Afterward was a doc on Machu Picchu, and I was struck by the rapid rise and fall of Inca civilization, and its remarkable communications network. In a generation or two, they conquered much of South America, and within a hundred years or so, their empire was gone. They had roads to rival the Romans, but no wheel or iron. They also had no written language, and I wondered what Harold Innis would make of that -- an empire with a huge space bias, but an oral culture. But even so, perhaps writing of some kind is necessary in any civilization that lasts: after all, oral cultures in the Innisian dichotomy still have writing, only they seem to save it for writing down the most important things in more durable media.
Finally, speaking of space/time empires, it's been officially announced that the Star Wars hexology is coming to Blu-Ray this September. I've put in a request for a review copy, so stay tuned for more info once it's available. While there are a lot more extra features that weren't on the DVD releases, at this point I'd be happy if they fixed the color timing on the original trilogy that made Darth Vader's lightsaber pink!