Many modern artists have used the window as a metaphor for the way we see representational painting, but no one complicated the metaphor as Rene Magritte did. In Matisse's paintings, for example, windows appear often, both as light sources and as affirmations of his view of art. For Matisse intended us to see his paintings as refreshing glimpses beyond the grinding reality of modern life. Magritte's attitude was more confrontational. He wanted us to face fully the paradoxical character of painting in our time. Like the other artists who called themselves Surrealists, Magritte seems to have believed that rationality misrepresents the real energies of life and that to live is to embrace their force and unpredictability. Although much of his painting can be read as witty reflection upon formal conventions traditional to the making and interpretation of pictures, it also lets us rehearse our tolerance for contradiction and surprise in everyday events.
''La Clef des Champs'' is a unique case of the painting as window. The metaphor makes sense generally because in entering into a pictorial illusion we look beyond the picture's surface as if it were actually transparent. Magritte shows us the paradox in this familiar experience by shattering the pictured window. What results is true to the nature of the picture (what's really there) rather than that of a window. The shards of broken glass affirm the identity of image and surface that we tend to forget when we become absorbed in a picture. It is as if the landscape view beyond the window were caught in glass as it broke. But just so we don't get too comfortable with this sense of the matter, Magritte has also left the landscape intact; we have to wonder whether the glass still in place is transparent or is the remains of an image as improbably coincident with the scene behind it as the fallen fragments suggest.
In a number of his paintings Magritte depicted painted canvases whose subjects coincide perfectly with the portion of landscape that they obscure. His use of the window in ''La Clef des Champs'' is a variant of this figurative theme. Beyond the clever musing on pictorial illusion that such images involve, we may infer a more abstract philosophical point. A highly literate artist, Magritte was surely aware of Immanuel Kant's influence on European thought. One of Kant's key arguments is that we can never know the nature of things in themselves, because we cannot tell what effect our ways of knowing have on their reality: we must be satisfied with being warned that we are liable to confuse our means of apprehension with aspects of the world we wish to know with certainty. Magritte's painting may be seen as a kind of joke about this philosophical impasse.
The view that adheres to the window (as the broken shards describe the matter) exactly matches the landscape vista behind it. If we regard the window as a symbol for our faculty of knowing, then its perfect coincidence with the world seen through it implies a humorous rejoinder to Kant. The image as a whole can be taken to suggest that the reality we can never know directly just happens to correspond in its true nature to the order imposed by our effort to grasp it. To a Surrealist like Magritte, the cosmic irony of such a possibility would have been irresistible.