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.

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.

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.

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.

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?

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?

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.

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.

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.

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.