War Forges Civilization

Thursday, March 28th, 2013

Warfare has transformed us from living in villages to living in huge states, Peter Turchin argues — ultimately making our lives more peaceful:

First, the critical glue that holds societies together is cooperation. Second, the reason humans learned how to cooperate is — paradoxically — warfare, lethal conflict between groups. And third, by creating a selective pressure for ever-larger societies warfare will eventually put itself out of business, when we learn to cooperate at the level of the whole humanity.

When he argued this at a public debate, the audience sounded voted for the opposing side. War is bad, after all.

His first two points seem reasonable. His third reminds me of the underwear gnomes’ business plan — or Marx’s notion that the state will wither away under true Communism. (Unless we can expect an alien invasion…)

Humans are ultrasocial (his first point), and the logic for why (his second point) is simple:

Groups of people who can’t cooperate to put together an army, will be overrun by those who can. The result is that genetic and cultural traits for noncooperation will go extinct.

More generally, cooperative traits are spread by the process of group selection. Selfish traits win in competition within groups, but altruistic, cooperative traits are favored by competition between groups. If between groups selection is strong enough, cooperative traits will spread.

Human groups can compete in many ways, but historically the most extreme form of such competition has been warfare. Warfare is the main engine of social evolution and it explains how small bands of hunter-gatherers (a few dozen people) evolved over the last 10,000 years into the huge societies of today. Because warfare pushes cooperating groups to become larger. As Napoleon said, “God favors big battalions.” The tribe that could mobilize more warriors had a better chance of surviving in war. This is the basic logic that drove the evolution of ever greater societies and states, and ever greater scale of warfare.

The story is of course much more complex than that. First, before warfare could do its thing, humans had to invent agriculture. Agriculture is a necessary condition for the evolution of truly complex societies. Why is absolutely obvious, and all scientists, including the participants of this debate, agree on it. But agriculture is only a necessary, not sufficient condition — many regions of the world had agriculture for milennia and did not make the transition to complex societies until they were colonized by European Great Powers.

Second, evolution had to solve a multitude of problems in order to ensure that large societies would not simply split apart at the seams (in fact, most early states and empires did just that). So such cultural traits as monumental architecture; records, writing, and literacy; division of labor; professional bureaucracies, taxation, and formal legal systems; state rituals and ideologies, and so on, evolved to enable megasocieties to function without falling apart. But the fundamental driver was warfare.

However not any kind of warfare has this ‘creative’ nature. It doesn’t matter how many people are killed, what is important is the high chance of group extinction. This is what drives social evolution. In the mountains, for example, warfare does not drive evolution of social complexity. So you lose a battle, but you can always survive by retreating to a mountain fastness. The chance of extinction is small, and in rugged areas complex societies do not evolve. The opposite thing happens. People living there evolve away from the state.

In the plains, on the other hand, if you lose the war, you are history.

Although large societies fight big wars, citizens in such societies have a much lesser chance of being killed by other human beings:

One reason is that strong states suppress internal warfare, banditry, and murder. Another is that among hunter-gatherers everybody (at least, all males) had to be a warrior, but in large-scale societies, typically, only a small proportion fights in wars. The chances that you or I will get killed are much smaller.

More importantly, social evolution molded humans in ways that reduce violence. Earlier I mentioned that most people have a very strong aversion to killing fellow human beings. It was the same at the dawn of humanity, except ‘fellow human beings’ were only those personally known to you — relatives and friends. Or members of your tribe. Others were subhumans who needed to be exterminated.

Turchin cites Ian Morris (Why the West Rules — For Now):

The late historical sociologist Charles Tilly coined the phrase, “war made the state, and the state made war.”

Ian Morris prefers a different variant: “war made the state, and the state made peace.”

This is an uncomfortable conclusion:

But nobody proposes that we administer a “healthy dose” of “blood and iron” (to use the immortal phrase of the Prussian Chancellor Otto von Bismarck) to encourage state building in such places as equatorial Africa. In fact, many African countries are already mired in an endless cycle of war. Not only such violence causes a huge amount of human misery, it has done nothing for bringing about more effective governance. On the contrary, in a number of places warfare destroyed the last vestiges of state-level organization.

So, there are productive and unproductive wars. The Lucky Latitudes, where agriculture took off early, on balance favored productive war:

The size of empires increased during the Bronze and Iron Ages (roughly, the second and first milennia BC).

Empires Sizes Over Time

It increased especially rapidly during the centuries between 800 and 200 BC. Then it stopped increasing. Ian actually suggests that the size of empires decreased between 1 AD and 1415 AD. It doesn’t look that way to me, but it is undeniable that the size of largest empires stopped increasing — empires rose and collapsed but the areas they controlled at the peak oscillated around 3 million square kilometers — the size of modern India or Argentina. The two peaks you see in the eighth and thirteenth centuries are the Islamic Caliphate and the Mongolian Empire of Chinggis Khan and his successors. Neither was sustained for very long.

Ian’s conclusion is that before 1 BC warfare in the Lucky Latitudes was, on balance, productive, but between 1 AD and the end of the Middle Ages it was (again, on balance) counterproductive. The culprit was the horse nomad from the steppes. As Ian says in the Cliodynamics article, “the success of the empires of the Eurasian lucky latitudes had changed the meanings of geography in radical ways, with disastrous results.” The rise of steppe pastoralists, and their disastrous effect on the agrarian societies, was a kind of a ‘blowback’ response when the great agrarian empires overreached themselves.

It’s not war in itself that is either productive or unproductive, but competition between groups and societies:

Violence is unproductive when it pitches people against other people within societies, taking forms such as murders between individual people or civil war between organized groups. It can be ‘productive,’ despite killing people and destroying property, when it is whole societies fighting other societies. But the key is not killing people, it’s between-group selection — competition that eliminates societies, whose members are unable to cooperate with each other, or to invent and adopt innovations and acquire or sustain prosocial norms and institutions. It’s not being good at killing.


Conversely, high rates of violence, as those found in the Inuit (where 30 percent of adult male deaths were due to murders), or incessant between-village warfare in New Guinea and the Amazon (Yanomami!) have been completely unproductive for the evolution of large-scale cohesive and productive societies.

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