When it comes to the march of civilization (and how to portray it in fiction) there are many things to take into account. They've all got to work together if an author wants to draw his readers into his fictional world, make them feel comfortable in it, and engross them in its events.
I've just put up an article about that over at Mad Genius Club, the shared writers' blog at which I'm a contributor. Click over there and read it if the subject interests you. It's titled 'How to assess a civilization'.
As for the title I've used here, it's explained in that article. Those of you who've seen the movie 'Demolition Man' will understand the 'three seashells' reference. For those of you who haven't . . .