Colored Vases, 2006

It sounds almost reductive to refer to Ai Weiwei as an ‘artist’. Outspoken humanitarian and political dissident, he’s just as much celebrated as an icon of social and international freedom as for his creative talents. But for Ai Weiwei himself, the heroic prominence he has earned in both the fields of art and politics is one and the same. ‘I would not separate art from my so-called activism,’ he says – and his 2015 retrospective at the Royal Academy illustrates the full magnitude of his work.

For where there’s a human crisis, Ai Weiwei’s voice is never far away, and art is his most effective medium of expression. Over the last decade, his work has attacked the regressive, totalitarian regimes of his native China, always with unrelenting fearlessness. He famously challenged the government’s refusal to reveal the names of the students killed in the 2008 Sichuan earthquake, a move which saw him detained for 81 days by Chinese authorities who perceived his rebellion as a threat to the system.

Bicycle Chandelier, 2015

Increasingly upheld as a spokesperson for the oppressed in society, Ai Weiwei has since acquired a global authority. He most recently hit headlines in support of the Syrian migrants, posting an image of himself posing as a drowned refugee to his Instagram account to raise awareness of their plight. When Denmark announced laws to seize assets from asylum seekers, Ai Weiwei cancelled his exhibition in Copenhagen. So politically charged his work has become, last year he found his studio in Beijing bugged with listening devices. It’s no surprise that the Art Review described him as the most powerful artist in the world.

His affinity with art as a crucial mode of expression proved itself early on, through various forms of experimentation. After studying at the Beijing Film Academy, he moved onto the Parsons School of Design in New York. Becoming enticed by the bohemian subcultures of the city, however, he later dropped out, turning to photography and street portraits to make a living. It was then that he became deeply influenced by the legacies of Joseph Beuys and Marcel Duchamp, creating sculptures and conceptual pieces out of readymade objects.

Straight, 2008-12

He continued to hone this multifaceted creativity upon his return to Beijing in 1993 – the starting point of this exhibition – fusing contemporary Western art with established Chinese practices. The result is often subversive, even on a lower scale: Chinese pots are dipped in high chrome paint, and a 7000 year-old Neolithic bowl is gaudily inscribed with the Coco-Cola logo – Warhol’s Pop Art meeting the Stone Age – quietly indicative of the more controversial direction his bolder works would later take.

Indeed, Ai Weiwei is first and foremost a conceptual artist, often in the vein of Duchamp (whose portrait profile itself appears in the exhibition, shaped by a coat hanger). ‘I don’t care that much about “art”,’ he says; ‘rather, I think about whether something is a good idea.’ His works are often abstract, composed with recycled materials and objects, and displayed on a grand scale. On show outside the Academy is Trees (2009-10), a forest of eight trees assembled from dead trunks and branches, and a fitting introduction to Ai Weiwei’s conceptual aesthetic.

Trees 2009-10

But visual inventiveness aside, his work is unremittingly thought-provoking and alive with commentary. In Grapes (2010), he fixes together 32 Qing Dynasty (1644-1911) stools, denoting the socio-political changes facing rural China in the 21st century. In S.A.C.R.E.D (2011-13), he forces the audience to peek inside six sculptures that each illustrate a different scene of his imprisonment, a haunting depiction of surveillance. There’s also Bicycle Chandelier (2015), the final piece of the exhibition, and hopeful in its implications of social freedom.

As one of the leading conceptual artists of his generation, it’s notable that Ai Weiwei has largely evaded the derision usually levelled at practitioners of this genre. But it seems to me that his conceptual art is invested with a kind of humanitarian authenticity, and this is what elevates him above others. In Straight (2008-12), for instance, Ai Weiwei gathers the steel reinforcing rods from the buildings destroyed by the Sichuan earthquake, painstakingly straightening each of them out to their original form. As the names of the victims adorn the surrounding wall, it’s a stark meditation on life and loss, and one of the most thought-provoking installations of the exhibition.

Grapes, 2010

If there’s more to art, then Ai Weiwei convinces us that there’s more to conceptual art, but there are many other reasons why this exhibition triumphs so memorably. Ai Weiwei reminds us that art has an immediate, as well as an enduring appeal; that art has the ability to challenge established values, and tackle social and political ideas; that artists, put simply, have power. Asked if he would consider working as a politician, Ai Weiwei replied: ‘I am an artist. However, my art always relates to freedom of speech, and that is very political. So in a way I have already been a politician for a long time – fighting for essential qualities of human life.’

In acknowledgement of his own value as an artist and an activist, he adds: ‘It is a tradition for intellectuals to speak out against power. This is why artists and poets are so valued by society’. And his work continues to push boundaries and question the status quo, I can think of no other living artist who serves as a more fitting testament to these ideals – or has fulfilled them more completely.