivity, biological engineering, and climate change are dramatically altering the parameters of human life. What can we say about how this will extend into the future? Will the pace of change level off, or smoothly continue, or hit a singularity in a finite time? In this informal solo episode, I think through what I believe will be some of the major forces shaping how human life will change over the decades to come, exploring the very real possibility that we will experience a dramatic phase transition...

When it comes to social change, two questions immediately present themselves: What kind of change do we want to see happen? And, how do we bring it about? These questions are distinct but related; there's not much point in spending all of our time wanting change that won't possibly happen, or working for change that wouldn't actually be good. Addressing such issues lies at the intersection of philosophy, political science, and social dynamics. Sahar Heydari Fard looks at all of these issues through the lens of complex systems theory, to better understand how the world works and how it...

Welcome to the March 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.

Big congrats this month to Ryan Funakoshi, winner of this year's Mindscape Big Picture Scholarship! And enormous, heartfelt thanks to everyone who contributed. We're...

In the 1860s, James Clerk Maxwell argued that light was a wave of electric and magnetic fields. But it took over four decades for physicists to put together the theory of special relativity, which correctly describes the symmetries underlying Maxwell's theory. The delay came in part from the difficulty in accepting that light was a wave, but not a wave in any underlying "aether." Today our most basic view of fundamental physics is found in quantum field theory, which posits that everything around us is a quantum version of a relativistic wave. I talk with physicist Matt Strassler about ho...

The twentieth century was something, wasn't it? Margaret Mead, as well as her onetime-husband Gregory Bateson, managed to play roles in several of its key developments: social anthropology and its impact on sex & gender mores, psychedelic drugs and their potential use for therapeutic purposes, and the origin of cybernetics, to name a few. Benjamin Breen discusses this impactful trajectory in his new book, Tripping on Utopia: Margaret Mead, the Cold War, and the Troubled Birth of Psychedelic Science. We talk about Mead and Bateson, the early development of psychedelic drugs, and how the possibility of a realistic utopia didn't alw...

Evolution is sometimes described -- not precisely, but with some justification -- as being about the "survival of the fittest." But that idea doesn't work unless there is some way for one generation to pass down information about how best to survive. We now know that such information is passed down in a variety of ways: through our inherited genome, through epigenetic factors, and of course through cultural transmission. Chris Adami suggests that we update Dobzhansky's maxim "Nothing in biology makes sense except in the light of evolution" to "... except in the light of information." We talk about information th...

Welcome to the February 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 questions and transcript: https://www.preposterousuniverse.com/podcast/2024/02/12/ama-february-2024/

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