For
Creativity and expression matter more than rules.
Against
Theory gives structure and understanding to music.
Anonymous excerpts, translated where noted.
“Many people with no formal theory training are successful, while many with formal training are not.”
“You definitely don't need sheet music to become a musician.”
“Without theory, you trial and error until something fits; it is possible, but not efficient.”
“I can't get any better than I am now without learning scales, notes and theory.”