[analog31]

Indeed, "theory" is not an all-or-nothing affair. There's a level of "theory" that's just learning why certain intervals are harmonious in the 12 tone system, and the names of things. I certainly learned those things, but if asked whether I know "theory," my answer is no. Virtually everything I know about harmony in jazz is due to hearing and recognizing recurring patterns.

In my case, I've gotten through 40 years of performing with jazz groups, so in some sense I'm doing OK, but I also know that I struggle with ultra-modern jazz harmonies. This came into pretty sharp relief when I played with some musicians who were composing all of their own tunes. I reach the end of my mental map, and then I have to fake it, or improvise directly from the melody.

But I agree that "ear" and perception of harmonic structure are closely related. It's hard to describe, and might make a psychologist cringe, but a musician develops a "mental ear." And I wouldn't recommend my approach to a young player. Most people want to become proficient in fewer than 40 years. ;-) There are things I can't do. I can't compose or arrange anything worth playing. Without exception, every musician I've played with who could compose or arrange decent jazz material has a music degree.