Sure, if it goes on without end then a society will go extinct. That idea leans heavily on nervous extrapolation. It's like the people who saw a few decades of

Sure, if it goes on without end then a society will go extinct. That idea leans heavily on nervous extrapolation. It's like the people who saw a few decades of rapid population growth and imagined apocalyptic fiction like Soylent Green or The Population Bomb in response. Japan was early to demographic contraction. The UN estimates that its population will shrink to 85 million by the year 2100 if things keep going on like this [1]. That would be about the same as its population in the early 1950s [2]. Is that considered dangerously underpopulated? I understand the argument that it's risky not having enough healthy young workers to take care of the aged. But an ever-wider population pyramid just delays the problem and makes its absolute magnitude greater. There are a few ways to theoretically deal with the needs of the old without continual population growth: - Let them go without. People would die sooner after they become unable to work. A decades-long "retirement" period later in life would be unusual. This was the pre-industrial norm. (Not a good option, but the default!) - Increase the health span of people so that they can continue to take care of themselves later in life. This could be currently science-fictional projects like Strategies for Engineered Negligible Senescence or just instilling healthy habits to prevent diabetes, reduce cancer risk, maintain muscle mass and heart health, et cetera [3]. An elder-heavy but otherwise healthy population places fewer demands on younger people than elderly long time smokers, drinkers, or diabetics. - Deliver medical care and other support services with more machines, less human labor. This is also a bit science fictional but at least takes advantages of existing trends. Environmental alterations can also make it easier for elderly people to continue to perform routine self-care tasks like cooking and bathing. [1] https://qz.com/1295721/the-japanese-population-is-shrinking-faster-than-every-other-big-country/ https://qz.com/1295721/the-japanese-population-is-shrinking-... [2] https://en.wikipedia.org/wiki/Demographics_of_Japan#Vital_statistics https://en.wikipedia.org/wiki/Demographics_of_Japan#Vital_st... [3] I'm not sure if it is more outlandish to hope that medical interventions will prevent debilitation by old age or that people will adopt healthy habits en masse.