Book summary “The better angels of our nature”: summary

Introduction

You likely believe that you live in an exceptionally violent era. Daily news feeds deliver a relentless stream of war, terrorism, crime, and cruelty, which leads you to conclude that humanity is morally degenerating. This impression shapes your worldview, your politics, and your fears for the future.

Statistical analyses and historical trends demonstrate that violence has declined across all scales over the course of human history.

Steven Pinker argues in The Better Angels of Our Nature that this widespread pessimism is an illusion. You are actually living in the most peaceable era in our species' existence. The apparent surge in awareness of violence stems not from its increase, but from our heightened sensitivity to it and our instant global communication.

To understand how this transformation happened, you must examine the deep history of human behavior. The book maps this transition through six major historical trends that chart the decline of violence from prehistoric raids to modern human rights movements. It investigates the five psychological motives that drive violence, known as your inner demons, and contrasts them with four better angels of your nature that foster cooperation. Finally, it analyzes the five historical forces that have successfully strengthened these peaceable faculties over the centuries.

You will find answers to several crucial questions as you read further. How deadly were ancient societies compared to modern states? What mechanisms drove the dramatic fall of homicide rates in Europe? How did Enlightenment thinkers abolish institutionalized torture and slavery? Which forces created the relative stability of the modern world?

1. A Foreign Country

Prehistoric and ancient societies experienced extraordinarily high rates of violent death compared to modern industrialized nations.

You might imagine the distant past as a golden age of peace before modern states corrupted human relations. Historical records and archaeological findings reveal a drastically different reality. Prehistoric life was dominated by chronic conflict, raids, and sudden attacks.

Discoveries of ancient remains frequently bear forensic evidence of violent death. Ötzi the Iceman, a 5000 years old body found in the Tyrolean Alps, was discovered with an arrowhead embedded in his shoulder, unhealed hand cuts, and blood from four different people on his equipment. Kennewick Man, dated at 9400 years old, likewise displays signs of traumatic injury.

Human Prehistory and Early Violence

Early humans faced constant mortal danger from rival groups. Skeletal remains from multiple archaeological sites show high proportions of injuries caused by weapons.

The Historical Reality of Biblical and Classical Warfare

Archaic literature and sacred texts depict total warfare as a normal part of existence. Homer's epics portray wars aimed at the complete annihilation of enemy populations, alongside widespread pillaging and the enslavement of women. King Agamemnon outlines plans to leave not a single Trojan alive, down to babies in their mothers' wombs, while female captives serve as routine spoils of war.

The Hebrew Bible contains numerous accounts of divinely commanded genocides, massacres, and brutal punishments. Moses becomes enraged that soldiers spared female captives after a battle with the Midianites and commands them to kill every male child and every woman who has known man, keeping virgin girls alive for themselves.

Atrocitologist Matthew White estimates that specifically enumerated mass killings in the Bible total 1.2 million deaths, excluding the approximate 20 million added victims of the Noachian flood.

2. The Transition to States

The emergence of centralized states acting as a Leviathan successfully reduced internal rates of violence and homicide among subjects.

In evolutionary biology, violence is not a mindless urge or thirst for blood, but a strategic tool deployed when expected benefits outweigh costs. Because other organisms can fight back and inflict severe injury, natural selection disfavors indiscriminate attacks, leading intelligent species to use violence selectively based on cost-benefit analysis.

The Evolutionary Logic of Violence

Thomas Hobbes identified three principal causes of human quarrel in a state of nature: competition, diffidence, and glory. You can see how men use violence for gain through competition, for safety through preemptive strikes via diffidence or fear, and for reputation or credibility through glory or honor.

• Competition for resources
• Diffidence for safety
• Glory for reputation

These incentives create a Hobbesian trap or security dilemma where every party must strike first to avoid being destroyed. Fewer than a hundred words were used by Hobbes in Leviathan to lay out this analysis of violence incentives.

Violence in Human Ancestors and Nonstate Societies

Pre-state societies, including hunter-gatherers and horticulturalists, experience extraordinarily high rates of violent death compared to modern industrialized nations. Systematic reviews of archaeological data and ethnographic records show that sneaky raids, ambushes, and blood feuds result in massive casualties.

