The Better Angels of Our Nature — Chapter-by-Chapter Outline

Author: Steven Pinker First published: 2011 Edition covered: Penguin Books U.S. paperback, published September 25, 2012 (ISBN 978-0-14-312201-2; 832 pages), read against the 2011 Viking first U.S. edition. I found no evidence in the accessible publisher, author, Google Books, Open Library, or library-catalog records of chapters added or removed between the 2011 Viking edition and the 2012 Penguin paperback. The structural units are an unnumbered Preface plus 10 numbered chapters; notes, references, and index are not outline units. Edition facts and table of contents were cross-checked against Penguin Random House, Steven Pinker's official book page, Open Library, Lancaster Theological Seminary Library, Salk Library, and Google Books.

Central thesis

Pinker argues that many forms of physical violence have declined over long stretches of human history: homicide, raiding, war, genocide, torture, slavery, capital punishment, domestic violence, child abuse, lynching, persecution of sexual minorities, and cruelty to animals. The claim is comparative and statistical, not sentimental: the decline is uneven, reversible, incomplete, and often easier to see in rates than in raw counts.

The book's explanation is psychological and institutional. Human beings have motives that can produce violence, but they also have motives that restrain it. Historical changes such as state authority, commerce, literacy, cosmopolitan media, women's empowerment, human-rights movements, and rational criticism have shifted incentives and norms so that the nonviolent motives more often prevail.

If human nature still contains motives for violence, what changed in history to give the peaceable motives more power?

Preface

Central question

Why does a book arguing that violence has declined need so much evidence, qualification, and explanation?

Main argument

The resistance to the thesis. Pinker begins from a predictable reaction: people surrounded by news of terrorism, murder, war, and cruelty find it hard to believe that the present may be less violent than the past. He treats this disbelief as psychologically understandable but empirically testable.

Rates, not impressions. The Preface sets up the book's method. Violence must be compared across time by using rates, denominators, and long-run datasets, not by recalling salient horrors. A growing population can contain more total victims while also giving any one person a lower chance of violent death.

Human nature and history. Pinker does not promise that human beings have become saints. The project is to explain how social arrangements can inhibit violent motives and strengthen self-control, empathy, moral concern, and reason.

Why the book is organized as a long argument. Pinker signals that the claim must be built in layers. The reader first has to see that the past was violent, then that the declines are measurable, then that they are psychologically intelligible. The Preface therefore previews the book's unusual combination of statistics, history, political theory, moral philosophy, and cognitive psychology.

Key ideas

• Vivid news and recent memory make the present feel unusually violent.
• A serious comparison requires rates per population, not only absolute counts.
• The book is about physical violence against sentient beings, not every metaphorical use of "violence."
• Progress does not mean smoothness, inevitability, or final victory.
• Explaining decline requires both history and psychology.
• A long book is necessary because the claim contradicts ordinary perception and many political intuitions.

Key takeaway

The Preface frames the book as an evidence-heavy answer to a counterintuitive empirical question: whether violence has declined, and why.

Chapter 1 — A Foreign Country

Central question

How violent was ordinary life in the past, and why do modern readers underestimate it?

Main argument

The shock of the past. Pinker opens with a tour through human prehistory, Homeric Greece, the Hebrew Bible, Rome, early Christianity, medieval knighthood, early modern Europe, honor cultures, and the twentieth century. The point is not that every past society was equally violent, but that practices now treated as monstrous were once normal, entertaining, sacred, lawful, or honorable.

Examples as moral contrast. The chapter uses familiar cultural materials: epic heroes slaughtering captives, biblical massacres, Roman spectacles, gruesome punishments, duels over insults, violent fairy tales, and casual domestic coercion. These examples show that modern revulsion is itself historically significant.

From anecdote to measurement. Chapter 1 does not rest the case on anecdotes. It prepares the reader for later chapters by showing why the baseline matters: people often compare today's worst events with a sanitized memory of the past.

The moral importance of changed sensibilities. Pinker also wants the reader to notice their own reaction. If torture, slavery, public executions, and ritualized cruelty now look barbaric, that reaction is evidence of a changed moral environment. The chapter turns repugnance into a clue: many people are less tolerant of violence than their ancestors were.

