Has the Decline of Violence Reversed since The Better Angels of Our Nature was Written?

Questions about Definitions

How do you define “violence”?

I don’t. I use the term in its standard sense, more or less the one you’d find in a dictionary (such as The American Heritage Dictionary Fifth Edition: “Behavior or treatment in which physical force is exerted for the purpose of causing damage or injury.”) In particular, I focus on violence against sentient beings: homicide, assault, rape, robbery, and kidnapping, whether committed by individuals, groups, or institutions. Violence by institutions naturally includes war, genocide, corporal and capital punishment, and deliberate famines.

What about metaphorical violence, like verbal aggression?

No, physical violence is a big enough topic for one book (as the length of Better Angels makes clear). Just as a book on cancer needn’t have a chapter on metaphorical cancer, a coherent book on violence can’t lump together genocide with catty remarks as if they were a single phenomenon.

Isn’t economic inequality a form of violence?

No; the fact that Bill Gates has a bigger house than I do may be deplorable, but to lump it together with rape and genocide is to confuse moralization with understanding. Ditto for underpaying workers, undermining cultural traditions, polluting the ecosystem, and other practices that moralists want to stigmatize by metaphorically extending the term violence to them. It’s not that these aren’t bad things, but you can’t write a coherent book on the topic of “bad things.”

Questions about the Origins of the Book

What led you to write a book on violence?

As I explain in the Preface, it was an interest in human nature and its moral and political implications, carried over from my earlier books. In How the Mind Works (518–519) and The Blank Slate (166–169, 320, 330–336), I presented several kinds of evidence that violence had declined over time. Then in 2007, through a quirky chain of events, I was contacted by scholars in a number of fields who informed me there was far more evidence for a decline in violence than I had realized. Their data convinced me that the decline of violence deserved a book of its own.

You’re a linguist. What made you think you could write a work of history?

Actually, I’m an experimental psychologist. Better Angels concentrates on quantitative history: studies based on datasets that allow one to plot a graph over time. This involves the everyday statistical and methodological tools of social science, which I’ve used since I was an undergraduate—concepts such as sampling, distributions, time series, multiple regression, and distinguishing correlation from causation.

Does this book represent a change in your politics? After all, a commitment to human nature has traditionally been associated with a conservative fatalism about violence and skepticism about progressive change. But Better Angels says many nice things about progressive movements such as nonviolence, feminism, and gay rights.

No, the whole point of The Blank Slate was that the equation between a belief in human nature and fatalism about the human condition was spurious. Human nature is a complex system with many components. It comprises mental faculties that lead us to violence, but it also faculties that pull us away from violence, such as empathy, self-control, and a sense of fairness. It also comes equipped with open-ended combinatorial faculties for language and reasoning, which allow us to reflect on our condition and figure out better ways to live our lives. This vision of psychology, together with a commitment to secular humanism, has been a constant in my books, though it has become clearer to me in recent years.

How and why has it become clearer?

Though I have always had a vague sense that a scientific understanding of human nature was compatible with a robust secular morality, it was only through the intellectual influence of my wife, the philosopher and novelist Rebecca Newberger Goldstein, that I understood the logic connecting them. She explained to me how morality can be grounded in rationality, and how secular humanism is just a modern term for the world view that grew out of the Age of Reason and the Enlightenment (in particular, she argues, from the ideas of Spinoza). To the extent that the decline of violence has been driven by ideas, it’s this set of ideas, which I call Enlightenment humanism (pp. 180–183), which has driven it, and it offers the closest thing we have to a unified theory of the decline of violence (pp. 694–696).

Questions about Data and Methodology

Where did you get your data?

It depends. For the contrast between nonstate and state societies, I used data from forensic archeology and from quantitative ethnography. For the history of homicide in Europe, data from coroners and town records go back centuries. Western governments today keep good data on homicides (the violent crime of choice, because a dead body is hard to explain away), and several of them conduct crime victimization surveys for other crimes (which avoid the distortion of how willing victims are to report crimes to the police). For wars large and small, and other kinds of armed conflict since 1946, we have the Uppsala Conflict Data Project/Human Security Report Project and the Peace Research Institute of Oslo. For larger wars since 1816, I used datasets from the Correlates of War Project. Some historians and political scientists (such as Pitirim Sorokin, Quincy Wright, Peter Brecke, and Jack Levy) have tried to quantify war deaths in earlier periods, and “atrocitologists” such as Matthew White and Rudolph Rummel have done so for genocides, deliberate famines, and other kinds of mass violence. And of course in recent decades almost no aspect of life has gone unquantified by pollsters, government bureaucrats, and social scientists.

