Far be it from me to answer that one. I think of Busoni's wonderful comment that technical exercises should be assigned the way doctors prescribe toxic medications. What is he talking about?
I think he's talking about hands, yours and mine. Hands command such a huge portion of our brains that it is almost unbelievable that they occupy so few cubic inches of our total body mass. Yet, so many sensory systems are focused right there, so much information is gathered and put to immediate use by our hands - they are truly extensions of our innermost selves.
Technique a la Czerny exercises tends to reduce the infinite variability of each finger and every hand to a set of prescribed motions and falsely idealized results - evenness, for example. Who wants evenness? I strive for the maximum variability in everything I do with my hands because they show the vitality of my ear.
Touching the sounds I hear in my imagination--you can't learn that from a book, any book.
