Some weeks it is hard to know what to worry about most. Terrorist attacks? Mass migration triggered by war? Trump or Brexit? And yet all this could easily pale into insignificance if the world's most populous country were to repeat its own history.
The Chinese people account for just under a fifth of all humanity, far greater than the American share (4.4 per cent) or the British (0.9 per cent). Any crisis in China thus has the potential to affect a staggering number of people. To give just two examples: the mid-19th-century Taiping rebellion cost the lives of at least 20 million people, making it a far bigger calamity than the American Civil War. The Great Leap Forward - Chairman Mao's disastrous attempt to force the pace of industrialisation between 1958 and 1961 - killed up to 45 million.
So when China-watchers worry, we all need to pay attention. The Economist recently used the headline "Mao, diluted" to characterise the personality cult around President Xi Jinping. Others go further. "Not since the 1970s when Mao still reigned and the Cultural Revolution still raged", wrote Orville Schell in The New York Review Of Books last month, "has the Chinese leadership been so possessed by Maoist nostalgia". Them's fightin' words from one of America's most respected China hands.
Having just spent two weeks in Beijing, however, I am relieved to report that I saw scarcely any sign of "Maostalgia". There is a kind of Cultural Revolution going on in China. But it is not one that looks back with any fondness to the craziness of the 1960s.
Of course, I can see why people worry. Since Mr Xi became General Secretary of the Chinese Communist Party in 2012, there have been numerous nods to the bad old days. A year after coming to power, he approved document No. 9, which bans the discussion in universities of seven taboo subjects, including Western democratic ideas, freedom of the media and independence of the judiciary. Shortly before I arrived in Beijing, there was a concert in the Great Hall of the People that featured the song Sailing The Seas Depends On The Helmsman - a Cultural Revolution classic.
Yet no one I met in Beijing showed the remotest sign of wanting to revisit that era. Quite the reverse. And no wonder.
It was 50 years ago, in the summer of 1966, that Mao Zedong launched the Cultural Revolution, urging the Chinese youth to rise up against the bourgeois elements that he claimed were subverting the communist revolution. Formed into Red Guards, students were encouraged to subject their teachers and other figures of authority to beatings, torture and ritualised humiliation.
At the Experimental High School Attached to Beijing Normal University, a group of girls turned on their vice-principal . According to one recently published account: "The girls wrote slogans over her clothes, shaved her head, jabbed her scalp with scissors, poured ink on her head and beat her until her eyes rolled into her head. When she started foaming at the mouth, they laughed and ordered her to perform manual labour by scrubbing the toilets. She collapsed and died there, her clothes soaked in blood and faeces."
One of the girls involved, Song Binbin, was publicly praised by Mao for her role in this atrocity. He urged her to change her name to Yaowu , which means "be martial". An article appeared under her new name declaring that "violence is truth". That August, in Beijing alone, 1,772 people were killed.
What began as a state-sponsored generational revolt rapidly descended into anarchy and, in places, civil war. Rival gangs of Red Guards fought in the streets. In an attempt to regain control, the army stepped in, sending thousands of militant students to the countryside for "re-education". During 10 years of insanity, between 11/2 million and two million people lost their lives. It is all chillingly documented in Frank Dikotter's brilliant new book, The Cultural Revolution: A People's History, 1962-1976 .
Last week, I sipped tea with a delightful elderly woman who had been subjected to the signature torture of the Red Guards - to stand for hours with her knees bent and her arms stretched behind her in the so-called jet plane position. Like everyone who remembers those dark days, she could think of nothing worse than a new Cultural Revolution.
Could Mr Xi really think otherwise? It seems implausible. His elder half-sister died in the mayhem. His father, appointed vice-premier in 1959 but purged by Mao three years later, was subjected to persecution and imprisonment throughout the Cultural Revolution. Mr Xi, as the son of a senior official, was identified as a "child of a black gang" in Red Guard parlance. At one point, he was forced to stand on a stage wearing a cone-shaped metal hat while a crowd (including his own distraught mother) chanted: "Down with Xi Jinping!"
The Communist party certainly dislikes open discussion of the Cultural Revolution, but that is surely not because anyone contemplates a repetition of it. Since 1981, the official line has been that the Cultural Revolution was "70 per cent successful and 30 per cent a failure". Last week, the People's Daily went further, calling it "a mistake that cannot and will not be allowed to repeat itself".
Indicative of the real revolution under way in China today was the front page story two weeks ago in the People's Daily, which quoted an "authoritative insider" arguing for "supply-side structural reform" of the economy. This article caused great excitement in Beijing as a signal that President Xi is backing tougher action to deal with the massive debts and industrial overcapacity that are the legacy of the government's post-2008 economic stimulus. But to me, its significance was as much cultural as economic. Warning against "high leverage" and arguing that China faced an "L-shaped" rather than "U-shaped" or "V-shaped" recovery, the authoritative insider sounded remarkably like one of his counterparts in the West.
China's new cultural revolution has nothing to do with Chairman Mao. It is the revolution that follows logically from the economic reforms that became possible only after his death. Since the late 1970s, China's economy has surged from producing just under 2 per cent of global output to nearly 18 per cent. Among the unintended consequences of this astounding growth are a host of western-style problems: property price bubbles, stock market busts, "shadow" banks and, above all, a mountain of debt.
The real cultural revolution, in short, is that the leader of the Chinese Communist Party needs to grapple with pretty much the same problems as his western counterparts. And my bet is that Mr Xi understands better than most western China-watchers that the worst possible remedy would be to resort to "Maostalgia" - and risk rousing the "monsters and demons" of 50 years ago.
THE SUNDAY TIMES, LONDON