How did you decide which data to plot?

I had two guidelines. The first was to use data only from sources that had a commitment to objectivity, with no ideological axe to grind, avoiding the junk statistics commonly slung around by advocacy groups and moral entrepreneurs. The second was to plot the datasets in their entirety: no finagling the start and stop dates, or second-guessing the inclusion criteria, or slicing and dicing subsets, or cherry-picking the best examples. The few exceptions involve well-motivated historical intervals (for example, the period since World War II) and one case in which the authors themselves had played fast and loose with their criteria (data on terrorist deaths from the Bush administration); these are discussed explicitly.

For comparisons of a single place at different times, or comparisons of different places at a single time, I generally present deaths as a proportion of the population of that place at the time (most often countries, but sometimes states, cities, tribes, or samples). For comparisons across vast ranges of times and places (such as comparison of the atrocities of the 20th century with those of earlier centuries), I generally use the population of the entire world at the time. Population estimates of smaller jurisdictions in the distant past are iffier, and there is too much latitude to push the numbers around by choosing different denominators (the city? the country? the continent?).

Your claim that violence has declined depends on comparing rates of violence relative to population size. But is that really a fair measure? Doesn’t a victim of violence suffer just as much regardless of what happens to other people of the time? Was the value of a life less in the 13th century than in the 21st just because there are more people around today? Should we give ourselves credit for being less violent just because there has been population growth?

You can think about it in a number of ways, but they all lead to the conclusion that it is the proportion, rather than the absolute number, of deaths that is relevant. First, if the population grows, so does the potential number of murderers and despots and rapists and sadists. So if the absolute number of victims of violence stays the same or even increases, while the proportion decreases, something important must have changed to allow all those extra people to grow up free of violence.

Second, if one focuses on absolute numbers, one ends up with moral absurdities such as these: (a) it's better to reduce the size of a population by half and keep the rates of rape and murder the same than to reduce the rates of rape and murder by a third; (b) even if a society’s practices were static, so that its rates of war and violence don’t change, its people would be worse and worse off as the population grows, because a greater absolute number of them would suffer; (c) every child brought into the world is a moral evil, because there is a nonzero probability that he or she will be a victim of violence.



As I note on p. 47: “Part of the bargain of being alive is that one takes a chance at dying a premature or painful death, be it from violence, accident, or disease. So the number of people in a given time and place who enjoy full lives has to be counted as a moral good, against which we calibrate the moral bad of the number who are victims of violence. Another way of expressing this frame of mind is to ask, `If I were one of the people who were alive in a particular era, what would be the chances that I would be a victim of violence?’ [Either way, we are led to] the conclusion that in comparing the harmfulness of violence across societies, we should focus on the rate, rather than the number, of violent acts.”

Skeptical Questions about Whether Violence Has Really Declined

Wasn’t the 20th century the most violent in history?

Probably not; see chapter 5, especially pp. 189–200. Historical data from past centuries are far less complete, but the existing estimates of death tolls, when calculated as a proportion of the world’s population at the time, show at least nine atrocities before the 20th century (that we know of) which may have been worse than World War II. They arose from collapsing empires, horse tribe invasions, the slave trade, and the annihilation of native peoples, with wars of religion close behind. World War I doesn’t even make the top ten.

Also, a century comprises a hundred years, not just fifty, and the second half of the 20th century was host to a Long Peace (chapter 5) and a New Peace (chapter 6) with unusually low rates of death in warfare.

Atheist regimes in the 20th century killed tens of millions of people. Doesn’t this show that we were better off in the past, when our political and moral systems were guided by a belief in God?

This is a popular argument among theoconservatives and critics of the new atheism, but for many reasons it is historically inaccurate.

First, the premise that Nazism and Communism were “atheist” ideologies makes sense only within a religiocentric worldview that divides political systems into those that are based on Judaeo-Christian ideology and those that are not. In fact, 20th-century totalitarian movements were no more defined by a rejection of Judaeo-Christianity than they were defined by a rejection of astrology, alchemy, Confucianism, Scientology, or any of hundreds of other belief systems. They were based on the ideas of Hitler and Marx, not David Hume and Bertrand Russell, and the horrors they inflicted are no more a vindication of Judeao-Christianity than they are of astrology or alchemy or Scientology.

Second, Nazism and Fascism were not atheistic in the first place. Hitler thought he was carrying out a divine plan. Nazism received extensive support from many German churches, and no opposition from the Vatican. Fascism happily coexisted with Catholicism in Spain, Italy, Portugal, and Croatia. See p. 677 for discussion and references.

