In it he shows that in a culture without writing, epic poems and stories are not shared by memorising them word for word, line for line. Each and every performance - even from the same speaker, is a reconstruction, a re-creation.
A storyteller is able to do this because they work within an enabling framework, in the form of some key constraints. For example:
The storyline is well-known by everyone, so things have to happen in the order they are meant to happen.
The heroes and heroines are well-known to everyone, they are recognised by certain key characteristics, summed up in familiar phrases. These phrases must appear, attached to the right people in the story (or perhaps mis-attached for comic effect) for it to be 'true'.
A poem must follow a particular rhyme and rhythm or metre. This severely limits the number of words it is possible to use, and therefore the number of words the reciter has to hold in memory.
The storyteller operates inside a culture, which has certain expectations about how the world works. These must be reflected in the recitation if it is to be successful.
The point is that even though each recitation effectively starts from scratch and is actually different from every other, it is perceived by both the speaker and their audience as being a word-perfect, faithful repetition of the last time they heard it. Every telling is perceived as identical to all other tellings, because against all the criteria that matter, it is.
Once we have writing, everything changes. Writing is of course a way of putting knowledge 'in the world', rather than 'in the head'. But there are drawbacks. Multiple versions of an epic poem get written down, but from now on they are read, not re-created. All too often a single version becomes canonical - the one against which all others are judged. We gain in practicality, but lose sponteneity, creativity, surprise.
It seems to me though that it is possible to have the best of both worlds:
The bones of a storyline are written down so everything happens in the right order;
Key roles are written down so they can be identified and clearly signalled;
Stock phrases and formulas are given to act as starters for ten until practice has enabled a person to generate their own;
Cultural boundaries are clearly stated - "the least that should happen is...", "Remember this part of our Promise of Value here".
That's what makes a good Customer Experience Score. Enough constraints to ensure the experience is perceived as consistent, plenty of room for a given person to make that experience personal. Written down so everyone can learn it, practice it and improve it. On purpose.