Brink Lindsey's Doubts

Brink Lindsey and I recorded the above conversation on fertility, wherein we agreed on a lot. Afterward, Brink wrote on two “points of difference”.

First, Lindsey doubts fertility is a cause, not consequence, of civ decay:

Robin is convinced that fertility decline was a frequent driver of civilizational decline in the pre-modern world. … pretty much the opposite of the Malthusian conventional wisdom that I’ve always assumed to be true. … after civilizations peak, various forms of decline set in: declining income from plunder and rising costs of administration, leading to tax increases, leading to more unrest in the provinces, leading to higher military expenditures and higher taxes, in a downward spiral. As imperial control degrades, trade suffers, the division of labor unravels, and the shrinking economy can no longer support the population, and thus Malthusian dynamics kick in to reduce numbers. … I’m quite open to the idea that elites could successfully control fertility; I’m much more skeptical that society-wide birth control was engaged in effectively enough to drive down birth rates. 

The main fertility control in history has been infant exposure, well known and just as available to non-elites as elites. And contemporaries report efforts to cut fertility well past those driven by Malthusian pressures, and cite such efforts as contributing to their civ declines. (See history quotes.)

Second, Lindsey wonders if the fertility fall that looks consistent world-wide across centuries is actually a bunch of random local factors that just happen to line up:

Second, Robin is pessimistic about the possibility of spontaneous reversals in fertility because of the multiplicity and robustness of the factors underlying the current decline. Because declining fertility is associated with a number of the most universal trends of modern social development … ongoing decline in fertility seems massively overdetermined. … Maybe fertility decline isn’t this monolithic trend that started in France in the 18th century and gradually covered the planet; maybe there have been important differences in the main drivers of fertility decline over time. 

Many of the features of contemporary fertility decline — rising ages for marriage and children, declining marriage rates, … — are novel, which suggests that the factors involved have shifted. Instead of a cumulative process in which various master trends of modernity combine to exert a steadily increasing downward pressure on fertility, maybe the most important drivers of sub-replacement fertility are less deep-seated — and therefore more easily reversible — than the factors that propelled the transition from big to small families.

Yes, proximate causes seem to vary across space and time, and if fertility trends were just a coincidence that would in fact give more hope for reversing them. Seem unlikely to me, but if so, then unless we feel confident we can identify the main local causes, that still seems to me to suggest the same remedy: borrow to pay parents lots to have kids, so we can buy a search for ways to change culture.