Helena Valero recounted a brutal Yanomamö raid in the Venezuelan rain forest where children were killed and impaled on bows, and William Buckley described Australian aborigines mutilating enemy bodies. Prehistoric archaeological sites show a 15 percent average death rate from violence, and contemporary hunter-gatherer societies show a 14 percent average death rate from warfare. Montenegrins suffered a 24.5 percent violent death rate.

The Leviathan Solution

A centralized government authority with a monopoly on force can lift societies out of violent anarchy by eliminating incentives for aggression. By penalizing aggressors and acting as a disinterested third party, the Leviathan defuses fears of preemptive attack and removes the need for individuals to maintain hair-trigger retaliation.

Early states functioned largely like protection rackets, extracting resources while imposing order to stop cycles of raiding and feuding that wasted economic productivity. Archaeological comparisons of Native American skeletons show that living in a civilization reduced an individual's chances of violent trauma fivefold, dropping from 13.4 percent of pre-Columbian hunter-gatherer skeletons to 2.7 percent of pre-Columbian city dweller skeletons.

An Auyana man in New Guinea under the Pax Australiana noted that life improved because men could walk out safely without fear of being shot.

3. The Civilizing Process

Historical court and county records reveal a massive, multi-century decline in homicide rates across Western Europe.

Ted Robert Gurr and Manuel Eisner compiled extensive historical data showing that homicide rates plummeted by factors of ten, fifty, or even a hundred across various English and European jurisdictions. This massive reduction occurred independently of modern medical advances and highlights a profound civilizing process in human behavior.

Homicide rates in Oxford dropped from 110 homicides per 100,000 people per year in the 14th-century to less than 1 homicide per 100,000 in mid-20th-century London. In England, the homicide rate reached 0.8 per 100,000 in the 1950s.

The European Homicide Decline

The historical decline of European homicide was driven by a psychogenetic shift from a culture of honor to a culture of dignity, where people learned to control impulses and exercise empathy. Over several centuries, Europeans increasingly anticipated long-term consequences and inhibited their immediate violent drives. This transformation originated in explicit behavioral instructions for elites and trickled down to all social strata until it became second nature.

Historical etiquette manuals reveal that medieval people possessed extremely crude habits regarding bodily functions, table manners, and violence. Works like Desiderius Erasmus's On Civility in Boys laid down strict rules against basic animalistic behaviors, demonstrating that modern standards of hygiene, refinement, and self-restraint had to be laboriously acquired over centuries.

Erasmus instructed readers not to blow their nose onto the tablecloth, not to spit into washing bowls, and not to gnaw on bones and put them back into the serving dish.

Civilizing Norms and Etiquette

The consolidation of centralized states with a monopoly on the legitimate use of force acted as an exogenous trigger to suppress feudal feuding. As monarchs built bureaucracies and national legal systems, homicide was redefined as an offense against the state rather than a private tort, making vendettas obsolete and rewarding courtly manners over violent prowess. Europe consolidated from 5,000 independent political units in the 15th century to 500 at the time of the Thirty Years' War in the early 17th century, 200 at the time of Napoleon in the early 19th century, and fewer than thirty in 1953.

King Henry I of England nationalized justice by redefining homicide as an offense against the crown, ensuring that fines and forfeitures went to the king instead of the victim's family.

The transition from a zero-sum agrarian economy to a positive-sum commercial market fostered empathy, impulse control, and mutual utility. Economic development, the division of labor, and the spread of money and trade made trading partners more valuable alive than dead, rewarding foresight, honesty, and perspective-taking over violent predation.

4. The Humanitarian Revolution

The Enlightenment sparked a rapid Humanitarian Revolution that successfully abolished torture, institutionalized sadism, and arbitrary state violence across the Western world.

Driven by explicit humanist arguments, reason, and an expanding capacity for empathy, society underwent a profound shift in sensibilities during the 17th and 18th centuries. This movement placed human life and happiness at the center of moral values, dismantling centuries of brutal penal practices.

Culture of Cruelty and Torture

Medieval and early modern European societies maintained an institutionalized culture of cruelty where torture, mutilation, and sadistic executions were publicly celebrated features of everyday life. Unlike clandestine modern human rights violations, medieval torture was woven into legal codes, secular governance, and church inquisitions to extract confessions, punish nonviolent infractions like heresy or blasphemy, and maximize agonizing physical suffering using specialized anatomical devices.

The Museo della Tortura in San Gimignano displays devices like Judas’s Cradle, the iron maiden, and The Pear, which were engineered to tear internal tissues and prolong victim suffering.

