It is not uncommon to speak of musical “ideas”. It has become very common, in fact, since a number German music writers in the early eighteenth century started speaking of musikalische Gedanken.
A musical idea is more or less what musicians and music analysts call a “theme”. One might think of a theme as a purely musical idea, a sound pattern. But Gedanke is more like thought, and “thought” suggest a thought process — typically, about something — rather than just sound patterns or shapes. Musical “thoughts” are what’s implied in musical “sentences”.
And what these thoughts are about is not necessarily something that can be put into words. Often, subconscious associations, which may switch seamlessly between vocal expression (the shape or “melody” of a sentence as we speak it), gesture, human action, natural processes, patterns of light and colour, and so on. Not or barely verbalizable, and therefore easily acquiring an air of mystery (“the ineffable”).
A sensitive performer reconstructs, in his or her mind, the notes and themes as ideas, as a thought process. Inevitably, an element of subjectivity is involved — but one that attempts to express itself from within the musical ideas, rather than impose itself upon them. This is what we call musical “interpretation”.
In the process of articulating our thoughts, we sometimes abandon them, run ahead of them. As when you’re talking, but finish your sentence mechanically, because another idea has already entered your head.
That’s what I was reminded of while listening to Josef Hofmann playing the opening solo of Chopin’s second Piano Concerto. The way the descending chords are broken sounds almost absent-minded. The forte bass octaves — padá-deedám — are like a call to order, but the second time a decrescendo sets in, the contours are softened by the pedal, and it sounds as if the thought is slipping from his mind, which may be anticipating the next idea, the cantabile melody.
Hofmann (1876-1957) is recognized as one of the greatest of romantic pianists. Few performers nowadays would dare or care to do something that so clearly goes against the score (the fioritura is marked con forza). Taking one outstanding modern recording for comparison, Krystian Zimerman’s second recording of 1999: it is striking how seriously every note, every phrase is put into place, how fully the sentence comes to a close. The interpretation is fully focused on the moment.
But sometimes our thoughts are ahead of us … I mean … well, never mind, that’s another matter.
Hofmann’s 1936 recording on youtube, starting at 1’40”.