Orthogonality

Sorry, 'orthogonal' is jargon. In my corner of science, it's used so often that I use the term informally now. 'x is orthogonal to y' means that these two variables are independent of each other. For example, the color of a candy (say an M&M) is orthogonal to its flavor, they have nothing to do with each other.

Hence 'solipsism is orthogonal to palimpsism', meaning that whether or not you believe you're the center of the universe has no bearing on how many times something has been written on that manuscript over there (or how many times you've revised your history). But that's not-so-strict usage of the term.

Interesting, I think it'd be harder to do a solipsistic character/religion than a palimpsistic one. UO seems close to what you were saying, Mark, with a character's journal apart from the main narrative, which is a fantastic idea; I'd love to run a campaign where the 'master narrative' isn't quite clear.