As Steven Pinker observes, we recall the twentieth century as an age of unparalleled violence, and we characterize our own epoch as one of terror. But what if our historical moment is in fact defined not by mass killing but by the greatest levels of peace and safety ever attained by human­kind? By way of this provocative hypothesis, the acclaimed psychologist and cognitive neuroscientist aims to liberate us from the overblown victimhood-by-contiguity of the present moment, maintaining quite credibly that we ought to be grateful for living when we do.

In his vivid descriptions of the distant and recent past, Pinker draws from a wide range of fields beyond his own to chart the decline of violence, which he says "may be the most important thing that has ever happened in human history." He argues that prehistory was much more violent than early civilization and that the past few decades have been much less violent than the first half of the twentieth century. He is opposing two common and related presumptions: that the time before civilization was a golden age and that the present moment is one of unique danger. Pinker rejects the idea that violence is "hydraulic," a pressure within individuals and societies that at some point must burst through. He prefers to see violence as "strategic," a choice that makes sense within certain historical circumstances. Thus, he describes two fundamental transitions: from the anarchy of hunting and gathering societies to the controlled ­violence of early states and then from a "culture of honor" associated with these states to a "culture of dignity" characteristic of the better moments of modernity. In Pinker's view, the state monopolizes violence and creates the possibility of fruitful trade and intellectual exchange, which in turn permit the development of a new, irenic individuality.

Pinker's first target is the tendency to romanticize the distant past. Since he believes that people fantasize about a peaceful prehistory, he deliberately over­emphasizes its violence, dwelling at length on the bloodiest passages of the Old Testament. His cheerful admission of this writerly tactic presages not only the friendly tone of the entire book but also one of its shortcomings. Although Pinker writes as a scientist, his approach in this book is discursive rather than deductive, charmingly but not quite persuasively advancing his ex cathedra views about life in general. The research of others, although abundantly and generously cited, too often seems to footnote Pinker's own prior assumptions. He is most likely correct that prehistoric life was more violent than life in agrarian civilizations and modern states, but the way he pitches the evidence raises suspicions from the very beginning. He provides horrifying descriptions of premodern killings, but not of their modern counterparts, which generates a certain narrative bias. The evidence of strikingly brutal premodern warfare and sacrifice is less conclusive than he suggests, since archaeologists are more likely to find the remains of people who die in unusual ways, beyond the reach of communal cremation or at the center of a communal ritual. The book features neat charts showing the relative decline of violence over time. But the sources Pinker cites for the numbers of dead are themselves just aggregates of other estimates, the vast majority of which, if one follows the thread of sources to the end, turn out to be more or less informed guesses.

Yet even if Pinker is right that the ratio of violent to peaceful deaths has improved over time (and he probably is), his metric of progress deserves a bit more attention than he gives it. His argument about decreasing violence is a relative one: not that more people were killed annually in the past than are killed in a given year of recent history but that more people were killed relative to the size of the overall human population, which is of course vastly larger today than in earlier eras. But ask yourself: Is it preferable for ten people in a group of 1,000 to die violent deaths or for ten million in a group of one billion? For Pinker, the two scenarios are exactly the same, since in both, an individual person has a 99 percent chance of dying peacefully. Yet in making a moral estimate about the two outcomes, one might also consider the extinction of more individual lives, one after another, and the grief of more families of mourners, one after another.

Today's higher populations also pose a deeper methodological problem. Pinker plays down the technical ability of modern societies to support greater numbers of human lives. If carrying capacity increases faster than mass murder, this looks like moral improvement on the charts, but it might mean only that fertilizers and anti­biotics are outpacing machine guns and machetes -- for now.

There is also a more fundamental way in which the book is unscientific. Pinker presents the entirety of human history in the form of a natural experiment. But he contaminates the experiment by arranging the evidence to fit his personal view about the proper destiny of the invdividual: first, to be tamed by the state, then, to civilize himself in opposition to the state. The state appears in Pinker's history only when it confines itself to the limited role that he believes is proper, and enlightenment figures as the rebellion of intelligent individuals against the state's attempt to exceed its assigned role.

