Of the other elements which enrich See Aristot. Poet. 6.2 . tragedy the most important is song-making. Spectacle, while highly effective, is yet quite foreign to the art and has nothing to do with poetry. Indeed the effect of tragedy does not depend on its performance by actors, and, moreover, for achieving the spectacular effects the art of the costumier is more authoritative than that of the poet. After these definitions we must next discuss the proper arrangement of the incidents since this is the first and most important thing in tragedy. We have laid it down that tragedy is a representation of an action that is whole and complete and of a certain magnitude, since a thing may be a whole and yet have no magnitude. A whole is what has a beginning and middle and end.