Inexplicably, a rough-hewn antique door stands in a dimly lit dead-end corridor in the Philadelphia Museum of Art. For those curious enough to investigate and look through its peepholes, what they see startles them. It is the final project of Marcel Duchamp, an artist who repeatedly redefined art in the twentieth century. Exploring how his art challenges viewers is essential to understanding his creativity and much of the art of the last century.
The challenging nature of his art
Duchamp’s art is highly innovative and extremely varied. Many of his works don’t fall into the traditional genres of fine art, such as painting and sculpture. They include “readymades”—already manufactured objects chosen by Duchamp and treated as artworks—notes and publishing projects, and even motorized machines. On top of that, they are often made with unconventional media, such as glass, dust, found objects, and even body hair. To complicate things even further, many of Duchamp’s pieces relate to others in his oeuvre (output). The Green Box, for instance, is a boxed collection of carefully reproduced handwritten notes about his large, complex The Bride Stripped Bare by Her Bachelors, Even (The Large Glass). A further challenge for viewers is that his artworks frequently make references to literature, math and science, philosophy, and even chess. Indeed, Duchamp’s art asks a lot from his audience!
The role and experience of the viewer
Despite the often aloof, cerebral quality of his pieces, for Duchamp the viewer was critically important. In a 1957 lecture, he described how “The creative act is not performed by the artist alone; the spectator brings the work in contact with the external world by deciphering and interpreting its inner qualifications and thus adds his contribution to the creative act.” 
Rotoreliefs featured in Duchamp’s film Anémic Cinéma (1926) © Succession Marcel Duchamp (The Museum of Modern Art)
As if to emphasize the viewer’s role, many of Duchamp’s pieces explore notions of visual perception. In the 1920s he constructed two large, motorized machines on standing frames. Rotary Glass Plates (1920) and Rotary Demisphere (1925) are made of, respectively, spinning rectangular plates which are read as a completed circle when in motion, and a rotating spiral which creates a dizzying dimensionality. Their whole purpose was simply to create these visual effects in the eye of the viewer.
Relatedly, Duchamp also created Rotoreliefs—boxed sets of six cardboard disks printed with various circular patterns. When a disk is placed on a rotating record turntable it produces a compelling illusion. These days Duchamp’s optical works are considered predecessors of the psychedelic-era “Op Art” of the 1960s and 70s.
The importance of the viewer for Duchamp is also suggested by the fact that some of his works invite participation, at least implicitly. This is especially true of the readymades. It is hard to resist turning the Bicycle Wheel, made from a wheel and fork mounted on a stool, or shake With Hidden Noise, a ball of twine with metal plates on either end, to hear the rattling object inside. A person might consider clearing sidewalks with the ordinary snow shovel In Advance of the Broken Arm or relieving themselves in the commercially produced urinal “Fountain” (this actually happened, in the first instance, by a janitor outside a museum in the 1940s, and then later by an artist in 1990).
Duchamp sometimes gave the viewer specific (and absurd) instructions for experiencing his pieces. For instance, the title of an optical glass work he made in 1917 reads, To Be Looked At (from the Other Side of the Glass) with One Eye, Close to, for Almost an Hour (1918). And for the cover of a 1947 exhibition catalogue, Duchamp painted almost a thousand rubber “falsies” (prosthetic breasts), and attached a label asking the viewer to “Prière de Toucher” [“Please Touch”]. These strategies disrupt the usual, distant relationship between art objects and the audience, but they also critique and complicate it.
Perhaps Duchamp’s most elaborate and sophisticated challenge to creative norms was his invention of a separate artist altogether: “Rrose Sélavy” (c. 1920-21). Her name has been translated in many ways, but most often phonetically as “Eros [love], that is life.” To photograph Rrose, Duchamp enlisted the help of friends Louise Norton, a writer and editor, and Man Ray, a photographer and artist. Duchamp himself is done up in drag, dressed as a stylish, modern woman wearing a dress, wig, hat, and make-up. Norton crouched behind him, and it is her more feminine arms and hands that we see. Another photograph of Rrose was also featured on the label for a “rectified readymade,” a fake commercial cologne bottle labeled Belle Haleine, Eau de Voilette [Beautiful Breath, Veil Water] (1920–21). Imitating a commercial product poses interesting questions about commodity versus artistic production.
Appearing at a time when Duchamp was famously thought to have given up art altogether, Rrose continued to “make” pieces. Her name appears on many of Duchamp’s pieces including the “assisted readymade,” Why Not Sneeze, Rose Sélavy (1921/1964), a birdcage filled with marble cubes, a thermometer, and a bird’s cuttlebone. Her name is part of a tongue-twisting pun on the aforementioned Rotary Demisphere and as the signature on Fresh Widow (1920), a reduced scale French-style window with black leather panes. Rrose’s importance to Duchamp is evident in the very title of his miniature, portable display of his own art: Box in a Suitcase: from or by Rrose Sélavy or Marcel Duchamp (1935–41). In the last two decades, scholars have been extremely interested in the gender-transforming nature of Rrose, drawing on feminism, gender studies, and queer theory to understand the implications of Duchamp’s radical creation.