Third, according to the most recent compendium of history’s worst atrocities, Matthew White's Great Big Book of Horrible Things (Norton, 2011), religions have been responsible for 13 of the 100 worst mass killings in history, resulting in 47 million deaths. Communism has been responsible for 6 mass killings and 67 million deaths. If defenders of religion want to crow, “We were only responsible for 47 million murders—Communism was worse!”, they are welcome to do so, but it is not an impressive argument.

Fourth, many religious massacres took place in centuries in which the world’s population was far smaller. Crusaders, for example, killed 1 million people in world of 400 million, for a genocide rate that exceeds that of the Nazi Holocaust. The death toll from the Thirty Years War was proportionally double that of World War I and in the range of World War II in Europe (p. 142).

When it comes to the history of violence, the significant distinction is not one between thesistic and atheistic regimes. It’s the one between regimes that were based on demonizing, utopian ideologies (including Marxism, Nazism, and militant religions) and secular liberal democracies that are based on the ideal of human rights. On pp. 337–338 I present data from Rummel showing that democracies are vastly less murderous than alternatives forms of government.

Wasn’t the spread of Christianity the main historical force that drove down violence? Jesus preached love, peace, and forgiveness. The Spanish missionaries eliminated human sacrifice in Latin America. Abolitionism in the 19th century, and the Civil Rights movement in the 20th, were inspired by the morality of Christianity and led by Christian ministers. The two world wars show what happens when people depart from the teachings of Christianity.

Jesus deserves credit for stigmatizing revenge, one of the main motives for violence over the course of human history. But things started going downhill in 312 when Christianity became the official religion of the Roman Empire, and the historical facts are not consistent with the claim that Christianity since then has been a force for nonviolence:

The Crusaders perpetrated a century of genocides that murdered a million people, equivalent as a proportion of the world’s population at the time to the Nazi holocaust.

Shortly afterwards, the Cathars of southern France were exterminated in another Crusader genocide because they had embraced the Albigensian heresy.

The Inquisition, according to Rummel, killed 350,000 people.

Martin Luther’s rant against the Jews is barely distinguishable from the writings of Hitler.

The three founders of Protestantism, Luther, Calvin, and Henry VIII, had thousands of heretics burned at the stake, as they and their followers took Jesus literally when he said, “If a man abide not in me, he is cast forth as a branch, and is withered; and men gather them, and cast them into the fire, and they are burned.”

Following the biblical injunction, “Thou shalt not suffer a witch to live,” Christians killed 60,000-100,000 accused witches in the European witchhunts.

The European Wars of Religion had death rates that were double that of World War I and that were in the range of World War II in Europe.

Christian conquistadors massacred and enslaved native Americans in vast numbers, and perhaps twenty million were killed in all (not counting unintentional epidemics) by the European settlement of the Americas.

World War I, as I recall, was a war fought mostly by Christians against Christians. As for World War II and its associated horrors, see my answer to the previous question.

Certain Christian denominations, such as the Quakers, did indeed mobilize the abolitionist movement, but they came late to the party. Christianity had no problem with slavery for more than 1500 years, and agitation against the institution only took off with the writings of John Locke and other philosophers of the Age of Reason and Enlightenment, who found plenty of good secular reasons why slavery was abominable. The American abolitionists fought against a slaveholding South that was, of course, thoroughly Christian, including many ministers who defended slavery because it was approved in the Bible.



As for Martin Luther King, in his essay “Pilgrimage to Nonviolence” he discusses his inspirations: ancient Greek and Enlightenment philosophers, renegade humanistic theologians who rejected orthodox Christian doctrine, and most of all, Gandhi. And of course the segregationists he opposed were all Christians, and several of the civil rights activists they murdered were Jewish.



This is not to single out Christians or Christianity as a source of violence; many of the contemporary alternatives were just as bad. And there have been times in recent history when Christian ideas and movements have been pacifying forces, particularly when they have been influenced the humanitarian currents I discuss in the book. But to say that Christianity has, overall, been a force for peace in history is factually inaccurate.

I’ve read that at the beginning of the 20th century, ninety percent of deaths in warfare were suffered by soldiers, but at the end, ninety percent were suffered by civilians.

This is a bogus statistic; see pp. 317–320.

You say that cruel punishments and slavery have been abolished. But torture was practiced by the United States during the Bush administration, and human trafficking still takes place in many countries.