Key ideas

• The phrase "the past is a foreign country" becomes a warning against nostalgic moral memory.
• Violence was not only committed privately; it was often celebrated by law, religion, entertainment, and honor.
• Modern sensibilities make many historical practices hard to imagine as normal.
• The twentieth century was horrific, but its horrors must be compared proportionally and historically.
• The book begins with moral contrast before turning to statistical demonstration.
• A central danger is "presentism" in reverse: assuming modern horrors are uniquely revealing while past horrors were exceptional or exaggerated.

Key takeaway

The chapter makes the past strange enough that the question of declining violence becomes plausible rather than absurd.

Chapter 2 — The Pacification Process

Central question

Did the rise of states reduce the chronic violence of nonstate societies?

Main argument

The logic of violence. Pinker draws on Hobbes to argue that violence can be instrumentally rational under anarchy. Competition for resources, fear of preemptive attack, and reputation for toughness can produce raiding and revenge even among people who would prefer peace.

State authority as pacification. The chapter compares nonstate societies with early agricultural states and later governments. Pinker's claim is that when a state monopolizes legitimate force and punishes private violence, it can reduce feuding, raiding, and vendetta. This is the Leviathan argument.

The costs of civilization. Pinker does not deny that states create new harms: taxation, hierarchy, punishment, war, and domination. The narrower claim is that even flawed states tend to lower the individual risk of violent death compared with persistent anarchy.

Why pacification is ambivalent. The chapter is careful about the word "civilization." A state may pacify its subjects while exploiting them, and an empire may reduce local feuds while expanding organized war. Pinker's claim is comparative: when people cannot rely on courts, police, or enforceable contracts, they often protect themselves through threats, honor, and revenge.

Key ideas

• Nonstate societies can sustain cycles of revenge because no neutral authority can enforce settlements.
• Hobbes's "war of all against all" is treated as a strategic problem, not merely a bleak mood.
• Archaeology and ethnography are used to compare rates of violent death in state and nonstate societies.
• The first major decline is the move from chronic raiding to governed settlement.
• The Leviathan reduces private violence by making retaliation a public function.
• Pacification is not moral purification; it trades some forms of violence for others.
• The chapter introduces a recurring method: identify a strategic incentive for violence, then ask which institution changes that incentive.

Key takeaway

The first historical decline comes from replacing private vengeance with third-party authority.

Chapter 3 — The Civilizing Process

Central question

Why did homicide rates in Europe, and later in other regions, fall so sharply from the late medieval period onward?

Main argument

Elias's civilizing process. Pinker builds on Norbert Elias's thesis that state formation and courtly manners changed behavior from the outside in. As kings consolidated authority, nobles and commoners alike had more reason to control impulses, settle disputes legally, and cultivate reputations for restraint.

Commerce and self-command. Urban life, trade, and bureaucratic order made other people more valuable as partners than as targets. Violence became less useful and more costly. Manners, etiquette, and shame then helped internalize self-control.

Class, region, and recivilization. The chapter extends the homicide decline beyond elite Europe, while noting variation. It also addresses the mid-twentieth-century rise in crime, especially the 1960s spike, and the later decline in the 1990s. The civilizing process can reverse or stall when norms and enforcement weaken.

Manners as violence prevention. Elias's point is not that forks and etiquette directly save lives. It is that the same social pressures that make people monitor speech, bodily habits, anger, and sexual behavior also make impulsive violence less acceptable. Self-command becomes a public virtue before it becomes a private habit.

Key ideas

• European homicide rates fell by orders of magnitude over several centuries.
• Centralized justice reduced private feuds and honor violence.
• Etiquette mattered because self-control became socially rewarded.
• Commercial interdependence made peaceful exchange more attractive.
• The United States shows regional differences tied partly to honor cultures and state capacity.
• The 1960s crime rise is treated as a decivilizing episode, not a refutation of the long trend.
• The chapter links macro-history to micro-behavior: state formation changes what ordinary people must do to be respected.

Key takeaway

The civilizing process turns violence from a normal tool of status and retaliation into a socially punished failure of self-control.

Chapter 4 — The Humanitarian Revolution

Central question

How did societies come to reject public torture, slavery, religious persecution, human sacrifice, and other once-normal forms of institutional cruelty?

Main argument

From cruelty as spectacle to cruelty as scandal. Pinker surveys the decline of human sacrifice, witch hunts, blood libel, persecution of heretics, judicial torture, gruesome executions, capital punishment, slavery, despotism, and major war. The central change is moral: suffering that once seemed deserved, entertaining, or divinely required became shameful.