SOLID STATE

Following a long tradition that he associates with Thomas Hobbes, Pinker emphasizes the durable coercive state as the fount of social order. States are important because they suppress the individual violence that occurs whenever people compete for limited resources. States solve the security dilemma: when one institution monopolizes violence, individuals or tribes do not have to worry incessantly that other individuals or tribes will strike them first and thus need not strike first themselves. So far, so good. But the creation of states necessitates a second level of analysis in the book, one that Pinker does not really sustain. If the subject is violence, and states are in the picture, then the analysis requires a theory of interstate violence -- war, in other words -- as well as a sociological analysis of the development of pacific individuals within each state. After all, some of the very traits that maintain social order, such as the habit of obedience to authority, also make total wars and policies of mass killing possible. Instead of facing this problem squarely, Pinker conflates homicide and war. But as Pinker knows, states with low homicide rates have initiated horribly aggressive wars.

Pinker's account of the development of the state more or less stops around the French Revolution, in 1789, when his focus shifts to Enlightenment thinkers concerned with human rights and the protection of individuals from state power. The state begins as a solution for barbarians, then becomes a problem for intellectuals. Since Pinker's picture of the state is almost entirely restricted to its capacity to repress violence, it is not surprising that he focuses on the risks posed to a free society by the state's power to coerce. But the state is not just a machine for controlling the violence of individuals, and its institutional development did not end in the eighteenth century.

In Pinker's portrait of the modern era, the state is far in the background, even as it becomes far more capable of both good and evil. The main action is the advance of gentle commerce and human rights rhetoric, which Pinker presents as taking place apart from, or even despite, the state. But commerce is only gentle when a state can enforce property rights, overpower local rent seekers, and regulate trade. And human rights are enshrined and protected only through state action. Pinker, in a characteristically lucid formulation, notes that the emergence of the state transformed "warriors into courtiers." But his minimalist conception of the state does not include a crucial component: its ability to transform those courtiers into taxpayers. Elites who pay homage might be pacified on an individual basis, but those who pay taxes contribute to an entire system of pacification.

Throughout the book, Pinker pays surprisingly little attention to obviously relevant achievements of the state in the nineteenth and twentieth centuries, such as mass education, pollution control, and public health. He believes that literacy pacifies but does not dwell on how the masses learn to read. He admits toward the end of the book that the prospect of "additional decades of existence" makes people less violent but has little to say about how lives got longer in ways that do not involve the simple reduction of violence. Disease has always taken more lives than killing, so medical care affects life expectancy more than homicide and war.

Instead of tracking modern political history, Pinker reduces it to a matter of good faith and good ideas. When people read the right things, he thinks, they have the right ideas, and they are less violent. Pinker argues that reading generates understanding for those different from oneself and thus a capacity for reflective empathy. This is no doubt true, but the empathy is not necessarily universal. It is impossible to imagine the Reformation and the Counter-Reformation -- and thus the religious wars of the sixteenth and seventeenth centuries -- without the advent of the printing press. Pinker treats that period as one of religious madness, but it is hardly satisfying to read a critique of ideas that does not acknowledge why they had appeal or how they spread, especially when the technique of propagation is supposed to bring peace. Nationalism, which Pinker thinks led to the deaths of "tens of millions" of people, is also inconceivable without books, especially bad history books. For Pinker, religion and nationalism are simply the wrong ideas, and he casts himself as a kind of referee of intellectual history, showing a red card and removing the bad players from the field.

