Some fascinating replies here! Thanks everyone.
I'm particulkarly interested in the comic writers who've responded. I think, sometimes, comedy can be one of the most powerful carriers of literary themes... when the reader is really laughing, but then stops and wonders "hang on... what exactly AM I laughing at?"
I felt that early on, studying Moliere at school. I never found the plays 'funny'... more tragi-comic.
vanessa
I'm surprised to hear that there could be writers out there who feel they don't include thematic content in their stories. Maybe it's from years of literature study at school or uni, but I can't get past the first page of a book without mentally compiling a list of the themes and issues that it is addressing. I think that for a philosopher/thinker, the novel is a great way to get their idea through to the public without seeming too academic or preachy. The Life of Pi did that very well, I think, and the great philosophers did it too.