I had a thought today as I was teaching first-species counterpoint to my freshmen. I think the received wisdom is that music theory is a long, long list of rules that you have to learn, and that most of these rules are cast as prohibitions. I realized that I was telling them what not to do (i.e., avoid parallel perfect consonances, avoid dissonant intervals, don't write more than three of any interval in a row, don't this, don't that...) more often than I was telling them what to do.
Thoughts?