Want sustainability - observe the old ways

Hmm.  Two different links in Scott Alexander's Links for November 2023, together answer a sort of shared question; What can we do about below replacement total fertility rates?  The two links are:

A post from More Births which ties to another post:

Several futurists have called the low birthrate crisis civilization's greatest threat. One cause is society has moved away from marriage. So, a big way to increase birth rates is by having more marriages and having them at younger ages.
A🧵. [Thanks for RTs and follows!] pic.twitter.com/oAMJBmnjIN

— More Births (@MoreBirths) July 15, 2023

And then Insights from 2,961 First Dates by Dan Kras.  He notes that 29% of men and women have not had sex in the past year.  

Together they are suggestive.  Want to solve the Total Fertility Rate crisis?

Encourage people to:

Marry

Marry younger

Have more sex

Seems straightforward.  But, as ever, the devil is in the details.

Interestingly, virtually every religion and most robust cultures have these lines of cultural code built-in.  One might describe the TFR crisis as a crisis of affluent modernity.  A crisis arising because people have the temporary luxury of be able to depart from old cultural norms.