Little Light put up a post about antecedents and record-keeping:
History is full of these things, no matter where you go, things we can circle around, draw rough outlines of, even make very good educated guesses about. But we don’t have them any more, and we’re different people now, and nobody thought to leave us careful instructions because they just assumed that what they had would always be there. There’s an entire genre of Song Dynasty Chinese poetry that’s really song lyrics, but we don’t have the tunes any more in part because they were so popular they didn’t need to be written down. There are buried cities that periodically turn up all over Arabia that we don’t even know the names of, any more–huge capitals of trade and art just vanished, when once everyone knew where to go to find them.
Her essay touches on a lot of aspects of remembering and defending continuity in the face of erasure; like she says, it isn’t only time that creates this kind of loss. I wish I had something brilliant to contribute myself, but it’s just that good.
So, go read the whole thing.