If you want to lose friends and alienate people in the art world, try telling them you support Britain leaving the EU. As someone on the left, I’ve always argued a left-wing case for leaving. It is, to say the least, an unfashionable position, usually met with anxious looks, sullen silence or overt hostility from one or other artist, curator or art bureaucrat.

That the art world should be against Brexit should come as little surprise. It’s striking, however, how far art has become involved in the burning political questions and controversies of the moment, to the extent that making art is often seen as nothing more than an extension of political activism — as happened last month when London’s Photographers’ Gallery staged a project by Swedish artist Jonas Lund, a four-day event titled Operation Earnest Voice, in which Lund opened a ‘fully functioning propaganda office’ whose mission was to ‘devise an online campaign to reverse Brexit’.

Much contemporary art is now steeped in rehearsing the full spectrum of cultural–political issues. Last year’s edition of the Turner Prize was a case in point — institutional racism, queer identity and the conflicts of the Middle East were the contemporary political backstory on which the artworks staked their ground. In the case of nominees Forensic Architecture — a team led by academic Eyal Weizman who use digital forensics to contest human-rights violations committed by states against citizens — the notion that what they do is art is entirely secondary to its function as political intervention. Commenting on his group’s nomination, Weizman quipped that: ‘I would … rather lose [art] prizes and win [human rights] cases.’

Two problems motor the growing rush of artists to dismiss the idea that art could be something different or distinct from political point-making. The first is the assumption that there is a consensus on political questions, that the ‘progressive’ position on a particular issue — the environment, Trump, racism, the Middle East, whatever — is settled, beyond debate or question. So settled, in fact, that the artwork can take up a ‘political’ stance without challenge or question, since for much of the time, the political perspectives of artists, curators and critics dovetail with the larger consensus of mostly liberal opinion, fringed with the edgy terminology of the ‘radical’ academy.

But what underpins that drift of art towards an uninflected, side-taking politics is a bigger failure of cultural thinking regarding how artworks might possess their own logic, their own sense, their own capacity to affect us in ways which can’t easily be directed or determined. This is where an artist’s political convictions and their artistic vision diverge. In the heated referendum campaign of 2016, artist and photographer Wolfgang Tillmans produced an impassioned, pro-EU poster campaign. It expressed his political sentiments and commitments. Many in the art scene agreed with him, and the posters were widely circulated. And yet Tillmans’ posters are a far cry from his photography, which fuses documentary and biography in a heightened visual language all his own, an intoxicating take on contemporary life, steeped in a love of light, colour, people and the richness of ordinary things.

I’ve always admired Tillmans’ images and I don’t agree with his politics, and it’s perhaps necessary today, more than ever, to insist that these positions aren’t incompatible. This divergence — that the art does something other than just transmit messages — might be what would be unfashionably called its aesthetic value. Politically minded critics tend to dismiss the concept of the aesthetic as falsely ‘disinterested’, caricaturing an interest in aesthetic worth as aloof and elitist — an apology for covert privilege and exclusivity, hidden in the beauty.

That criticism has always landed its punch on the assumption that art’s distinction from other kinds of culture is merely its social or class distinction. That way lies the conclusion that art should aspire to being propaganda or message-making, to be more ‘engaged’, more politically responsible.

But there’s an alternative case to be made for the aesthetic: it’s what keeps us open to the multiplicity of perspectives, facts and contradictions that make for a better, more complex understanding of how things are, or could be. Because even overtly political questions are complicated: present a left-wing case for Brexit to a diehard centrist Remainer and you find yourself having to re-explain all the intertwined questions of class, nation, globalisation and democracy that simply don’t fit the matrix of their dearly held good-bad oppositions. Reality is complicated, and pretending that it isn’t is the death of creative thinking in politics.

But creative, inquisitive thinking should also be what artists are good at, and what good art should provoke in us. Art which preaches politics demeans its audience, for the reason that the social, political world is a more complex place than any of the skewed orthodoxies that public debate can accommodate. If we’re honest enough to want to understand our political and social situation in more depth, we should expect art to take that risk also.

Like everyone else, artists have the right to take political positions, some more extreme than others: the Italian futurist Marinetti feted Mussolini’s fascism. Picasso joined the French Communist Party. But Marinetti’s myopic enthusiasm for fascism translated into a vapid, one-dimensional art. Later, the celebrated minimalist sculptor Donald Judd, when asked about American foreign intervention and the political responsibilities of artists, was supposed to have replied: ‘Of course artists should oppose US involvement in Nicaragua… just as dentists should.’

Judd’s point (whether he quite said it or not) still resonates because it insists that we tell the difference between making art as an artist and taking a political position as an ordinary citizen — and that we recognise that art does other things to us than preach. Still, while artists have no special claim to political insight, try telling them that. For many artists, making art that addresses the politics of today, and taking up the role of propagandist for social change through the platform of the artwork and art gallery, has become their raison d’être.

Art’s aesthetic dimension — what distinguishes it in a real sense — lies in how it gives shape to an understanding of reality that is richer, more complex and (often) contradictory than any narrow, reductive campaigning message, from either the political left or right, can ever allow. In a culture in thrall to the one-dimensional idea of art as an agent of politics, it’s time we remade the case for the open-ended speculation that is art’s aesthetic difference.