” A chair sits alongside a photograph of a chair and a dictionary definition of the word chair. Perhaps all three are chairs, or codes for one: a visual code, a verbal code, and a code in the language of objects, that is, a chair of wood. But isn’t this last chair simply . . . a chair? Or, as Marcel Duchamp asked in his Bicycle Wheel of 1913, does the inclusion of an object in an artwork somehow change it? “