Do not extrapolate from the recent past. China has had a hugely impressive four decades. After their triumph in the cold war, both the west and the cause of liberal democracy have stumbled. Should we conclude that an autocratic China is sure to become the world’s dominant power in the next few decades? My answer is: no. That is a possible future, not a certain one.

The view widely held in the 1980s that Japan would be “number one” turned out to be badly mistaken. In 1956, Nikita Khrushchev, then first secretary of the Communist party of the Soviet Union, told the west that “We will bury you!” He proved utterly wrong. The examples of Japan and the Soviet Union highlight three frequent mistakes: extrapolating from the recent past; assuming that a period of rapid economic growth will be indefinitely sustained; and exaggerating the benefits of centralised direction over those of economic and political competition. In the long run, the former is likely to become rigid and so brittle, while the latter is likely to display flexibility and so self-renewal.

Today, the fiercest political and economic competition is between China and the US. A conventional view is that by, say, 2040, China’s economy will be far bigger than that of the US, with India far smaller still. But might this view be mistaken? Capital Economics, an independent research firm, answers “yes”, arguing that China's period of stellar outperformance might be coming to an end quite soon. (See charts.)