Sam Harris: “Spirituality Is a Loaded Term.” (People I (Mostly) Admire Ep. 25)

He’s a cognitive neuroscientist and philosopher who has written five best-selling books. Sam Harris also hosts the Making Sense podcast and helps people discover meditation through his Waking Up app. Sam explains to Steve how to become spiritual as a skeptic and commit to never lying again.

Nathan Myhrvold: “I Am Interested in Lots of Things, and That’s Actually a Bad Strategy.” (People I (Mostly) Admire Ep. 6 Rebroadcast)

He graduated high school at 14, and by 23 had several graduate degrees and was a research assistant with Stephen Hawking. He became the first chief technology officer at Microsoft (without having ever studied computer science) and then started a company focused on big questions — like how to provide the world with clean energy and how to optimize pizza-baking. Find out what makes Nathan Myhrvold’s fertile mind tick, and which of his many ideas Steve Levitt likes the most.

Amaryllis Fox: “What Does This New Version of Mutually Assured Destruction Look Like?” (People I (Mostly) Admire, Ep. 24)

She spent nearly a decade as an undercover C.I.A. operative working to prevent terrorism. More recently, she hosted The Business of Drugs on Netflix. Amaryllis Fox — now Kennedy — explains why intelligence work requires empathy, and she soothes Steve’s fears about weapons of mass destruction.

How to Manage Your Goal Hierarchy (Ep. 458)

In this special crossover episode, People I (Mostly) Admire host Steve Levitt admits to No Stupid Questions co-host Angela Duckworth that he knows almost nothing about psychology. But once Angela gives Steve a quick tutorial on “goal conflict,” he is suddenly a fan. They also talk parenting, self-esteem, and how easy it is to learn econometrics if you feel like it.

Greg Norman & Mark Broadie: Why Golf Beats an Orgasm and Why Data Beats Everything (People I (Mostly) Admire Ep. 23)

Steve Levitt is obsessed with golf — and he’s pretty good at it too. As a thinly-veiled ploy to improve his own game, Steve talks to two titans of the sport: Greg “The Shark” Norman, who was the world’s top-ranked golfer for more than six years; and Mark Broadie, a Columbia professor whose data analysis changed how pros play the game.

Sal Khan: “If It Works for 15 Cousins, It Could Work for a Billion People.” (People I (Mostly) Admire, Ep. 22)

Khan Academy grew out of Sal Khan’s online math tutorials for his extended family. It’s now a platform used by more than 115 million people in 190 countries. So what does Khan want to do next? How about reinventing in-school learning, too? Find out why Steve nearly moved to Silicon Valley to be part of Khan's latest venture.

Pete Docter: “What If Monsters Really Do Exist?” (People I (Mostly) Admire, Ep. 21)

He’s the chief creative officer of Pixar, and the Academy Award-winning director of Soul, Inside Out, Up, and Monsters, Inc. Pete Docter and Steve talk about Pixar’s scrappy beginnings, why it costs $200 million to make an animated film, and the movie moment that changed Steve’s life.

John Donohue: “I’m Frequently Called a Treasonous Enemy of the Constitution.” (People I (Mostly) Admire, Ep. 20)

He’s a law professor with a Ph.D. in economics and a tendency for getting into fervid academic debates. Over 20 years ago, he and Steve began studying the impact of legalized abortion on crime. John and Steve talk about guns, the death penalty, the heat they took from their joint research, and why it’s frustratingly difficult to prove truth in the social sciences.

Marina Nitze: “If You Googled ‘Business Efficiency Consultant,’ I Was the Only Result.” (People I (Mostly) Admire, Ep. 19)

At 27— and without a college degree — she was named chief technology officer of the Department of Veterans Affairs. Today, Marina Nitze is trying to reform the foster care system. She tells Steve how she hacked the V.A.’s bureaucracy, opens up about her struggle with Type 1 diabetes, and explains how she was building websites for soap opera stars when she was just 12 years old.

Robert Sapolsky: “I Don’t Think We Have Any Free Will Whatsoever.” (People I (Mostly) Admire, Ep. 18)

He’s one of the world’s leading neuroscientists, with a focus on the physiological effects of stress. (For years, he spent his summers in Kenya, alone except for the baboons he was observing.) Steve asks Robert why we value human life over animals, why he’s lost faith in the criminal-justice system, and how to look casual when you’re about to blow-dart a very large and potentially unhappy primate.