Well, see, you have hit on the very point of Art as message and Artist as Speaker. The "message", I suppose, is "you create your own reality with your thoughts and beliefs". The second message follows that if you create reality then "you are a god, you do not need to bow and scrape to an imaginary one".
What is more godlike than Creation? Ergo...Artists (and this includes musicians, choreographers, architects etc)
Concerto #3 did mean something to the musician who composed it, and though it may SEEM that it could mean anything, I beg to differ. I think it conveys a message in its purest form, that without words the meaning can be more deeply "grokked" on an emotional level. Or, if that is too far out, think about in the sense that the hearer "creates" the meaning for himself as he listens, therefore assimilating the message and making it personal. It is impossible to look at or hear Art and have zero reaction. Even boredom or disgust is a reaction showing that "A" message, if not "THE" message was received. If someone looks at Michelangelo's David and stands in awe of humanity ("What a piece of work is a man...") or if he stands in front of it and is disgusted with the nudity...(Man delights not me, nor woman neither...) at least Art has made him think. Perhaps the image will remain in his memory and work on his negative beliefs. One day Man will indeed, "delight" him. He may be more susceptible to Art changing his beliefs in a constructive way than if he were lectured by a teacher.
IMHO
I just meant a Sethian slant on Shakespeare makes it worth a second look. 