Why then do we not also call a master carpenter a theorist, or a music theorist a master musician? Because there is a small distinction: the carpenter could never understand his craft in a merely theoretical way, whereas the usual music theorist has no practical skill at all – he is no master. And still another distinction: the true music theorist is embarrassed by the handicraft because it is not his, but that of others. Merely to hide his embarrassment without making a virtue of it does not satisfy him. The title, master, is beneath him. He could be taken for something else, and here we have a third distinction: the nobler profession must be designated by a correspondingly nobler title. For this reason, although even today the great artist is still addressed as ‘master’, music does not simply have instruction in its craft, its techniques – as does painting; music has, rather Instruction in Theory.

And the result: the evolution of no other art is so greatly encumbered by its teachers as is that of music. For no one guards his property more jealously than the one who knows that, strictly speaking, it does not belong to him. The harder it is to prove ownership, the greater the effort to do so. And the theorist, who is not usually an artist, or is a bad one (which means the same), therefore understandably takes pains to fortify his unnatural position. He knows that the pupil learns most of all through the example shown him by the masters in their masterworks. And if it were possible to watch composing in the same way that one can watch painting, if composers could have ateliers as did painters, then it would be clear how superfluous the music theorist is and how he is just as harmful as the art academies. He senses all this and seeks to create a substitute by replacing the living example with theory, with the system.

(Arnold Schoenberg)