A sheriff’s deputy arrived at Nathan and Danielle Clark’s front door on the outskirts of Springfield, Ohio, in September with the latest memento of what their son’s death had become. “I’m sorry that I have to show you this,” she said and handed them a flier with a picture of Aiden, 11, smiling at...

The controversial philosopher discusses societal taboos, Thanksgiving turkeys and whether anyone is doing enough to make the world a better place.