Platonism, Music and the Listener's Share

What is a musical work? What are its identity-conditions and the standards (if any) that they set for a competent, intelligent, and musically perceptive act of performance or audition? Should the work-concept henceforth be dissolved as some New Musicologists would have it into the various, ever-changing socio-cultural or ideological contexts that make up its reception-history to date? Can music be...