
Marcel Duchamp, Fountain, 1917
This kind of art —known as found object or readymade; I call it art by fiat—has huge implications for the philosophy of art. If an artist can declare anything to be art—a urinal, a bed, a switch plate—then art, conceptively, is aesthetically empty. The declaration is all that matters. Specific works may have aesthetic value, but this is coincidental to their being art. This makes defining art, at least in the visual sphere, simple: Art is any physical thing or group of things an artist has declared to be art. (As Tracy Emin once put it in an interview: “ . . . it’s art because I say it’s art.”) Or, to avoid being circular: Art is any physical thing or group of things an artist has declared to be worthy of our attention or consideration. The only question left to answer is how one becomes an artist.

Tracy Emin, My Bed, 1999
(I wonder if someday an artist will attempt to abandon physical objects altogether. Maybe someone already has. If aesthetics don’t matter, why bother with physical stuff? If an artist can claim a glass of water is an oak tree, why not claim an empty space is a glass of water? Or a beautiful painting? Or a beautiful painting of a glass of water that’s really an oak tree?)
I think there are good reasons to reject art by fiat. Aesthetically poor art cannot engage us the way aesthetically rich art can. A switch plate cannot inspire sympathy, longing, sorrow, comfort, hope, guilt, faith, perseverance, or love. A great painting can. If we grant a switch plate the same status as a great painting, we devalue art, artists, and museums; we elevate everyday objects to a level absurd; and we frustrate and alienate museum goers in search of an aesthetically meaningful experience.
As for Duchamp’s Fountain, Wikipedia states “in 2004 [it] was selected as ‘the most influential artwork of the 20th Century’ by 500 renown artists and historians.”