> Do you believe that there will be happier marriages and less domestic violence when brides are 16 years old and have little to no agency in choosing who marries them?

Comparison isn't necessarily binary. I'd posit these things are more likely determined by other socio-cultural variables, the individuals involved (which is partially contextualized by said variables) and a noisy baseline than whether or not a marriage is arranged. In otherwords, an independent variable (which means I disagree with the both of you)

> In every country in the world, higher quality of life (wealth, education, longevity, etc.) has lead to a decrease in population.

I'm not sure that holds. Do you mean that a higher quality of life leads to a decrease in fertility rate? It's obviously true that population booms eventually end, and historically large ones are usually followed by contraction as a correction. But overall those things you list result in an increase of population, it simply hits a ceiling and stabilizes. We just had the largest population boom in observable (more than recorded!) history, the industrial revolution dwarfs the agricultural one. It stands to reason we should see a pretty hefty population contraction which tapers into a very mild amount of growth until we raise the population ceiling once again.

I don't think he's particularly right that low fertility rates are caused by "marriage for love". It's more like many places with low fertility rates are currently correcting for overly explosive growth experienced in recent history. Other places are only just now having their local population booms, or correcting for other population effects (like war.) It's very unlikely we will contract more than a few billion over the next couple hundred years. Keep in mind the industrial revolution is what caused us to rocket into the billions in the first place. For reference the upper bound estimated population of the 10th century is 400 million, and the upper bound of the 17th is about 500 million. 25% global growth over 700 years. The last 300 years is something like 1700%.

Almost all rhetoric about birth rates never accounts for any of this. So again, independent variables.