If Helsinki man understands the situation, he will assign a 100% probability to him being duplicated and ending in both places. Similarly a physicist who believes in MWI will assign a 100% probability to him splitting and observing all possible outcomes. This is not, however, how people normally view these matters. The physicist feels that he had a (say) 50% chance of him observing spin-up despite his knowledge of the MWI, and I guess Helsinki man feels the same way about arriving in Moscow, if only because our brains are "wired" to think in terms of the single universe view. I think Bruno's take on this is acceptable in terms of how we think about things in everyday life.
Once the duplication has been performed, one copy of the man *then* has a 50% chance of being Moscow man, and his (spurious) sense of always only being the single unique copy of himself would lead him to feel that this was the chance beforehand. So it's fair for Bruno to ask Helsinki man how he estimates his chances of arriving in Moscow, assuming "folk psychology" is involved (ditto for the physicist). However this is only really quibbling about the fact that our everyday attitude often doesn't cover the realities of how the universe works. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
