If virtuosic perfection at least were achieved, one could—in a forgetful moment—be satisfied with that. But one cannot even claim this, since the leisurely attitude of the majority of classical players toward rhythmic accuracy is simply appalling, and would seem so to more people were it not so widespread as to be generally accepted. There is no question in my mind that the classical world can learn much about timing, rhythmic accuracy, and subtlety from jazz musicians, as jazz musicians can in dynamics, structure, and contrast from the classical musicians.
Gunther Schuller, “The Third Stream”, 13 May 1961 in The Saturday Review of Literature, as collected in Musings: The Musical Worlds of Gunther Schuller