This is a scrapbook of ideas. One can hardly call it a blog, but I maintain it to file away thoughts I find interesting, like shiny pebbles.

Welcome to the aging world

In 19 countries, from Singapore to Iceland, people have a life expectancy of about 80 years. Of all the people in human history who ever reached the age of 65, half are alive now. Meanwhile, women around the world have half as many children as their mothers. And if Japan is the model, their daughters may have half as many as they do.