How do you know when you are dreaming? In a sequence from Luis Buñuel and Salvador Dalí’s surrealist film Un Chien Andalou (1929), the protagonist appears to wake up lying on a bed, suggesting that the previous scene of a tussle with the object of his desire was merely a dream. But the woman in question remains in the same spot, looking surprised at his sudden appearance on the bed. Was he dreaming? Or is he an element of her dream? This would certainly explain the ants crawling out of a hole in his hand in the preceding sequence, not to mention the impossible spatial displacements.

Dreaming in art often serves to trouble our sense of presence and reality. Alice in Lewis Carroll’s Through the Looking Glass is told that she is just a “sort of thing” in the Red King’s dream and would vanish if he woke up. But whereas Alice’s awakening at the end of the story explains away her bizarre adventure, the wilful irrationality of Un Chien Andalou offers no logical conclusions. Instead the film itself is like a dream. It is full of strange mutations, as when the thronging ants in the man’s hand dissolve into a dark haze of hairs in a woman’s armpit, and it jumps inexplicably in space and time. As the audience of the film we are ourselves something like dreamers, trying and failing to make sense of the images and sounds unfolding before us.

The difference is that the true dreamer is endowed with a curious acceptance of the strangeness of the dream world, somehow knowing that “this must be how things are.” When watching a surrealist film, however, we are aware of a gap between screen and reality; we know we are witnessing a dream. Oddly, it is when watching more realist modes of film-making that we most resemble dreamers, losing ourselves in a simulation of the everyday.

The Surrealists, fascinated by dreams and their connection to the unconscious, were inevitably intrigued by the dream-like quality of cinema. They were mostly more interested in the cinematic experience of darkened room and projected images than the aesthetic possibilities of film. André Breton, the founder of the Surrealist movement and author of its manifestoes, used to go in and out of cinemas on a whim, never learning the films’ titles or discovering their plots.

And as a student Dalí was obsessed with the popular dances played by the mechanical pianos in cinema. He dreamed of locking himself in an empty auditorium to listen to the refrains without interference from the films. In Un Chien Andalou, however, as well as Dalí’s other collaboration with Buñuel, L’Âge d’Or (1930), it is film’s capacity for juxtaposition and discontinuity in sound and image that evokes the dream experience.

Yet unlike abstract avant-garde films like those by Hans Richter and Fernand Léger, which the Surrealists despised for their intellectual rejection of popular cinematic convention, Buñuel and Dalí’s films use common elements of mainstream cinema, such as the point-of-view shot and the close-up, only to subvert them with an irrational link or impossible image.

They also accord a primary importance to human beings, unlike the abstract geometric patterns of, say, Marcel Duchamp’s Anémic Cinéma (1926). After all, Surrealism had social aims, not purely artistic ones. It was intended as a complete liberation of the mind, a vehement attack on a society deemed utterly rotten, stifled by bourgeois convention and unthinking conformity. It was important then that audiences recognise the characters as people like themselves but completely derailed, freed from the constraints of logic and rationality. L’Âge d’Or, with which Dalí was less involved, went even further in the violence of its critique, including scenes of a father shooting his son for disobeying him and a couple having sex in full view of a middle-class crowd.

In a 1929 newspaper article, Buñuel and Dalí lambasted the public for its appreciation of Un Chien Andalou, claiming they had failed to understand that the film was intended as a bitter assault on its spectators. With L’Âge d’Or Buñuel succeeded in creating a truly shocking nightmare: the film was banned in France until 1981.

Even so, the critic Béla Balázs dismissed Surrealism’s attacks on convention as just another example of bourgeois escapism. And a similar acccusation might be levelled at later attempts to harness the power of shock. The 1997 Sensations exhibition at London’s Royal Academy, for example, included Mark Quinn’s head made of blood and Jake and Dinos Chapman’s children with penises for noses. Neither had any significant success in jolting us out of our social and political comfort zones and revolutionising our minds.

But while the Surrealist dream of freeing human consciousness from its constraints went unrealised, perhaps there is some political value in the lucid dreaming of surreal cinema. These days films increasingly mirror the fairy-tale polarity of much political discourse, where the world is divided into good and evil forces. From The Lord of the Rings to 300, we enter into this temptingly simple vision like dreamers. At least, as the razor slices through a calf’s eye in Un Chien Andalou, we remember that we are awake. ■

Isabelle McNeill
is an affiliated lecturer in French at the University of Cambridge and a fellow of Trinity Hall, specialising in French cinema and film theory