In discussing those passages of an opera in which not only the audience but also the characters of the story hear music, musicologists often write of "diegetic" music, adopting well-established terminology from film studies and narratology. The terms "diegesis" and "diegetic" stem from ancient Greek, and owe their long-standing fortune to their presence in seminal writings by Plato and Aristotle; scholars of narrative, drama, film, and music occasionally note, however, that the meaning assumed by "diegesis" and "diegetic" in recent decades is very different from (or even opposite to) the historical one. In fact, the two meanings coexist in current scholarly usage, engendering terminological (and therefore conceptual) confusion. The goal of this article is to explain how this situation came about. Ancient Greece witnessed the emergence of the basic narratological distinction between recounting and enacting, and its gradual (and far from straightforward) association with the terminological distinction between "diegesis" and "mimesis." A misinterpretation of Aristotle by French filmologues around 1950 gave rise to the modern meaning of "diegesis" ("storyworld," or even simply "story"), while the misapprehension by which the ancient and modern terminologies are deemed to have arisen entirely independently of each other originates in the influential work of narratologist Gerard Genette. The story reconstructed here involves to-ing and fro-ing between words and concepts: what may appear as a purely lexical study is also, of necessity, a study about ideas. Moreover, this story might serve more generally as an apologue, reminding us of the sometimes peculiar ways in which bits of our collective wisdom emerge and become accepted.
