Tolkien had an idea that we don’t really make up new stories. We pull them as leaves off the great “tree of tales”.
This sounds like the idea that when the conductor drops the baton, he’s is pulling an already-running beat out of the invisible river and not making one up on the spot. Well, on one hand I think that’s baloney. I don’t believe in a Platonic metronome. However, he may have subconsciously had the beat running in his head for some time. Perhaps it is associated with a particular memory. It seems to come from somewhere deeper than he can put his finger on. But this is about writing on the large scale, not one element of music.
Here (on p.221), Gyler references an interesting image (that is apparently pretty well-known):
Imagine that you enter a parlor. You come late. When you arrive, others have long preceded you, and they are engaged in a heated discussion, a discussion too heated for them to pause and tell you exactly what it is about. In fact, the discussion had already begun long before any of them got there, so that no one present is qualified to retrace for you all the steps that had gone before. You listen for a while, until you decide that you have caught the tenor of the argument; then you put in your oar. Someone answers; you answer him; another comes to your defense; another aligns himself against you, to either the embarrassment or gratification of your opponent, depending upon the quality of your ally’s assistance. However, the discussion is interminable. The hour grows late, you must depart. And you do depart, with the discussion still vigorously in progress.
-Kenneth Burke, The Philosophy of Literary Form: Studies in Symbolic Action
She also points out that Sayer’s expressed a similar notion about poetry:
“Poets do not merely pas on the torch in a relay race; they toss the ball to one another, to and fro, across the centuries. Dante would have been different if Virgil had never been, but if Dante had never been we should know Virgil differently; across both their heads Ezekiel calls to Blake, Milton to Homer”
-Dorothy Sayers, Further Papers on Dante
Bach died in 1750. His musical output hugely impacted others. But we know him differently through the rediscovery of his work by Mendelssohn when he reintroduced Bach to the world with the 1829 performance of the St. Matthew Passion in Berlin. We know him differently again by hearing his works transcribed for guitar or contemporary marimba – instruments that didn’t even exist in his time. It’s a complicated web and it’s changing even now. We project things back on him. When Pablo Casals played Bach with 1000 gallons of romantic rubato poured on thick, would Johann himself have recognized his own notes? When we listen to a performance of Bach, the light is being passed through many lenses.