Superstitious Killings and Witchcraft

Witch hunts and superstitious persecutions were eventually extinguished through the rise of scientific skepticism, rational legal reforms, and an expanding moral abhorrence of inflicting suffering. Driven by cognitive biases, self-serving motives, and treatises like the Malleus Maleficarum, European societies tortured and executed tens of thousands of accused witches. Skeptical judges, rational demonstrations, and growing empathy eventually exposed these trials as moral abominations and eliminated them.

French and German witch-hunters killed 60,000 to 100,000 accused witches over two centuries, with 85 percent of the executed victims being women. In 1749, authorities burned the last woman executed as a witch in Europe. A German duke and a Milanese judge exposed the absurdity of torture-induced confessions by trapping Inquisitors into accusing respected officials and servants of impossible witchcraft acts.

Abolition of Cruel Punishments

The 18th century marked a revolutionary turning point when institutionalized torture and cruel punishments were systematically abolished in the West. Historically, brutal punishments served a practical deterrent function and satisfied public enjoyment of cruelty. Influenced by Enlightenment thinkers who appealed to human sympathy and the goals of social utility, reformers successfully argued that penal systems should deter rather than torture.

Jean Calas, a 64-year-old French Protestant falsely accused of killing his son, was tortured with the strappado and water torture and broken on the wheel before being strangled.

In his 1764 bestseller On Crimes and Punishments, Cesare Beccaria established the principle that criminal justice must aim at the greatest happiness and rely on swift, certain, and proportional penalties rather than severity. He argued that punishments are only legitimate if they deter people from inflicting greater harm. Following these insights, 15 major European countries plus the United States explicitly abolished judicial torture.

5. Slavery and Humanitarian Reform

Chatter slavery and debt bondage were dismantled by powerful mass movements driven by moral revulsion and philosophical arguments for liberty.

The Demise of Chattel Slavery

Chatter slavery was long accepted as a natural institution. It caused 1.5 million Africans to die in transatlantic slave ships between the 16th and 19th centuries, while total deaths in the slave trade reached between 17 million and 65 million.

While some economists debated the economic efficiency of slave labor versus paid employment, the definitive end of slavery required organized political action, international policing, and devastating wars. First-person slave narratives and abolitionist literature played a vital role in shifting public morality.

Harriet Beecher Stowe's novel Uncle Tom's Cabin depicted wrenching family separations and catalyzed the abolitionist movement in the United States.

The systemic punishment and imprisonment of financial debtors was successfully eliminated through legal reforms in the 19th century. Historically, defaulting on loans led to enslavement or overflowing debtors' prisons. In early-1820s to 1840 America, thousands of individuals languished in debtors' prisons, with half imprisoned for debts amounting to less than ten dollars. Almost every American state abolished debt bondage during this timeframe, and most European governments followed suit in the 1860s and 1870s.

Constitutional Separation of Powers

Early states were predominantly despotisms that exercised unchecked authority to murder subjects arbitrarily. Despots historically held a monopoly on lethal violence, using political murder as the primary mechanism for transferring power, and 1 in 8 European monarchs were murdered in office between 600 and 1800 CE.

The Mogul governor of Surat in India threw a sudden rage and ordered all dancing girls present to be decapitated on the spot.

To prevent governments from becoming predatory, Enlightenment designers instituted the separation of powers and federalist systems to let ambition counteract ambition. By dividing authority among 3 separate branches of government, the state could enforce internal peace without tyrannizing its citizens.

6. The Long Peace

The post-World War II era achieved an unprecedented Long Peace among major powers and developed countries.

John Mueller argues that an articulate antiwar movement, combined with a powerful wave of war literature and satire in the 1920s and 1930s, caused a psychological retuning where war was no longer seen as glorious or rational. World War I transformed cultural attitudes, thoroughly discrediting romantic militarism and establishing the notion that aggressive war is immoral, futile, and absurd.

Classic antiwar literature like All Quiet on the Western Front and satires like the Marx Brothers' Duck Soup and Charlie Chaplin's The Great Dictator held military culture up to ridicule and horror.

The Long Peace Zeroes

The post-World War II era has achieved an unprecedented Long Peace among major powers and developed countries, defined by a stunning cluster of zero values. The historical probability of experiencing such prolonged stretches without great power wars or nuclear weapon usage, given previous centuries of conflict, is extremely low, confirming a profound structural and psychological shift in international relations.

