the prevalence of violence has been declining. cause unknown, but cause for optimism.

What went right? No one knows, possibly because we have been asking the wrong question—”Why is there war?” instead of “Why is there peace?” There have been some suggestions, all unproven. Perhaps the gradual perfecting of a democratic Leviathan—”a common power to keep [men] in awe”—has removed the incentive to do it to them before they do it to us. Payne suggests that it’s because for many people, life has become longer and less awful—when pain, tragedy, and early death are expected features of one’s own life, one feels fewer compunctions about inflicting them on others. Wright points to technologies that enhance networks of reciprocity and trade, which make other people more valuable alive than dead. Singer attributes it to the inexorable logic of the golden rule: the more one knows and thinks, the harder it is to privilege one’s own interests over those of other sentient beings. Perhaps this is amplified by cosmopolitanism, in which history, journalism, memoir, and realistic fiction make the inner lives of other people, and the contingent nature of one’s own station, more palpable—the feeling that “there but for fortune go I.”