ROBIN HANSON: How Long Will Population Fall? “Many, including my colleague Bryan Caplan, are confident that the widely forecasted world population fall based on fertility trends won’t last long, because: selection. Many papers that make this point. . . . Another set of papers cautions that, sans heritability, fertility may continue to decline to far below replacement levels, and that selection effects may not be strong enough to counter such culturally-induced decline. For example, a 2022 Demography paper titled ‘Intergenerational Transmission Is Not Sufficient for Positive Long-Term Population Growth.’ I find it suspicious that though we didn’t see such selection effects over the many centuries decline of the Ancient Greek and Roman empires, nor in other ancient empires, nor over the last few centuries of declining fertility, we are just now about to see it kick in strong enough to reverse fertility decline.”

Related: Free Will, Children, and the Great Filter: Thoughts on the Population Implosion.