Most conversations about artificial intelligence are focused on Earth: jobs, misinformation, education, politics, science, regulation, consciousness, safety, and the future of human society. But AI—and especially the possibility of reaching “AGI” (artificial general intelligence) and “superintelligence”—forces us to think on much larger scales. If advanced AI is possible, why hasn’t it already emerged elsewhere? If civilisations can build self-replicating probes, artificial scientists, or planet-scale computational systems, why does the universe still look so natural? And if intelligent life is common, where is everyone? In this episode, Henry and I discuss these and many other questions with David Kipping, Associate Professor of Astronomy at Columbia University, where he leads the Cool Worlds Lab. David’s research spans exoplanets, exomoons, Bayesian inference, technosignatures, and the search for life and intelligence beyond Earth. He is also one of the best science communicators working today through the Cool Worlds YouTube channel and podcast. Among other topics, we discussed: * David’s Red Sky Paradox: if most stars are red dwarfs, and red dwarfs live for vastly longer than stars like the Sun, why do we find ourselves orbiting a yellow star? * Whether anthropic reasoning — reasoning from the fact of our own existence — is a profound scientific tool, a philosophical minefield, or both. * The reference class problem: when we reason about “observers like us”, who or what exactly counts as being like us? * The Doomsday Argument, and why some apparently bizarre forms of probabilistic reasoning can nevertheless be powerful. * The Fermi Paradox: if the universe is so large, and if life or intelligence is not fantastically rare, why don’t we see clear evidence of extraterrestrial civilisations? * Whether advanced civilisations would spread through the galaxy using self-replicating probes — and why the absence of such probes might be one of the strongest constraints on extraterrestrial intelligence. * How recent developments in artificial intelligence affect the Fermi Paradox. If humanity is close to building systems that can massively accelerate science and engineering, shouldn’t someone else have got there first? * Whether artificial intelligence makes the simulation argument more plausible. * David’s experience using artificial intelligence in scientific research, and why a meeting at the Institute for Advanced Study changed how he thinks about the role of these tools in science. * Why David thinks artificial intelligence already has something close to “coding supremacy”, but is still far from being able to do science autonomously. * The risks of AI-generated scientific slop: papers, peer review, and training data polluted by low-quality machine outputs. * Whether artificial intelligence will make science more productive, or instead strip it of some of its deepest human value. * Why the future of science communication may depend on better collaboration between academic institutions and independent creators. Links and further reading * Cool Worlds Lab — David’s research group at Columbia University, focused on extrasolar planetary systems, exomoons, habitability, technosignatures, and related questions. * Cool Worlds on YouTube — David’s excellent science communication channel, covering astronomy, exoplanets, alien life, the Fermi Paradox, cosmology, and much else. * Cool Worlds Podcast — David’s podcast, featuring conversations on astronomy, technology, science, engineering, and related topics. * Cool Worlds Podcast: “We Need To Talk About Artificial Intelligence” — the solo episode in which David reflects on artificial intelligence and science after a meeting at the Institute for Advanced Study. * David Kipping’s Columbia profile — short institutional profile with background on his research. Conspicuous Cognition is a reader-supported publication. To receive new posts and support my work, consider becoming a free or paid subscriber. Transcript * Please note that this transcript has been lightly AI-edited and may contain minor mistakes. Henry Shevlin: Welcome back. Our guest today is David Kipping, Associate Professor of Astronomy at Columbia University, where he leads the Cool Worlds Lab. His research spans exoplanets, exomoons, and the search for extraterrestrial life and intelligence, and he brings a Bayesian rigor to questions that could easily drift into speculation. He’s also one of the best science communicators working today with over a million subscribers on his Cool Worlds YouTube channel, where I should confess, I’ve spent an embarrassing number of hours watching when I probably should have been doing philosophy of AI. David, like many of the best people, is a Cambridge alumnus, although unlike us, he actually studied something useful, namely natural sciences, before going on to do his PhD at UCL and postdoc at Harvard on the Sagan