Enlightenment humanism and empathy. The chapter links the shift to literacy, print, travel, salons, correspondence, novels, and the Republic of Letters. These widened perspective-taking and made strangers' suffering easier to imagine. Pinker follows Lynn Hunt in treating the rise of human rights as partly a cultural revolution in sympathy.

Reason against sacred violence. Humanitarian reform also required arguments: if people are sentient and comparable, then torture, slavery, and arbitrary killing demand justification they cannot meet. Pinker contrasts this current with "blood and soil" reactions that sacralize tribe, territory, and purity.

The puzzle of timing. The practices in this chapter were ancient, yet many declined within a few centuries. Pinker uses that compression to argue that ideas, media, and moral networks can change norms faster than genes or material conditions alone would predict.

Key ideas

• Several cruel institutions declined rapidly in the eighteenth and nineteenth centuries.
• The chapter treats the Enlightenment as a moral-psychological shift, not just an intellectual fashion.
• Novels and print culture helped readers inhabit other minds.
• Humanitarian reform joined empathy with reasoned criticism of tradition.
• Abolitionism, anti-torture movements, and early pacifism are parts of one larger pattern.
• The decline of one cruelty often prepared the moral language for rejecting another.
• The chapter supplies the book's most important bridge between data and ideals: measurable declines can follow from changed moral imagination.

Key takeaway

The humanitarian revolution widened the circle of beings whose suffering counted as a public wrong.

Chapter 5 — The Long Peace

Central question

Why have great powers and developed states largely stopped fighting one another since World War II?

Main argument

Statistics and narratives. Pinker asks whether the twentieth century was uniquely violent and argues that raw death counts mislead unless adjusted for world population. He uses datasets and historical estimates of deadly quarrels to compare the timing, magnitude, and concentration of war deaths.

The trajectory of major war. The chapter traces European and great-power conflict through dynastic wars, religious wars, sovereign-state competition, nationalism, and totalitarian ideology. World War II is treated as catastrophic, but not as proof that war was historically increasing without limit.

Explaining the post-1945 break. The Long Peace names the absence of direct war among great powers after 1945. Pinker evaluates several explanations: nuclear deterrence, democracy, trade, international institutions, declining territorial conquest, memory of devastation, and changing norms about war's legitimacy. His favored explanation is broadly Kantian: democracy, commerce, and international organizations reinforce one another.

Why "peace" needs explanation. The chapter treats non-events as data. If great powers once fought repeatedly and then stopped doing so for decades, the absence of war is not empty space in the historical record; it is a pattern that needs causes. Pinker argues that historians and citizens often underrate peace because it has no battlefield images.

Key ideas

• Major wars are rare and lumpy, so explanation must handle both statistics and contingency.
• Proportional death rates change the ranking of history's worst conflicts.
• Great-power war declined after centuries of interstate rivalry.
• Nuclear deterrence may matter, but Pinker argues it is insufficient by itself.
• Democratic peace, liberal peace, and Kantian peace are treated as overlapping mechanisms.
• The Long Peace is an empirical pattern, not a prediction that major war is impossible.
• A central statistical problem is distinguishing a real trend from a lucky run in a domain where wars are rare but catastrophic.

Key takeaway

The Long Peace is Pinker's central modern example of institutions and norms making a formerly routine form of violence abnormal.

Chapter 6 — The New Peace

Central question

Has organized violence outside the developed great-power system also declined since the end of the Cold War?

Main argument

War beyond the great powers. Pinker turns from Europe and the great powers to civil wars, postcolonial conflicts, genocide, repression, and terrorism. The evidence is more recent and more fragile than in earlier chapters, but he argues that the post-Cold War world saw reductions in several forms of organized violence.

Genocide and mass killing. The chapter treats the twentieth century's state-sponsored atrocities as products of ideology, dictatorship, war, and administrative capacity. After the Cold War, the rate and scale of mass killing declined, though Rwanda, the Balkans, Darfur, and other cases show that the danger did not disappear.

Terrorism and fear. Terrorism receives separate treatment because it is psychologically powerful but statistically small compared with war, homicide, and genocide. Pinker argues that terrorism succeeds partly by using spectacular violence to distort public perception.

Humanitarian constraint after atrocities. Pinker also treats the postwar and post-Cold War world as one in which governments, NGOs, courts, journalists, and international organizations have become more likely to monitor and condemn mass killing. These institutions do not prevent every atrocity, but they change the political cost of open extermination.