There is an enormous difference between a clandestine, illegal, and universally decried practice in a few parts of the world and an open, institutionalized, and universally approved practice everywhere in the world. Human trafficking, as terrible as it is, cannot be compared to the African slave trade (see pp. 157–188), nor can the recent harsh interrogation of terrorist suspects to extract information, as indefensible as it was, be compared to millennia of sadistic torture all over the world for punishment and entertainment (see pp. 130-132 and 144–149). In understanding the history of violence, one has to make distinctions among levels of horror.

Haven’t we just been lucky? If Churchill hadn’t stood up to Hitler, if Stalin hadn’t been willing to sacrifice tens of millions of Russians, if German scientists had succeeded in their nuclear program, then most of the world would be living under the horrors of the Third Reich.

True, but these counterfactuals go both ways. As John Mueller has put it, “had Adolf Hitler gone into art rather than politics, had he been gassed a bit more thoroughly by the British in the trenches in 1918, had he, rather than the man marching next to him, been gunned down in the Beer Hall Putsch of 1923, had he failed to survive the automobile crash he experienced in 1930, had he been denied the leadership position in Germany, or had he been removed from office at almost any time before September 1939 (and possibly even before May 1940), Europe’s

greatest war would most probably never have taken place.”

One could argue that in fact the world has just emerged from a run of stupendous bad luck, one in which three extraordinarily bloodthirsty men—Hitler, Stalin, and Mao—managed to take over powerful states, and were responsible for a majority of the deaths from war and genocide in the 20th century. Many historians have argued as follows: No Hitler, no Holocaust; no Stalin, no Purge; no Mao, no Great Leap Forward and Cultural Revolution. See the section “The Trajectory of Genocide,” particularly pp. 331–336–338, 343.

I repeat: Haven’t we just been lucky? On a number of occasions, such as the Cuban Missile Crisis, the world came just this close to nuclear annihilation.

According to the most recent analyses of documents from the Cuban Missile Crisis (see, e.g., Max Frankel’s High Noon in the Cold War), both the US and USSR desperately tried to get out of the crisis, avoiding unnecessary provocations and offering greater concessions than they had to. Other allegedly just-this-close brushes with Armageddon, such as the Vietnam and Yom Kippur wars, were even less perilous. As Mueller puts it, the metaphor of an escalator, in which one misstep could have carried leaders up and away to all-out nuclear war, is misleading. A better metaphor is a ladder: each rung made leaders increasingly acrophobic, and in every case they nervously sought a way to step back down.



As long as nuclear weapons exist, one cannot say that we are living in less-violent times, especially since it is inevitable that they will be used at some time in the future.

There is no answer to the question of how to compare the decline in actual deaths from dozens of high-probability categories (homicide, war, domestic abuse, and so on) with the increase in hypothetical deaths from one low-probability category – it is, as they say, a philosophical question. But it’s far from certain that nuclear weapons will ever be used again. The 67-year history of nonuse suggests that, contrary to predictions that blundering politicians and trigger-happy generals have always been on the verge of unleashing nuclear weapons, the likelihood of their being used is probably very small. Of course, even an event with an extremely low odds, when the probability is exponentiated over enough years, becomes extremely probable, but that curve has to be set off against the one representing the probability that the Global Zero project will succeed and that nuclear weapons will go the way of chemical weapons, human sacrifice, and slave auctions – also a low-probability event, but one which has a nonzero chance of happening in this century.

How can you say that violence has declined when we continue to murder millions of unborn babies?

As I discuss on pp. 426–428, the rate of abortion worldwide has been in decline. I also discuss the question whether people perceive abortion as a form of violence, given the evolving understanding of the locus of moral value over the centuries.

What about all the chickens in factory farms?

I discuss the chickens in a section on Animal Rights in chapter 7, pp. 469–473.

What about the American imprisonment craze?

As unjust as many current American imprisonment practices are, they cannot be compared to the lethal sadism of criminal punishment in earlier centuries (pp. 144-146). For a discussion of the causes and effects of today’s imprisonment binge, see pp. 121–123.

If you measure violence in terms of homicides or war deaths, couldn’t the decline of violence just be a by-product of advances in lifesaving medical care?

