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Disease and fertility

November 10, 2021

There are two, large features that shape the developed world. The first is that we no longer die young from infectious disease. “Toward the end of the nineteenth century, in the United States and Britain, a great threshold was crossed for the first time in the history of our species: noninfectious causes of death — cancer, cardiovascular disorders, and other chronic and degenerative diseases — accounted for a greater portion of total mortality than did infectious diseases.”

The second is the demographic transition. As societies become developed, their fertility rate declines, and their population growth slows. Kyle Harper ties these together:

Despite the variety of human cultures, and variations in the timing and mechanisms, the demographic transition has virtually always happened in the same sequence: mortality falls, then total population grows for a time, then fertility falls.

There is some irony that as demographers were recognizing the broad character of the demographic transition, a half century past, a French author wrote a dystopian novel about the developed world being over-run by brown hordes, The Camp of Saints. That became a touchstone for the modern, populist right, playing to their base fear that the world will be different in a generation or two. Which, of course, it will.  Regardless of what anyone does. The rest of us can work to making that future better, rather than to a fantasy of preserving some golden past.

One Comment leave one →
  1. Michael Grossberg permalink
    November 10, 2021 12:14 pm

    Excellent post.
    I wish more people today were educated – about history, the advance of medicine and health – routinely in schools and colleges about the incredible progress that humans have made in fighting disease and getting closer to reaching our “natural” full life-spans over the past century or two.
    One great writer about that is the great liberal professor Steven Pinker (Enlightenment Now is a great primer, full of statistics and charts about the extraordinary progress our species has made around the world in the past few centuries, thanks largely to the spread of liberty, markets, science and technology.
    P.S. As an experiment, over the years, I routinely ask friends and acquaintances to guess the average lifespan in the United States in 1900.
    Almost everyone overestimates it significantly. (They guess 60 most often, or 55 to 65…)
    As I recall, the actual average age in the U.S. in 1900 was about 47 – and that itself was a huge improvement from the previous century.

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