“When Parfit thinks about the future, he wonders whether life for future people will be better or worse than it is now. He wants to be optimistic, but he cannot ignore the terrible suffering that people have endured in the past. Has it all been worth it? Has the sum of human happiness outweighed the sum of suffering?”

— Larissa MacFarquhar, How to be Good (The New Yorker, September 5, 2011)