Does art exist without an observer? If I shoot a photograph, and never develop the film, can that be art? What if I develop it and make a fantastic print, but shred it immediately? What if I make the print, mount it, and place it on a wall nobody ever looks at?
These are, really, just silly questions. What sensible person really cares about the answers to these, and are there any answers anyways? The point is not to answer the questions, but to consider what idea spin off from them.
Related, from a discussion elsewhere. Are naturally occurring objects, objects created without the hand of man art? If I select the right object and photograph it, or place it on a pedestal, that's probably art. At what point and in what manner does the object become imbued with art-ness?
These are not really questions with answers. If you try to hard you'll invent Postmodernism or Conceptual Art or something, and that's not something anybody approves of. They're good to think about, though.