Unlikely, for a number of reasons. First, before the late 19th and early 20th century, most medicine was quackery, and doctors killed as many patients as they saved, yet many of the declines I document occurred before that time. Second, many forms of violent crime move up and down in tandem—for example, rapes and robberies went up in the 1960s and down in the 1990s, just like homicides—so it’s unlikely that any of these trends simply consist in a constant amount of violence which has been reallocated from deaths to injuries thanks to quick-acting EMTs. Third, while medical technologies have improved, so have weapon technologies. Fourth, advances in medicine can only move the numbers around for the statistical sliver consisting of the victims of violence who are injured so severely that they would have died with even with the primitive medical care in the past, but not so severely that would have died even with the advanced medical care of the present. Yet many of the declines are from scorched-earth campaigns of violence in which no amount of medical care could have reduced the death tolls to current levels—Mongol invasions, deliberate sieges of cities (in which doctors, even if they were around, would not have been allowed in), over-the-top frontal assaults into machine-gun fire, Dresden, Hiroshima, carpet-bombings, the deliberate killing or starvation of prisoners of war.

But most important, the development and deployment of medical care to save the lives of soldiers is itself a part of the very phenomenon I'm exploring—that war leaders and battlefield commanders today treat the lives of their soldiers as far more precious than in the days when they were used as fodder. Not only have armed forces invested in lifesaving technologies at tremendous cost, but battlefield commanders have avoided the temptation to compensate for the advanced lifesaving care by putting more soldiers in riskier situations, keeping casualty rates constant.

With lifesaving technologies, as with lifetaking technologies (that is, weaponry), far more of the variance in deaths over time depends on how the technologies are applied—whether people want other people dead or alive—than on what they technologies can do. (See “Weaponry and disarmament" pp. 673–674.)

You can’t really be arguing that violence has declined. That would mean that you believe in progress—that Mahler was an advance over Beethoven, who was an advance over Bach, and old-fashioned notions like that.

Huh?

Questions about the Future

Have you heard the one about the turkey who, on the eve of Thanksgiving, remarked on the extraordinary 364-day era of peace between farmers and turkeys he is lucky enough to be

living in? Or the man who fell off the roof of an office building and shouted to the workers

on each floor, “So far so good!” Maybe violence is cyclical, and the whole system is going to blow at any moment.

There is a big random component to the timing of wars, but there is no deterministic momentum, nor hydraulic cycles of buildup and release; see pp. 190–193 and 200210. A lengthy war-free period does not imply that war is becoming increasingly likely.

Aren’t you in danger of becoming a laughingstock like the journalist Norman Angell, who predicted that war was obsolete just five year before the outbreak of World War I?

Actually, Angell wrote only that war was economically counterproductive, not that it was obsolete—he worried, correctly, that leaders might blunder into war in their drive for national glory and other non-economic motives (see pp. 244–249). As for myself, I’m not predicting that large wars will never happen in the future, only that they haven’t taken place in the recent past—a phenomenon which needs to be explained (see pp. 251-255, 361–362, 377).

Have there been times in history when violence has increased? If so, couldn’t it happen again?

Of course. Examples of increases of violence I discuss include a rise in the concentration of destructiveness of European wars up until World War II, the heyday of genocidal dictators in the middle decades of the 20th century, the rise of crime in the 1960s, and the bulge of civil wars in the developing world following decolonization. Yet every one of these developments has been systematically reversed.

The decline of violence isn’t a steady inclined plane from an original state of maximal and universal bloodshed. Technology, ideology, and social and cultural changes periodically throw out new forms of violence for humanity to contend with. The point of Better Angels is that in each case humanity has succeeded in reducing them. I even present some statistical evidence for this cycle of unpleasant shocks followed by concerted recoveries (pp. 292–294).

As to whether violence might increase in the future: of course it might. My argument is not that an increase in violence in the future is impossible; it’s that a decrease in violence has taken place in the past (pp. 361–362, 377, 671). These are different claims.

Isn’t it inevitable that some fanatical terrorist group will get its hand on a nuclear weapon, and send the death counts through the roof?

I discuss kooks with nukes on pp. 361–362 and 368–373.

Speaking of kooks with nukes, isn’t Mahmoud Ahmadinejad going to hasten the arrival of the Twelfth Imam by attacking Israel with nuclear weapons?

I discuss this possibility on pp. 373–375.

Won’t climate change lead to widespread war?

Maybe, but maybe not (pp. 375–377). Most wars are not fought over shortages of resources such as food and water, and most shortages of resources don’t lead to war. The Dust Bowl of the 1930s did not lead to an American Civil war; nor did the tsunamis of 2003 and 2011 lead to war in Indonesia or Japan. And several statistical studies of recent armed conflicts have failed to find a correlation between drought or other forms of environmental degradation and war. Climate change could produce a lot of misery and waste without necessarily leading to large-scale armed conflict, which depends more on ideology and bad governance than on resource scarcity.

