"Fiction is an art that calls for the strictest attention to the real - whether the writer is writing a naturalistic story or a fantasy. I mean that we always begin with what is or with what has an eminent possibility of truth about it. Even when one writes a fantasy, reality is the proper basis of it. A thing is fantastic because it is so real, so real that it is fantastic. Graham Greene has said that he can't write, "I stood over a bottomless pit," because that couldn't be true, or "Running down the stairs I jumped into a taxi," because that couldn't be true either. But Elizabeth Bowen can write about one of her characters that "she snatched at her hair as if she heard something in it," because that is eminently possible. I would even go so far as to say that the person writing a fantasy has to be even more strictly attentive to the concrete detail than someone writing in a naturalistic vein - because the greater the story's strain on the credulity, the more convincing the properties in it have to be."