“INDEED it is difficult,” wrote Gottfried Leibniz in 1699, “to describe how beautifully all the laws of the Chinese, in contrast to those of other peoples, are directed to the achievement of public tranquillity and the establishment of social order.” Leibniz was not the only European Enlightenment-era thinker to see in China a worthy and enviable model of an idealised state under the rule of benevolent—and, yes, enlightened—leaders.Today social order and public tranquillity (of a sort) remain a top Chinese priority. Nowhere is this more evident than at central Beijing's politically fraught Tiananmen Square, where a German-sponsored exhibition, “The Art of the Enlightenment”, opened this month in the newly refurbished National Museum of China. But to much of the outside world, the Chinese government's often thuggish approach to maintaining social order looks anything but exemplary.Not surprisingly, this has generated some tension in the staging of this ambitious year-long exhibit. Tilman Spengler, a German sinologist, was listed as part of the “expert group” arranging a companion series of panel sessions. But having spoken last year at an event honouring Liu Xiaobo, a Chinese dissident and Nobel Peace prize laureate, Mr Spengler was denied a visa. According to Dong Junxin, a top official in China's Culture Ministry, Mr Spengler had “hurt the feelings of the Chinese people.” His exclusion hardly seems in line with the Enlightenment ideals of open inquiry and freedom of thought; Mr Dong insisted it had nothing to do with the exhibition.There is nothing surprising about China's desire to concentrate on the art and glide over the more provocative aspects of Enlightenment thought. With more than 190,000 square metres of floor-space, the National Museum of China is now the world's largest, and its treatment of China's own history is similarly slanted away from the controversial or unflattering. The disastrous decade of the Cultural Revolution, for example, is barely mentioned, and what is covered hews closely to China's tendentious official line.Speaking at the exhibition's opening, Guido Westerwelle, Germany's Foreign Minister, emphasised the ideals embodied in the art of the Enlightenment, such as respect for personal dignity, rule by law and individual freedom. These concepts, he said, brought about the fall of the Berlin Wall. But mindful of the views of his Chinese hosts, he added that these notions do not run counter to stability.The €10m exhibition has been organised by three of Germany's leading institutions—the Dresden State Art Collections, the Berlin State Museums and the Bavarian State Painting Collections—and features an impressive selection of nearly 600 works. These include paintings by Antoine Watteau, Caspar David Friedrich and Francisco de Goya, as well as sculpture, furniture, clothing and artefacts.Divided into nine chapters, the show explores Europe's Enlightenment-era court life, the emergence of modern science, conceptions of history, love and nature. One notable chapter, called “Emancipation and the Public Sphere”, admirably broaches the tricky subject of tolerance for the voices of individuals. A bust of Immanuel Kant stands near the entrance to this section, engraved with his words, “Have the courage to use your own understanding!”This remains a troublesome concept in today's China. Your correspondent intended to ask Ai Weiwei, one of China's most prominent and outspoken contemporary artists, for his views on the exhibition and the relevance to China of the European Enlightenment. But two days after the exhibit opened, Mr Ai was arrested, his studio searched, computers confiscated and colleagues detained for questioning. Before his arrest, however, he lamented to German media that China's approach to dissent was more like the Middle Ages.