At 12:26 -0700 30/09/2002, Tim May wrote: >If the alternate universes implied by the mainstream MWI (as opposed >to variants like consistent histories) are "actual" in some sense, >with even the slightest chance of communication between universes, >then why have we not seen solid evidence of such communication?
I am not sure I understand why you oppose the "mainstream MWI" and the consistent histories (although many does that, I don't know why). In all case, if QM is right (independently of any interpretation), parallel histories or parallel universes cannot communicate, they can only interfere(*). The same happens with comp. Probability measures are global and depends on the whole collection of relative computational histories, but this does not allow the transfer of one bit from one computation to another. BTW, Tim, I am discovering n-categories. Quite interesting. John Baez has written good papers on that, like his categorification paper. Have you read those stuff. Could be useful for the search of coherence condition in "many world/observer" realities ... (*) Unless Plaga is right, and it exists 100% non elastic interaction, which I doubt ... Bruno