Open Parachute skips lightly from epistemology to ethics. What fun they're having in New Zealand! There's no way I'm going to float the following on that forum... they're moving too fast to annoy them with new ideas. But the discussion reminds me of the unresolved riddle of ethics in a multiverse.
In The Fabric of Reality, David Deutsch argues that life as we know it is best explained by Hugh Everett's "many worlds" interpretation of quantum mechanics. Deutsch says that every possible world is real; by which he means that every real choice you face leads you down two different timelines. You hear the Gospel at a revival meeting and you feel a strange stirring. In Deutsch's model, one "you" goes up front to the altar and ends up gloriously saved, while the other rejects the invitation and goes out to a life of crime.
Deutsch's theory gets a little exotic--he not only argues that every common-sense timeline is real, but every physically-possible timeline is real. Given the weirdness of quantum mechanics, that's a LOT of timelines, including ones (according to Deutsch) where people fly around on brooms playing Quidditch. It's not the laws of physics change in such Harry Potter universes--it's just that there's a statistical possibility that every atom in the broom will go up at the same moment. Over and over. All the way through a Quidditch tournament!
That's an extreme position, but it opens up another possibility that Deutsch seems not to have thought about. Frank Tippler has a different take on quantum mechanics. In The Omega Point, Tippler argues that there is only one timeline but that it must maintain an "observer" forever, and will therefore at some point produce a super-scientific race that is able to reconstruct human minds through technology. I'm not persuaded by Tippler's reasoning, but I'm impressed by his imagination--and the super-scientific resurrection technology he describes would appear to be a whole lot easier to produce than a well-played Quidditch match. So it only seems fair to add Tippler's resurrection technology to Deutsch's multiverse.
Which brings us to the ethical issue. It would seem to me that any rational "Fabric of Reality" fan should make a utilitarian calculation designed to maximiz his personal happiness over all possible worlds. He needs to balance his short-term pleasures in this life against the knowledge that he must certainly endure an eternal conscious existence in a future resurrection. To make things more complex, it won't be just one resurrection. He must assume that Catholics, Protestants, Jews, Muslims, Hindus, and Buddhists all have their own super-technological worlds where he will be raised to face their form of judgment.
If you only have one life to live here and now, how do you prepare yourself for a hundred different hells? Deutch doesn't. (My attempt to raise this question on the Fabric of Reality yahoo group met with the thundering silence it deserved.) But the beauty of a thought experiment is that it generates interesting new insights without ever having to shop for lab equipment.
If you knew you had to face the judgment of every possible creed and cult and endure eternal conscious torment if they didn't like the choices you make today, how would you live?
My own answer is sincere, but probably won't satisfy any readers. I'd rather follow Jesus, even if I knew that I would be tormented for it forever, than any other option. This is not just because most of the other major religions give Jesus a pass (although they do), but because I think I might be able to face an endless eternity of agony if I did it for Him.