Here is a question that I think about a lot.In the year 1950, much as today, the two largest countries in the world by population were China and India. China was a good deal larger at the time, holding 22 percent of the world’s population to India’s 15 percent; but really the two were in a very similar position. Both of them were giant countries that had assumed their current state—India as the independent Republic of India, China as the People’s Republic of China—in the preceding three years. B...