In the days when it was held, as Boileau states in L 'Art poétique (II, 130), that ‘tout poème est brillant de sa propre beauté’, those impertinent genres, satire and parody, knew their place, but the tendency is now to regard them as transgeneric ‘modes’, ranging over a wide variety of texts. ‘Diversity of form’, as Alastair Fowler notes, ‘is paradoxically the “fixed” form of satire’, which ‘catalyzes generic mix’, as the etymology of the term [satura, mixture] implies. Parody, too, in a literary context, rather than being a particular type of ‘poem’, includes works or parts of works created in opposition to texts of any possible literary kind or any set of conventions. ‘La parodie’, writes Jean-Marie Schaeffer, ‘est une relation textuelle possible (elle est de tous les temps et de tous les lieux), alors qu'un genre est toujours une configuration historique concrète et unique.’ Like the world of antimatter in its relation to the material world, parody opens up the possibility of counterforms, usually with a devalorising effect, any time a literary work comes into being. Satire is more precisely focused – on the vices and follies of men – but is similarly universal in its application. Both involve some degree of imitation (of the text or the world) and both freely employ irony for their effects. As Linda Hutcheon observes: L'ironie est essentielle au fonctionnement de la parodie et de la satire, bien que ce soit de maniére différente.