Show Notes
Thomas is joined by Dr. Eric Jaffe, biologist, dinosaur enthusiast, and high school biology teacher, for a conversation that starts with a deceptively simple question: what are biological definitions actually doing? It turns out that biology is far more like history than math, and that difference has enormous consequences for anyone trying to weaponize phrases like "the biological definition of sex." Dr. Jaffe walks through why definitions in inductive sciences are descriptive, not prescriptive, and what that means for species, chromosomes, fungi, LeBron James, and trans people. "Exceptions aren't the exceptions in biology. They are built into what we call biological systems." Plus: Patreon Q&A questions on alien DNA, how new chromosomes evolve, the 97% chimp figure, CRISPR vs. what came before, and Trump's research budget cuts. Cells at Work (anime recommended by Dr. Jaffe)
Project Hail Mary (film referenced)
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More from Serious Inquiries Only
We welcome back Dr. Eric Jaffe to help us understand a really cool, groundbreaking scientific discovery! Our brains are not one organ! Turns out your forebrain and your hindbrain might be two completely separate lineages that never actually came from each other, more like two kids in a trench coat than one continuous evolution. Why does that matter for ALS research? And how far back in evolution does the split actually go? Are you an expert in something and want to be on the show? Apply here! Please support the show at patreon.com/seriouspod! You get ad-free episodes, early episodes, and other bonus content!
You've seen the headline: AI "solved" one of math's Millennium Prize problems. Thomas and Jenessa (here as a friend, not an expert) are joined by David Souther, a software engineer and LLM researcher, who's SO annoyed about it. Why did he answer Jenessa's text in all caps? And what's the deal with a rushed phone call between OpenAI and a math professor? Are you an expert in something and want to be on the show? Apply here! Please support the show at patreon.com/seriouspod! You get ad-free episodes, early episodes, and other bonus content!
How does AI use affect learning? You’d be surprised how much we already know. Dr. Jenessa Seymour takes us through the research on screen use, metacognition, cognitive offloading, and some recent papers Sources: Clinton, V. (2019). Reading from paper compared to screens: A systematic review and meta-analysis. Journal of Research in Reading, 42, 288-325. Deslauriers, L., McCarty, L.S., Miller, K., Callaghan, K., & Kestin, G. (2019). Measuring actual learning versus feeling of learning in response to being actively engaged in the classroom. PNAS, 116, 19251-19257. Risko, E.F. & Gilbert, S.J. (2016). Cognitive offloading. Trends in Cognitive Sciences, 20, 676-688. Bastani, H., Bastani, O., Sungu, A., Ge, H., Kabakci, O., & Mariman, R. (2025). Generative AI without guardrails can harm learning: Evidence from high school mathematics. Economic Sciences, 122, 1-8. Tian, J. & Zhang, R. (2025). Learners’ AI dependence and critical thinking: The psychological mechanism of fatigue and the social buffering role of AI literacy. Acta Psychologica, 260. Are you an expert in something and want to be on the show? Apply here! Please support the show on Patreon! You get ad-free episodes, early episodes, and other bonus content! https://www.patreon.com/seriouspod
Kids are weird, like really weird, but in a fun way? Dr. Jenessa Seymour is back to tell us about some classic child development paradigms that really need to be reevaluated. Depending on when you learned about these experiments, you were either taught that they were the gospel truth, with established ages where kids can and cannot pass these tests, and major consequences for late development, or maybe you heard that recent studies show it’s a bit more complicated. Still makes for some cute and funny demonstrations either way. Sources: The marshmallow test is really about trust The “curse of knowledge” Autistic kids pass theory-of-mind tests on a computer Passing the theory-of-mind test with implicit looking measures at 15-months-old and 13-months-old Kids pass the conservation test sooner when they do it themselves Are you an expert in something and want to be on the show? Apply here! Please support the show on Patreon! You get ad-free episodes, early episodes, and other bonus content! https://www.patreon.com/seriouspod
Dr. Tania Lombrozo, professor of psychology at Princeton University (affiliated with its philosophy and cognitive science departments), joins Thomas to discuss her forthcoming book Why We Ask Why: The Science of Explanation and the Human Drive to Understand. Why are humans so driven to explain things, but only some things? Why does understanding go beyond just being able to predict? And what happens when asking why makes you the social liability in the room? Are you an expert in something and want to be on the show? Apply here! Please support the show on Patreon! You get ad-free episodes, early episodes, and other bonus content! https://www.patreon.com/seriouspod