Recently I viewed a valuable documentary about Keith Jarrett, in which he had a lot to say about his art. I also saw a valuable Q and A session with Joe Henderson about learning how to improvise. Both of them emphasized the importance of memorization. Jarrett, whose trios played standards, usually not deciding in advance which ones they would play at a given concert, told how he memorized countless standards early in his career. Henderson talks about listening to records, transcribing solos, and playing from memory. Jarrett and Henderson did what they did naturally, without teachers telling them that's what they should be doing.
Not every expert musician is a great memorizer. But a professional jazz musician ought to know the melodies of hundreds of standards as well as their underlying harmonies and to be able to improvise according to those harmonies by ear. A musician who can't do that will become some other kind of player.
Certain types of classical music also demand memorization. Concert pianists and other soloists are expected - and expect of themselves - to memorize the music they perform, an ability that astounds me. Some of the works they play are long, technically difficult, and very complex. It appears that the process of mastering a concerto includes memorizing it.
When I was young, taking piano lessons, I think I was told to memorize pieces, but it didn't stick, and I never became even a fair pianist. All my subsequent musical education was based on reading notes well, and I never felt confined by that emphasis. I was never a natural musician, and that hasn't prevented me from enjoying playing.
However, I think it's important to address my weaknesses as a musician, even at my advanced age, so I try to memorize pieces and I sometimes go through the exercise of playing a memorized piece in a number of keys. Since I play saxophones in Eb and Bb as well as flute, I have to be able to play tunes in three different keys, an interesting challenge.
One of the pieces I am trying to memorize is Charlie Parker's "Blues for Alice." It's difficult for me, partially because the changes (the chords) aren't those of a standard blues. I assume that Parker didn't write the music down and play it from the written notes before improvising on it. He probably composed it in his head and played it from memory. Among many others, Roland Kirk recorded it. Since he was blind, he had to learn it by listening to it and playing it by memory, not a feat one should take for granted, as the melody is tricky.
Even if one is not a natural musician like the great masters of jazz improvisation, one can inch forward toward greater competence.
