Originally Posted by GuitarBizarre

Your point about can and should depends on musical context. Germanic tradition says we should NEVER compose music that moves in parallel fifths, yet some of the earliest recorded music from the western world is plainsongs and chants that do exactly that. You can do anything in a valid context. Popular music might not be that context, but experimental music and art music most certainly could be.

For the same reasons, a song comprised entirely of silence would have a lot of people claiming it isn't music. Yet John Cage argues that the only thing we can truly say is not music, is that which lacks a defined structure. Take structure away from any sound and it is not music. Give it even a basic structure and it becomes music.