Glenn Gould is up at the family cabin. He's young, playing on the family piano. Something by Bach. You can hear the articulation click-clack on the left hand line and then he's up and over by the window. The relentless flow of information continues, he's still practicing, still playing, but looking at the lake.
Haptics are the physical actions required to play an instrument, the sense of touch, the interaction with mechanics. That's part of what we're seeing here.
There's a structure, an underlying phenomenon, the Ineluctable Modality of Bach, let's call it. There's this other thing, let's call it Glenn Gould. Imagine a Venn Diagram. Some part of Glenn Gould interacts with the Ineluctable Modality of Bach. Some other part of Glenn Gould moves through a world of chairs and dogs and fingernails. The intersection of the three is at the keyboard, to "play the piano" .
When I write music, I can't hear notes. I've never had a great ear, sightsinging and ear-training I just wasn't very good at it. What I do get is a sense of what it would feel like if my body were the shape. A sense of gesture. If Messiaen wrote by Synaethesia, I'd describe this as a sense of "Kinaesthesia". It's not dancing, I don't visualize choreography or movements. But I do feel muscular contraction. My body isn't convulsed, I'm not talking about actual movement. Rather, there's the intuition of a gesture.
If I could compose in the medium of physiological twitches and quiverings, I think I would. Sound is an epiphenomenon of these Kinaesthetic whispers.
I always write at the piano. The exercise of compositional craft is to be able to recognize when I've fit the right notes to the gesture. Today I spent an hour trying to figure out a rhythm I'd been tapping on my fingers this morning on the bus. I'm spending the time trying to figure out if I need to notate a precise tuplet rhythm, or a trill with poetic license. There's something about the difference between an appogiatura and a grace note that I feel could define a big piece. But I can't remember the damn thing.
Most of the time, the music under my fingers at the piano ends up not feeling right. Composition requires time, sure: but we all have time. What it really requires is urgency and if that's lacking, then it requires faith.