Will the moral momentum of the various rights revolutions culminate in universal vegetarianism? Will our 22nd-century descendants be as horrified that we ate meat as we are that our ancestors kept slaves?

Maybe, but maybe not. See pp. 473–474.

So are you really unwilling to make any predictions about violence in the future? Isn’t that a copout?

I think that the humanitarian movements that have gathered momentum since the Enlightenment will continue to make progress. The burning of heretics, gruesome executions, blood sports, slavery, debtors’ prisons, foot-binding, eunuchism, and wars between developed states won’t make a comeback any time soon. Most likely capital punishment, violence against women, human trafficking, the beating and bullying of children, and the persecution of homosexuals will continue to decline, albeit bumpily and unevenly, over a span of decades. I’m willing to go out on this limb because international moral shaming campaigns in the past (such as those against piracy, whaling, and slavery) have generally succeeded over the long term. I think there is also a non-negligible chance that within the next 25–50 years there will be fewer bloodthirsty despots, and that nuclear weapons could be abolished (see pp. 276–278). But terrorist attacks, civil war, and wars involving non-democracies are too capricious to predict, since they depend so much on the actions of individuals. Also, crime rates have defied every expert prediction, and it would be foolish to say that they could not go back up.

Questions about Explanations of the Decline of Violence

Are you saying that in recent centuries people have literally evolved to be innately less violent?

It’s possible, but that’s not my argument. See the section called “Recent Biological Evolution?”, pp. 611–622

You attribute a part of the decline of violence to the forces of modernity and enlightenment. Yet Germany before the Nazi takeover was the most cultured, advanced, sophisticated, civilized, enlightened, cosmopolitan society in the world. Doesn’t this show that cultural and intellectual sophistication are no protection against barbarism?

It’s misleading to essentialize an entire society as if it were a single mind. Weimar Germany did have subcultures that were sophisticated and cosmopolitan. But it also had subcultures, both elite and grassroots, that loathed secular modernity and Enlightenment universalism and signed on to Counter-Enlightenment sentiments of romantic militarism and nationalism—the valorization of blood and soil. The problem was that members of the second subculture murdered the members of the first. In a section called “Ideology” (pp. 556–569) I discuss computer simulations and social psychology experiments showing how the silencing of dissenting views can result in the takeover of a society by a belief system that few of its individual members hold individually—the phenomenon of “extraordinary popular delusions and the madness of crowds.”

Why do we need a fancy explanation of the decline of violence? People are innately empathic and averse to harming others, as we see in the fact that most soldiers can’t bring themselves to fire their weapons in battle. If violence is not encouraged by a society, it will naturally die out.

It’s true that people have an aversion to causing direct bodily harm to a stranger (presumably because it gives that person and his allies a motive to fight back). But it’s wrong to conclude that people are averse to harming other people in general. Skittishness about personal violence is easily set aside under a variety of circumstances. One is vengeance, in which a person coolly plots to harm an adversary under conditions where the adversary cannot defend himself. A second is rampage (sometimes called Forward Panic), where a group of men who have endured a prolonged state of fearful apprehension suddenly isolates a vulnerable adversary; this can trigger an explosion of savage aggression. A third is sadism, where a person pleasurably savors the ability to overcome the inhibition to harming someone else, much like a connoisseur acquires a taste for strong flavors or extreme sports.

These and other avenues toward and away from violence are systematically laid out in the two chapters on the psychology of violence, Inner Demons and Better Angels. I argue against various popular theories that paint Homo sapiens across the board as innately violent (killer apes, a death instinct, aggression genes, a violent brain, testosterone poisoning) or innately nonviolent (peaceful savages, reluctant soldiers, empathy neurons, universal moral rules). Humans, I argue, are equipped with five distinct motives of violence, and four faculties that allow them to inhibit or avoid violence.

Oh yeah, I’ve read about why violence has declined. It has something to do with the Roe v. Wade Supreme Court decision.

You’re referring to a theory proposed by the economist Steven Levitt and made famous in his bestseller (with Stephen Dubner) called Freakonomics. Levitt proposed that the American crime decline in the 1990s was the long-term result of fewer unwanted babies having been born after the 1973 legalization of abortion. But later he went on to adduce three additional causes of the crime decline. Of the four, the abortion hypothesis has pretty much been refuted, for reasons I review on pp. 119–121.

The explanation for the decline of violence in the second half of the 20th century is obvious: The bomb.

