Ordinary fiction operates on the assumption that the objects of perception are real—exist independent of the observer—and that events occur in space-time in a cause-and-effect, historical pattern for which the ideal model is a set of equations. Such fictions may introduce characters for whom none of these things is true, for whom reality is a world of images in the mind, in which a cloud will shift from camel to weasel to whale according to laws other than nature’s. But even such characters are usually but mad north-north-west; and the voice of the story itself is always wholly “sane.”