There’s a very unusual idea near the end of the level on Changes:
When the bass notes change along with the shape, the new bass note takes on the feeling, ever so slightly, of being a new anchor note. And yet, that new anchor still wants to pull back to the main anchor note of the song.
When you start paying attention to this, you’ll find that it’s true of all bass note changes, whether or not the shape changes along with them. So a bass note change is like an anchor change, only at a different, more subtle level, floating above the main anchor note of the song, and wanting to pull back to it.
So far, the changing bass notes have resembled the musical structures you’ve been playing in relation to the anchor note. But now, they’ve also taken on the quality of an anchor, while still retaining their feeling of tension to the main anchor note of the song.
This means that we have two different levels of anchor notes, and it turns out that the relationship between these levels is very closely aligned with the standard concepts of chord and key.
When we think about it in these terms, the anchor note is like the song’s key note, and the changing bass notes represent changing chords—they are chord-level anchors. But where do shapes play into all of this? Are there also shapes that can change independently at the chord and key levels, and that have a relationship to one another?
In order for a bass note to represent a chord, it has to be taken along with its shape. The combination of the shape and the chord-level anchor give us a context that can fully describe the chord. But it is only in the sense that the other notes of the shape are also tensions to the chord-level anchor that they have a relationship to the key-level anchor. The shape itself represents a different experience entirely—the experience of notes that feel like they fit or don’t fit with the song at that particular moment.
So you are playing in a shape, there are changing chord-level anchors within that shape, or across changing shapes, that organize all the other notes into tensions that pull both to the chord-level anchor, and to the key-level anchor. Each note in the song has a feeling of tension at these two different levels, and also, independently has the feeling that it fits or doesn’t fit with the shape.
But this suggests something surprising about the shape. If the feeling that certain notes fit or don’t fit changes when the shape changes, and shape changes occur at the same level as bass note changes, then this means that the shape is at the chord level, and not at the key level.
Thinking back to our earlier levels, when each song had only a single shape and anchor, the bass notes did indeed change at the chord level, but the shape associated with each chord-level change remained the same. So while a single shape did indeed describe the entire song, it was only because the same shape described any and all changes that took place at the chord level.
Meanwhile, the anchor note remained at the key level, and we heard the changing bass notes as tensions to that key-level anchor. Or, perhaps more accurately, you could say that the key-level anchor emerged from the changing chord-level anchors, because it was emphasized, in one way or another, by those changes.
If you were to imagine a shape at the key level, it might be something like the shape that best describes the overall collection of notes across potentially multiple shape changes at the chord level. If you wanted to continue having the immediate experience of notes that fit or don’t fit—which is the central experience of a shape—you would want to follow along with the chord level changes. But by staying at the key level, you will have taken a step outside of the experience of a shape, into a theoretical abstraction across multiple changing shapes.
This kind of abstraction is a common occurrence in music notation, when the staff is mapped to a single key signature throughout a song, even though the song changes shapes. And it is also a common occurrence when we use an idea like key to describe an entire song.
This is precisely why the shape and anchor need to be two separate concepts, and not a hybrid concept like key. It allows us to recognize these different aspects of our musical experience independently, and to allow them to work at different levels of musical context, so that they remain connected to our immediate, intuitive experience.