What The Worldwide Decline In Violence Means About The Arc Of Unity

When you tell people that violence has declined over centuries, most react with disbelief. Some get angry. A few accuse you of minimizing current suffering. This reaction is understandable and wrong.

The evidence base for the long-term decline in violence is one of the most robust findings in the social sciences. It draws on archaeology, criminology, political science, epidemiology, and historical records spanning millennia. Let's walk through it systematically.

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The archaeological record tells a stark story. Studies of skeletal remains from prehistoric sites worldwide show rates of violent death between 10-25%, depending on the time period and region.

A 2013 study published in Science by Samuel Bowles examined archaeological and ethnographic evidence from 21 societies and estimated an average violent death rate of approximately 14% for prehistoric humans. For comparison, the violent death rate in the 20th century — including both World Wars and every genocide — was roughly 3%.

Lawrence Keeley's War Before Civilization documented that pre-state societies experienced warfare rates that dwarf anything in modern history when scaled to population size. The Crow Creek massacre in South Dakota (circa 1325 CE) killed nearly 500 people — roughly 60% of the village's population — in a single raid. Scale that up to the population of a modern nation and you get numbers that make World War II look proportionally mild.

This is not to minimize World War II. It's to contextualize the present.

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The most granular data comes from homicide records, particularly in Europe, where court and coroner records go back centuries.

Criminologist Manuel Eisner compiled data on homicide rates in Europe from 1200 CE to the present. His findings:

- England, 1200s: approximately 23 homicides per 100,000 people per year - England, 1600s: approximately 7 per 100,000 - England, 1900s: approximately 1 per 100,000 - England, 2000s: approximately 1 per 100,000

Similar patterns appear across Western Europe. Italy went from roughly 73 per 100,000 in the 1400s to about 0.6 today. The Netherlands from about 47 per 100,000 in the 1400s to 0.6 today.

These are not cherry-picked exceptions. The pattern is consistent across every Western European nation with sufficient records.

What drove the decline? Historian Norbert Elias called it the "civilizing process" — the gradual internalization of self-control, driven by the consolidation of state power (which monopolized legitimate violence), the growth of commerce (which created mutual dependency between strangers), and changes in manners and social expectations that made impulsive violence socially costly.

Steven Pinker, who compiled much of this data in The Better Angels of Our Nature, extended the analysis globally and identified several overlapping trends he calls the "Pacification Process," the "Civilizing Process," the "Humanitarian Revolution," the "Long Peace," the "New Peace," and the "Rights Revolutions." Each represents a distinct domain in which violence has declined.

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The post-1945 period has been called the "Long Peace" — the longest period without direct military conflict between major world powers in modern history. The great powers of the early 20th century — the kind of nations that had been fighting each other roughly every decade for centuries — have not gone to war with each other for 80 years.

War is not gone. Civil wars, proxy wars, and interventions continue. But the trend in battle deaths per capita is unmistakably downward:

- 1950s: roughly 240 battle deaths per million people per year (Korean War, French-Indochina War) - 1970s-80s: roughly 100-180 per million (Vietnam, Iran-Iraq, Soviet-Afghan War) - 2000s: roughly 10-30 per million - 2010s: roughly 5-20 per million (despite Syria)

The Uppsala Conflict Data Program — the gold-standard dataset for armed conflict — tracks every conflict globally. The number of active state-based conflicts has fluctuated, but battle deaths per capita have trended downward since the end of the Cold War.

This is not because human nature changed. It's because the cost of interstate war became catastrophic (nuclear weapons), the incentives for trade became enormous (economic interdependence), and international institutions — however flawed — created mechanisms for dispute resolution that didn't exist before.

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The decline extends beyond war and homicide:

Genocide and mass atrocity. The frequency and scale of genocides has decreased since mid-century, though they have not been eliminated. The Genocide Convention (1948), the International Criminal Court (2002), and the Responsibility to Protect doctrine (2005) have created at least partial accountability structures that didn't exist before.

Domestic violence. In nations with longitudinal data, reported rates of domestic violence have declined significantly. This is partly due to improved reporting (previously hidden violence becoming visible) and partly due to genuine cultural and legal change. In the U.S., intimate partner violence declined by approximately 63% between 1994 and 2012.

Violence against children. Corporal punishment of children has been banned in over 65 countries. The percentage of children experiencing physical punishment has declined in nearly every nation where data exists.

Capital punishment. More than 100 countries have abolished the death penalty in law or practice. In 1980, most nations retained it. The direction is clear.

Torture. While torture persists in many nations, the number of countries where it is legally sanctioned has decreased dramatically. International norms against torture are far stronger than they were even 50 years ago.

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If violence has declined so dramatically, why does it feel like the opposite?

1. The availability heuristic. We judge the probability of events by how easily examples come to mind. A single school shooting generates weeks of coverage and is seared into memory. The 10,000 schools where nothing violent happened today are invisible.

2. Negativity bias. Human cognition is wired to prioritize threats. A negative event carries roughly 2-3 times the psychological weight of an equivalent positive event. This served us when threats were local and immediate. In a globalized information environment, it means we're processing threats from everywhere simultaneously while registering almost no positive signals.

