Some of the most terrifying moments of my life have been in the midst of conflict: with American Marines in Fallujah in 2004 and with armed bands in Sierra Leone in 1993. I stood next to mounds of dead Iranian soldiers, teenagers actually, during the Iran-Iraq War in 1984.

The horror of war is a reality I have experienced firsthand. And yet an analyst must never give in to his or her emotions. He or she must view history with a heart of ice to find patterns that others miss. This is what Stanford classics professor Ian Morris does in his new book, “War! What Is It Good For? Conflict and the Progress of Civilization from Primates to Robots.” Morris, an archaeologist and a historian, surveys thousands of years of history and comes away with the seemingly startling thesis that human progress has been helped, rather than hindered, by war.

As he writes: “By fighting wars, people have created larger, more organized societies that have reduced the risk that their members will die violently.”

“ Hard as it may be to believe, imperialism has advanced humanity by making it safer and wealthier, and by aspiring to a universalism beyond tribe and ethnicity. ”

Indeed, in the Stone Age, you had as much as a 20% chance of dying violently at the hands of another human being. But in the 20th century — even with the trenches, even with Hitler, with Hiroshima, with terrorism and with a panoply of Third World wars — you had only a 1% or 2% chance of dying violently. Yes, as many as 200 million people may have died in wars throughout the 1900s, but roughly 10 billion lives were lived during that period. One may argue that this has merely been a matter of food production outpacing the production of assault rifles, so that violence has not so much been suppressed as overwhelmed by science. But Morris sees another factor: the rise of Hobbesian Leviathans that could only come about by war itself.

A Leviathan is the horrifying monster that Job beheld in the Bible, the “king over all the children of pride.” The 17th century English philosopher Thomas Hobbes used the concept as a metaphor for a strong central government that, by monopolizing the use of force, would make men no longer fear each other but only the authorities above them. Such was the way toward peaceful progress. Morris shows that, ironically, throughout history Leviathan has generally been created not by reasoned discussion but by war. He laments that this is so but demonstrates that humanity has thus far found no other way.

Morris recounts the sheer dreadfulness of Rome’s conquests over the northern tribes of Europe. “Rome had made a wasteland and called it peace,” went the famous adage. But that wasteland, he goes on, became the most productive and the most developed part of Greater Europe and the Mediterranean basin, even as life under Roman rule was safer and more predictable for the average person compared to any of the so-called barbarian precincts adjacent to Rome. Leviathan quelled violence, even as it demanded it. The political philosopher Francis Fukuyama in his 2011 book, “The Origins of Political Order,” posed the question, how do we get to Denmark? (Denmark is a metaphor for a humane and efficient polity.) Morris essentially answers that we get to Denmark by starting with Rome.

A theme that runs through Morris’ book is that while some idealists worship primitive societies and the noble savages who populate them, primitive societies rather than idyllic retreats have more often been filled with the terrifying human monsters associated with William Golding’s 1954 novel, “Lord of the Flies.” Thus, the idea is to incorporate primitive societies within Leviathan, and that has usually happened through military conquest.

Of course, Leviathan can periodically be worse than the less organized societies it conquers. Hitler’s Germany and Stalin’s Soviet Union were Leviathans. So, too, on a smaller scale, were Hafez al Assad’s Syria and Saddam Hussein’s Iraq. But remember, Morris is writing about grand patterns throughout the entire sweep of history, and therefore his generalizations cannot, by definition, be perfect. He admits that “theorizing about how war works over a timescale of millennia would surely have seemed like a cruel joke” to the real people being killed in armed conflicts as far back as antiquity, so that the “moral implications” of his thesis are, perforce, “unsettling.” For as Shakespeare put it in Henry V, “few die well that die in a battle.”

Moreover, the march toward a more peaceful humanity from the Stone Age to the 20th century has not been steady but full of wild zigzags. In particular, Morris calls the anarchy of the Middle Ages the culmination of a millennium of “counterproductive wars that followed the breakdown of the ancient empires.” Hard as it may be to believe, in general, imperialism has advanced humanity by making it safer and wealthier, and by aspiring to a universalism beyond tribe and ethnicity. Hitler’s attempt at imperialism burnt out after a few years because of his very extremism, whereas Rome, ancient Persia, Venice, Holland, France, Great Britain and America have all fostered, more or less, human development through various kinds of imperialist or imperial-like enterprises. And they have all done so in significant measure through war.

Imperialism has led ultimately to what Morris calls a “globocop,” a role that the United States has played, however imperfectly, since the collapse of the Soviet Empire. America may get into Middle Eastern quagmires, but its Navy and Air Force, not to mention the reputation of its land forces and intelligence apparatus, project power sufficiently throughout the world so as to reduce the level of conflict and so far eliminate major interstate war. The United States, for its part, has become the complex and productive society it is largely thanks to the rigors it has passed through in planning for armed conflict, especially World War II and the Cold War. Morris might have added to his text that mass college education, the explosion of suburban life and civil rights for minorities were all expressions of the further democratization of American life that would have been hard to imagine without the national unity enforced by having to fight the Nazis and the Japanese.

Morris explores various scenarios for future warfare, from guerrilla insurgencies to robotic warriors to missiles in space. He tends to be optimistic, believing that humanity after millennia of war may reach a culmination point, in which the number of humans killed by other humans continues to drop dramatically. In this, he is in league with Harvard psychology professor Steven Pinker’s 2011 book, “The Better Angels of Our Nature,” which also sees a continuation in the decline of human violence.

Keep in mind, though, that these optimistic scenarios and others may, among other things, be products of their times. For we still live in the relatively benign aftermath of World War II, in which the greatest interstate war in history has led to 70 years without interstate war between the great powers. The 19th century in Europe, between the conclusion of the Napoleonic Wars and the outbreak of World War I, was a similar period when many people lost their sense of the tragic only to be shocked by what came afterward. We can only hope that Morris’ defense of war actually proves accurate so that we can continue to enjoy relative peace.

Robert D. Kaplan is chief geopolitical analyst for Stratfor. This article was republished with permission.