When I use the dubious concept of computer-generated music (most recently here), a remark is in its place: A computer is just a tool, although an excellent one; a computer can't create music. The creator if any is the programmer/composer which uses the computer tool. Here again I think the concepts of rules, chance and choice can be useful in explaining the idea: The programmer/composer chooses which rules that are to be used and much other things. The programmer/composer also chooses which elements of the music that are to be governed by chance. The impression that the computer in fact creates the music, is perhaps enhanced by an extensive use of elements of chance. When the music clearly isn't  by human hand it is easy to attribute it to the computer. But again the computer is just a tool and similar result could potentially be produced by another less powerful tool, e.g. a dice. The important thing in this case is I think that the programmer/composer is choosing where chance is applied.