Calculus in practice involves a lot of symbol manipulation, so it's important to understand the symbols. Jazz in practice involves a lot of playing an instrument, so it's important to understand…
Fill in the blank. I don't know about you, but I don't fill it in with “music theory”.
... how to use music theory to develop efficient practice routines for your instrument(s), goals, and current abilities.
— jazz musician of 25 years
(this calculus metaphor is pretty far off - music theory in practice, by a working jazz musician, doesn’t involve “manipulation of symbols”, at least not in the same way as one works mathematical problems and proofs. it involves a lot of time on your instrument, applying theory in practical and experiental ways. oftentimes we will write out a lead sheet, or transpose something, and use theory to do that. and so there’s some calculations happening. it becomes second nature with practice).
> Fill in the blank. I don't know about you, but I don't fill it in with “music theory”.
That's because you aren't a jazz musician. Jazz features lots of complex harmonies, and theory is a big part of writing and playing it. Certain subgenres are virtually impossible to perform without a solid theory foundation. You think you can just solo over Giant Steps by feel?
Fill in the blank. I don't know about you, but I don't fill it in with “music theory”.