Key ideas

• The New Peace refers mainly to the post-1989 decline in civil wars and organized conflict.
• Cold War patronage, decolonization, and weak states helped fuel earlier conflict.
• International peacekeeping, diplomacy, norms, and monitoring contributed to later declines.
• Genocide is not ancient savagery but often a modern state project.
• Terrorism is designed for attention and fear, making it easy to overestimate as a death risk.
• The New Peace is more tentative than the Long Peace because the time span is shorter.
• The chapter's caveats matter: recent improvement is not the same as a permanent law of declining conflict.

Key takeaway

The chapter extends the decline-of-violence thesis into recent global conflict while keeping stronger caveats about uncertainty and reversal.

Chapter 7 — The Rights Revolutions

Central question

How did the postwar human-rights movements reduce smaller-scale violence against disfavored groups?

Main argument

Rights as humanitarianism brought home. Pinker presents civil rights, women's rights, children's rights, gay rights, and animal rights as late-twentieth-century extensions of the humanitarian revolution. The targets are not only war and punishment, but lynching, pogroms, rape, battering, infanticide, spanking, bullying, gay-bashing, criminalization of homosexuality, and cruelty to animals.

Moral circles and social movements. The chapter emphasizes activism, law, journalism, education, and public shaming. Practices once defended as family discipline, local custom, masculine privilege, racial order, or harmless amusement became candidates for reform.

From history to psychology. The chapter bridges the historical evidence and the psychology chapters that follow. If violence declines across many domains, then the explanation must include mental faculties that can be redirected: empathy, self-control, moral judgment, and reason.

The scale shifts downward. After chapters on war, genocide, and state punishment, this chapter shows that violence also declines through changes in intimate and local authority: husbands, parents, teachers, police, employers, majorities, and pet owners lose some former permissions to dominate by force.

Key ideas

• Civil-rights activism delegitimized lynching, pogroms, and open racial terror.
• Feminist movements reframed rape and domestic violence as public wrongs rather than private matters.
• Children's-rights movements challenged infanticide, corporal punishment, abuse, and bullying.
• Gay-rights movements weakened the legal and social permission for persecution.
• Animal-rights campaigns widened concern beyond human beings.
• The rights revolutions show that moral progress can occur below the level of war and homicide statistics.
• Pinker treats social shame as a real historical force because it changes what respectable people and institutions will defend in public.

Key takeaway

The rights revolutions show the expanding circle moving into everyday hierarchies and private life.

Chapter 8 — Inner Demons

Central question

What psychological motives make violence possible in the first place?

Main argument

Against one-drive theories. Pinker rejects the idea of a single hydraulic aggression drive that builds up and must be discharged. Violence has multiple motives, and different institutions restrain different motives.

Five demons. Predation is instrumental violence used to get something. Dominance seeks status, sexual access, or control. Revenge deters future harm but fuels cycles of retaliation. Sadism is pleasure in suffering, often learned and escalated. Ideology makes unlimited harm seem justified by a sacred or utopian goal.

The moralization gap. Perpetrators often see themselves as provoked, righteous, or reluctantly defensive, while victims experience pure injury. This gap undermines the myth that most violence is committed by people who understand themselves as evil.

Key ideas

• Human beings are not uniformly violent, but they have several violence-producing motives.
• Instrumental violence can be rational when costs are low and benefits are high.
• Dominance and honor violence depend heavily on reputation.
• Revenge is morally satisfying because it presents harm as deserved.
• Sadism is rarer than other motives but can intensify through habituation and dehumanization.
• Ideology is especially dangerous because it moralizes violence in pursuit of purity or salvation.

Key takeaway

Violence declines only when societies understand and block the specific motives that make it tempting.

Chapter 9 — Better Angels

Central question

What psychological faculties can steer human beings away from violence?

Main argument

Four restraining faculties. Pinker identifies empathy, self-control, the moral sense, and reason as the better angels. Each can inhibit violence, but each has limits. Empathy can be parochial; self-control can weaken under stress; morality can sanctify cruelty; reason can serve bad premises as well as good ones.

Not a simple biology story. The chapter considers recent biological evolution but does not rely on it. The main argument is that stable institutions, literacy, schooling, norms, and incentives can bring existing faculties into wider and more consistent use.

Reason's special role. Reason can expose contradictions, detect reciprocal interests, challenge sacred taboos, and turn revenge into a problem to be solved. It does not replace emotion, but it can discipline moral emotions and widen their scope.

