Bloom, the empathy doubter, counsels that people don’t need empathy, with its high “emotional toll,” to make moral choices. Empathy implies a certain arrogance: the idea that someone can fully enter into the life of a very different person, that, for instance, a white person who grew up under privileged circumstances could know exactly what it feels like to be a black victim of police brutality. But, he said, “I don’t have to know what it’s like to be the victim of sexism or racism to know that it’s wrong.”

It may be still possible to be empathic, said Stanford psychologist Jamil Zaki, if we simply think about empathy a little differently. Zaki has interviewed a number of E.R. doctors and social workers, who, he said, “deeply suffer from their empathic relationship,” although their patients benefit. Empathy is a tool that requires practice and work, he said. The ability to expand it beyond our immediate circle, to exercise it under extraordinary circumstances, and then to turn it off when we need to rest, may not come naturally to everyone. But it can be learned. “People can control their empathy,” he said – and if we’re to survive together in a more complicated, more frightening world, we may have no choice but to teach ourselves how.