In Tales of the Hasidim, Martin Buber tells the story of a Jewish master, Rabbi Zusya. The rabbi had led a life of extraordinary devotion and certitude, and yet, when he was dying, he cried inconsolably. This behavior of Zusya completely baffled his students who were present in the same room at the time. They tried to pacify him by saying all kinds of positive things, but Rabbi Zusya wouldn’t stop shedding tears.

“Take heart, Rebbe,” the students spoke, “you lived an exemplary life. You have been as wise as Moses and as kind as Abraham, so...