Francis Alys, ‘Tornado Milpa Alta’, 2000-10, video. Courtesy David Zwirner New York

The reasons why a given artist reaches a particular level of success are usually rather obscure and arbitrary, but in the case of Francis Alÿs, the basis of his wide influence, indeed his status as something of a cult figure, seem readily apparent. It lies in his altogether unexpected fusion of two of the most prevalent artistic modes of the time, modes that to all appearances should be mutually incompatible: on the one hand, an aesthetic of charm, embodied in an art that values lightness, indirection, naïveté, and a sort of whimsical subjectivity or absurdity—the aesthetic of a Karen Kilimnik, say, or in a different way of an Andreas Slominski, among many others; and on the other, an aesthetic of responsibility, the notion that art should not be merely expressive or self-indulgent but should instead, as curator Mark Godfrey puts it in his catalogue essay in ‘Francis Alÿs: A Story of Deception’, ‘address the urgent political and economic crises of contemporary life’. In the title of his essay, Godfrey neatly uses the typographic convention of the slash to enact the connection / division between these modes: ‘Politics / Poetics’, echoing the artist’s own disarmingly modest yet resolute dictum, Sometimes doing something poetic can become political, and sometimes doing something political can become poetic. Thanks to this ambiguity, Alÿs’ art can be admired by viewers who would otherwise not agree; his oeuvre becomes a meeting ground for disparate publics, where they can momentarily feel like they are part of a bigger public.

The poetic pole of Alÿs’ work may be most obvious in his paintings, with their mutely enigmatic, dreamlike figurative imagery, halfway between urban folklore and surrealism; one series is called ‘Le Temps du Sommeil’, 1996–present, as if to emphasise a distance from the measured time of daylight, of the working world and the clock that rules, and a regression into the time when the self encloses itself in silence and darkness. One thinks of the French Symbolist Saint-Pol-Roux who appar-ently used to guard his slumbers with a sign reading, ‘Do Not Disturb, Poet at Work’.

But as Alÿs’ famous action ‘When Faith Moves Mountains’ (his contribution to the 2002 Lima Biennale, documented on video, which involved 500 people using shovels to shift a massive sand dune by ten centimeters) demonstrates, the poet’s dreams as easily disturb reality as vice versa. This is a work that may be a bit boring to look at in the Tate Modern, and might not even have been that engaging to contemplate on the outskirts of Lima eight years ago, but as a chimera in the mind’s distance it is hard to let go of. Like a dream image, and therefore like the images in Alÿs’ paintings, it is utterly concrete and utterly unfathomable. It seems related less to the land art of 40 years ago than to Leon Trotsky’s prophecy in 1924 of land art as utopian political action: ‘Nature’, he wrote, will become more ‘artificial’. The present distribution of mountains and rivers, of fields, of meadows, of steppes, of forests, and of seashores, cannot be considered final. Man has already made changes in the map of nature that are neither few, nor insignificant. But they are mere pupils’ practice in comparison with what is coming. Faith merely promises to move mountains, but technology, which takes nothing ‘on faith’, is actually able to cut down mountains and move them. Up to now this was done for industrial purposes (mining) or for railways (to make tunnels). In the future this will be done on an immeasurably larger scale, according to a general industrial and artistic plan.’

Alÿs’ action, one he describes ‘at once futile and heroic, absurd and urgent,’ turns Trotsky’s revolutionary bravado on its head but also remembers it as a rebuke to the complacency of the present. The artist’s own stance is finally as inscrutable as any dreamer’s. Tellingly, while Alÿs himself is visible in the video and photographic documents of many of his actions, his face is often turned away or in shadow. He is an elusive, almost anonymous figure. His work deflects the viewer’s gaze. Perhaps for that reason, the Tate’s wide-ranging selection of Alÿs’s many-faceted work offers no overview; it leaves me feeling that I’ve missed the centre of this oeuvre, that I have undergone a kind of mystification—not exactly a deception, as the exhibition’s subtitle might seem to imply, but a loss of certainty.

Barry Schwabsky is a writer based in London