History has no final verdicts. Major shifts in events and power bring about new subjects for discussion and new interpretations.
Fifty years ago, as decolonisation accelerated, no one had a good word to say for imperialism. It was regarded as unambiguously bad by both ex-imperialists and their liberated subjects.
Schoolchildren were taught about the horrors of colonialism and how it exploited conquered peoples. There was little mention, if any, of imperialism's benefits.
Then in the 1980s, a revisionist history came along. It was not just that distance lends a certain enchantment to any view.
The West, mainly the Anglo-American part of it, had recovered some of its pride and nerve under the US president Ronald Reagan and the British prime minister Margaret Thatcher. And there was the growing evidence of post-colonial regimes' failure, violence and corruption, especially in Africa.
But the decisive event for the revisionists was the collapse of the Soviet empire, which not only left the US top dog globally but also seemed to vindicate western civilisation and values against all others.
With the EU extending its frontiers to embrace many ex-communist states, the West became again, if briefly, the embodiment of universal reason, obliged and equipped to spread its values to the still-benighted parts of the world. Francis Fukuyama's The End of History and the Last Man testified to this sense of triumph and historical duty.
Such conjuncture set the stage for a new wave of imperialism, although the reluctance to use the word remained. In doing so, it was bound to affect interpretations of the old imperialism, which was now extolled for spreading economic progress, the rule of law, and science and technology.
Foremost among the new generation of revisionist historians was Niall Ferguson of Harvard University, whose TV series, based on his new book Civilization: the West and the Rest, has started showing in Britain.
In its first episode, Mr Ferguson appears amid the splendid monuments of China's Ming Dynasty, which, in the 15th century, was undoubtedly the greatest civilisation of the day, with its naval expeditions reaching the coasts of Africa.
After that, it was all downhill for China (and "the Rest") and all uphill for the West.
Mr Ferguson summarises the reasons for this reversal in six "killer apps": competition, science, property rights, medicine, the consumer society and work ethic. Against such tools - unique products of western civilisation - the rest had no chance.
Understandably, this thesis has not met with universal approbation. The historian Alex von Tunzelmann accused Mr Ferguson of leaving out all of imperialism's nasty bits: the Black War in Australia, the German genocide in Namibia, the Belgian exterminations in the Congo, the Bengal famine, the Irish potato famine, and much else.
But that is the weakest line of attack. Edward Gibbon once described history as little better than a record of the "crimes, follies, and misfortunes of mankind". Imperialism certainly added its quota.
But the question is whether it also provided the means to escape from them. Even Marx justified British rule in India on these grounds. Mr Ferguson can also make a sound argument for such a proposition.
The most serious weakness in his presentation is his lack of sympathy for the civilisations dismissed as "the rest", which also points to the most serious limit of the revisionist case. The "triumph of the West" that followed the collapse of communism in Europe was clearly not the "end of history".
As Mr Ferguson must know, the main topic of discussion in international affairs nowadays concerns the "rise" of China, and more generally Asia. Of course, the Chinese may prefer to talk about "restoration" rather than "rise".
Chinese savings are underwriting much of the US civilising mission Mr Ferguson applauds. The pattern seems clear: the West is losing dynamism and the rest are gaining it.
The rest of this century will show how this shift plays out. For now, most of us have lost the historical plot. It is possible to imagine a "western world" (one that applies Mr Ferguson's "killer apps") in which the West is no longer the dominant factor: America simply passes the torch to China, as Britain once did to America. But it seems to me extremely unlikely that China, India and "the rest" will simply take over western values wholesale.
Some syntheses and accommodations between the West and the rest will accompany the shift in power and wealth from the former to the latter. The only question is whether the process will be peaceful.
A Robert Skidelsky, a member of the British House of Lords, is professor emeritus of political economy at Warwick University
* Project Syndicate