Re: Many-Worlds again

On Sat, 20 Oct 2007 08:32:53 -0700, Sir Frederick
<mmcneill@xxxxxxxxxxxx> wrote:

The popular literature is full of that stuff :
--------------------------------------------------------------------
http://www.newscientist.com/article/mg19626261.300-universal-guilt.html
Universal guilt
20 October 2007
NewScientist.com news service
Jeremy Stone, London, UK

David Papineau suggests one consequence of the branching universe is that you should feel guilty about "the passengers your other
self has killed" in a car crash that did not quite happen in the actual world, but might have done (22 September, p 7). This cannot
be right.


I'd say you don't have to feel "guilty" any more than you
should feel guilty about peeing or growing fingernails. My
take on many worlds is that anything that can happen,
does happen in one(some) branch(es) off from current
reality. Why can't that be right? There's no reason it
can't be right, other than the argument from incredulity
which is a well-known logical error that humanity has
stumbled over again and again, throughout history.



For me to feel guilty about the crash that occurred, I have to be the person in the other branch where that is what happened. But I
am not, the crash didn't occur, and "I" am the lucky driver in this branch. I may feel guilty about driving in a manner that might
at some time cause death and destruction, and resolve to be more careful in future, but I can't split my identity in such a manner
as to take credit (or blame) for events that happen in other branches, because it isn't me that participates in those events.


If all possible things happen, then every action you
take that might end disastrously will, in some world(s),
end disastrously. Since it's always possible you
might get hit by a meteor at 6:07 AM tomorrow, in
some world(s), you actually will get hit by a meteor
at 6:07 AM tomorrow.



Probably (if that is the appropriate word) the criterion of personal identity needs to be couched in terms of looking back from the
latest node in the branching structure. It is a sum only over such histories as lead through here (but not to other present and
future branches that spring from points in our common pasts).


As Flatulucius said, the tree has many branches,
but only one trunk: each branch has many branchlets,
but they all lead back to the same branch.

("Flatulucius" isn't a real person - he's just a combination
of Confucius and Flatulo. Flatulo, and his foil Posturpedio,
are two stock characters from my imagination who have
two different approaches to and perspectives on life, which
might be surmised from their names. I have a bit of both
of them in me, as does I think everyone else.)



From Andrew Yake
Like all ideas that require quantum logic, the logic of many worlds runs afoul of itself. Suppose we accept the premise of many
worlds that every possible quantum contingency resolves into every possible quantum outcome such that each unique outcome generates
its own world.

Thus, as David Papineau suggests, every game is both won and lost by every team involved. Surely, then, the quantum physics team
cannot be on the winning side of their game in more than half of all worlds. How do our would-be quantum heroes pretend to know
which world we are in? In broad strokes, by the logic of quantum theory, quantum theory both is and is not valid. Whoops!


There's no problem. Mr. Papineau's construction
makes no sense to me, which I think is because it
makes no sense at all. If one is in a car-crash, one
probably would not identify the world one was in as a
"winning" world at least in the sense of the car crash,
but certainly car crashes do occur. There's at least one
world in which there has never been a car crash, but
we're in a world where at one time there were only two
cars in the whole state of Ohio and they got into an
accident.

You might at the moment be floating on a straw that
went down branch Y instead of branch X of a river.
You can only see the Y world now, but all the X's and
Y's were once superimposed, before the river branched.
At that earlier time, it made no sense to speak of X and
Y, because that would be like calling your dog "Spot"
and "Fido" as though he were two different dogs, just
because at some future time you might give the dog to
neighbor A who would call him "Spot" or to neighbor B
who would call him "Fido".

Check out question Q13 at:
http://www.hedweb.com/manworld.htm
"Is many-worlds a deterministic theory?" The answer
is "YES"! Many-worlds restores determinism to
Quantum Mechanics. An observer who got into a
car crash can't see the non-car-crash world(s), but
it(they) exist(s) anyway. Likewise, the same observer
who split off into a non-car-crash world can't see the
car-crash world(s), but it it(they) exist(s) anyway.
Which is the "true" world? They all are, though both
car-crash and non-car-crash instances of the
observer will say that theirs is now the "true" world,
only because they can't see the other worlds.
Likewise a straw going down branch Y of a stream
will look around and say that Y is the "true" world,
because that's all it sees, but a "god" up on a
mountain can look down and see all branches of
the river. He can see, as plainly as can be, that
there's an X world just over a ridge from the Y world,
which the Y straw can no longer see, but that world
is just as valid and "real" as the Y world.



Pittsburgh, Pennsylvania, US

From issue 2626 of New Scientist magazine, 20 October 2007, page 27

.

Relevant Pages