What is art?

In the process of its creation, the artist must have been trying to optimize some non-objective characteristic about his or her work.

This includes a great many things that might not be traditionally considered art. It also excludes a few (I'm not positive if any) works which just kind of happened -- a product of randomness -- without the artist exhibiting any control or optimization.

This means "But is it art?" cannot be answered without "inside" information about the artist and how the work was created.

The inspiration for this was a meditation about scientific hypotheses and how they must be rejectable. Thus a stronger condition than the above is that not only must the artist be trying to maximize some measure of "quality" but he or she must also have a threshold of "acceptable" quality below which he or she will "reject" the work, which means something like not publishing or exhibiting it. Art must be rejectable.