In 1995 Ai Weiwei held up an ancient Chinese ceramic vessel, opened his arms to let it go, and stood there as it shattered. His new exhibition about craft and fakery includes a recent remake of Dropping a Han Dynasty Urn in Lego. It’s impressive how the black, white and grey Lego bricks create shadowy Warholian images of the artist in three stages of smashing a masterpiece. I feel obliged to explain. But I can’t, really. I don’t actually know what is clever about smashing an archaeological treasure – the Han dynasty ruled China when the Roman Empire ruled Europe – so I will quote the exhibition guide instead: the “transformative act” of destroying a 2,000-year-old work of art (transforming it into little tiny pieces, I guess) “drew attention to the Chinese government’s widespread destruction of the country’s heritage”. And there you have this exhibition in a nutshell: a display of sometimes amusing but superficial art that we are urged to appreciate as “important” because of the artist’s unquestionably heroic political acts. Ai Weiwei is a true hero of free speech, braver than most of us will ever be, and – in his tireless campaigning for refugees – compassionate, too. I admire him deeply. But this exhibition made me seriously doubt whether he is a good artist. The problem with his new version of Dropping a Han Dynasty Urn is that he wants to have his cake and smash it. The alleged campaigning, critical point is the direct opposite of what it actually makes us feel. Seeing him smash an urn, we laugh. We don’t ponder the erosion of China’s heritage. Instead we enjoy seeing it happen before our eyes. And remaking the original photographs in Lego just accentuates that celebration of irony, freedom, the throwaway modern world. I think even that is an overreading. The gesture is – literally – throwaway. For in this show it sometimes seems Ai Weiwei is better at throwing concepts in the air than clarifying what he means by them, as they crash to earth. The Lego shares a gallery with old-fashioned wood-framed display cases containing a collection of ancient art from China that Ai Weiwei bought in 2020. It’s a mix of styles and periods, including a buckled-up image of a crouching hare in red sandstone and a sensual broken limestone Buddha. The artist claims at least five of these apparently time-hallowed sculptures are modern fakes. For the forgery business is so refined in contemporary China it is transforming the historical record. The gallery points out the “fakes”. For what it’s worth I think they do look dodgy. Their surfaces are cleaner and sharper. The signs of age appear artificial. But perhaps Ai Weiwei is playing with my mind, presenting the real as fake, the fake as real. If only I cared. The myth of authenticity, the fascination of the fake – this is the small change of postmodernism that has been around for decades now. As with smashing a Han urn, mixing real and fake ancient Chinese art just gets in the way of any chance, as a westerner, I might have of responding aesthetically to this art. We live in an entire world of inauthentic replicas. It is not at all daring or memorable to point that out, again. At least when Damien Hirst celebrates the inauthentic he does it on a colossal scale in his bad taste epic museum of fake treasures, The Wreck of the Unbelievable. But I suspect snooty, cosy Kettle’s Yard wouldn’t touch Damien with a surgical glove on the end of a bargepole. This exhibition is boring because its urge to provoke is constantly checked by an insistence on Ai Weiwei’s moral excellence. I cannot believe Ai Weiwei has put his name to a set of blue and white porcelain plates with childish paintings of refugees on them. A helicopter buzzing a crowd! A boat crammed with people – painted on a porcelain plate! It’s the kind of cheap, easy “gesture” I’d expect of Grayson Perry. Though that may be unfair – at least Perry aspires to satire. These well-meaning platters are merely mawkish and sentimental. I feel offended to have my distress at the treatment of refugees pandered to in this way. One sad possibility is that Ai Weiwei has the same problem now as dissident writers who fled communist Europe in the 1970s or 80s. The real meaning and power of his art lay in the sheer courage of his opposition to China’s dictatorial state. In exile, he is adrift. Some of the art here muddies his previously clear stance for freedom by implying democracy is just as unfree as a totalitarian state. Surveillance Camera and Plinth is a marble replica of a security camera – it might be anywhere, from Beijing to Cambridge city centre. But the meaning of these objects surely depends on how they are used, why and where. Anyway, the marble is overstated and artistically heavy. There are other everyday objects imitated in stone – a marble toilet roll, a jade sex toy and smartphone. Funny for a moment, but so what? Their meanings remain in the shallow end. Marcel Duchamp, more that a century ago, “chose” objects from the world as readymade art. His levity mocks Ai Weiwei’s stone gravity. Turning readymades into marble and jade is a ponderous way to make your point. In another brilliant act of antiquity abuse, he’s painted the Coca-Cola logo on a Han vase. It symbolises this exhibition, which itself resembles the cool Cambridge outlet of a global brand. But the guy is phoning it in, on a jade iPhone. Ai Weiwei: The Liberty of Doubt is at Kettle’s Yard, Cambridge, from 12 February to 19 June