In almost all hunter-gatherer societies, 300 is about the maximum number of individuals that can live together before people start ripping each other’s heads off (and that is much better than our closest relative, the chimpanzee).
Yet humans were able to scale up and enjoy the benefits of modernity with one simple trick — religion. Heinrich cites the anthropologist Donald Tuzin, who investigated an unusual New Guinea tribe, the Arapesh, unusually living in a group of up to 2,500 without bloodshed; Tuzin found that they had developed beliefs about gods that allowed them, unlike their rivals, to nurture solidarity.
Religion allows humans to co-exist in much larger groups, but as Heinrich’s book argues, one particular religion was able to accelerate this on an unprecedented scale — Roman Catholicism. By banning marriage between cousins in particular, the medieval Church crushed the strength of clans and created a society in which people were willing to cooperate and share with strangers. WEIRD [Western Educated Industrialised Rich Democratic] societies.
Even today, people from countries in which cousin marriage was banned the longest still consistently donate more blood, give more to charity and are less likely to cheat in exams or avoid paying parking fines — and also have the most successful democracies. Those parts of western Europe in which the Catholic Church struggled to ban cousin marriage also, and not by coincidence, produced Don Corleone and Tony Soprano.
One result of this high-trust form of society was, of course, liberalism, an entirely novel worldview that relies on people thinking way beyond their clan, to far more abstract levels of society — even to humanity in the general.
Yet liberalism is still unnatural, after centuries, and most people are “default conservatives” — they believe that family should come before strangers, and countrymen before foreigners. They feel stung if their flag is burned or their ancestors mocked. However anti-social their own instincts, they, like Tony Soprano, feel an obligation to defend their country from external threats. Conservatism is our default setting, designed for a world that is dangerous and in which we need to be courageous, defend our family and group, defer to superiors and share acquisitions fairly. Liberalism, with its focus on individual rights, is a mutation.
Yet “social conservatism”, as we imagine it in the West, is not the same thing; like liberalism, it is an interpretation of Christianity, although a more disciplined (and perhaps less immediately enjoyable) one. Christianity is the most unnatural of self-disciplines; loving your enemies and laying down your life for non-kin go against all our instincts and Tony Soprano would never be foolish enough to do so. Sexual restraint, especially among powerful men, requires a role model as persuasive and powerful as St Paul, one who can overcome their Roman urge to dominate with guilt. …
Western social conservatism, like liberalism, is weird, and WEIRD. It takes discipline and education, and social conservatives tend to be highly conscientious and well-educated, partly because Christianity is complicated and requires great self-control.
So what happens when altruistic, high trust societies import large numbers of people from societies that are not that way? Much human behavior has genetic roots, so don’t be too glib in assuming the narrative is entirely correct on this matter.