The result is that other people become more valuable alive than dead, and violence declines for selfish reasons. As Wright put it, "" Among the many reasons that I think that we should not bomb the Japanese is that they built my mini-van. "" (Laughter) The fourth explanation is captured in the title of a book called "" The Expanding Circle, "" by the philosopher Peter Singer, who argues that evolution bequeathed humans with a sense of empathy, an ability to treat other peoples' interests as comparable to one's own. Unfortunately, by default we apply it only to a very narrow circle of friends and family.