By Steven Pinker.

Christmas gift. 700 pages of small print can be summed up neatly by the subtitle of the book: Violence has declined. There are a lot of interesting nuggets and turns of phrase in this book, but there really could be more editorial restraint.

I spent 4 months trying to read this book, and stalled out on page 377. Though part of that stall is due to the release of the latest Zelda, Tears of the Kingdom game. I learned something about consuming books like this: life is too short to read every word. Glean something and move on. You won’t remember it all anyways!

It’s on my list to follow up from interesting “paradox of probability” on page 202: Suppose you live in a place that has a constant chance of being struck by lightning at any time through the year. Suppose that the strikes are random: every day the chance of a strike is the same, and the rate works out to one strike a month. Your house is hit by lightning today, Monday. What is the most likely day for the next bold to strike your house?” Answer: Tomorrow, Tuesday. “Almost no one gets this right.” and I agree.

1. A Foreign Country

The past was violent. Full of gory examples of how terrible us humans are to each other throughout most of history. Reminded me of Dan Carlin’s Hardcore History podcast Painfotainment episode.

2. The Pacification Process

• The logic of violence. Hobbes and Darwin philosophies on society.
• Violence in human ancestors. Groups of chimpanzees will kill solitary chimpanzees in neighboring territory.
• Kinds of human societies.
• Rates of violence in state and nonstate societies. Good charts. State societies are less violent than non-state. Unsurprising.
• Civilization and its Discontents.

3. The Civilizing Process

• Why is it rude to use your knife to help guide food onto your fork while eating? Aha moment halfway through the chapter but spoiler: etiquette has evolved to prevent people from stabbing each other at the table.
• European homicide decline. Norbert Elias wrote The Civilizing Process in 1939, showed a shocking 100-fold decline in violence from 13 to 20th centuries, and inspired the author to write this book.
• Explaining the European homicide decline. Men are responsible for 92% of killings. Man on man killing declined much more than domestic violence. Elias’ Standards of Propriety. Consolidation of state governments. Societal trust.
• Violence and class. Violence higher for the poor, feel like have to take justice into their own hands.
• Violence around the world.
• Violence in the United States. USA has 5 times the violence of England. We have a lot of guns.
• Decivilization in the 1960s. Homicide rate doubled. Many factors.
• Recivilization in the 1990s. (Not because of abortion.) We put a lot of people in jail (fivefold increase). Better policing. A wave of “civilizing offensives” because people were tired of the violence.

4. The Humanitarian Revolution

Meh. Skimmed.

5. The Long Peace

• Statistics and Narratives. Trends in war are random and declining as a whole.
• Was the 20th century really the worst? 14 of 20 most deadly events were before 20th century. Adjusted for population, the worst was the An Lushan Revolt, 8th Century China’s Tang Dynasty. Ghenghis Khan: “The greatest joy a man can know is to conquer his enemies and drive them before him. To ride their horses and take away their possessions. To see the faces of those who were dear to them bedewed with tears, and to clasp their wives and daughters in his arms.” Whoa.
• The statistics of Deadly Quarrels:
  • Timing of wars. Richardson measured “deadly quarrels” of “malice aforethought”, which is a squishy problem. Randomness is clumpy (doesn’t look random). Start of wars is a Poisson distribution, same with the stop of wars. Clearly the author is a statistics nerd: “The possibility that war might decline over some historical period, then, is alive. It would reside in a non-stationary Poisson process with a declining rate parameter.”
  • Magnitude of wars. Is a power-law relationship (a straight line on log/log plot), same as city populations.
• The trajectory of European war. 4 phases: Skirmishes, Wars of Religion, French Troubles, and World Wars.
• The Hobbesian Background and the Ages of Dynasties and Religions. Three principle causes of quarrels. Funny bit about troubles with succession.
• The long peace:
  • Some numbers. Since WWII: Zero counts of many war categories. E.g. nuclear devices. Great powers fighting. Ha, he says “developed countries expanding their borders by conquering another country.” Have to update that to some fraction of Ukraine.
  • Attitudes and Events. We’ve changed our attitudes towards war. Required service and military personnel counts are down.
  • A nuclear peace? Hopefully we get to a nuclear-weapon-free world.
  • A Democratic peace? Ha, a list of possible counterexamples to democracies that have fought each other. Clearly democracies are much more peaceful to each other and to others.
  • A Liberal peace? (“liberal” in the sense of political and economic freedom.) Gentle commerce. Seems like there is good correlation.
  • A Kantian peace? Does a “global government” like NATO prevent wars? Not completely but yes a strong correlation.

6. The New Peace

The long peace is since WWII. The new peace is since ~1990. Why do we think the world is worse now? “But mainly, I think, it comes form the innumeracy of our journalistic and intellectual culture.”

• The trajectory of war in the rest of the world. PRIO Battle Deaths Dataset began in 1946, measures battles in entire world, not just Euro-Centric. Big drop off after WWII, and interstate war in general. War is “development in reverse”. Part of decline of death due to a “burst of peacekeeping” (e.g. Child Survivor Revolution). Civilians suffer around half of deaths in war, that hasn’t changed over time. There are fewer deaths during wars in the developing world now. Note that North Vietnam willing to lose 10x soldiers to hold out against USA, and they did.
• The trajectory of genocide. Low-cost ways of killing many people… Fill a barge with people, submerge it for 30 minutes, dump them out, then load it with more people. Put 100s or thousands of people in a big room, lock the doors, and leave it without food or water for 15 days. People in genocide are treated terribly. Sometimes genocide is like “clearing the brush” to get land or resources. Other times just gotta kill everyone, or their kids grow up and get revenge. Genocide has killed more people than wars. Utopian ideas invite genocide. Most genocide caused by communist & authoritarian regimes & Marxist ideologies. Not great data but big spike of genocide from 1915 - 1965 with big spike in WWII. Predictive of genocide: Stable government, democracy, interstate commerce, “humanistic ruling philosophies”. Not predictive of genocide: Ethnic diversity & economic conditions.
• The trajectory of terrorism. “Worldwide death toll from terrorism is in the noise.” “In every year but 1995 (Oklahoma City bombing) & 2001 (9/11), more people die of lightning, deer, peanut allergies, bee stings, etc. Fear of terrorism can cause more deaths, e.g. they drive instead of flying even though flying is much safer.
• Where angels fear to tread. Violence in the Muslim world has not declined in the last few decades like the non-Muslim world has. Climate change is unlikely to cause war. Future violence isn’t predictive, but follows power-law curve. Violence is much less likely, but there is a chance for random spikes.