For the first time in human history, we're not having enough children to keep the world's population from falling. And fertility is collapsing fastest not in rich nations but in places like Colombia, Thailand, and Guatemala, upending decades of economic wisdom. Economist Jesus Fernandez-Villaverde tells EconTalk's Russ Roberts that falling fertility has accelerated sharply over the past decade and defies easy explanation. Declining religiosity, smartphones and social media, soaring housing costs, and changing gender norms are popular, but unconfirmed, theories. Fernandez-Villaverde offers his own speculative answer, that modern life makes a third child costly and childlessness easy, but admits the puzzle is unsolved. What's clearer is why it matters: as retirees become the dominant voting bloc, spending on pensions and health care crowds out roads, schools, and defense. Shrinking economies make public debt harder to service, and fewer births mean fewer scientists, artists, and inventors.

Why do we keep doing things we know we shouldn't? And is that really a failure of will? Author Meghan O'Gieblyn spent years trying to answer that question, first in response to her struggle with alcoholism and her loss of faith, and then by means of Simone Weil, William James, and Iris Murdoch, who argue that the will is powerless over the things we want to change most. Listen as she speaks with EconTalk's Russ Roberts about her new memoir, Will and Attention, which explores why paying attention does what effort alone can't, why we can reason ourselves into doing destructive things, and why the choices that most shape our lives are the "choices in between the choices," or the ones we barely notice making at all.

Before you give the government new powers, try the Munger Test: cross out "government" and insert the name of the politician you trust least. Then see if you still like the idea. In his 52nd EconTalk appearance, Mike Munger talks with host Russ Roberts about public choice, politics without romance, and why treating government like a loving family (or your family like a business), ends badly. Along the way, they talk about why Edmund Burke's famous defense of legislators voting their conscience cost him his seat in Parliament, how a group lunch explains politics, and why voters rationally know so little.