Thank you, Jerry for starting this thread. This should prove insightful for beginners like me.
What Mike said makes a lot of sense to me, regarding the relationship between improv and composition. And the idea of graphing the entire piece is pretty cool. No wonder that helps to create coherent large scale structures. Ive heard that sketching an outline as the approach used by many great composers, from Beethoven to contemporary ones like Corigliano.
I come from a tradition (Indian classical music) where there is no written music and everything is done on the spot. However, there are many predefined phrases from which the artist chooses, and in a way their improv is already pre composed. The more sophisticated the artist is, the more phrases he/she knows and it almost sounds like they are making new musi as they go alone (this also depends on the sophistication of the listener).
So I wonder if 'improv' and 'composition' become more and more indistinguishable when the artist's musical knowledge becomes more sophisticated? So that every new note or chord they come up with is already well thought out, and its only secondary matter of they put it on a piece of paper (composition) or play it on an instrument (when its called improv)....of course this leaves out the element of the sub conscious and spontaneity that makes us so human.
Anand