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)

Are you an expert in something and want to be on the show? Apply here!

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Thomas is joined by Dr. Jenessa Seymour to dig into the brain science behind a surprisingly strange phenomenon: why do astronauts who spent just nine days in space need weeks of physical therapy to walk normally again?

The answer turns out to involve ancient calcium carbonate ear stones, the same material crabs use for shells, a multi-layered sensory system your brain is constantly running without your knowledge, and a wild evolutionary theory about why motion sickness exists at all. Also: why pilots fly perfectly good planes directly into the ground, and what deaf NASA research participants revealed about how proprioception actually works.

Come see me at SkeptiCal!

Are you an expert in something and want to be on the show? Apply here!

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The history of disability rights is often treated as a modern story, but what if that framing misses centuries of earlier, more complicated history? This week, Thomas is joined by Professor Sari Altschuler, Associate Professor of English at Northeastern University, to explore her new book Before Disability: A History of American Citizenship.

In the book, Professor Altschuler traces how disability and citizenship have been intertwined since the founding of the United States, and what that reveals about who America decided belonged and who didn't. In the early Republic, many physical and mental differences were accommodated within the framework of citizenship; by the antebellum era, however, those same differences had been weaponized as tools of racial exclusion, and eventually as justification for eugenics.

Thomas and Professor Altschuler dig into the intersections of race, disability, and civic belonging, and what early American history can teach us about the fights happening today.

• Be sure to buy Before Disability: A History of American Citizenship (release date: 6/16/2026)!

• Touch This Page! Making Sense of the Ways We Read

Are you an expert in something and want to be on the show? Apply here!

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Continuing the discussion of the CNN Rape Academy article. It gets even worse. And also, how our information environment is ruined and getting ruineder.

You might have seen the CNN article from a while back entitled Exposing a global 'rape academy'. While most of the article is technically true, the broad takeaway that virtually everyone had (including me) was wildly, irresponsibly false. Even if you came across debunks of this, there's a good chance that I'm debunking this even more than you've seen. I don't think people have fully grasped how misleading it was.

We continue the pruning of idiotic Butler Shooting conspiracy theories. Once we establish the facts using actual sources, what room is there left for a conspiracy or staging theory?

It wasn't staged. None of them were staged. Yes Trump was shot in the ear. I thought you all were doing a bit, but apparently you weren't. This isn't good and you should stop doing it, please. In discussing this current shooting, I found that way too many of you think that it was a hoax and even more think that Trump wasn't shot in the ear. So, let's go through the Butler shooting and see why YES HE F-CKING WAS.

Well, what do you know - it's a day that ends in y so the internet has a woman to hate. You might have seen some of the chatter about child-hating Chappell Roan lately, and it's just so depressing every single time one of these hate campaigns rears its ugly head. Lydia joins the show as resident Chappell Roan fan to discuss what actually happened, and why society so quickly jumps on these opportunities to hate women.

• The Chappell Roan Harassment Campaign Is Plain Old Misogyny (Alex Nguyen - Mother Jones, 4/14/2026)

• X profits from turning Chappell Roan into a viral villain (Kat Tenbarge, 3/30/2026)

Are you an expert in something and want to be on the show? Apply here!

Popular media will tell you that placebos, inert inactive substances taken as if they're medication, can work miracles. …Placebos don't "work". But what does that even mean? And if that's true, why would we include a placebo group in a study? Is there anything remotely like a "true"'placebo effect, where belief in a medication could influence the body? Jenessa walks us through scientific study design, statistical artifacts, and one study that shows maybe just maybe there's a little something like an actual placebo "effect"… but it's still not magic! Tune in to hear how on earth that could be possible.

• Nolan, T.A., Price, D.D., Caudle, R., Murphy, N.P., & Neubert, J.K. (2012). Placebo-induced analgesia in an operant pain model in rats. Pain, 153, 2009-2016.

• Brissonnet, J. (2015). Placebo, are you there? Science Based Medicine.

• Studeman, D. (2007). But I regress… The Hardball Times.

• McCambridge, J., de Bruin, M., & Witton, J. (2012). The effect of demand characteristics on research participant behaviours in non-laboratory settings: A systematic review. PLoS One, 7.

Are you an expert in something and want to be on the show? Apply here!

Everyone's favorite biologist and dinosaur enthusiast Dr. Eric Jaffe is back! Project Hail Mary is a very fun, and quite good, sciency movie that is cleaning up at the box office right now. You should see it! Eric is going to take us through the biology of the movie (and book) and what it gets right, and what it gets quite wrong.