Jared Diamond on vengeance and human nature:
This question of state government’s recent origins, and, conversely, of its long failure to originate throughout most of human history, is a fundamental concern for social scientists. Until fifty-five hundred years ago, there were no state governments anywhere in the world. Even as late as 1492, all of North America, sub-Saharan Africa, Australia, New Guinea, and the Pacific islands, and most of Central and South America didn’t have states and instead operated under simpler forms of societal organization (chiefdoms, tribes, and bands). Today, though, the whole world map is divided into states. Of course, most of that extension of state government has involved existing states from elsewhere imposing their government on stateless societies, as happened in New Guinea. But the first state in world history, at least, must have arisen de novo, and we now know that states arose independently in many parts of the world. How did it happen?
…anthropologists, historians, and archeologists tell us that state governments have arisen independently under one of two sets of circumstances. Sometimes external pressure from an encroaching state has placed a people under such duress that it ceded individual rights to a government of its own that would be capable of offering effective resistance. For instance, about two centuries ago, the formerly separate Cherokee chiefdoms gradually formed a unified Cherokee government in a desperate attempt to resist pressure from whites. More frequently, chronic competition among warring non-state entities has ended when one gained a military advantage over the others by developing proto-state institutions: one example is the formation of the Zulu state by a particularly talented chief named Dingiswayo, in the early nineteenth century, out of an assortment of chiefdoms fighting each other.
We regularly ignore the fact that the thirst for vengeance is among the strongest of human emotions. It ranks with love, anger, grief, and fear, about which we talk incessantly. Modern state societies permit and encourage us to express our love, anger, grief, and fear, but not our thirst for vengeance. We grow up being taught that such feelings are primitive, something to be ashamed of and to transcend.
There is no doubt that state acceptance of every individual’s right to exact personal vengeance would make it impossible for us to coexist peacefully as fellow-citizens of the same state. Otherwise, we, too, would be living under the conditions of constant warfare prevailing in non-state societies like those of the New Guinea Highlands.