1. A few materials subjected to many transformations.
We hear a lot about this one. In school, economy is paramount -- everything must be connected to one chord, one melody. It doesn't seem to matter whether these connections are audible. If they're on the page, you can't argue -- they're coming into your ears. It adds up to a kind of modernist's mysticism: you can't hear its unity, but once you know its there, can't you feel it?
This feeling of unity is faith, though few would call it that, and it profoundly shapes our listening. Analysis class turns out to be primarily a faith-raising exercise -- Boulez sounds illogical doesn't he? Well look, he's not! The details tend to not be important except in that they demonstrate a Deep Unity and Serious Intellectual Rigor, (and we're easily impressed). Put it back on the stereo and, if we bought the analysis, we listen differently, reverently, trying to be open to the Mystery as it pours in.
It's a rare thing to get to be both a humanist and a mystic. I think that's probably why I'm drawn to it. But there are a lot of problems with this model, specifically hylomorphism and essentialism, which I'll outline soon.
2. Many materials subjected to few transformations.
This approach is very exciting to me and, as far as I can tell, underexplored. Transformation is the foreground -- the materials are irrelevant except that, in passing, they describe unseen forces. The music is a river or a whirlwind; leaves, dirt, houses may pass through them, but it doesn't matter which. They can be in any order, have come from any place. All that matters is that they help reveal the whirlwind's form. It's the 'melting pot' -- unity isn't in the ingredients, its in the fact they've all been melted.
Some material can be a description a force -- dirt is great for a whirlwind, anvils are not. But a diversity of materials is best. We need to see the behavior of both dirt and an anvil to know the extent of the whirlwind's power. The greater the variety of materials, the better they describe the unseen force. As a result, it 'works' differently than other music. It works exactly like Contact Improvisation, in which coherent dances are effortlessly created by funneling all freedom through a single constraint.
(This is how I hear James Dillon, and why I'm wild about his music. The details are chaotic but the forces acting on them are clear, effortless to follow.)
So this music's form and construction is in its negative space. The positive space -- the sound -- spontaneously takes on forms generated by (but not simply the inverse of) the negative space.
I suppose you could say that this is how the Boulez-types construct -- the method-machine is the negative space and the music is what happens when you turn it on. But there is a distinction to be made: while the sonic matter of the piece may be an accurate product of the method's generative forces, it does not necessarily follow that they are meaningful description of them.
To be a meaningful description of forces, the forces have to be recoverable -- if you listen and find it impossible to meaningfully abstract, if you cannot take a derivative and see a line -- there has been a rupture, a disunity, between the form of the music and the form of the music's source. This position takes too small a view of music. It's like studying an animal but ignoring its environment. We should take the larger view. Unity isn't a function of numerical correspondence, motivic development, thematic return, arc shape -- although these all may be evidence for it. Unity is continuity between a form and the forces that formed it.
And we learned everything we know about forces from our bodies.