Starting from the analysis of linguistic errors as examples of the creative appropriation of language through style, the essay revisits three types of errors linked to mirror images (a passage from Kant, the origin of Carroll's Through the Looking-Glass, the mirror-stage in Lacan) and from this proceeds to develop a theory of four worlds, including a mirror world. The description of the mirror world accounts for the generation of four kinds of fiction (realist, marvellous, nonsense, fantastic).