2. An excuse the ignorant make to put down artists that try to push the boundaries of contemporary music. All the while these same ignoramuses believe poor technique and slop equate with good music just because everybody else thinks so. These people also have never bothered to actually listen to the music they loathe so much.
3. A set of (flexible) rules that dictate the manner in which music functions.
Serving suggestion: Musical theory best served with at least 2 years experience with actual musical instrument.