THE WORLD WARS

A similar intervention Pinker makes in his own experiment is to dismiss the two world wars and the episodes of mass killing that took place in the first half of the twentieth century. Pinker describes these horrors powerfully and eloquently but claims they are irrelevant to his argument. He is right that historians often impose too much coherence on that time period, wanting all the violence to somehow make sense. But Pinker errs toward the other extreme, portraying the two world wars as "horrifically unlucky samples from a statistical distribution," and the major episodes of mass murder as resulting from "a few contingent ideas and events." In other words, it was bad luck to have two big conflicts so close to each other, and more bad luck that they were associated with especially bad ideas. No doubt: but what does the brute fact that the wars happened mean for Pinker's argument, and for the immediate future?

The central psychological virtue of modern civilization, Pinker claims, is "self-control." Over the centuries, after people are pacified by the state, they learn to think ahead, to see the perspectives of others, and to pursue their ends without immediate violent action. Violence becomes not only impractical but also taboo. Nazi Germany, as Pinker seems to sense, represents a tremendous problem for this argument. Germany in the 1930s was probably the most functional state of its time, with low homicide rates and a highly literate population. Mastery of self was not the Nazis' problem; self-control was in fact a major element of the SS ethos, as preached by Reinhard Heydrich and Heinrich Himmler. Even Adolf Hitler practiced his emotive speeches. Lack of self-control was also not the problem for Joseph Stalin's executioners, or for Stalin and Stalinists generally. Individual Soviet NKVD men killed hundreds of people, one by one, in a single day; this can hardly be done without self-control of a very high order.

To rescue his argument from the problem posed by the mass killings of the mid-twentieth century, Pinker resorts to claiming that a single individual, in the German case Hitler, was "mostly responsible." Here, he misrepresents the historians he cites. It is true that most historians would subscribe to some version of "no Hitler, no Holocaust." But what they mean is that Hitler was a necessary condition for such a calamity, not that he was a sufficient one. There were many other necessary conditions for Nazi racial imperialism. Take, for example, worries about the food supply. In the 1930s, food was highly valued in both Berlin and Moscow. This fact did not dictate which ideologies would define the two states. But in practice, both Hitler and Stalin were obsessed with mastering and exploiting fertile soil, the former to transform Germany into a self-sufficient, racially pure empire, the latter to finance the industrialization of the Soviet Union.

Without recognizing the importance of scarce resources, it is impossible to understand the very different plans for agrarian colonization that the Nazi and Soviet ideologies sanctioned. But Pinker dismisses any claim that resources (rather than bad ideas) were related to the bloodiest conflicts in modern history as a "nutball conspiracy theory." This is an odd position for him to take, since his own history begins in a premodern world of conflict over resources. By insisting that ideas alone were to blame, he oversimplifies the issue. A more rigorous explanation would explain how political ideas interacted with scarcity, rather than insist that either one or the other must have been the problem.

Modern ideologies were not, as in Pinker's metaphors, "toxic" forces that "drove" people to do this or that. They provided narratives to explain why some groups and individuals had better access to resources, and appealing visions of the future after an aggressive reordering. Nazi Germany and the Soviet Union were ideological states, but they cannot be dismissed from history simply because they were organized around the wrong ideas. Each of them had plans for economic development that were meant to privilege one group at the expense of others -- plans that were inextricably entangled with justifications for why some people deserved more, others less, and others nothing but death (the extreme and unprecedented case being the Holocaust). These ideologies were effective in part because they motivated, and they motivated in part because they delivered, if not plenty, then at least visions of plenty.

We are different from the Nazis and the Soviets not because we have more self-control -- we don't. We are different largely because postwar improvements in agricultural technology have provided the West with reliable supplies of food, our massive consumption of which says much about our limited self-control. But what if food were to become scarcer and more expensive, as seems now to be the trend? What if unfavorable climate change were to outrun our technical capacities? Or what if melting glaciers leave societies such as China without fresh water? Pinker claims, unpersuasively, that global warming poses little threat to modern ways of life. But it hardly matters whether he is right: states are already taking action to minimize its consequences. China, for example, is buying up land in Africa and Ukraine in order to compensate for its own shortage of arable soil. The fresh water of Siberia must beckon. If scientists continue to issue credible warnings about the consequences of climate change, it would be surprising if leaders did not conjure up new reasons for preemptive violent action, positioning their states for a new age of want.