The theory of the Nuclear Peace is evaluated in chapter 5, pp. 268–278. I think it’s unlikely. World War II proved that conventional warfare was already unthinkably destructive, so the superpowers were already deterred plenty from provoking a third world war. Also, since the destructive power of nuclear weapons is so disproportionate to any strategic goal, its threat is for all practical purposes a bluff, which is why so many non-nuclear powers have defied nuclear ones since 1945. Finally, the Nuclear Peace theory can’t explain why non-nuclear powers have avoided war, too—why Canada and Spain, for example, never escalated their dispute over flatfish to a shooting war.

You obviously must discuss Michel Foucault’s Discipline and Punish, the book that explains the decline of judicial torture in Europe.

Actually, I don’t. Despite being a guru in the modern humanities, Foucault is not the only scholar to have noticed that European states eliminated gruesome punishments, and his theory in particular strikes me as eccentric, tendentious, and poorly argued. See J. G. Merquior’s “Charting carceral society” in his book Foucault (UC Press, 1985), for a lucid deconstruction.

Other Questions

What did you think of Elizabeth Kolbert’s review of Better Angels in The New Yorker?

Not much. It begins with the sensationalist, anecdote-driven style of journalism that has so distorted people’s understanding of violence: five paragraphs (a fifth of the review) on last summer’s spree killing in Norway. Kolbert must know that a single horrific incident, however irrelevant to long-term trends, has more emotional impact on readers than any amount of data analysis.

She then spends three paragraphs recounting studies which show that prehistoric and medieval societies were, contrary to popular belief, extraordinarily violent. But instead of acknowledging that these are just the facts that the book seeks to explain, she blows them off as “old thinking”: “The savages, it turns out, really were savage! The medievals did, in fact, go medieval!” The sarcasm is typical of her treatment of data: she can’t actually deny that rates of violence have come down, yet she implies that it is somehow unseemly, or futile, or reactionary, to acknowledge these facts and try to explain them.

Kolbert repeatedly plays the race and colonialism cards:

“The scope of Pinker's attentions is almost entirely confined to Western Europe.” In fact the section called “The European Homicide Decline” is followed by a section called “Violence Around the World” (complete with a world map of homicide rates, and a detailed case study from New Guinea) and a section called “Violence in These United States” (which, contra Kolbert, shows that the four regions in the US duplicated the main decline documented for Europe). And chapter 5, on the history of war in Europe and among great powers (which, incidentally, include non-western-European powers such as the Ottoman Empire, Russia, Japan, and China) is followed by chapter 6, on the history of war in the rest of the world.

“Pinker's views on African-Americans and Southerners probably indicate, there is much in The Better Angels of Our Nature that is confounding.” What she calls “Pinker’s views” are the undisputed facts, long known to criminologists, that homicide rates are higher among southerners than northerners, and higher among blacks than whites.

The Better Angels of Our Nature “Pinker is virtually silent about Europe’s bloody colonial adventures. (There's not even an entry for ‘colonialism’ in the book's enormous index.)” In fact the book’s has a list of the 21 worst atrocities in history which includes the “Annihilation of the American Indians,” the “Atlantic Slave Trade,” “British India,” and the “Congo Free State.” And the book reviewer’s old trick of finding some term that was not in the index is particularly disreputable in the age of e-books, when a quick search would have turned up more than 25 places in which the book discusses colonial conquests, wars, enslavements, and genocides.

“What does it reveal about the impulse control of the Spanish that...they were systematically butchering the natives on two continents? Or about the humanitarianism of the British that, as they were turning away from such practices as drawing and quartering, they were shipping slaves across the Atlantic?” Kolbert shows no signs of having read the two chapters on the psychology of violence, which take up this very question: “To understand the role of the moral sense in the decline of violence, we have to solve a number of psychological enigmas [such as] how the moral sense can be so compartmentalized: …[for example] why liberal democracies can practice slavery and colonial oppression.”

Also twisted is my account of the role of modernity in the decline of violence: “Though Pinker would like to pretend otherwise, Fascism and Communism are inventions that are every bit as modern as women's rights and the eurozone.” The book makes it utterly clear that I am not using the term “modernity” to refer to every idea that has influenced the world during the past 250 years. I use it to refer to one specific idea—classical liberalism, or Enlightenment humanism—which intellectually excludes, and has historically superseded, Fascism and Communism.

