Recently, in the wake of the Ofili controversy, an artist friend and I were discussing the difference between art and expression. She was having difficulty coping with the incredible exposure Ofili's work was getting in the media, not to mention the Brooklyn Museum of Art itself. The difference is this. Expression could be just an oral statement, which would not be considered art. Art must take some kind of tangible form. And mere expression could also be very UNcreative, simply repeating something heard, done, or seen elsewhere. It's original thoughts that count when we refer to CREATIVE EXPRESSION.
For art to exist however, creative expression has to be effective in projecting a point of view or message. The effectiveness of creative expression is determined by the artists primarily, but also to some degree, the viewer (or listener as in the case of music). Art is, after all creative communication. For communication to take place, the message must be adequately RECEIVED as well as SENT. A beautiful poem in Polish would not be art to me but then it would be largely MY fault because I have never bothered to learn the language, not the artist-writer's. With the visual arts, the situation is not so clear-cut. The "failure to communicate" could lie at either end of the line (or both ends). If the artist is speaking a visual language so esoteric ONLY he or she is likely to understand it, then any message intended by the artist is likely to be muddled, any communication quite accidental; which lays a tremendous burden on both the artist and viewer in the case of abstract art.
Titles help, of course. They may NOT (and perhaps SHOULD NOT) explain the art, but at least the put the viewer in the right ballpark and suggest the direction the artist's thoughts and feelings were headed. Abstract painters often need these titles, but at the same time are often the artists most likely to eschew them, feeling that a title that is in any way explanatory (communicative) indicates the art is somehow inadequate in its attempt to communicate creatively. Quite often, the abstract artist insists that the viewer meet him or her halfway, inputting a significant part of the creative communication effort themselves. In a sense, the artist is sharing their role as artist with the viewer. From a different point of view however, they are also IMPOSING the role of artist upon their viewer. And all too often, the viewer may be too lazy or unwilling to accept this role (or can't accept it because of a lack of basic knowledge of the medium or message). This is when art breaks down and controversy arises on both sides as artist and viewer blame one another for their "failure to communicate."