There are those who believe that science will eventually explain everything—including our enduring belief in heaven. The thesis here is very simple: heaven is not a real place, or even a process or a supernatural event. It’s something that happens in your brain as you die.

I first encountered this idea as I was researching my new book, Heaven: Our Enduring Fascination With the Afterlife. I was having lunch with my friend and colleague Christopher Dickey, who told me that his father, the writer James Dickey, had a fantasy of heaven in which all of his closest friends were sitting around a swimming pool, chatting. “There was nothing special about the pool itself,” wrote Chris in Summer of Deliverance: A Memoir of Father and Son. “Nobody walked on the water. And he never told me who the friends were … But what he took away from the dream was a sense of contentment, of being at ease with himself and the world, as if he had gotten a preview of heaven. He called that place ‘The Happy Swimming Pool.’ ” Chris believes that everything we think we know about heaven happens in the moments before death. After that, there’s nothing.