Dear Philippe,
Since we have been asked to contribute a work on “the scene” [la scène], I'd like to sieze the occasion to revive a debate which we have broached several times, long ago. I will, then, summarize the theme in the Greek word opsis, which designates, in Aristotle's terms, just about what we call “staging” [mise en scène]. (“Just about”: here already is a problem of translation, and consequently of meaning and nuance. It can also be translated by “performance” [spectacle]. We will be able to return to this problem later.)
The opsis is one of the six “parts” of the tragedy, according to the Poetics (50a), which, “involves everything,” listing the five other parts. A passage to be interpreted delicately, it could simply mean that when there is performance, there is everything else as well, plot, text, etc. (cf. the note of R. Dupont-Roc and J. Lallot; I will note their edition simply with a P). A little further along, when Aristotle details the nature of these parts, he declares that the opsis is on the one hand “seductive” (“psychagogical”, 50bl7), but, on the other hand, foreign to art [atekhnotaton), and not at all in its rightful place in the Poetics. If there is, in this case, tekhnē, it is that of the prop master [skeuopoios), not that of the poiétés. For “the tragedy achieves its finality even without enactment and without actors” (50bl8). Consequently, its entire effect is found only in its reading. (I would remind you, in passing, that this signifies, for a Greek, reading aloud, which implies something quite different from our silent reading.)