The world these days hardly seems like a peaceful place. But recent scholarship offers room for optimism.
First, Pinker offers mountains of historical evidence that the world is actually less violent today than ever before and that this trend shows no signs of reversing. With over a hundred graphs and charts, he documents how violence is at its nadir globally in terms of rape, infanticide, genocide, wife-beating, slavery, torture, war, homicide rates, and even animal cruelty. His data show that life in pre-state societies was comparatively Hobbesian—nasty, brutish, and short. For instance, prehistoric graves from hunter-gatherers reveal violent deaths five to ten times that of modern Europe. And from 1300 C.E. to today, the odds of being murdered has plummeted by up to fifty times. Violence of all stripes began to decline markedly during the Enlightenment and has fallen off precipitously since World War II.
Pinker does not sugarcoat the horrors of the twentieth century, especially the ravages of World War II, which killed 55 million people, an unprecedented figure in absolute terms. He notes, however, that this highly lethal event relative to the worldwide population did not break historical records. In relative terms, World War II ranks as only the ninth most deadly event over the past 1,200 years. In eighth-century C.E. China, the An Lushan civil war killed an estimated thirty-six million people, equivalent to 429 million deaths in the mid-twentieth century. The second most lethal event in relative terms was the thirteenth century Mongol conquest of Asia, which killed forty million people, the equivalent of 278 million around the time of Hitler and Stalin. And the third most lethal was the Middle East slave trade.
Muslim governments summarily execute criminals, treat adultery as a capital offense, and permit female genital mutilation; but, like the rest of the world, violence in Muslim countries is on the decline. Pinker attributes the reduction of international violence to a host of historical factors that expand the circle of empathy beyond family, tribe, nation, or even species; these include the development of agriculture, state structure, international commerce, literacy, and democracy.
Second, Chenoweth and Stephan provide an alternative causal mechanism, demonstrating statistically that nonviolent protest outperforms violent resistance. They compare the political outcomes of over 300 campaigns between 1900 and 2006 in which non-state actors demanded that governments accommodate their demands. All else being equal, the use of violence in these campaigns lowered the odds of government compliance. If research, particularly by this author, suggests that terrorist violence impedes government concessions, Chenoweth and Stephan broaden the argument by showing how all forms of non-state violence may be politically counterproductive.
If so, then aggrieved groups have a powerful incentive to avoid violent escalation, which may account for its growing scarcity. Indeed, the Arab upheavals are as much a repudiation of al-Qaeda's extreme means as its extreme ends.