invention

You see, I think Mussorgsky was accurate in his observation and wrong in his concept: I think his observation that Mendelssohn was a strait-laced man who liked nice, tidy sixteen-bar paragraphs was quite correct. What he forgot to notice was that Mendelssohn was inventive on another level altogether. In order to comprehend his invention, one has to first accept that placidity that is the most abundant feature of his music. Having accepted that, Mendelssohn can then surprise you by the gentlest movement; he needs only the tiniest change, as they say in the jazz field, to make his effect felt. Whereas in the case of Mussorgsky, he has to hit you over the head with a forte-piano contrast, or a quasi-modal moment or something—I happen to like Mussorgsky, by the way, I really do. He wasn't very competent technically, of course, but then neither were the Beatles. However I think that the point was indicative of a misunderstanding—and this wouldn't apply just to composers—that has always muddied the waters for artists who assume that invention has something to do with the noise you make while breaking rules. Needless to say, I don't think it does. I think it has to do with the subtlety with which you adhere to premises somewhat different from those that may be expected of you.

-- Glenn Gould, in Conversations With Glenn Gould by Jonathan Cott