When the Soviet Union invaded Afghanistan in 1979, the United States responded not on the battlefield, but by withdrawing its team from the Moscow Summer Olympics.

Key historical indicators mark this period:

• 0 number of times nuclear weapons have been used in conflict
• 0 number of times the two Cold War superpowers fought each other on the battlefield
• 0 number of times great powers have fought each other since 1953
• 0 number of interstate wars fought between countries in Western Europe since World War II

Causes of the Long Peace

The freezing of national borders and the establishment of a territorial-integrity norm largely took territorial expansion off the table. The United Nations established the norm that existing borders are sacrosanct, framing any attempt to alter them by force as illegal aggression. Since territorial disputes historically drove most interstate wars, fixing boundaries reduced major conflicts despite creating certain local injustices.

Saddam Hussein invaded Kuwait in 1990, marking the sole time since 1945 that a UN member swallowed another whole, prompting a multinational coalition to swiftly push him out.

Democratic states are significantly less likely to engage in militarized disputes or wars with each other compared to nondemocratic regimes. Immanuel Kant first theorized that democracies externalize their internal consensual rule of law, share mutual trust because of transparent structures, and hold leaders accountable to citizens who bear the costs of war. Economic openness, international trade, and market capitalism exert a powerful pacifying effect on nations, often referred to as the Liberal Peace.

7. The New Peace

Civil wars, battle deaths, and interstate conflicts outside the West experienced a sharp decline in the late 20th century.

To objectively measure global conflicts over time, researchers rely on datasets that strictly count direct battle deaths rather than speculative indirect deaths. The PRIO Battle Deaths Dataset and similar records count direct fatalities from armed conflicts starting from 1946. Indirect deaths from disease or starvation are excluded because estimating them requires speculative simulations of alternate histories. The PRIO dataset lists every known armed conflict killing at least twenty-five people in a year, promoting those with a thousand deaths to wars.

The Trajectory of War in the Rest of the World

Colonial wars have completely vanished, and major interstate wars have become remarkably rare and less lethal. As empires dissolved in the greatest transfer of power in history, extrastate colonial wars disappeared. Meanwhile, interstate wars have plummeted in frequency and average death toll as developing regions increasingly embrace a peaceful rise. France attempted to retain Vietnam between 1946 and 1954, resulting in 375,000 battle deaths, and Algeria between 1954 and 1962, resulting in 182,500 battle deaths.

International peacekeeping missions dramatically reduce the risk that civil wars will reignite by breaking Hobbesian traps and enforcing compliance. Peacekeeping forces raise the material and reputational costs of aggression, verify that adversaries are not secretly rearming, and take over everyday policing. Even lightly armed or unarmed missions provide a vital tripwire and allow leaders to make concessions without losing face. Rebel leader Afonso Dhlakama signed a peace agreement in Mozambique partly because the UN treated him with respect and allowed him to attend cocktail parties.

The Trajectory of Genocide and Terrorism

Genocide, politicide, and democide target people for their group identity rather than their individual actions, causing massive civilian death tolls that historically rival or exceed those of conventional wars. Matthew White calculates that in the 20th century, 81 million people were killed by democide and 40 million by man-made famines, totaling 121 million deaths compared to 82 million deaths from wars. Statistical analyses by Rummel and Harff demonstrate that totalitarian regimes commit the vast majority of democides, whereas democracies are far less likely to perpetrate mass killings due to institutional checks and nonviolent conflict resolution.

Terrorist organizations virtually never achieve maximalist goals and almost always self-destruct or die out over time. Datasets compiled by political scientists Max Abrahms and Audrey Cronin demonstrate that the vast majority of terrorist groups fail to attain their strategic aims and typically last only between five and nine years before dissolving. The Red Brigades in Italy self-destructed in 1978 after kidnapping and murdering former prime minister Aldo Moro, which alienated their supporters and triggered an all-out state crackdown.

8. The Rights Revolutions

In the latter half of the twentieth century, a cascade of rights movements successfully stigmatized and criminalized various forms of violence and discrimination against vulnerable groups.

Steven Pinker terms this phenomenon the Rights Revolutions. Following the precedent of the Humanitarian Revolution, individual rights functioned as an escalator where prohibitions against violence expanded from mass atrocities down to hate crimes, domestic abuse, corporal punishment, and recreational violence.

