Cage is sermon. When one knows exactly the sound he wants, there are only a few notes in any instrument that will suffice. Choosing actual pitches then becomes almost like editing, filling in detail, finishing things off. Isn't it curious that in the classical period the selection of range and timbre, i.e., orchestration, was the secondary finishing-off thing. Just the opposite.
Music can imply the infinite if enough things depart from the norm far enough.
The reason I don't like theater pieces is that one usually has to sacrifice some of the musical for the sake of the theatrical. I wrote a solo trumpet piece where the player talked, removed valves, talked through the horn, and did other actions, but theater is not my medium, and I've dropped this piece from the catalog. That is the finest kind of integration of music and theatrics. You have to find a place for everything. Every idea needs to find its place in time, its context, its environment, a world in which it can exist.