Unlike some of the time-travel movies I love like 'Primer' or '12 Monkeys ' 'Looper' is not about time travel. It's about this situation that time travel creates and the people dealing with that situation. So narratively the big challenge was to have time travel get out of the way.
From the beginning I knew intuitively that if nothing else music was safe and that nobody could tell me anything about it. Music didn't need a middleman whereas all the other things in school needed some kind of explanation.