The Decline of Violence

Since the beginning of our species, for instance, every known society has been based on the domination of women by men. (Rumors of past matriarchal societies abound, but few archaeologists believe them.) In the long view, women's lack of liberty has been as central to the human enterprise as gravitation is to the celestial order. The degree of suppression varied from time to time and place to place, but women never had an equal voice; indeed, some evidence exists that the penalty for possession of two X chromosomes increased with technological progress.
Even as the industrial North and agricultural South warred over the treatment of Africans, they regarded women identically: in neither half of the nation could they attend college, have a bank account, or own property. Equally confining were women's lives in Europe, Asia, and Africa. Nowadays women are the majority of U.S. college students, the majority of the workforce, and the majority of voters. Again, historians assign multiple causes to this shift in the human condition, rapid in time, staggering in scope. But one of the most important was the power of ideas --- the voices, actions, and examples of suffragists, who through decades of ridicule and harassment pressed their case. In recent years something similar seems to have occurred with gay rights: first a few lonely advocates, censured and mocked; then victories in the social and legal sphere; finally, perhaps, a slow movement to equality.
Less well known, but equally profound: the decline in violence. Foraging societies waged war less brutally than industrial societies, but more frequently. Typically, archaeologists believe, about a quarter of all hunters and gatherers were killed by their fellows. Violence declined somewhat as humans gathered themselves into states and empires, but was still a constant presence. When Athens was at its height in the fourth and fifth centuries BC, it was ever at war: against Sparta (First and Second Peloponnesian Wars, Corinthian War); against Persia (Greco-Persian Wars, Wars of the Delian League); against Aegina (Aeginetan War); against Macedon (Olympian War); against Samos (Samian War); against Chios, Rhodes, and Cos (Social War).
In this respect, classical Greece was nothing special --- look at the ghastly histories of China, sub-Saharan Africa, or Mesoamerica. Similarly, early modern Europe's wars were so fast and furious that historians simply gather them into catchall titles like the Hundred Years' War, followed by the shorter but even more destructive Thirty Years' War. And even as Europeans and their descendants paved the way toward today's concept of universal human rights by creating documents like the Bill of Rights and the Declaration of the Rights of Man and of the Citizen, Europe remained so mired in combat that it fought two conflicts of such massive scale and reach they became known as "world" wars. Since the Second World War, however, rates of violent death have fallen to the lowest levels in known history. Today, the average person is far less likely to be slain by another member of the species than ever before --- an extraordinary transformation that has occurred, almost unheralded, in the lifetime of many of the people reading this article. As the political scientist Joshua Goldstein has written, "we are winning the war on war." Again, there are multiple causes. But Goldstein, probably the leading scholar in this field, argues that the most important is the emergence of the United Nations and other transnational bodies, an expression of the ideas of peace activists earlier in the last century.
As a relatively young species, we have an adolescent propensity to make a mess: we pollute the air we breathe and the water we drink, and appear stalled in an age of carbon dumping and nuclear experimentation that is putting countless species at risk including our own. But we are making undeniable progress nonetheless. No European in 1800 could have imagined that in 2000 Europe would have no legal slavery, women would be able to vote, and gay people would be able to marry. No one could have guessed a continent that had been tearing itself apart for centuries would be free of armed conflict, even amid terrible economic times. Given this record, even Lynn Margulis might pause (maybe).
Preventing Homo sapiens from destroying itself à la Gause would require a still greater transformation --- behavioral plasticity of the highest order --- because we would be pushing against biological nature itself. The Japanese have an expression, hara hachi bu, which means, roughly speaking, "belly 80 percent full." Hara hachi bu is shorthand for an ancient injunction to stop eating before feeling full. Nutritionally, the command makes a great deal of sense. When people eat, their stomachs produce peptides that signal fullness to the nervous system. Unfortunately, the mechanism is so slow that eaters frequently perceive satiety only after they have consumed too much --- hence the all-too-common condition of feeling bloated or sick from overeating. Japan --- actually, the Japanese island of Okinawa --- is the only place on earth where large numbers of people are known to restrict their own calorie intake systematically and routinely. Some researchers claim that hara hachi bu is responsible for Okinawans' notoriously long life spans. But I think of it as a metaphor for stopping before the second inflection point, voluntarily forswearing short-term consumption to obtain a long-term benefit.