[C]omparing the “duration” of a narrative to that of the story it tells is a trickier operation, for the simple reason that no one can measure the duration of a narrative. What we spontaneously call such can be nothing more . . . than the time needed for reading; but it is too obvious that reading time varies according to particular circumstances, and that, unlike what happens in movies, or even in music, nothing here allows us to determine a “normal” speed of execution.43