Improvisation

A letter to a student ... Miss Cecilia, (1839).   

At present, as your execution is so considerably formed, and as you are beginning to make a progress in thorough-bass , you should attempt, sometimes when alone, sometimes in the presence of your teacher, to connect together easy chords, short melodies, passages, scales, arpeggioed chords; or, which is much better, leave it to your fingers, to effect ths connection, according to their will and pleasure. For extemporising possesses this singular and puzzling property, that reflection and attention are of scarcely any service in the matter. We must leave nearly everything to the fingers and to chance.

I meant to copy out more from this extract of Czerny, but this short fragment already raises a few interesting points. Firstly, Czerny is aware that beginning in improvisation is a delicate and self-conscious affair - you should attempt, sometimes when alone ... This corresponds with my own experience, that is necessary to begin in private, as the mere presence of others is a horrible distraction and prevents any kind of constructive work being done! Why? I think that when we are alone we can concentrate on the process of construction, of trial and error; when we think someone is listening, then we become aware of the product of what we are doing. This product takes on a kind of significance - we imagine people are listening to our improvised music as if it was a composer masterpiece!

Secondly, Czerny introduces the puzzling question of conscious control, a problem which plagues so much of the discussion and experience of improvisers. How much do we think about it? And doesn't it get in the way? Czerny interestingly makes a distinction between (1) the 'attempt ... to connect together easy chords, short melodies ...' and other devices which need a lot of conscious thought, planning and control; and (2) a different approach, in which conscious working out is supressed or somehow turned off, and one feels ones way forward, letting the fingers do the thinking. This second approach he says is better, and is presumably more to do with performance. 

Is this a solution for all kinds of performance? Could there be other styles of music or approaches to improvisation which require conscious thought in some form? Can one not think or plan during improvising without inhibiting the flow of ideas and patterns of execution?