The Chinese are as persuaded of the eternity of the Middle Kingdom as are the Jews of the eternity of Israel. Nations may rise and fall, languages may fall silent forever, but China as concept and culture has no end. In this vastness the rock and refuge of the individual has always been the family. China has had a “modern” dimension — centralisation and unifying literacy — since its foundation, and Chinese families have had thousands of years to learn to cope with it. Among the many things that Jews and Chinese have in common is a firm belief that they have a future to look forward to. Of all the factors that figure into the decision to have children, this is among the most powerful.

That is not true elsewhere in East Asia, where nations founded on ethnicity feel deeply the ennui and fragility of the modern world. Japanese peasants who move from farming villages to urban apartment buildings leave behind the Shinto spirits who infested their rural life. Uprooted Japanese become deracinated, and it is not surprising that Japan has become the world’s largest market for specialised pornography. Koreans do not have the Japanese’s taste for pornography, but their sex trade generates more revenues relative to GDP (at 1.6 per cent of the total) than any other rich country in the world. The two economic powerhouses of East Asia appear to have lost their cultural compass in the modern world, and that may be why their interest in raising children has diminished so drastically.

In 2013, China relaxed the one-child policy for urban areas, allowing families to have two children if one parent is an only child. There has been no birth surge in response, and some analysts argue that the incentive to concentrate the whole of a family’s resources on one “princeling” will trump the desire for more children. It is too early to guess the outcome. But China has done nothing but surprise the world for the past half-century. It is as dangerous as it is facile to assume that demographic decline will attenuate China’s growing power.