Why teach? The question makes perfect sense when you think that for every lesson, the teacher is getting worse and the student is getting better. The teacher could be practicing – something he doesn’t have much time to do.
Is there an alternative to teaching? Perhaps not, but I think Roger Stevens [principal of the Los Angeles Philharmonic] made a good suggestion when he said, "Teach the student to teach himself." How do you teach a student to teach himself? The simplest way is one that Marcel Moyse stumbled on. Take something that you play well and something you play poorly and compare the two.
You don’t need a teacher to tell you that your E is bad and your A is good. You can hear it. So you play E-A, E-A, and compare the sound yourself playing the E until it sounds as good as the A. You don’t need a teacher to tell you that your D trill is poor and your C trill is fantastic. So you practice by comparing the trills. You always find something you can improve.
This can be done with keys as well. You play a piece in one key you know well, then play it in a key you don’t know so well. You know immediately yourself how it should and could sound. You don’t need a teacher. We teachers spend most of our time being policemen. We should give out traffic tickets; or perhaps if we collected fines for every wrong fingering ….
Teaching yourself goes further than this idea which leads me to class teaching. Class teaching is marvelous. Not only can the teacher get results much faster, but there are two things that can only be taught in a class – intonation and ensemble. (Actually intonation can be taught alone, but it’s better taught in a class.) As far as ensemble is concerned, here’s an example. Two people play duets, but they don’t try to play together. Instead they decide who’s going to take the lead. One of them says, "O.K., you change the tempo any way you like, now fast, now slow. I’m going to stay right with you all the way." Then the other person takes the lead – plays completely out of time and the partner tries to stay with him. After that they just play the way the music is written. If you try this you’ll be amazed how well your ensemble becomes. Most of the time you’re not giving your ear enough of a challenge. Experimenting with this procedure does.
So, a good teacher will teach the student to teach himself. In the end, the best teachers produce students better than themselves.