Kolbert does raise a substantive point about the list (adapted from Matthew White) of history’s worst atrocities: “Pinker's math here is, at best, fishy. According to his own calculations, the Second World War was, proportionally speaking, the ninth-deadliest conflict of all time…yet the war lasted just six years. The Arab slave trade, which ranks as No. 3 on Pinker's hit list, was an atrocity that took more than a millennium to unfold. The Mongol conquests, coming in at No. 2, spanned nearly a century.” But it’s Kolbert’s math that is fishy. She’s suggesting that historical trends in violence should be quantified by the speed of killing: How many people can be dispatched per unit of time? But surely it’s the amount of violence that is more relevant: For how long did the killing at that rate last? Imagine that that slave trade was abolished after a year, or that Genghis Khan was defeated after a month, or that the Holocaust was called off after a week. Would we not judge those events as vastly less violent? According to Kolbert’s math, we shouldn’t.

The penultimate paragraph degenerates into the postmodernist sophistry that the New Yorker so often indulges when reporting on science: “Name a force, a trend, or a ‘better angel’ that has tended to reduce the threat, and someone else can name a force, a trend, or an ‘inner demon’ pushing back the other way.” Well, yes, someone can always do that, but would they be right? Would they have evidence and logic on their side? And if threats of violence were really buffeted every which way by all those forces someone can name, then why have rates of violence—as Kolbert grudgingly concedes—gone down? Doesn’t that imply that some forces have been more powerful than others?

She continues: “And such is the logic of the dialectic that these two sides are, as often as not, connected.” The “logic” of this dialectic is far from obvious, but somehow it leads Kolbert to the old theory that the “the most compelling explanation for Europe's past half century of peace is the prospect of the alternative”—namely, all-out nuclear war—but that “we have grown so used to this ‘sublime irony’ that we barely talk about it anymore.” Actually, some of us do talk about it: me, for example. Kolbert failed to notice the section of the book entitled “Is the Long Peace a Nuclear Peace?” which shows that the Nuclear Terror theory of the postwar peace, far from being compelling, is probably false.

In her final paragraph, Kolbert waves the bloody Norwegian shirt one more time, and informs us, “Hate and madness and cruelty haven't disappeared, and they aren't going to.” No honest reviewer would imply that this is the message of the book.

But aren’t you just being defensive? Authors always think that negative reviews of their book are wrong. Has anyone else replied to Kolbert?

Razib Khan has a response in the Gene Expression blog on the Discover magazine Web site: http://blogs.discovermagazine.com/gnxp/2011/10/relative-angels-and-absolute-demons/

What’s your next book?

A style manual for the 21st century, applying the insights of linguistics, psycholinguistics, and cognitive psychology to the crafting of clear and stylish prose.

Can you recommend other books on violence?

Violence has always brought out the best in novelists and playwrights, and it has produced brilliant nonfiction writing as well. Here are some good books on bad behavior, written with insight, wit, and panache:

Brownmiller, S. (1975). Against our will: Men, women, and rape. New York: Fawcett Columbine.

Courtwright, D. T. (1996). Violent land: Single men and social disorder from the frontier to the inner city. Cambridge, MA: Harvard University Press.

Chagnon, N. A. (1997). Yanomamö (5th ed.). Fort Worth, TX: Harcourt Brace.

Daly, M., & Wilson, M. (1988). Homicide. New York: Aldine De Gruyter.

Goldstein, J. S. (2011). Winning the war on war: The surprising decline in armed conflict worldwide. New York: Dutton.

Gottschall, J. (2008). The rape of troy: Evolution, violence, and the world of Homer. New York: Cambridge University Press.

Keeley, L. H. (1996). War before civilization: The myth of the peaceful savage. New York: Oxford University Press.

McCullough, M. E. (2008). Beyond revenge : the evolution of the forgiveness instinct. San Francisco, CA: Jossey-Bass.

Payne, J. L. (2004). A history of force: Exploring the worldwide movement against habits of coercion, bloodshed, and mayhem. Sandpoint, ID: Lytton Publishing Co.

Richardson, L. F. (1960). Statistics of deadly quarrels. Pittsburgh: Boxwood Press.

Rummel, R. J. (1994). Death by government. New Brunswick, NJ: Transaction.

Mueller, J. (1989). Retreat from doomsday: The obsolescence of major war. New York: Basic Books.

Schechter, H. (2005). Savage Pastimes: A history of violent entertainment. New York: St. Martin's Press.

Valentino, B. (2004). Final solutions: Mass killing and genocide in the 20th century. Ithaca, NY: Cornell University Press.

White, M. (2011). The Great Big Book of Horrible Things: The Definitive Chronicle of History's 100 Worst Atrocities. New York: Norton.