Key ideas

• Empathy makes another being's suffering psychologically present, but it is easier with identifiable and familiar victims.
• Self-control restrains impulses long enough for consequences and norms to matter.
• The moral sense can condemn violence, but it can also divide the world into sacred goods and enemies.
• Reason allows people to notice symmetry: others have interests comparable to one's own.
• Education and cognitive habits can strengthen the practical use of reason.
• Better angels are capacities, not guarantees; circumstances decide whether they prevail.

Key takeaway

The same human nature that permits violence also contains faculties that institutions and culture can recruit against it.

Chapter 10 — On Angels' Wings

Central question

Which historical forces have allowed the better angels to overcome the inner demons often enough to produce measurable declines in violence?

Main argument

Five forces. Pinker synthesizes the book around the Leviathan, gentle commerce, feminization, the expanding circle, and the escalator of reason. These are not independent laws of history; they are interacting forces that alter incentives, norms, and imagination.

The pacifist's dilemma. Peace can be exploited by aggressors unless enough institutions exist to punish aggression and protect cooperators. This is why Pinker does not defend unilateral innocence. The problem is to create systems in which restraint is rewarded and predation is costly.

Reflections on progress. The final chapter returns to contingency. Violence has declined before, but it can rise again. The appropriate conclusion is neither complacency nor fatalism, but attention to the institutions and ideas that have made violence less useful, less honorable, and less morally acceptable.

Key ideas

• The Leviathan reduces private violence through credible third-party enforcement.
• Gentle commerce makes living people more valuable as partners than as targets.
• Feminization reduces the prestige of male honor, dominance, and militarized values.
• The expanding circle extends concern to strangers, outgroups, children, women, minorities, and animals.
• The escalator of reason exposes cycles of violence as mutually destructive.
• No single force explains every decline; the argument is cumulative and plural.

Key takeaway

The book ends by arguing that peace is a historical achievement of incentives, institutions, norms, and reasoned moral expansion.

The book's overall argument

1. Preface — Pinker states the counterintuitive problem and explains why only long-run evidence can answer it.
2. Chapter 1 (A Foreign Country) — The book first defamiliarizes the past, showing how much violence earlier societies normalized.
3. Chapter 2 (The Pacification Process) — It then identifies the first major decline: the replacement of private vendetta by state authority.
4. Chapter 3 (The Civilizing Process) — It shows how centralized government, commerce, manners, and self-control reduced homicide.
5. Chapter 4 (The Humanitarian Revolution) — It traces the moral rejection of torture, slavery, persecution, and other institutional cruelties.
6. Chapter 5 (The Long Peace) — It moves to war among great powers and asks why that form of violence largely stopped after 1945.
7. Chapter 6 (The New Peace) — It broadens the analysis to recent civil wars, genocide, repression, and terrorism outside the great-power core.
8. Chapter 7 (The Rights Revolutions) — It shows the humanitarian logic expanding into race, gender, childhood, sexuality, and animal welfare.
9. Chapter 8 (Inner Demons) — It turns from historical trends to the motives that make violence psychologically available.
10. Chapter 9 (Better Angels) — It identifies the faculties that can restrain those motives: empathy, self-control, morality, and reason.
11. Chapter 10 (On Angels' Wings) — It synthesizes the historical forces that have shifted the balance toward restraint.

Common misunderstandings

Misunderstanding: Pinker says violence has disappeared.

The book repeatedly says violence remains real and can increase. Its claim is about comparative declines across many domains, not the absence of war, murder, oppression, or cruelty.

Misunderstanding: The decline is smooth or guaranteed.

Pinker emphasizes reversals: genocidal dictatorships, world wars, the 1960s crime rise, postcolonial civil wars, terrorism, and possible future catastrophes. Progress is conditional on institutions and norms.

Misunderstanding: The thesis depends only on raw body counts.

The book often uses rates per population because the question is the risk faced by people living in a given time and place. Absolute counts still matter morally, but they answer a different question.

Misunderstanding: Pinker says humans are naturally good.

Chapters 8 and 9 reject both pure optimism and pure pessimism. Human nature contains violent motives and restraining faculties; history changes which side has more leverage.

Misunderstanding: The state is simply good.

The Leviathan reduces private violence, but states can also wage war, punish brutally, and commit genocide. Pinker's argument depends on constrained, accountable authority, not state power as such.

Misunderstanding: Modernity automatically means peace.

Pinker distinguishes Enlightenment humanism, commerce, rights, and reason from modern ideologies of blood, soil, race, class, and utopia that intensified violence.

Misunderstanding: The book ignores domestic and symbolic hierarchies.

