Schroedinger's cat isn't really about parallel universes
it basically says that until something (a tiny particle etc.) is measured then it exists in all quantum states. it's called quantum superposition. i.e. the cat is both alive and dead until you open the box.

my understanding of the alternate universes thing is that essentially any time anything happens there is another universe where it didn't happen, or where something else happened.

what level this happens on is debatable, but seeing as we (humans) are pretty insignificant, it's not going to be based on something as fiction-friendly as when we make a life changing decision a la sliding doors.
( Vipros. clever got me this far, then tricky got me in, Mon 18 Aug 2008, 10:24, Reply)