It struck me this morning that a key feature that distinguishes art from science is that art is studied in the context of the artist, while science is not. When you learn calculus, mechanics, or optics, you don't read Newton. Science has content that can be abstracted out of one context - including the context of its creation - and studied and used in other contexts. This is a defining characteristic. Whereas art can't be easily removed from its context - one could argue art is context. When we study art, we study the original work by a single artist, to get that artist's vision.
(This isn't a defining characteristic of art - it wasn't true until the twelfth century, when writers and artists began signing their works. In ancient Greece, through the Middle Ages in Europe, the content, subject, or purpose of art was considered primary, in the same way that the content of science is today. "Homer's" Iliad was a collaborative project, in which many authors (presumably) agreed that the story was the important thing, not one author's vision of it, and (also presumably) added to it in much the way that science is cumulative today. Medieval art generally glorified the church or the state.)
However, because this is the way western society views art today, we can use this as a test. Is it art or science? Well, is its teaching organized around the creators, or around the content?
Philosophy and linguistics are somewhere between art and science by this test. So is symbolic AI, while data mining is pure science.
There definitely are parallels between studying either the process or the "content" of a scientific field and studying what I would refer to as "technique" in the art world. Musical composition is one example, and as a visual artist I can add things like color theory, semiotics, visual composition, and the handling of various mediums. These are phenomena that can and have been taught and written about. They can be as objectively addressed as any scientific subject in that you can say "if you follow procedure X, you'll get Y result".
But these things are supplemental to the primary goals of art/artists which are profoundly different from the goals of science/scientists. The goals of artists are generally personal and/or subconscious. They don't (normally/consciously) involve a hypothesis to be proven or disproven (and artist statements are typically written after the work is complete, not beforehand).
There are formal studies of what groups of artists may be trying to achieve (surrealists, cubists, expressionists, etc), but the cultural and biographical details are usually very relevant. I guess I'd say that your test is one possible measure of a more general question: "Is the endeavor more focused on making a statement, or on answering a question?". The more it emphasizes the former the more likely it is to be art (or politics, or lunatic raving. Or all three, depending on how entertaining, persuasive, or coherent it is), the more it emphasizes the latter the more likely it is to be something deserving of the name science (even if it may also deserve to be preceded by the words "sloppy" or "pseudo").