L'ÉTAT, C'EST NOUS

Treating Nazi Germany as a historical aberration also allows Pinker to sidestep the question of how Germans and central and western Europeans became such peaceful people after the demise of Nazism. This is a strange oversight, since European pacifism and low European homicide rates are where he begins the book. Today's Europe is Pinker's gold standard, but he does not ask why its levels of violence are the lowest in all of his charts. If, as he contends, the "pleasures of bourgeois life" prevent people from fighting, Pinker should also consider the place where these are most fully developed, and how they became so. Pinker persuasively relates how postwar economic cooperation among European states led to a pacifying interdependence, but he fails to stress that the postwar rebirth of European economies was a state-led enterprise funded by a massive U.S. subsidy known as the Marshall Plan. And he says very little about the concurrent development of redistributive social policy within those states. State power goes missing in the very places where states became preoccupied with welfare rather than warfare.

Pinker believes that people are more pacific when they have the time and the occasion to repeat interactions and reconsider their actions. Yet he has trouble ­acknowledging that, according to his own story, the one and only agent that can create that sort of cushioned society with educated minds and spare time has been the functional welfare state. This refusal seems rooted in Pinker's commitment to free-market libertarianism. His book's vision of a coming age of peace is a good example of how two trends favoring political passivity -- the narcissistic discursiveness of the American left and the antistate prejudices of the American right -- conspire in the same delusion: that while we talk, talk, talk, markets do the work of history. Unlike the Enlightenment thinkers he lauds, Pinker fails to see that the state is not simply, as he puts it, "an exogenous first domino" that fell long ago, beginning a chain of events but remaining motionless itself. L'état, c'est nous: the state is what we do, how we vote, the military service we do or do not perform, the taxes we do or do not pay, the federal grants that we do or do not apply for.

Pinker shows his libertarian hand when he casually claims that "economic illiteracy" causes redistributive policies and thus "class conflict." Many have made this claim, of course, but as he notes without seeming to realize he is disproving his own hypothesis, today's redistributive European welfare states are the most peaceful in world history. Pinker, who exhibits no economic expertise, confuses economic literacy with a blind faith that unconstrained markets are a self-sustaining good.

A principle of the scientific method is to arrange experiments so that one's own prior beliefs can be challenged. Pinker's natural experiment with history generates instead a selective rereading, in which his own commitments become the guiding moral light for past and future. But of course libertarianism, like all other ideologies, involves a normative account of resource distribution: those who have should keep. There is nothing scientific about this, although again, like all other ideologies, libertarianism presents itself simply as a matter of natural reason, or, in Pinker's case, "intelligence." Pinker goes so far as to suggest that libertarianism is equivalent to intelligence, since holding libertarian views correlates with high IQ scores. Since he believes that the need to regularly adjust IQ tests to preserve an average score of 100 means that we are growing more intelligent generation by generation, he deduces that we are becoming more libertarian. Pinker also conflates libertarian ideology with ethics, allowing him to conclude that we are therefore becoming increasingly moral. Each step in this argument is shaky, to say the least. As Pinker might have learned from Kant or Hume or any of the other Enlightenment figures he mentions, one cannot jump from reason to morals in this way. Even if each generation is brighter than the last, as Pinker believes, being smart is not the same thing as being just. To have an account of ethics, one needs to begin from ideas of right and wrong, not simply from mental habits that happen to be widespread in one's own milieu and moment.

Pinker is to be praised for asking a crucial question -- perhaps the crucial question -- of modern history. But as he moves between the premodern world of violence and a postmodern style of discourse, he loses sight of the modern world in which we actually live. What he provides is less an answer to his question than a mode of reasoning that has little to do with the scientific study of the past and much to do with a worldview that happens to be his own.