To track this linguistic shift, Google Books digitized five million books, and the Bookworm program analyzed terminology used between 1948 and 2000. School districts banning dodgeball because it teaches children that winning involves hurting others exemplify the modern cultural revulsion against physical aggression.

Civil Rights and Racial Violence

Official government discrimination against ethnic minorities declined dramatically worldwide between 1950 and 2003, increasingly replaced by remedial policies. Political scientists Victor Asal and Amy Pate analyzed a dataset of 337 ethnic minorities across 124 countries, tracking the percentage of governments with discriminatory versus affirmative action policies.

Official state discrimination dropped sharply:

• 44 percent of governments had invidious discriminatory policies in 1950
• 19 percent of governments had invidious discriminatory policies by 2003

Governments shifted from imposing restrictive apartheid and exclusionary laws to implementing affirmative action, educational head starts, and racial quotas.

Women's Rights and Domestic Violence

The second wave of feminism, catalyzed by works like Susan Brownmiller's Against Our Will, revolutionized the legal and cultural treatment of rape. Feminist activism exposed how institutional structures trivialized or condoned rape. Susan Brownmiller's 1975 book Against Our Will documented the historical and cultural trivialization of rape and helped place rape law reform on the national agenda.

Legal reforms compelled criminal justice systems to treat sexual assault with extreme seriousness and achieved significant milestones:

• 50 out of 50 American states have outlawed marital rape
• rape crisis centers were established across nations
• mandatory arrest laws and protective orders were introduced

Rates of severe domestic assaults and intimate partner homicides experienced major declines in Western nations. Statistics from the U.S. Bureau of Justice show that intimate partner homicide rates dropped significantly between 1976 and 2005, with the risk of a man being killed by his partner dropping sixfold. Reported violence against women by intimate partners fell by nearly two-thirds from 1993 to 2005, and reported violence against men fell by nearly half during the same period.

Children's Rights and Animal Welfare

Between the 1870s and 1930s, middle- and upper-class parents in the West underwent a sacralization of childhood, making children economically worthless yet emotionally priceless. Society began viewing children as precious individuals requiring state and social protection from labor, abuse, and neglect. England passed the Infant Life Protection Acts in 1872 and 1897 to combat neglect.

In Manhattan in 1874, neighbors of abused orphan Mary Ellen McCormack used the American Society for the Prevention of Cruelty to Animals to rescue her via a creative habeas corpus petition, leading to the creation of the first child protection society.

The animal rights movement expanded significantly from the 1970s onward, transforming cultural attitudes and legal frameworks regarding animal welfare. Ruth Harrison published Animal Machines in 1964, and Peter Singer published Animal Liberation in 1975, which became a foundational text for the animal rights movement by arguing against the infliction of avoidable pain on sentient beings. Activists established concepts like speciesism and secured protections in research, entertainment, and agriculture, while 7 percent of people in the U.K. have maintained a vegetarian diet over the past two decades.

9. The Inner Demons

Human aggression stems from distinct neurobiological and social systems called inner demons rather than a single hydraulic urge.

Steven Pinker argues against the hydraulic theory of violence. Aggression does not build up an inner pressure that must be discharged. Instead, human violence stems from specific neurobiological and social systems with different environmental triggers and logics.

Taxonomy of Violence

You can categorize human violence into five distinct psychological roots:

• predation
• dominance
• revenge
• sadism
• ideology

Predation is simply the use of force as a means to an end. Dominance drives supremacy over rivals. Revenge seeks to repay harm in kind. Sadism derives joy from hurting. Ideology weaves motives into a destructive collective creed.

The Moralization Gap and Revenge

People involved in disputes systematically distort memories and details of harmful events to present themselves as innocent victims and their opponents as malicious perpetrators. Arlene Stillwell and Roy Baumeister asked students to retell an ambiguous story about a broken promise regarding coursework from alternating first-person perspectives. Both victims and perpetrators rewrote narratives in self-serving directions while neutral third parties remained objective.

The powerful human urge for revenge is an adaptive mechanism that deters others from exploiting you. Blood revenge is explicitly endorsed in 95 percent of the world's cultures. Revenge motivates 10 to 20 percent of worldwide homicides. Apache chief Geronimo described the intense joy of battle and victory while recalling his massacre of four Mexican army companies, viewing it as sweet revenge even after his nation was broken.