Challenging exhibition spaces
When Duchamp was asked to design exhibitions for fellow artists and groups, his imaginative set-ups often disrupted traditional viewing. For a 1938 show of Surrealist art, he placed artists’ works on department store revolving doors, covered the floor with sand and leaves, and put four large beds in each corner. Overhead he suspended coal bags stuffed with newspaper—a genuine fire hazard given the coal dust sifting down from them. Finally, Duchamp shrouded the space in almost complete darkness; Man Ray handed out flashlights to visitors with which to view the artworks.
Four years later, Duchamp designed the exhibition First Papers of Surrealism, in which he laced the exhibition space with a huge quantity of string, seriously impeding viewers’ ability to get close to the artworks. As if this were not enough, for the show’s opening, Duchamp invited children to play raucously in the space. It seems Duchamp was intent on flouting art world norms. In 1953, for an exhibition of Dadaism at New York’s Sidney Janis Gallery, Duchamp crumpled up an information sheet listing the artists and their artworks. Upon entering, visitors had to pull them out of a wastepaper basket. It was an appropriately iconoclastic gesture for a show of Dada art and another example of how Duchamp worked to subvert traditional expectations around viewing. 
The last word
Duchamp continued challenging his public, even posthumously. Just months after his death, a major new work was unveiled at the Philadelphia Museum of Art, the one mentioned at the start of this essay. He had been secretly working on Étant donnés for more than twenty years, from 1944 to 1966. Its long title: Étant donnés: 1. La chute d’eau, 2. Le gaz d’éclairage… (Given: 1. The Waterfall, 2. The Illuminating Gas…) is meant to imitate the dry language of a mathematical theorem. Peering into the holes in the door, the solitary viewer sees into a lighted diorama. Past a ruined brick wall are the hyper-realistic torso, limbs, and blond hair—but not the face––of a nude woman. She lays on a bed of twigs, legs wide open, and holds a lamp aloft. In the background is a detailed painting of a landscape with a mechanical waterfall that appears to be flowing.
Just as he had outraged viewers with his famous Nude Descending a Staircase, #2 at the Armory Show half a century earlier, so Duchamp hoped to shock his audience well into the future. Étant donnés (Given) can be related to the deliberately outrageous and sometimes women-objectifying art of the Surrealists, with whom Duchamp collaborated. But its themes are high-minded and include the nature of representation itself, artistic inspiration, and, of course, the individual experience of the viewer. Thinking about his future audience, Duchamp even left a notebook of instructions for its museum set-up and maintenance.
For those who approach the Étant donnés’s inexplicable rustic door in the Philadelphia Museum of Art and choose to peer inside, there may be both surprise and disgust. There may also be an immediate, self-conscious awareness that someone may catch them gawking, and that they, the viewer, are somehow involved in the scene before them. Ultimately, however, Duchamp implicates more than the individual viewer. He implicates the very act of looking, as well as a long history of art that similarly tries to lure the viewer’s attention and participation. 
As he said in his talk “The Creative Act”: “In the last analysis, the artist may shout from all the rooftops that he is a genius: he will have to wait for the verdict of the spectator…and that, finally, posterity includes him in the primers [textbooks] of Art History.” Despite—or perhaps because of—the intriguing challenges Duchamp’s art poses to viewers, his historical importance continues to grow over time.
 From a talk given by Duchamp in Houston at the meeting of the American Federation of the Arts, April 1957. In Michel Sanouillet and Elmer Peterson, The Essential Writings of Marcel Duchamp (London, 1975), p. 138–140.
 The Duchamp-designed exhibitions referenced above are, in order:
a. The Exposition Internationale du Surréalisme (January 17–February 24, 1938), Galérie Beaux-Arts, Paris.
b. First Papers of Surrealism (October 14–November 7, 1942), Whitelaw Reid Mansion, New York.
c. Dada: 1916–1923 (April 15–May 9, 1953), Sidney Janis Gallery, New York.
 Rosalind E. Krauss, The Optical Unconscious (Cambridge: MIT Press, 1993), pp. 111–15.
Duchamp reading “The Creative Act,” Aspen 5 +6, the Minimalism Issue, 1967, Ubuweb.com
Marcel Duchamp on The Metropolitan Museum of Art’s Heilbrunn Timeline of Art History
Dawn Ades, David Hopkins, Neil Cox, Duchamp (London: Thames & Hudson, 2021)
Calvin Tomkins, Duchamp: A Biography (New York: Museum of Modern Art, 2014)