when a person tries to develop his capacity to expand and improve the way he HEARS the sounds going on around him, he is faced with several problems which aren't necessarily present when reading music or chords symbols from the written page. having "good ears" means having the ability to HEAR the roots to the various chord or scales that are being played; having the ability to HEAR the quality of the chord scale ... major, minor (what kind of minor?), pentatonic, diminished, hole tone etc.; it means having the ability to tell what note of the scale or chord is being played at any point in the solo... "ah, that note was the #4 resolving to the 6th resolving to the 5th!"; it means HEARING the piano, bass, soloist, drums etc., individually as well as collectively. There are many levels of HEARING. Some people can hear. Some people can really hear!. And some people seem to hear and identify almost anything that is being played. They can seem to sing or play back portions of solos right after the performer has played. How can they HEAR so well? when most of the people can't even find the roots, scales, qualities, or what time signature the piece is in? If all the students from the first grade (even kindergarten) through their last year were exposed to simple ear training exercises that allowed them the opportunity to identify what they were HEARING on the radio, tv, records, jazz, opera, chorus etc., our music scene in general would be much different and the public would demand music of a much higher calibre that they are presently consuming. Why would they demand "better" music?. Because they would HEAR that the music they are being fed is too repetitious, trite, and banal to warrant our attention, much less our money on the sales of records or concert attendance. One of the reasons jazz music (especially the music from Bebop to the present) has never had a big audience is due the amount of thinking required to actually get the essence of the music. The average person today doesn't want to think about music, he just wants to enjoy it. And he usually will settle for the same thing day after day. He feels life is too difficult to have to think about the music he is listening to. Hence the gap between the performer and the listener in the world today. Of course that doesn't mean that HEAR intellectual music is not enjoyable.