Episodes

Rationally Speaking #190 - Amanda Askell on "Pascal's Wager and other low risks with high stakes"  

You've probably heard of Pascal's Wager: That it's rational to believe in God, because if you're wrong it's no big deal, but if you're right then the payoff is huge. This episode features philosopher Amanda Askell, who (though not religious herself) argues that it's much trickier to rebut Pascal's Wager than most people think. Amanda and Julia also discuss how to handle other decisions where a risk has very low probability but would matter a lot if it came true -- should you round them down to zero? Does it matter how measurable the risk is? And should you take into account the chance you're being scammed?

Rationally Speaking #189 - Stephan Guyenet on "What causes obesity?"  

In this episode Julia sits down with neuroscientist and obesity researcher Stephan Guyenet, to talk about what scientists know so far about the causes of obesity, and in particular the brain's role in regulating weight gain. Julia and Stephan cover questions such as: Why did obesity start to increase in the United States in the latter half of the 20th century? Does the body have a "set point" of fat that it tries to defend, and what affects those set points? Are low-carb diets more effective for weight loss than low-fat diets, and if so, what explains the difference?

Rationally Speaking #188 - Robert Kurzban on "Being strategically wrong"  

In this episode, recorded live at the Northeast Conference on Science and Skepticism, Julia interviews evolutionary psychologist Rob Kurzban, author of "Why Everyone (Else) is a Hypocrite." Rob describes the "modular mind" hypothesis, and how it explains hypocrisy, self-deception, and other seemingly irrational features of human nature. Rob and Julia argue about how useful these kinds of "strategic wrongness" really are.

Rationally Speaking #187 - Jason Weeden on "Do people vote based on self-interest?"  

What determines which policies a person votes for? Is it their personality, their upbringing, blind loyalty to their political party? Or is it self-interest -- people voting for policies that will benefit themselves and the groups they belong to? This episode features psychologist Jason Weeden, arguing that self-interest is a much bigger determinant of voter behavior than most political scientists think it is. Jason and Julia talk about why researchers disagree over this question, and what "self-interest" even means.

Rationally Speaking #186 - Tania Lombrozo on “Why we evolved the urge to explain”  

Humans have an innate urge to reach for explanations of the world around us. For example, "What caused this tragedy?" or "Why are some people successful?" This episode features psychologist and philosopher Tania Lombrozo, discussing her research on what purpose explanation serves -- i.e., why it helps us more than our brains just running prediction algorithms. Tania and Julia also discuss whether simple explanations are more likely to be true, and why we're drawn to teleological explanations (e.g., "Why does the sun shine? So that plants can grow.")

Rationally Speaking #185 - Hans Noel on "The role of ideology in politics"  

We're used to conflating political parties (Republican and Democrat) with political ideologies (conservative and liberal), but the two were very distinct only a few decades ago. In this episode of Rationally Speaking, Julia talks with political scientist Hans Noel about why the Democrats became the party of liberalism and the Republicans the party of conservatism, whether voters are hypocrites in the way they apply their ostensible ideology, and whether politicians are motivated by ideals or just self-interest.

Rationally Speaking #184 - Gregory Clark on "What caused the industrial revolution?"  

Nothing changed the course of human history as much as the industrial revolution. Yet its cause is a mystery: Why did it occur in the late 1700s, and not sooner (or later)? Why did it occur in Britain, a relatively small and geographically isolated country, and not somewhere much bigger like China, or elsewhere in Northern Europe like the Netherlands? This episode features economic historian Gregory Clark, author of A Farewell to Alms and one of the leading scholars of the industrial revolution. Greg and Julia explore different theories, as well as the epistemological challenges of answering this kind of causal question about history.

Rationally Speaking #183 - L. A. Paul on "Transformative Experiences"  

What if you had the opportunity to become a vampire, irreversibly -- and everyone you knew who had become one said "It's utterly indescribable." Would you take the leap, not knowing what it would feel like, or how it would change your personality and values? That's an example of what philosopher L. A. Paul calls a "transformative experience," one that's especially hard to choose (or forgo) rationally, because of how unknowable it is and how it changes your very preferences. In this episode, she and Julia discuss real life examples of transformative experiences -- such as having children -- and debate how to deal with them.

Rationally Speaking #182 - Spencer Greenberg on "How online research can be faster, better, and more useful"  

This episode features mathematician and social entrepreneur Spencer Greenberg, talking about how he's taking advantage of the Internet to improve the research process. Spencer and Julia explore topics such as: how the meaning of your research can change dramatically when you ask people *why* they gave the answers they did on your survey, how the sheer speed of online research can help us solve the p-hacking problem, and how to incentivize scientists to share their data and methods.

