Here is the analysis that preceded the famous “life of man” passage:
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 first 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.46
First, competition. Natural selection is powered by competition, which means that the products of natural selection—survival machines, in Richard Dawkins’s metaphor—should, by default, do whatever helps them survive and reproduce. He explains:
To a survival machine, another survival machine (which is not its own child or another close relative) is part of its environment, like a rock or a river or a lump of food. It is something that gets in the way, or something that can be exploited. It differs from a rock or a river in one important respect: it is inclined to hit back. This is because it too is a machine that holds its immortal genes in trust for the future, and it too will stop at nothing to preserve them. Natural selection favors genes that control their survival machines in such a way that they make the best use of their environment. This includes making the best use of other survival machines, both of the same and of different species.47
If an obstacle stands in the way of something an organism needs, it should neutralize the obstacle by disabling or eliminating it. This includes obstacles that happen to be other human beings—say, ones that are monopolizing desirable land or sources of food. Even among modern nation-states, raw self-interest is a major motive for war. The political scientist Bruce Bueno de Mesquita analyzed the instigators of 251 real-world conflicts of the past two centuries and concluded that in most cases the aggressor correctly calculated that a successful invasion would be in its national interest.48
Another human obstacle consists of men who are monopolizing women who could otherwise be taken as wives. Hobbes called attention to the phenomenon without knowing the evolutionary reason, which was provided centuries later by Robert Trivers: the difference in the minimal parental investments of males and females makes the reproductive capacity of females a scarce commodity over which males compete.49 This explains why men are the violent gender, and also why they always have something to fight over, even when their survival needs have been met. Studies of warfare in pre-state societies have confirmed that men do not have to be short of food or land to wage war.50 They often raid other villages to abduct women, to retaliate for past abductions, or to defend their interests in disputes over exchanges of women for marriage. In societies in which women have more say in the matter, men still compete for women by competing for the status and wealth that tend to attract them. The competition can be violent because, as Daly and Wilson point out, “Any creature that is recognizably on track toward complete reproductive failure must somehow expend effort, often at risk of death, to try to improve its present life trajectory.”51 Impoverished young men on this track are therefore likely to risk life and limb to improve their chances in the sweepstakes for status, wealth, and mates.52 In all societies they are the demographic sector in which the firebrands, delinquents, and cannon fodder are concentrated. One of the reasons the crime rate shot up in the 1960s is that boys from the baby boom began to enter their crime-prone years.53 Though there are many reasons why countries differ in their willingness to wage war, one factor is simply the proportion of the population that consists of men between the ages of fifteen and twenty-nine.54
This whole cynical analysis may not ring true to modern readers, because we cannot think of other people as mere parts of our environment that may have to be neutralized like weeds in a garden. Unless we are psychopaths, we sympathize with other people and cannot blithely treat them as obstacles or prey. Such sympathy, however, has not prevented people from committing all manner of atrocities throughout history and prehistory. The contradiction may be resolved by recalling that people discern a moral circle that may not embrace all human beings but only the members of their clan, village, or tribe.55 Inside the circle, fellow humans are targets of sympathy; outside, they are treated like a rock or a river or a lump of food. In a previous book I mentioned that the language of the Wari people of the Amazon has a set of noun classifiers that distinguish edible from inedible objects, and that the edible class includes anyone who is not a member of the tribe. This prompted the psychologist Judith Rich Harris to observe:
In the Wari dictionary
Food’s defined as “Not a Wari.”
Their dinners are a lot of fun
For all but the un-Wari one.
Cannibalism is so repugnant to us that for years even anthropologists failed to admit that it was common in prehistory. It is easy to think: could other human beings really be capable of such a depraved act? But of course animal rights activists have a similarly low opinion of meat eaters, who not only cause millions of preventable deaths but do so with utter callousness: castrating and branding cattle without an anesthetic, impaling fish by the mouth and letting them suffocate in the hold of a boat, boiling lobsters alive. My point is not to make a moral case for vegetarianism but to shed light on the mindset of human violence and cruelty. History and ethnography suggest that people can treat strangers the way we now treat lobsters, and our incomprehension of such deeds may be compared with animal rights activists’ incomprehension of ours. It is no coincidence that Peter Singer, the author of The Expanding Circle, is also the author of Animal Liberation.
The observation that people may be morally indifferent to other people who are outside a mental circle immediately suggests an opening for the effort to reduce violence: understand the psychology of the circle well enough to encourage people to put all of humanity inside it. In earlier chapters we saw how the moral circle has been growing for millennia, pushed outward by the expanding networks of reciprocity that make other human beings more valuable alive than dead.56 As Robert Wright has put it, “Among the many reasons I don’t think we should bomb the Japanese is that they built my minivan.” Other technologies have contributed to a cosmopolitan view that makes it easy to imagine trading places with other people. These include literacy, travel, a knowledge of history, and realistic art that helps people project themselves into the daily lives of people who in other times might have been their mortal enemies.
