Does music theory hinder creativity?

I recently got into a very inconclusive argument with one of my good friends and fellow musicians. He argued the point that many people have stated that music theory is nothing more than a stigma in a musicians creative mind, and that true music doesn't need these boundaries that were set forth way back when by the Greeks. As much as i respect the creativity of my fellow musicians, i don't believe this to be completely true. I believe that with 100% knowledge of all music theory, one has unreach...