The big question is, Why do our minds contain such a staircase? I believe it’s because there was a long period in human evolution during which it was adaptive to lose the self and merge with others. It wasn’t adaptive for individuals to do so, but it was adaptive for groups. As evolutionary biologists David Sloan Wilson and Edward O. Wilson have proposed, religiosity is a biological adaptation for binding groups together and helping them enter a mind-set of “one for all, all for one.” Groups that developed emotionally intense, binding religions were able, in the long run, to outcompete and outlast groups that were not so tightly bound.

If the human capacity for self-transcendence is an evolutionary adaptation, then the implications are profound. It suggests that religiosity may be a deep part of human nature. I don’t mean that we evolved to join gigantic organized religions — that kind of religion came along too recently. I mean that we evolved to see sacredness all around us and to join with others into teams that circle around sacred objects, people and ideas. This is why politics is so tribal. Politics is partly profane, it’s partly about self-interest. But politics is also about sacredness. It’s about joining with others to pursue moral ideals. It’s about the eternal struggle between good and evil, and we all believe we’re on the side of the good.