Q&A for a History of Mankind (31)

The cousin marriage debate again, plus questions on Meta-Ethnic Frontiers, the Eve theory of Consciousness, Chamberlain, Adam Tooze, Coding & Guns

This is the thirty-first Q&A for History of Mankind. Paying subscribers received an email asking for questions; and those are right below the paywall.

As usual, a quick reminder: all new paying subscribers get an electronic copy of my 2023 book ”Emperor Whisperers: a comparative history of ancient Western and Chinese philosophy” (also available here).

Before we get to subscribers’ questions, I’d like to highlight a four-year-old paper I recently came across, which again looks at the subject of the prevalence of cousin marriage in ancient societies, an issue about which I’ve written quite a bit already (I know), and about which I promise to shut up going forward.

Like I explained in Farmers Vs Herders, almost three years ago now, the Indo-European ancestors of modern peoples of European descent were patrilocal and practiced exogamy – that is, they protected property along the male line, like most other societies, but also were very open to exchanging brides between clans and tribes. This is a distinct European preference that eventually set societies in the continent apart from those in the Fertile Crescent, more averse to marrying their women to outsiders; these, over time became more and more open to cousin marriage, the ultimate way to isolate groups from potential hostiles:

Livy reports that in ancient Rome marriages within the seventh degree of relationship were not permitted. The ban remained in place by the mid-Republic, reinforcing social cohesion as it decreased clannish propensions. Persistent aversion to cousin marriage appears to have been an Indo-European super-power; in India, Aryan invaders brought with them an aversion with cousin marriage that, faced with cousin-marriage tolerance among the older Dravidian population, only eroded over time: the Manusmriti, a compilation of Aryan laws first written down in around the 2nd century AD, forbids marriage between a man and the daughter of his maternal uncle or paternal aunt; Medatithi, a 10th century commentator on the text, stated that such cross-cousin marriages are against dharma; but Madhava, a 14th century commentator who apparently lived in a part of South India where such marriages were socially accepted, already objected against the ban, citing Vedic passages and custom. As of the 21st century AD, still around 10% of marriages involve first- or second-degree cousins – but early on it was far from an exclusively Indo-European trait: in the 2021 Nature paper “Parental relatedness through time revealed by runs of homozygosity in ancient DNA,” Harald Ringbauer et al looked at genomic data from 1,785 ancient humans who lived in the last 45,000 years, and detected low rates of first cousin or closer unions across most ancient populations, with only around 3% of them being cousins.

In recent years, Joseph Henrich gained a lot of fame with misleading claims on the role of the Christian Church and the Judeo-Christian tradition when it comes to regulations against first-cousin marriage in European societies. These claims essentially amount to stating that it was the Church, rather than pre-existing Indo-European customs, that did away with cousin marriage in Europe. I expressed severe criticism of this view here.

My criticism was echoed in a recent Substack essay, where Emil Kirkegaard pointed to various other people who attacked Henrich’s conclusion. I certainly recommend reading the essay:

Why did NW Europeans become WEIRD?

In that piece, Kirkegaard also cited a paper that I didn’t know of, and that I’ve found very interesting: “Human inbreeding has decreased in time through the Holocene,” by Francisco C. Ceballos et al (Current Biology, 2021), concluding that the contemporary Middle East’s social preference for cousin marriage is clearly evident in their study of 411 genomes from the last 15,000 years.

In the paper, the authors find that inbreeding has decreased over time pretty much everywhere else, and yet they find an “excess of individuals with high autozygosity” in the Middle East, which could be attributed to consanguinity, rather than drift-related processes such as caste endogamy: “This result is consistent with documented cultural preferences for first-cousin matings in some contemporary societies.”

This is pretty clear evidence of the role of Islam (all the groups cited as having high rates of cousin marriage are overwhelmingly Muslim), the religion with the strongest attachment to its traditional Semitic roots, in spreading and supporting the custom.

Now for the questions from paying subscribers, on Meta-Ethnic Frontiers, the Eve theory of Consciousness, Chamberlain, Adam Tooze, Coding & Guns.