[ExI] Is the Multiverse unscientific nonsense?

[John Clark]

*I read an article called The multiverse is unscientific nonsense
<https://iai.tv/articles/the-multiverse-is-unscientific-nonsense-auid-2668>
by Jacob
Barandes, a lecturer in physics at Harvard University, and I wrote a letter
to professor **Barandes commenting on it. He responded with a very polite
letter saying he read it and appreciated what I said but didn't have time
to comment further. This is the letter I sent: *
===========


*Hello Professor Barandes*

*I read your article The multiverse is unscientific nonsense with interest
and I have a few comments:*

*Nobody is claiming that the existence of the multiverse is a
proven fact, but I think the idea needs to be taken seriously because: *

*1) Unlike Bohr's Copenhagen interpretation, the Many Worlds theory is
clear about what it's saying. *
*2) It is self consistent and conforms with all known experimental
results. *
*3) It has no need to speculate about new physics as objective wave
collapse theories like GRW do.*

*4) It doesn't have to explain what consciousness or a measurement is
because they have nothing to do with it, all it needs is Schrodinger's
equation.  *


*I don't see how you can explain counterfactual quantum reasoning and such
things as the Elitzur–Vaidman bomb tester without making use of many
worlds. Hugh Everett would say that by having a bomb in a universe we are
not in explode we can tell if a bomb that is in the branch of the
multiverse that we are in is a dud or is a live fully functional bomb. You
say that many worlds needs to account for probability and that's true, but
then you say many worlds demands that some worlds have “higher
probabilities than others" but that is incorrect. According to many worlds
there is one and only one universe for every quantum state that is not
forbidden by the laws of physics. So when you flip a coin the universe
splits many more times than twice because there are a vast number, perhaps
an infinite number, of places where a coin could land, but you are not
interested in exactly where the coin lands, you're only interested if it
lands heads or tails. And we've known for centuries how to obtain a useful
probability between any two points on the continuous bell curve even though
the continuous curve is made up of an unaccountably infinite number of
points, all we need to do is perform a simple integration to figure out
which part of the bell curve we're most likely on.*

*Yes, that's a lot of worlds, but you shouldn't object that the multiverse
really couldn't be that big unless you are a stout defender of the idea
that the universe must be finite, because even if many worlds turns out to
be untrue the universe could still be infinite and an infinity plus an
infinity is still the an infinity with the same Aleph number. Even if there
is only one universe if it's infinite then a finite distance away there
must be a doppelgänger of you because, although there are a huge number of
quantum states your body could be in, that number is not infinite, but the
universe is. *


*And Occam's razor is about an economy of assumptions not an economy of
results.  As for the "Tower of assumptions" many worlds is supposed to be
based on, the only assumption that many worlds makes is that Schrodinger's
equation means what it says, and it says nothing about the wave function
collapsing. I would maintain that many worlds is bare-bones no-nonsense
quantum mechanics with none of the silly bells and whistles that other
theories stick on that do nothing but get rid of those pesky other worlds
that keep cropping up that they personally dislike for some reason. And
since Everett's time other worlds do seem to keep popping up and in
completely unrelated fields, such as string theory and inflationary
cosmology.*


*You also ask what a “rational observer” is and how they ought to behave,
and place bets on future events, given their self-locating uncertainty. I
agree with David Hume who said that "ought" cannot be derived from "is",
but "ought" can be derived from "want". So if an observer is a gambler that
WANTS to make money but is irrational then he is absolutely guaranteed to
lose all his money if he plays long enough, while a rational observer who
knows how to make use of continuous probabilities is guaranteed to make
money, or at least break even. Physicists WANT their ideas to be clear,
have predictive power, and to conform with reality as described by
experiment; therefore I think they OUGHT to embrace the many world's idea.
 *


*And yes there is a version of you and me that flips a coin 1 million times
and see heads every single time even though the coin is 100% fair, however
it is extremely unlikely that we will find ourselves that far out on the
bell curve, so I would be willing to bet a large sum of money that I will
not see 1 million heads in a row.  You also say that "the Dirac-von Neumann
axioms don’t support oft-heard statements that an atom can be in two places
at once, or that a cat can be alive and dead at the same time" ,  but there
are only two possibilities, either there is an alive cat and a dead cat in
two different places or there is a live/dead cat that instantly snaps into
being either alive or dead by the act of "measurement" even though the
standard textbook Copenhagen interpretation can't say exactly what a
measurement is, or even approximately what it is for that matter. In many
worlds a measurement is simply any change in a quantum system, it makes no
difference if that quantum system is a human being or an unconscious brick
wall. So in that sense many worlds is totalitarian because everything that
is not forbidden by the laws of Quantum Physics and General Relativity must
exist.  *

*You correctly point out that nobody has ever "seen an atom in two places
at once, let alone a cat being both alive and dead", but nobody has ever
seen infinite dimensional operators in Hilbert space that the Dirac-von
Neumann axioms use either, all they've seen is ink on paper in mathematical
books. And you can't get milk from the word "cow". *





*I'll close by just saying although I believe there is considerable
evidence in favor of the many worlds view I admit it falls far short of a
proof, maybe tomorrow somebody will come up with a better idea but right
now many worlds is the least bad quantum interpretation around. And
speculation is not a dirty word, without it science would be moribund,
Richard Feynman said science is imagination in a tight straight jacket and
I agree with him. Best wishesJohn K Clark*
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