Rationally Speaking #181 - William MacAskill on "Moral Uncertainty"  

This episode introduces "moral uncertainty," the idea that you shouldn't be overly confident in your moral judgments -- like whether it's okay to eat meat, for example, or whether it's okay to abort a baby. The episode's guest is Will MacAskill, a founder of the effective altruism movement and Oxford professor of philosophy. Julia and Will discuss how to take multiple moral systems into account when making a decision, and how to deal with "absolutist" theories that insist some actions have infinite badness, like lying.

Rationally Speaking #180 - David Roodman on "The Worm Wars"  

In this episode of Rationally Speaking, Julia talks with economics and public policy expert David Roodman about the "Worm Wars" in social science -- the debate over whether deworming pills are an effective way to fight poverty. Along the way they discuss how to analyze a study, the differences between economists and epidemiologists, and how to make high stakes decisions when all your evidence is flawed.

Rationally Speaking #179 - Dani Rodrik on "Is economics more art or science?"  

This episode features Harvard economist Dani Rodrik, talking about the epistemology of economics: Are there any general "laws" of economics that we can be really confident in? Do economists discard models if the data doesn't support them? And why do economists disagree with each other?

Rationally Speaking #178 - Tim Urban on "Trying to live well, as semi-rational animals"  

This episode features Tim Urban, author of popular longform illustrated blog Wait But Why. Julia and Tim explore one of their common interests: the tension between the rational and irrational aspects of human nature. Is there any value in the "irrational" parts of us (such as Tim's colorfully named "instant gratification monkey" and "social approval mammoth")? And can recognizing that tension help us live better -- or are we stuck struggling between our animal and rational selves?

Rationally Speaking #177 - Dylan Matthews on "The science and ethics of kidney donation"  

If you're a healthy adult, should you donate one of your kidneys to a stranger? This episode features journalist Dylan Matthews, who donated his kidney last year. He and Julia discuss the clever design of "donor chains," how we should evaluate the science about whether kidney donation is safe, and whether we have an ethical obligation to donate.

Rationally Speaking #176 - Jason Brennan on "Against democracy"  

Churchill famously called democracy "the worst system of government, except for all the others that have been tried." Could we do better? On this episode of Rationally Speaking, Julia chats with professor Jason Brennan, author of the book "Against Democracy," about his case for why democracy is flawed -- philosophically, morally, and empirically.

Rationally Speaking #175 - Chris Blattman on "Do sweatshops reduce poverty?"  

This episode explores the economics and ethics of low-paying factories (which some might call "sweatshops") in Ethiopia. Do they make their workers better off, relative to those people's outside options? Professor Chris Blattman has run some well-designed randomized controlled trials exploring this question, and he discusses what surprised him and how he's updated his views from his research. Julia and Chris also discuss an innovative program to reduce crime in Liberia using cognitive behavioral therapy.

Rationally Speaking #174 - John Ioannidis on "What happened to Evidence-based medicine?"  

Over the last two decades, the Evidence-Based Medicine (EBM) movement has transformed medical science, pushing doctors to rely less on intuition or "common wisdom" in choosing treatments, and more on evidence from studies. Sounds great -- but has EBM become a victim of its own success? This episode features John Ioannidis, Stanford professor of medicine, health and policy, and statistics, and author of the famous paper, "Why Most Published Research Findings are False." John and Julia discuss how EBM has been "hijacked," by whom, and what do do about it.

Rationally Speaking #173 - Brendan Nyhan on "What can we learn from the election?"  

Since Trump's surprising win in the 2016 presidential election, there's been a flurry of discussion about why things turned out this way. But which explanations are well-supported, and which are wrong (or simply rationalizations)? This episode features political scientist Brendan Nyhan, who talks with Julia about questions like: Were the polls and models wrong? If so, why? How surprised should we have been by Trump's win? And why didn't the markets react badly to it?

Rationally Speaking #172 - Brian Nosek on "Why science needs openness"  

There's a growing anxiety about the quality of scientific research, as a depressingly large fraction of articles fail to replicate. Could "openness" solve that problem? This episode features Brian Nosek, a professor of psychology and founder of the Center for Open Science. He and Julia discuss what openness means, some clever approaches to boosting openness, and whether openness could have any downsides (for example, in the cases of peer review or data sharing).

Rationally Speaking #171 - Scott Aaronson on "The ethics and strategy of vote trading"  

It can be pretty frustrating to live in a "safe" state during national elections, where the chance your vote will affect the overall results is practically zero. This episode, with professor Scott Aaronson, explores an unorthodox solution to the problem: "swapping" your vote with someone in a swing state who was going to vote for a third party candidate. Scott and Julia explore the game theory of vote swapping, and whether there are any ethical problems with it.

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