Ideological Violence and Conformity

The common belief in pure evil is a myth rooted in the psychological perspective of the victim. Evildoers from serial killers to political leaders never think they are doing wrong. They act according to what they feel are reasonable, moral circumstances and perceived provocations. Serial killer John Wayne Gacy, responsible for 33 boys kidnapped, raped, and murdered, rationalized his horrific actions by framing himself as kind, gentle, or victimized.

Ordinary people will inflict severe pain on strangers when instructed by an authority figure, heavily influenced by their immediate social milieu. Stanley Milgram polled psychiatrists who predicted almost no one would go to the maximum shock, but 65 percent of participants went all the way to 450 volts. Jerry Burger's 2008 replication showed that 70 percent of participants went to 150 volts.

10. The Better Angels

Human nature includes specific peaceable motives and cognitive faculties that can counterbalance aggressive impulses.

The faculties that orient you away from violence include empathy, self-control, a moral sense, and the faculty of reason. This reason allows you to step outside your parochial vantage points.

Empathy and Its Limits

Daniel Batson's empathy-altruism hypothesis demonstrates that genuine perspective-tracking prompts unselfish motivation to reduce another's suffering regardless of personal escape options. Through experiments involving a confederate named Elaine receiving shocks, researchers proved that when participants feel similarity and sympathy, they volunteer to take her place. You can see this effect clearly in cooperation rates:

• a 20 percent baseline cooperation rate in a Prisoner's Dilemma
• a 70 percent cooperation rate when participants were induced to feel empathy

Empathy has a dark side because it is parochial and directly conflicts with the foundational moral principle of fairness. Because empathy is easily triggered by attractive victims, kin, or personal identifiers, it leads you to subvert fair rules. Batson found that participants primed to empathize with a sick ten-year-old girl named Sheri actively opted for her to jump the medical queue ahead of other children who needed treatment more urgently.

Self-Control and Willpower

Self-control acts like a muscle that undergoes ego depletion when exerted and temporarily loses strength.

Roy Baumeister and collaborators demonstrated that engaging in tasks requiring willpower exhausts a limited mental resource. This depletion impairs your performance on subsequent unrelated self-control tasks and unmasks underlying individual differences.

Participants who were forced to resist eating chocolate chip cookies and had to eat radishes instead gave up much faster on unsolvable geometric puzzles. Cookie eaters spent an average of 18.9 minutes and made 34.3 attempts. Radish eaters managed only 8.4 minutes and 19.4 attempts after a fifteen minutes waiting period.

The Escalator of Reason

umeister and collaborators demonstrated that engaging in tasks requiring willpower exhausts a limited mental resource. This depletion impairs your performance on subsequent unrelated self-control tasks and unmasks underlying individual differences.

Participants who were forced to resist eating chocolate chip cookies and had to eat radishes instead gave up much faster on unsolvable geometric puzzles. Cookie eaters spent an average of 18.9 minutes and made 34.3 attempts. Radish eaters managed only 8.4 minutes and 19.4 attempts after a fifteen minutes waiting period.

The Escalator of Reason

Reason inherently compels you toward nonviolence because logic cannot distinguish between me and you or favor one individual over another. When you persuade someone not to harm you by appealing to reasons, you are caught in a logical commitment to avoid harming others as a general rule.

Rising abstract intelligence has accelerated an escalator of reason, helping to eradicate legally sanctioned moral atrocities and shift societies toward greater humanitarian concern. Historical leaders held compartmentalized, morally backward views because their intellectual spotlight did not rigorously scrutinize their traditions. Woodrow Wilson segregated federal employees and praised the Ku Klux Klan, while Winston Churchill defended punitive village destructions and expressed hatred toward Indians.

Reason serves as the supreme engine for moral progress because empathy and self-control possess inherent biological limitations. Adam Smith illustrated in The Theory of Moral Sentiments that you would not sacrifice your own minor misfortune to prevent a massive disaster to strangers based on empathy alone, but are compelled to do so by reason. That reason considers 100 millions of hypothetical Chinese lives used in Adam Smith's moral thought experiment through the eyes of an impartial spectator.

11. The Five Historical Forces

Exogenous forces operating in the practical and intellectual realms have engaged human mental faculties to drive down violence.

