ONE of the anxieties haunting the 21st century is a fear that technological change will soon make many human lives seem essentially superfluous.

It’s a fear as old as the Luddites, but the promise of computing, robotics and biotechnology has given it new life. It suddenly seems plausible that a rich, technologically proficient society will no longer offer meaningful occupation to many people of ordinary talents, even as it offers ever-greater wealth, ever-widening powers and, perhaps, ever-longer life to the elite.

That anxiety dominates the most provocative conversation you can eavesdrop on this week, between the Nobel laureate Daniel Kahneman [4] and the Israeli historian Yuval Noah Harari [5] on the website Edge.org [6]. ...