As a composer, I couldn't help but be particularly interested in the chapter on notation in Music: A Very Short Introduction. The idea of notation is something that, as a composer, one struggles with everyday in a way that is very different than the way a performer struggles with notation. I won't write too much about a performer's interaction with notation, as that is more familiar to most people than a composer's interaction.
For me, notation is a very fluid thing. The idea of notation as something equivalent to written gospel is nonsensical. Composition is at times for me more about the design of a dynamic, adaptable system that can yield a number of interesting, meaningful possibilities than about the preservation of any one particular thought or idea; I am more concerned about the spirit or the essence of a composition than in consistent and predictable material substance, a static object. Now, this isn't always the case—at times, I like a definite idea with a concrete implementation, but this is on a case by case basis, born out of what the composition is trying to be, on the impulse that gives rise to the composition. Of course, there are also matters of practicality—in electronic music, there are certain sounds that can only be achieved in concrete form, so a static object is the only possible outcome. However, notation, in general, is something that I treat with a certain disregard—it is not the music, and it is the product of a society that believes in the permanence of an object. I do not believe in the permanence of a musical object. I believe that possibly the only cultural truth (or at least, what is statistically consistent) is change.
To a certain extent, composition is inseparable from philosophy. I think that, as a composer in today's world, it is impossible (or at least, should be difficult) to be unaware of the philosophical underpinnings of the way music is composed. Notation, or lack of it if that be the case, is a very natural extension of a philosophical position.
For example, one of the many important developments in Western classical music is the allowance of performers to play “whatever they want.” This idea is often not appreciated. There is the reaction of contempt for this statement, that the composer is lazy or incompetent; there is a more willing reaction where the performer attempts to play, but it often takes on a very static character, and to my ears, usually sounds very much the same from performance to performance. The reason for both reactions is, in my opinion, a lack of understanding of the philosophy behind this music. Notation, as mentioned, is assumptive of the idea of permanence, of a single, static way that things should be. As it has been the primary means of communicating a musical idea in the West (and mixed with the idea of sacralization of Western music), it seems natural that a certain amount of static behavior would develop in the practitioners of music. The idea of a the player “doing whatever they want” is actually a knowledgeable and pointed attempt at liberating the performer from a system of musical behavior that diminishes their role and assumes, and sometimes encourages, a lack of creativity on the part of the performer, that they merely be a playback device. The composer is honoring the performer and offering them a larger role; it is a form of respect and encouragement.
Unfortunately, I think many composers have merely adopted improvisation as another technique in their academic bag of tricks, and unfortunately, many performers have in response developed what has become a stereotypical style of improvisation to match. But the underlying idea is an important one, and when I sit down to compose, I try to be keenly aware to what extent and in what ways I want notation to have an effect on a piece of music (including, for example, even the idea of authorship; notation is a way of owning a piece of music).