Historical declines in violence were catalyzed by exogenous triggers. These forces engaged human mental faculties over millennia:

• The Leviathan state monopoly on force
• Expanding commerce
• The feminization of cultures
• Cosmopolitanism
• The escalator of reason

The Leviathan and Gentle Commerce

A state with a monopoly on force acts as a consistent violence-reducer. It imposes penalties that flip the appeal of aggression toward peace. By introducing impartial penalties that outweigh the gains of aggression, a Leviathan alters the rational-actor arithmetic of the Pacifist's Dilemma.

Gentle commerce turns zero-sum warfare into positive-sum mutual profit. This removes the adversary's incentive to attack. Supported by infrastructure such as finance, transportation, and contract enforcement, commercial exchange sweetens mutual pacifism. Engaging in voluntary trade encourages agents to take each other's perspectives.

Feminization, the Expanding Circle, and Reason

Feminization reduces violence by shifting values away from male-dominated zero-sum competition, manly honor, and status-seeking. Males commit the vast majority of violent crimes, wars, and genocides driven by competition for sexual access and status. Tsutomu Yamaguchi survived both Hiroshima and Nagasaki, living for sixty-five years after surviving atomic blasts before his death at age ninety-three in 2010. He prescribed that only nursing mothers should be allowed to govern countries with nuclear weapons.

The expansion of the circle of sympathy through literacy, cosmopolitanism, and media helps humans inhabit the minds of others and reduces violence. Technological advances in publishing and transportation foster perspective-taking, allowing people to feel empathy for distant or diverse groups. The escalator of reason uses superrationality to treat different perspectives as equivalent. Reason purges superstitions and drives humanistic moral progress. It allows humans to ascend to an Olympian perspective where personal and others' interests are evaluated neutrally.

Conclusion

You live in the most peaceable era of our species' existence, where violence has declined across all scales from personal feuds to global wars.

This historical progress is not an accident of nature or a permanent biological guarantee. It is the fragile outcome of an ongoing contest between your innate destructive passions and your peaceable motives. Your inner demons of predation, dominance, revenge, sadism, and ideology constantly threaten to break through the thin veneer of civilization. They are checked only when external civilizing forces engage your better angels of empathy, self-control, reason, and a sense of fairness.

To maintain and extend this hard-won arc of historical improvement, you must consciously support the institutions and practices that keep violence at bay. You can apply the lessons of history to your daily choices and civic life through a few practical rules:

1. Strengthen the Leviathan by respecting the rule of law, supporting impartial police and judicial systems, and rejecting vigilantism or private vengeance.
2. Foster commerce and economic interdependence by engaging in mutually beneficial trade that makes peaceful cooperation more valuable than violent conflict.
3. Cultivate cosmopolitanism and reason by exposing yourself to different perspectives through literacy, travel, and historical education to expand your circle of empathy.
4. Champion the rights revolutions by recognizing the dignity of vulnerable groups, rejecting discrimination, and stigmatizing casual cruelty in all its forms.
5. Apply reason to your moral judgments by resisting romanticized narratives of violence, questioning tribal loyalties, and evaluating policies based on their practical reduction of human suffering.

You must guard against both naive complacency and cynical despair. The decline of violence shows that human institutions and human nature can improve when reason is applied to collective problems. By understanding the historical forces that shaped the modern world, you can help ensure that the better angels of our nature continue to prevail.

10 Key Ideas

1. Statistical analyses and historical trends demonstrate that violence has declined across all scales over the course of human history.
2. The emergence of centralized states acting as a Leviathan successfully reduced internal rates of violence and homicide among subjects.
3. Historical court and county records reveal a massive, multi-century decline in homicide rates across Western Europe.
4. The Enlightenment sparked a rapid Humanitarian Revolution that successfully abolished torture, institutionalized sadism, and arbitrary state violence across the Western world.
5. The post-World War II era achieved an unprecedented Long Peace among major powers and developed countries.
6. In the latter half of the twentieth century, a cascade of rights movements successfully stigmatized and criminalized various forms of violence and discrimination against vulnerable groups.
7. The common belief in pure evil is a myth rooted in the psychological perspective of the victim.
8. Empathy has a dark side because it is parochial and directly conflicts with the foundational moral principle of fairness.
9. Self-control acts like a muscle that undergoes ego depletion when exerted and temporarily loses strength.
10. Reason serves as the supreme engine for moral progress because empathy and self-control possess inherent biological limitations.