We have also seen how the circle can shrink. Recall that Jonathan Glover showed that atrocities are often accompanied by tactics of dehumanization such as the use of pejorative names, degrading conditions, humiliating dress, and “cold jokes” that make light of suffering.57 These tactics can flip a mental switch and reclassify an individual from “person” to “nonperson,” making it as easy for someone to torture or kill him as it is for us to boil a lobster alive. (Those who poke fun at politically correct names for ethnic minorities, including me, should keep in mind that they originally had a humane rationale.) The social psychologist Philip Zimbardo has shown that even among the students of an elite university, tactics of dehumanization can easily push one person outside another’s moral circle. Zimbardo created a mock prison in the basement of the Stanford University psychology department and randomly assigned students to the role of prisoner or guard. The “prisoners” had to wear smocks, leg irons, and nylon-stocking caps and were referred to by serial numbers. Before long the “guards” began to brutalize them—standing on their backs while they did push-ups, spraying them with fire extinguishers, forcing them to clean toilets with their bare hands—and Zimbardo called off the experiment for the subjects’ safety.58
In the other direction, signs of a victim’s humanity can occasionally break through and flip the switch back to the sympathy setting. When George Orwell fought in the Spanish Civil War, he once saw a man running for h
is life half-dressed, holding up his pants with one hand. “I refrained from shooting at him,” Orwell wrote. “I did not shoot partly because of that detail about the trousers. I had come here to shoot at ‘Fascists’; but a man who is holding up his trousers isn’t a ‘Fascist,’ he is visibly a fellow creature, similar to your self.”59 Glover recounts another example, reported by a South African journalist:
In 1985, in the old apartheid South Africa, there was a demonstration in Durban. The police attacked the demonstrators with customary violence. One policeman chased a black woman, obviously intending to beat her with his club. As she ran, her shoe slipped off. The brutal policeman was also a well-brought-up young Afrikaner, who knew that when a woman loses her shoe you pick it up for her. Their eyes met as he handed her the shoe. He then left her, since clubbing her was no longer an option.60
We should not, however, delude ourselves into thinking that the reaction of Orwell (one of the twentieth century’s greatest moral voices) and of the “well-brought-up” Afrikaner is typical. Many intellectuals believe that the majority of soldiers cannot bring themselves to fire their weapons in battle. The claim is incredible on the face of it, given the tens of millions of soldiers who were shot in the wars of the last century. (I am reminded of the professor in Stoppard’s Jumpers who noted that Zeno’s Paradox prevents an arrow from ever reaching its target, so Saint Sebastian must have died of fright.) The belief turns out to be traceable to a single, dubious study of infantrymen in World War II. In follow-up interviews, the men denied having even been asked whether they had fired their weapons, let alone having claimed they hadn’t.61 Recent surveys of soldiers in battle and of rioters in ethnic massacres find that they often kill with gusto, sometimes in a state they describe as “joy” or “ecstasy.”62
Glover’s anecdotes reinforce the hope that people are capable of putting strangers inside a violence-proof moral circle. But they also remind us that the default setting may be to keep them out.
SECONDLY, DIFFIDENCE, IN its original sense of “distrust.” Hobbes had translated Thucydides’ History of the Peloponnesian War and was struck by his observation that “what made war inevitable was the growth of Athenian power and the fear which this caused in Sparta.” If you have neighbors, they may covet what you have, in which case you have become an obstacle to their desires. Therefore you must be prepared to defend yourself. Defense is an iffy matter even with technologies such as castle walls, the Maginot Line, or antiballistic missile defenses, and it is even iffier without them. The only option for self-protection may be to wipe out potentially hostile neighbors first in a preemptive strike. As Yogi Berra advised, “The best defense is a good offense and vice versa.”
Tragically, you might arrive at this conclusion even if you didn’t have an aggressive bone in your body. All it would take is the realization that others might covet what you have and a strong desire not to be massacred. Even more tragically, your neighbors have every reason to be cranking through the same deduction, and if they are, it makes your fears all the more compelling, which makes a preemptive strike all the more tempting, which makes a preemptive strike by them all the more tempting, and so on.
This “Hobbesian trap,” as it is now called, is a ubiquitous cause of violent conflict.63 The political scientist Thomas Schelling offered the analogy of an armed homeowner who surprises an armed burglar. Each might be tempted to shoot first to avoid being shot, even if neither wanted to kill the other. A Hobbesian trap pitting one man against another is a recurring theme in fiction, such as the desperado in Hollywood westerns, spy-versus-spy plots in cold-war thrillers, and the lyrics to Bob Marley’s “I Shot the Sheriff.”
But because we are a social species, Hobbesian traps more commonly pit groups against groups. There is safety in numbers, so humans, bound by shared genes or reciprocal promises, form coalitions for protection. Unfortunately, the logic of the Hobbesian trap means there is also danger in numbers, because neighbors may fear they are becoming outnumbered and form alliances in their turn to contain the growing menace. Since one man’s containment is another man’s encirclement, this can send the spiral of danger upward. Human sociality is the original “entangling alliance,” in which two parties with no prior animus can find themselves at war when the ally of one attacks the ally of the other. It is the reason I discuss homicide and war in a single chapter. In a species whose members form bonds of loyalty, the first can easily turn into the second.
