Casadevall leads by example. A single conversation with him is liable to include Anna Karenina, the Federalist Papers, the fact that Isaac Newton and Gottfried Leibniz were philosophers as well as scientists, why the Roman Empire wasn’t more innovative, and a point about mentoring in the form of a description of the character Mentor from Homer’s Odyssey. “I work at it,” he said, smirking. “I always advise my people to read outside your field, everyday something. And most people say, ‘Well, I don’t have time to read outside my field.’ I say, ‘No, you do have time, it’s far more important.’ Your world becomes a bigger world, and maybe there’s a moment in which you make connections.”