In his Reflections on 'The Name of the Rose', the novelist and theorist Umberto Eco explains his idea of postmodernism as a kind of double-coding, and as a transhistorical phenomenon:
These ponderings attempt to let themselves be appropriated by the event. (Beiträge zur Philosophie (Vom Ereignis), Martin Heidegger, 1936–38/1989)
[P]ostmodernism ... [is] not a trend to be chronologically defined, but, rather, an ideal category – or better still a Kunstwollen, a way of operating. ... I think of the postmodern attitude as that of a man who loves a very cultivated woman and knows that he cannot say to her "I love you madly", because he knows that she knows (and that she knows he knows) that these words have already been written by Barbara Cartland.
Still there is a solution. He can say "As Barbara Cartland would put it, I love you madly". At this point, having avoided false innocence, having said clearly it is no longer possible to talk innocently, he will nevertheless say what he wanted to say to the woman: that he loves her in an age of lost innocence.[50]
https://en.wikipedia.org/wiki/Postmodern_literature