CREATING ART IS CREATING SPACE
Defining rules means defining a space — a space of validation that allows certain things and disallows others. In essence, defining rules is an act of both inclusion and exclusion. Creating a finite work of art necessarily involves defining such spaces, which pertain not only to the inclusion or exclusion of materials but also to how these materials are allowed or disallowed to be composed together.
In music, such rule-based thinking encompasses a wide range of activities across different musical cultures and times. An improvisation in traditional Persian music (where the space is called a Dastgah: position of the hand), a sonata movement by Mozart (based on the tonal harmonic succession and motivic practices of the time), an integral-serial composition (a much narrower space), or a conceptual work like Alvin Lucier's 'I Am Sitting in a Room' (a very minimalistic space) are all examples of such spaces. Within each of these, a predefined set of handling acts on a predefined set of materials leads to the coherent and harmonious development of the music.
One can easily discern whether something belongs to the vocabulary of these musical languages or not. Having a well-defined, rigid vocabulary is a trait of a good art-work.
It is hard to imagine a human-comprehensible work that is not constrained by some set of rules. In fact, defining these constraints is one of the very first steps every creative worker takes. By declaring and defining the in-space materials and the morphological processes applicable to them (i.e. lying within the boundaries of the space), the artist ultimately shapes and defines the nature of his work.