Fellowship. His work also has a really fantastic philosophical dimension, particularly around anthropic reasoning and observation selection effects, which makes him a perfect guest for two cognitive scientists who are finally getting to talk to an actual scientist. So David, welcome to Conspicuous Cognition. David Kipping: Thank you for that very generous introduction. Henry Shevlin: This is a bit of a fanboy moment for me, for real though. I really have spent like hundreds of hours at this point on Cool Worlds. But I’m going to get past it. I’m going to be a serious host. David Kipping: It’s always weird when people say that to us, because I just imagine no one watches them. If it gets in my head that people are watching them, I’ll get tightened and anxious about what I’m saying. I just imagine I’m talking to a brick wall or something, and that’s much easier. Henry Shevlin: Honestly, half the Warhammer figures in this room were painted while I was listening to Cool Worlds. I’ll leave it at that. Maybe a good place to start would be discussing anthropic reasoning, since that’s a real natural intersection at the boundary of astronomy and philosophy. Could you just give us a brief view of how you see anthropic reasoning, and maybe tell us a little bit about the Red Sky Paradox, which is one of your distinctive contributions to this area? Anthropic Reasoning and the Red Sky Paradox David Kipping: Yeah, I think one of the most interesting data points when it comes to asking questions about the search for life in the universe and our own place in the universe is our own existence — just the fact that we’re here. Anthropic reasoning has in many ways really been born out of cosmology. Cosmology had a rich history of using this. I think one of the first successful examples was by Steve Weinberg, a cosmologist who’s really a giant in the field. I think he’s now passed away, but he showed that you could predict not only the existence of the cosmological constant, but also its value to within a factor of a few, just based off of anthropic reasoning. The argument was something like: the cosmological constant causes the universe to expand. It’s what causes the accelerating expansion of the universe. And so if you make that number too large, then structure would not form in the universe. You couldn’t form galaxies because everything would just fly apart too quickly. And if you make that number too small, or even negative, then you’d cause everything to recombine too quickly. So there has to be some Goldilocks value in order to explain our own existence. And so he predicted that. At the time, the cosmological constant was kind of even a controversial idea — that it should exist because, obviously, Einstein’s general relativity, there’s that whole history of it being like his greatest blunder, of whether that should really be in there or not. People were kind of thinking that could be a static universe, and he predicted it successfully. So that was a really powerful use of it. And then Brandon Carter was the one who really kind of championed it and used it in all sorts of contexts. In recent years, I’ve been thinking about it in an astrobiological context — how can we use it to ask questions about life in the universe especially, and our place in it? For the Red Sky Paradox in particular: one interesting curiosity that seems to violate the norms of probability. The norms of probability would be to say that if there’s a Gaussian, a bell curve of possibilities, you should expect really to be near the center of that bell curve. It would be kind of weird if you lived many, many sigmas, many, many standard deviations off to the outside, either negative or positive direction. You’d expect to be somewhere in the middle. We sometimes call it the mediocrity principle, or something like this. If you look at stars in the universe, most stars in the universe are red dwarfs. About 80%, 82% of stars are red dwarfs, which are stars less than half the mass of our own sun. So they’re very, very numerous. They’re called red dwarfs, of course, because they’re so low mass — they don’t have the internal pressure, the gravity, to fuse as much energy as the sun does. And thus they have less luminosity, and so their temperature is cooler. That’s why they look red. Not only do these stars have this 80%-plus frequency — Sun-like stars are something like 6%, I think, frequency, an enormous ratio, just straight off the bat, about 30 to one or something — but on top of that, they live really long. These stars live for trillions of years potentially, especially the lowest mass ones. And so if you flash forward into the future, tens of billions of years, hundreds of billions of years, there wouldn’t be any Sun-like stars left, really. There’d be very, very few of them. And the only stars that would be glowing would be these red dwarfs. So if you ask yourself — and this is sort of cal