The rights revolutions chapter specifically treats violence against racial minorities, women, children, gay people, and animals. The book's scope is physical violence, not every form of injustice.

Central paradox / key insight

The book's central paradox is that violence can decline without human beings becoming harmless. The same species still has predatory, dominant, vengeful, sadistic, and ideological motives. What changes is the surrounding system: law, trade, literacy, public criticism, rights movements, women's status, and rational norms make violence less rewarding and less honorable.

The key insight is that moral progress can be real without being mystical. It can be measured in lower risks of violent death and cruelty, while also remaining fragile because the motives for violence have not disappeared.

The decline of violence is not the defeat of human nature; it is a change in which parts of human nature history rewards.

Important concepts

Violence

In the book's working sense, physical force or treatment that harms sentient beings: homicide, assault, rape, robbery, kidnapping, war, genocide, torture, corporal punishment, and similar acts.

Rates versus absolute numbers

The distinction between total victims and the chance that a person in a population will suffer violence. Pinker usually emphasizes rates when comparing eras with very different population sizes.

Pacification process

The decline in chronic raiding and feuding associated with the rise of states and their monopoly on legitimate force.

Leviathan

Hobbes's name for sovereign authority, used by Pinker for the state or justice system that deters private violence and replaces revenge with third-party enforcement.

Civilizing process

Norbert Elias's term for the long decline in homicide and impulsive violence as state formation, manners, commerce, and self-control reshaped behavior.

Humanitarian revolution

The early modern and Enlightenment-era rejection of institutional cruelties such as torture, slavery, human sacrifice, witch hunting, sadistic punishment, and religious persecution.

Long Peace

The post-1945 absence of direct war among great powers and developed states, set against earlier centuries in which major-power war was routine.

New Peace

The more tentative post-Cold War decline in civil war, interstate war outside the developed world, genocide, repression, and some forms of organized violence.

Rights revolutions

Postwar movements that reduced or delegitimized violence against racial minorities, women, children, gay people, and animals.

Inner demons

Pinker’s name for five motives that can produce violence: predation, dominance, revenge, sadism, and ideology.

Better angels

The four faculties that can restrain violence: empathy, self-control, the moral sense, and reason.

Moralization gap

The gap between perpetrators, who often see their actions as justified or provoked, and victims, who experience the same actions as unjust harm.

Gentle commerce

The idea that trade and economic interdependence make other people more valuable alive as partners than dead as enemies.

Feminization

The historical increase in women's interests, status, security, and influence, which Pinker associates with reduced honor violence and militarized values.

Expanding circle

The widening of moral concern from kin and tribe toward strangers, outgroups, humanity as a whole, and sometimes nonhuman animals.

Escalator of reason

Pinker’s term, drawing on Peter Singer's image, for the way reasoning can push people toward impartiality, reciprocity, and rejection of self-defeating violence.

Kantian peace

The cluster of democratic government, commerce, and international organization that Pinker treats as a major explanation for the Long Peace.

References and Web Links

Primary book and edition information

• Steven Pinker. The Better Angels of Our Nature: Why Violence Has Declined. Viking, 2011; Penguin Books paperback, 2012.
  • Penguin Random House U.S. paperback page
  • Steven Pinker's official book page
  • Google Books record
  • Open Library work and edition records with table of contents
  • Lancaster Theological Seminary Library catalog record with contents
  • Salk Library catalog record with contents

Background and overview

• Wikipedia overview of The Better Angels of Our Nature
• Steven Pinker's FAQ on definitions, data, objections, and explanations
• Steven Pinker, "Taming the devil within us," Nature, 2011
• Harvard Gazette: Pinker explains "The Long Peace"

Key ideas, data sources, and source works

• Thomas Hobbes. Leviathan, 1651.
  • Project Gutenberg edition
• Norbert Elias. The Civilizing Process.
  • Google Books record
• Lynn Hunt. Inventing Human Rights: A History. W. W. Norton, 2007.
  • W. W. Norton book page
• Peter Singer. The Expanding Circle: Ethics, Evolution, and Moral Progress.
  • Princeton research record
• Uppsala Conflict Data Program
• Correlates of War Project
• Our World in Data: homicide rates over the long term

Additional chapter summaries and study resources

These are secondary summaries and should be used alongside, rather than instead of, the original book.

• SuperSummary overview and plot summary
• Shortform summary preview
• Blinkist key-ideas summary
• Hannah Givens chapter-oriented review and summary