When I first read it, Steven Pinker’s description of the Hobbesian trap gave me chills. Violence isn’t just something that’s “innate” or “human nature” or the result of a violent culture. It’s implied by sheer logic, given just a few basic assumptions about how we operate. The logic of the Hobbesian trap applies to anything shaped by evolution. Any population of self-replicators with differential survival rates will experience it. The following passage is from Pinker's The Better Angels of Our Nature, and a similar discussion is given in his book The Blank Slate. For a little context, Pinker gives a passage from Hobbes listing three principal causes of quarrel: competition, diffidence, and glory:
The second cause of quarrel is diffidence, a word that in Hobbes’s time meant “fear” rather than “shyness.” The second cause is a consequence of the first: competition breeds fear. If you have reason to suspect that your neighbor is inclined to eliminate you from the competition by, say, killing you, then you will be inclined to protect yourself by eliminating him first in a preemptive strike. You might have this temptation even if you otherwise wouldn’t hurt a fly, as long as you are not willing to lie down and be killed. The tragedy is that your competitor has every reason to crank through the same calculation, even if he is the kind of person who wouldn’t hurt a fly. In fact, even if he *knew* that you started out with no aggressive designs on him, he might legitimately worry that you are tempted to neutralize him out of fear that he will neutralize you first, which gives you an incentive to neutralize him before that, ad infinitum. The political scientist Thomas Schelling offers the analogy of an armed homeowner who surprises an armed burglar, each being tempted to shoot the other to avoid being shot first. This paradox is sometimes called the Hobbesian trap, or in the arena of international relations, the security dilemma.
The book describes in great detail the behaviors of warring tribes of hunter-gatherers. Such tribes often feud with their neighbors. They often have pitched battles with each other, and they will pick off stray male members of a neighboring tribe who wander into the wrong territory. They even occasionally conduct extermination raids of neighboring villages, attempting to finish off a rival tribe down to the very last person. For a more first-hand account of the violent behavior of hunter-gatherers, read Jared Diamond’s “The Third Chimpanzee.” Hobbes wasn’t just arm-chair theorizing, and Pinker isn’t just working out the logic of an irrelevant hypothetical. The Hobbesian trap is an accurate description of why some cycles of violence happen. It accurately predicts that such cycles are hard to break.
There is hope. If the ambient levels of violence decline, the threat of being exterminated by your neighbors can become irrelevant, then even unthinkable. So neighboring villages no longer consider slaughtering each other preemptively. The cycles of violence can be broken. If some pacifying force (say international peacekeepers, or even a strong-man dictator who threatens warring factions) can reduce the overall levels of violence, it can start a virtuous cycle where violence declines because violence declines. If the threat of being exterminated by your neighbors is ruled out of the question, you no longer have any reason to exterminate them, and the warring tribes can escape the Hobbesian trap. The overall thesis of the book is that violence has declined, and Pinker discusses the many reasons why. This breaking out of the Hobbesain trap is an important piece of that puzzle. It probably explains the massive difference in homicide rates between hunter-gatherer societies (very shockingly high) and modern state societies (orders of magnitude lower).
For some more context, here is an excerpt from Hobbes himself (Leviathan) that kicks off Pinker’s discussion:
So that in the nature of man, we find three principal causes of quarrel. First, competition; secondly, diffidence; thirdly, glory. The first maketh men invade for gain; the second, for safety; and the third, for reputation. The firs use violence, to make themselves masters of other men’s persons, wives, children, and cattle; the second, to defend them; the third, for trifles, as a word, a smile, a different opinion, and any other sign of undervalue, either direct in their persons or by reflection in their kindred, their friends, their nation, their profession, or their name.