In this interview with Mariella Frostrup, on The Book Show on Sky Arts, he confirms some of the conclusions about the writing process that I have arrived at in the course of working on my novel, i.e. that the very process itself is generative, and that an internal logic is established which necessarily dictates the course of events.
As the interview, at just under eight minutes. is longish, I have not included it, (go here), instead I have transcribed the episode where Pratchett talks about his work. (Errors and omissions accepted.)
Mariella: 'I wonder how much they've [the DiscWorld novels] become an opportunity for you to channel all the things you were thinking seriously about into a different world where they take on a different aspect? You are credited now with being this fantastic satirical writer.'
Terry: 'It just happens […] Asking an author like me is like asking an artist why that bit of the picture is blue. The artist is pretty certain that that bit of the picture should be there and that it should be blue.'
'When I start the books I have a few disjointed ideas, maybe a few prejudices, and they're stirred together, and a plot turns up out of them. A lot of the other things happen by what I call emergence - what scientists call emergence.'
'In the process of writing a book, it starts to write itself. Logical things happen one after the other. What I have to do is lots and lots of editing. The first draft is a terrible mess but stuff turns up, important stuff of value to the plot and to help me in my thinking, happily turns up during the writing process.'