It's kind of a continuation of the theme he picked up in Within you without you - life flows on, all things must pass, in the midst of life we are in death, but I think he was looking at it in a positive way, not a morbid way, as some westerners do. His brush with eastern philosophy must have had a lot to do with this perspective. It's also after the Beatles ended, so maybe it's a message to the fans that even something like the Beatles has to pass away, or move on to another way of being. Hmm, too heavy??