3. The expanding moral circle is self-defeating in perception. As we become more sensitive to violence, we notice more of it. A medieval person wouldn't have considered wife-beating newsworthy. We do. A 19th-century person wouldn't have considered sweatshop labor violent. Many of us do. Our expanding moral sensitivity means the same objective level of violence feels worse because more of it registers as unacceptable.

4. The news business model. News outlets compete for attention. Violence, conflict, and threat are attention magnets. The structural incentives of the information ecosystem systematically overrepresent violence and underrepresent peace.

5. Social media amplification. Every violent incident now has video, firsthand accounts, and global distribution within minutes. A bar fight in 1950 was a local event. A bar fight in 2025 is a viral video with 10 million views and a comment section where everyone argues about civilizational collapse.

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The declining violence trend maps directly to what philosopher Peter Singer calls the "expanding circle" of moral concern.

In deep prehistory, "us" meant immediate kin — maybe 30-50 people. Violence toward anyone outside that circle carried no moral weight.

Over time, the circle expanded: - Band to tribe (hundreds): shared language and mythology created broader solidarity. - Tribe to chiefdom (thousands): shared governance and resource management. - Chiefdom to state (millions): shared law, currency, and identity. - State to civilization (tens of millions): shared cultural and religious frameworks. - Civilization to humanity (billions): universal human rights declarations, international law, global communication.

Each expansion reduced the category of people it was acceptable to harm. Each expansion was resisted. Each expansion won — not completely, not irreversibly, but on net.

The decline in violence is a direct consequence of this expanding circle. The more beings that fall inside your moral boundary, the less violence you're willing to inflict or tolerate.

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Five factors consistently correlate with reduced violence across historical periods and regions:

1. Leviathan (state monopoly on violence). Functioning states reduce violence by making it expensive. If the state punishes murderers, the expected cost of murder rises. This only works when the state is constrained by law and accountability — otherwise, the state itself becomes the primary source of violence.

2. Commerce (gentle commerce thesis). Trade creates interdependence. You don't attack people you need as trading partners. The expansion of commercial networks historically correlates with declining violence between trading partners.

3. Feminization (influence of women in governance and culture). Societies with greater gender equality and more women in leadership positions are measurably less violent. This is partly because women are statistically less likely to endorse violence as a policy tool, and partly because the values associated with caregiving — empathy, negotiation, long-term thinking — gain more institutional weight.

4. Cosmopolitanism (exposure to other perspectives). Literacy, travel, media, and migration expose people to lives different from their own. This erodes parochialism and makes it harder to dehumanize people you've encountered through story, art, or interaction.

5. Reason and the escalator of reason. The application of logic to moral questions — "If it's wrong to hurt me, and you're similar to me, then it's wrong to hurt you" — progressively demolishes justifications for violence. Every expansion of the moral circle has been aided by rational argumentation.

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1. Name three forms of violence that were socially acceptable in your grandparents' generation that are unacceptable today. (Examples might include corporal punishment in schools, domestic violence as a "private matter," violent hazing.) 2. Name three forms of violence that are currently acceptable that you believe will be considered unacceptable in 50 years. 3. For each item in list 2, identify which of the five drivers above would most likely cause the shift.

The point: you are living inside the expanding circle. It hasn't stopped moving. The question is what you're doing to push it.

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The decline-in-violence thesis has legitimate critiques:

- It is not a law of physics. The trend can reverse. World War I happened during an era of optimism about peace. Nuclear weapons create the possibility of catastrophic violence at a scale that dwarfs anything in history. - It is not evenly distributed. Central America, parts of sub-Saharan Africa, and conflict zones remain deeply violent. The decline is real on average but not experienced by everyone. - Structural and slow violence persist. Poverty, pollution, medical neglect, and institutional racism kill people without anyone pulling a trigger. Whether these count as "violence" is a definitional debate, but the suffering is real. - Surveillance may suppress rather than eliminate. Some violence may have simply moved — to cyberspace, to economic coercion, to forms that don't leave visible marks.

These caveats are important. They do not overturn the core finding. They complicate it. Which is how reality works.

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If every person said yes — internalized the reality of declining violence and actively participated in the trends driving it:

- Homicide rates in the most violent countries begin converging with the least violent ones. Proven interventions (focused deterrence, violence interruption, economic opportunity) are funded and scaled. - The "Long Peace" between major powers extends and deepens. Nuclear arsenals are reduced. Conflict prevention replaces reaction. - The expanding moral circle accelerates. Animals, ecosystems, and future generations are brought inside the boundary of moral concern. - The perception gap closes. People understand that the world is getting less violent, which reduces fear-driven politics and the authoritarian impulse that feeds on perceived chaos.

The arc of history does not bend toward justice on its own. People bend it. And the record shows — clearly, across centuries, across every metric — that enough people have been bending it in the right direction to produce the least violent era humanity has ever known.

That's not cause for complacency. It's cause for confidence. The work works. Keep going.