Every detail is precisely calculated in both the dance and the song itself. But of course there was inspiration as well in the original kernel of the idea of the song, "single ladies" and in the decisions about the bare synthesized arrangement. But once these few creative choices were made, the rest was largely execution.
I'm writing about this because of an interesting comment left on my post "Long Lines of Winter Light", which was about a piece of mine for guitar orchestra. The commentor mentioned a fondness for "instinctive" music, which my piece certainly was. I can't trace how I wrote it (it was quite a few years ago), but I do know it was not planned out. I just had the idea of writing a lot of short little ideas, putting them in boxes and arranging them like a flow chart. The most planned part was how I conducted it because I rehearsed the orchestra in different ways until I found a way of organizing the piece that was musically satisfying. The score for that piece is just a box of tools that you can use to create a piece.
But the instinctive way doesn't always work. I probably have boxes and piles of instinctive scribblings that never gelled into a piece. Out of five pieces I write, or start to write, probably four are failures. I keep them, in case a little idea or motif can prove useful in some other context.
So that's me. What about other composers? A lot of them, like Stravinsky, either don't reveal much, or lie a lot about what they do. Others, like Bartók, are pretty clear about what they were doing. In his case, the influence of folk song and some mathematical ideas like the Fibonacci sequence are traceable in how he structures a piece. Others, like Schoenberg in his later music, are all too planned out. The 12-tone method is really a way of achieving theoretical unity through intense planning. His early music seems to be instinctive, but one cannot be sure...
Beethoven's way of working is one of the most interesting. He sketched and sketched and worked on and hammered out themes for years sometimes. There are whole books written about Beethoven's sketchbooks--many of which have been preserved. Here is a little sample:
When I do this, it usually results in a turgid mess. But it worked for Beethoven. Somehow, he could work on a piece exhaustively without it sounding belabored. Most of my music is better if I don't over-work it. I was reading about a composer who seems to represent the opposite extreme from Beethoven: he simply writes and writes and writes, never going back and never correcting. Apart from recalling he was English, I can't remember the composer's name.
Let's listen to some music by Beethoven. His Diabelli variations were written in two sessions, first in the spring of 1819. But then he ceased work on them in early 1820 and only picked them up again in mid-1822. They were finished in 1823. Again, whole books have been written on this piece of music and the process of composition. Here are the Diabelli Variations: one hour of simply terrifyingly brilliant music performed by the great Grigory Sokolov:
Mozart, on the other hand, just seemed to write down perfect music as if angels were dictating to him...