In The Better Angels Of Our Nature, evolutionary psychologist Steven Pinker claims humans have become less violent. He thinks we’ve never been more peaceful and that this trend towards peace has been sustained over the long term.
He finds evidence in declining rates of violent deaths per 100,000 of population, the elimination of customs such as human sacrifice, and the reduction of targeted violence such as lynching, pogroms, and spousal abuse. These changes arose from the rise of modern states, commerce, greater gender equality, cosmopolitanism and reason, despite the short-term setbacks of individual wars.
It’s impossible, however, to reach back into the past and calculate the proportion of people who died violent deaths with any precision. For instance, we lack global and historical data for intimate partner violence – likely the most common type of violence. Other forms of violence, such as colonial and criminal violence, are also systematically undercounted.
However one counts, the wars and genocides of the 20th Century were the deadliest in history. Using absolute rather than relative numbers, one dataset of war-related deaths since 1400 shows that violence might be cyclical rather than downwards trending. This shows that the choice of whether to use absolute or relative figures matters a great deal.
While relative estimates give us a better sense of the likelihood of dying a violent death in each period, they’re skewed by overall population size. Advances in commerce and medicine mean more of us live longer, so the proportion of violent death declines even as the number in absolute terms might increase. Thus, declining relative violence may have nothing to do with our declining propensity for violence and everything to do with medicine, wealth and technology.
For example, population growth, which isn’t wholly related to how violent we are, means that killing more people in absolute terms can still equate to killing fewer in relative terms. If one million Brits were killed in 1600, that would be a much higher relative rate than killing five million Brits today as the population is so much larger. So if we use only relative figures we appear to be getting more peaceful when in fact we’ve killed four million more people.
Can we achieve world peace?
A stronger case can be made that we’re getting more peaceful, just not over the long term. Data for the past two centuries is more robust, and contains evidence of declining battlefield deaths since around 1950 and fewer wars between great powers since 1600, but there are questions as to whether these are trends or merely cyclical moments.
It also remains the case that the data is skewed towards international wars and that civil wars, especially before 1950, are undercounted. Better data there would likely help the peace thesis by giving us a more accurate picture of the extent of civil conflict.
Signs of greater peacefulness are clearer regionally. Western Europe has experienced unprecedented peace since 1945 and violent conflict in Southeast Asia has declined significantly since the late 1960s, as it has in South America, though violent organised crime there has increased. These regional examples show that pockets of peace can be sustained for decades. If peace can be achieved in some times and places, then why not in all times and places?