Iain M. Banks writes grand books about utopian societies and people's complicity with evil — one of his books is actually called Complicity — but he says he really doesn't think about themes when he's writing:
I don't really do themes. I might accidentally, but themes are an emergent phenomena of the writing of the book, of just trying to get a story out there. These are the sort of things I rely on academics and critics to spot. I just come up with the stories and write them as well as I can. There's not really a great deal of strokey-beard thinking going on.
He also says that sometimes he's ambitious, in terms of trying to create a complex book, and sometimes he's just ambitious in the sense of trying to get a bigger audience. [The Scotsman]