My stepson, who’s nine, asked me last week if I was afraid of dying. “No,” I told him. “Not really.” He looked at me as though he absolutely did not believe me. “Everyone dies,” I said. “It’s nothing to be afraid of.” His gaze took on a derisive quality. “Everyone is afraid of dying,” he told me. Later on, I thought about this conversation. It was brief, like all of our chats, something I am...