Re: Many Fermis Interpretation Paradox -- So why aren't they here?

[r strasser]

Let's consider Tim May's question, "why have we not seen solid evidence of such communication," and Russell Standish's statement, "It could just mean that communication between the "universes" is impossible."   Now lets list the relevant constants and some interpretations of quantum theory as they could apply to the "many worlds" interpretation of quantum mechanics (Everett). 1. The theory mandates multiple states for every particle in existence. 2. The collapse model says our observations affect the outcome of experiments: it assigns a central role to consciousness. 3. Photons, electrons, and other subatomic particles are not hard and indivisible. They behave as both waves and particles. 4. Particles can appear out of nothing - a pure void - and disappear again. 5. Physicists have teleported atoms and moved them from one place to another without passing through intervening space. 6. A single particle occupies not just one position, but exists here, there, and many places in between. 7. Quantum theory must hold at every level of reality - not just the subatomic world (David Deutsch). 8. The double slit experiment offers a rare example of two overlapping realities, in which photons in one universe interfere with those in another. 9. All quantum states are equally real, and if we see only one result of an experiment, other versions of us must see all the remaining possibilities. 10. "I don't think there are any interpretations of quantum theory other than many worlds.........The others deny reality." (David Deutsch).   Given the constants and some interpretations of quantum theory, I would like a wide variety of views on what's theoretically required to communicate with "many worlds," and what would present "solid evidence of such communication."   For starters, let's consider David Deutsch's conjecture: "In fact, says Deutsch, a quantum computer could in theory perform a calculation requiring more steps than there are atoms in the entire universe. To do that, the computer would have to be manipulating and storing all that information somewhere. Computation is, after all, a physical process; it uses real resources, matter and energy. But if those resources exceed the amount available in our universe, then the computer would have to be drawing on the resources of other universes. So Deutsch feels that if such a computer is built, the case for many worlds will be compelling."   -Bob Strasser   ----- Original Message ----- From: Russell Standish Sent: Monday, September 30, 2002 6:49 PM To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: Re: Many Fermis Interpretation Paradox -- So why aren't they here?   It could just mean that communication between the "universes" is impossible. Which is not surprising, really, as the division between "universes" in the MWI is what allows conscious thought to exist. It is perhaps of more interest to other multi-universe scenarios that are independent of the anthropic principle - I'm thinking here of Smolin's black hole universes, and also patches that lie outside our lightcone, which is almost the same thing. There is a "cosmic censorship conjecture", that singularities can never be naked. Perhaps the Fermi "Where are they argument" almost proves the case. Cheers 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? > > Amongst the universes, many ("many" is a huge number, obviously)  of > them will be way ahead of us. Some will have had galactic civilizations > for a billion years. Some will be versions of Earth except that the > Egyptians pioneered electronics and hence the world is a few thousand > years "ahead" of our world...even assuming time is commensurate with > ours. > > And so on. You can all imagine the rich possibilities. > > If these universes are even remotely able to affect each other, through > perhaps enormously advanced technology, then the vast number of such > possible worlds would suggest that at least some of them have figured > out how to do so. > > And yet they aren't here. No visitors from alternate universes. No > signals sent in, a la Benford's "Timescape." > > Perhaps we don't know how to listen. Perhaps there are so many possible > universes to potentially visit that we just haven't been gotten to yet. > Perhaps in a multiverse of so many possibilities, ours is just not an > interesting destination. Maybe there's a kind of MWI censorship going > on: since we are still debating the validity of MWI, we obviously are > in a universe where MWI has not been proved through such a visit. > > (There are many divergent series here, making even crude estimates > difficult and probably worthless.) > > Hmmmhhhh.... > > > --Tim May Prime, resident of Earth Prime > ---------------------------------------------------------------------------- A/Prof Russell Standish            Director High Performance Computing Support Unit, Phone 9385 6967, 8308 3119 (mobile) UNSW SYDNEY 2052                     Fax   9385 6965, 0425 253119 (") Australia            [EMAIL PROTECTED]             Room 2075, Red Centre                    http://parallel.hpc.unsw.edu.au/rks             International prefix  +612, Interstate prefix 02 ----------------------------------------------------------------------------