or may be the "invisible narrator" or even the "all-knowing narrator" who speaks from above in the form of commenting on the action or the characters. In Book III of his Republic (c. 373 BC), Plato examines the style of poetry (the term includes comedy, tragedy, epic and lyric poetry): all types narrate events, he argues, but by differing means. He distinguishes between narration or report (diegesis) and imitation or representation (mimesis). Tragedy and comedy, he goes on to explain, are wholly imitative types; the dithyramb is wholly narrative; and their combination is found in epic poetry. When reporting or narrating, "the poet is speaking in his own person; he never leads us to suppose that he is anyone else;" when imitating, the poet produces an "assimilation of himself to another, either by the use of voice or gesture." In dramatic texts, the poet never speaks directly; in narrative texts, the poet speaks as himself or herself. In his Poetics, Aristotle argues that kinds of poetry (the term includes drama, flute music, and lyre music for Aristotle) may be differentiated in three ways: according to their medium, according to their objects, and according to their mode or manner (section I); "For the medium being the same, and the objects the same, the poet may imitate by narration—in which case he can either take another personality, as Homer does, or speak in his own person, unchanged—or he may present all his characters as living and moving before us." Though they conceive of mimesis in quite different ways, its relation with diegesis is identical in Plato's and Aristotle's formulations. In ludology, mimesis is sometimes used to refer to the self-consistency of a represented world, and the availability of in-game rationalisations for elements of the gameplay. In this context, mimesis has an associated grade: highly self-consistent worlds that provide explanations for their puzzles and game mechanics are said to display a higher degree of mimesis. This usage can be traced back to the essay "Crimes Against Mimesis". Dionysian imitatio Dionysian imitatio is the influential literary method of imitation as formulated by Greek author Dionysius of Halicarnassus in the 1st century BC, who conceived it as technique of rhetoric: emulating, adapting, reworking, and enriching a source text by an earlier author. Dionysius' concept marked a significant departure from the concept of mimesis formulated by Aristotle in the 4th century BC, which was only concerned