Isn't much of music -- at least that much that is not about speech-like communication -- the attempt to fill in the space between two moments of time?Charles Shere posted a serious response:
Well, not to me, no. I mean, yes: music as it was thought of in its Great European Age, say Bach to 1950, yes: it's attempts to fill in "space" between moments. Or so we think of it, though I feel that many masters manage to do this sort of mechanically (though very well indeed) when in fact they have a completely different idea in mind, and that's what I like about a lot of Berlioz, Schubert, Bruckner, Sibelius: their music may be about filling a duration, but it's also about getting completely away from a concern with that.
Point is, a lot of newer music (including much of my own) is not about moving from moment to moment, but about existing within time, doesn't matter what moments one might choose as kickers or closers.
I don't think that my claim is contradicted by Charles' point; in fact, I suspect that my claim is the necessary precondition to a music which -- perhaps dialectically, perhaps intuitively -- is all about allowing us to get beyond, or even forget the moment with its beginning and end and to transcend our everyday experience of time as duration.
This is a process which began, as far as I can tell, with the notion of polyphony and was later dramatically expanded with the use of multiple topics in late Viennese classicism. Polyphony, at root, is about doing different things (making different sounds) at the same time, allowing them to share a moment, and music history illustrates a course in which the definition of "different" was continuously expanded (systematic musicology would describe this on a continuum from more alike to more differentiated, or homophony to heterophony). Notable way stations on this path include the polytextual motet, the simultaneous tempi of Monteverdi's Concitato style (which is a rather simple relation to the extraordinary Javanese irama system*), the three simultaneous dances in Don Giovanni, and continue through the network technique of Wagner, Ives' use of polyphony to evoke physical spaces, etc..
The initial fork in the road is that between music as heightened speech communication and music as an aesthetic marking of time's passing. There have, in fact, been very good examples of music which has attempted to reconcile this, and often the means have been polyphonic; the contradictory accompaniments in Schumann's Im wunderschönen Monat Mai and Ives' The River come first to mind. But the more influential path seems to me to be in the diachronic play of musical topics which emerges an an alternative to the rhetorical systems cultivated in the baroque and classical eras and emerges most clearly with the late works of Mozart and throughout Beethoven's catalog. It is most central to the "figure in a clearing" topic, which I would date in absolute works to Beethoven's Pastorale Symphony**; this topic is characterized by a musical background (not yet an accompaniment, just an atmosphere) without significant temporal markers of its own before which foreground events occur. This topic is important to each of the composers Charles mentioned, and I would add Mahler, Ives, Cage (in the works with rhythmic structures and, later, time brackets) and Feldman (the composer on the grid) as well as any composer who begins by first laying down a persistant groove and then putting things on top of it.
* Paradoxically parallel tempi, creating environments in which it is unclear whether the prevailing tempo is slow or fast are fascinating. My favorite recent example is that of Alvin Lucier's string quartet, Navigations for Strings, in which the notes played by the strings are articulated at a very slow speed, but the resultant beats from the microtonal tuning often emerge as the vivid surface of the music, and are at times quite fast. Or another example from the history of film -- here's Jonathan Rosenbaum's article about tempo in the films of the extraordinary director Yasujiro Ozu, Is Ozu Slow?.
** The Pastorale is absolute music with a programmatic veneer: you get over the program quickly enough to realize that there really is music there.