Preface, I have taught jazz theory, improvisation and jazz guitar at the university level. I'm the author of the Sheets of Sound for Guitar series books. I'm well versed in traditional and jazz theory.
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Do you realize that theory, in particular -- western theory, is an after-the-fact analysis of composed music? We tend to think of theory as rules and formulas when it's simply a common language used to describe what someone else has done.
The common western theory taught in universities is based on the Baroque period of music (1600–1750).
And then, when jazz came along, we tried to analyze it in terms of Baroque rules and principles. Along came Bird, Trane, Herbie, Chick and up and up.
AND WE ARE STILL USING BAROQUE terminology to describe jazz. Of course, Barris Harris, Hal Galper, Dave Liebman updated these principles and helped usher in a period of what we now refer to as "Jazz Theory".
Of course, we are still taking after-the-fact analysis and attempting to generate rules and regulations about what is valid based on looking at things backwards.
Reality check -- You don't play by the rules. YOU MAKE THE RUlES. The rules will bend to follow what you played. If it sounds good, it *IS* good.
With all that being said, can you play a b9 against a Maj7 chord? Answer, YES OF COURSE YOU CAN. Try taking a tune like "You stepped out of a dream" and for ever tonic, Try using an altered dominant tonality. Does it work? Yes, does it fit the rule books? Who cares!!!
Let's stop trying to use western theory (baroque or otherwise) to govern what we can or cannot do in jazz.
Rules are like labels, jazz is not Mayonnaise.
I'll post some more articles like this in the future, perhaps taking these concepts forther.