Flow is a wierd, but pleasant, state to be in. Good programmers report going into Flow, as do good mathematicians when working on a problem. Flow is not simply the process of insipration. As you say, the back-brain keeps churning away, and conscious flashes of insight can arrive at the oddest times. But so long as those insights are locked in your head, they are of little use.
Flow is that state you get into when the words just pass from your brain directly onto the paper (or the screen, whatever), and when you look up it's nine hours later. It doesn't necessarily mean that those words are good words, but there does seem to be a correlation between developing the skill of entering Flow, and of developing the craft of good writing/programming/maths/whatever.
I have only ever been to music what a one-fingered typist is to stenography, but I imagine that Flow while performing would be where the audience doesn't distract, and may not even be noticed, but what there is is you, (and the other musicians,) and the music coming out of your instrument, and such trivial details as fingering are irrelevant; when the instrument becomes a part of you, like your own fingers, rather than something you have to manipulate. Again, it doesn't of itself guarantee that the music you are playing is good, but it does become effortless, and there tends to be a correlation between the ability to play music well and the ability to lose yourself in that music.
And the thing about flow is that it takes time to get into that state, and it can be really jarring to be yanked out of it. And some programmers have reported that Flow is in itself such a pleasant experience that they will find problems to solve so that they can enter Flow.
On Flow
Flow is that state you get into when the words just pass from your brain directly onto the paper (or the screen, whatever), and when you look up it's nine hours later. It doesn't necessarily mean that those words are good words, but there does seem to be a correlation between developing the skill of entering Flow, and of developing the craft of good writing/programming/maths/whatever.
I have only ever been to music what a one-fingered typist is to stenography, but I imagine that Flow while performing would be where the audience doesn't distract, and may not even be noticed, but what there is is you, (and the other musicians,) and the music coming out of your instrument, and such trivial details as fingering are irrelevant; when the instrument becomes a part of you, like your own fingers, rather than something you have to manipulate. Again, it doesn't of itself guarantee that the music you are playing is good, but it does become effortless, and there tends to be a correlation between the ability to play music well and the ability to lose yourself in that music.
And the thing about flow is that it takes time to get into that state, and it can be really jarring to be yanked out of it. And some programmers have reported that Flow is in itself such a pleasant experience that they will find problems to solve so that they can enter Flow.