In early November, a study published in the journal Science claimed to trace the whole social course of modernity — the decline of clan and tribe, the turn to nuclear families, the rise of individualism — back to Roman Catholicism’s opposition to incest.

The medieval church’s sweeping ban on cousin-marriage, the researchers argued, broke up traditional kinship networks and gave rise to new family patterns and eventually a new psychology — a less conformist, more individualist, very clearly modern mind-set that according to their research is much more common in regions that had sustained exposure to Catholicism before 1500 A.D.

“Practical men who believe themselves to be quite exempt from any intellectual influence,” runs a famous line from John Maynard Keynes, “are usually the slaves of some defunct economist.” This goes for practical modern people and deceased theologians as well: You may think that you don’t want to marry your cousin for sound reasons of genetic hygiene, but in fact you’re just following injunctions laid down by French ecclesiastics in the sixth century after Christ.

The Science study naturally provoked a certain discomfort among people disinclined to credit Western Christendom for anything save stained glass and inquisitions. The more interesting question, though, is what actual believing Christians should make of it, and of the larger genre to which it belongs: Historical accounts that emphasize our religion’s essential role in the making of the modern world, even as that same modernity has obviously been a time of dissolution for many people’s faith.