The danger is particularly acute for humans because, unlike most mammals, we tend to be patrilocal, with related males living together instead of dispersing from the group when they become sexually mature.64 (Among chimpanzees and dolphins, related males also live together, and they too form aggressive coalitions.) What we call “ethnic groups” are very large extended families, and though in a modern ethnic group the family ties are too distant for kin-based altruism to be significant, this was not true of the smaller coalitions in which we evolved. Even today ethnic groups often perceive themselves as large families, and the role of ethnic loyalties in group-against-group violence is all too obvious.65
The other distinctive feature of Homo sapiens as a species is, of course, toolmaking. Competitiveness can channel toolmaking into weaponry, and diffidence can channel weaponry into an arms race. An arms race, like an alliance, can make war more likely by accelerating the spiral of fear and distrust. Our species’ vaunted ability to make tools is one of the reasons we are so good at killing one another.
The vicious circle of a Hobbesian trap can help us understand why the escalation from friction to war (and occasionally, the de-escalation to detente) can happen so suddenly. Mathematicians and computer simulators have devised models in which several players acquire arms or form alliances in response to what the other players are doing. The models often display chaotic behavior, in which small differences in the values of the parameters can have large and unpredictable consequences.66
As we can infer from Hobbes’s allusion to the Peloponnesian War, Hobbesian traps among groups are far from hypothetical. Chagnon describes how Yanomamö villages obsess over the danger of being massacred by other villages (with good reason) and occasionally engage in preemptive assaults, giving other villages good reason to engage in their own preemptive assaults, and prompting groups of villages to form alliances that make their neighbors ever more nervous.67 Street gangs and Mafia families engage in similar machinations. In the past century, World War I, the Six-Day Arab-Israeli War, and the Yugoslavian wars in the 1990s arose in part from Hobbesian traps.68
The political scientist John Vasquez has made the point quantitatively. Using a database of hundreds of conflicts from the past two centuries, he concludes that the ingredients of a Hobbesian trap—concern with security, entangling alliances, and arms races—can statistically predict the escalation of friction into war.69 The most conscious playing-out of the logic of Hobbesian traps took place among nuclear strategists during the cold war, when the fate of the world literally hinged on it. The logic produced some of the maddening paradoxes of nuclear strategy: why it is extraordinarily dangerous to have enough missiles to destroy an enemy but not enough to destroy him after he has attacked those missiles (because the enemy would have a strong incentive to strike preemptively), and why erecting an impregnable defense against enemy missiles could make the world a more dangerous place (because the enemy has an incentive to launch a preemptive strike before the completed defense turns him into a sitting duck).
When a stronger group overpowers a weaker one in a surprise raid, it should come as no surprise to a Hobbesian cynic. But when one side defeats another in a battle that both have joined, the logic is not so clear. Given that both the victor and the vanquished have much to lose in a battle, one would expect each side to assess the strength of the other and the weaker to cede the contested resource without useless bloodshed that would only lead to the same outcome. Most behavioral ecologists believe that rituals of appeasement and surrender among animals evolved for this rea
son (and not for the good of the species, as Lorenz had supposed). Sometimes the two sides are so well matched, and the stakes of a battle are so high, that they engage in a battle because it is the only way to find out who is stronger.70
But at other times a leader will march—or march his men—into the valley of death without any reasonable hope of prevailing. Military incompetence has long puzzled historians, and the primatologist Richard Wrangham suggests that it might grow out of the logic of bluff and self-deception.71 Convincing an adversary to avoid a battle does not depend on being stronger but on appearing stronger, and that creates an incentive to bluff and to be good at detecting bluffs. Since the most effective bluffer is the one who believes his own bluff, a limited degree of self-deception in hostile escalations can evolve. It has to be limited, because having one’s bluff called can be worse than folding on the first round, but when the limits are miscalibrated and both sides go to the brink, the result can be a human disaster. The historian Barbara Tuchman has highlighted the role of self-deception in calamitous wars throughout history in her books The Guns of August (about World War I) and The March of Folly: From Troy to Vietnam.
A READINESS TO inflict a preemptive strike is a double-edged sword, because it makes one an inviting target for a preemptive strike. So people have invented, and perhaps evolved, an alternative defense: the advertised deterrence policy known as lex talionis, the law of retaliation, familiar from the biblical injunction “An eye for an eye, a tooth for a tooth.”72 If you can credibly say to potential adversaries, “We won’t attack first, but if we are attacked, we will survive and strike back,” you remove Hobbes’s first two incentives for quarrel, gain and mistrust. The policy that you will inflict as much harm on others as they inflicted on you cancels their incentive to raid for gain, and the policy that you will not strike first cancels their incentive to raid for mistrust. This is reinforced by the policy to retaliate with no more harm than they inflicted on you, because it allays the fear that you will use a flimsy pretext to justify a massive opportunistic raid.