Le ven. 14 févr. 2025, 10:29, Alan Grayson <[email protected]> a
écrit :
On Friday, February 14, 2025 at 2:17:37 AM UTC-7 Quentin Anciaux
wrote:
Le ven. 14 févr. 2025, 10:08, Alan Grayson
<[email protected]> a écrit :
On Friday, February 14, 2025 at 1:37:20 AM UTC-7 Quentin
Anciaux wrote:
Le ven. 14 févr. 2025, 06:13, Brent Meeker
<[email protected]> a écrit :
On 2/13/2025 4:57 AM, John Clark wrote:
On Wed, Feb 12, 2025 at 5:41 PM Brent Meeker
<[email protected]> wrote:
*>> Schrodinger's Equation is 100%
deterministic, so why is it necessary to
resort to probability at all?*
>///Because one thing of many possible happens./
*Why is that "one" thing special? I can answer
that; because it's not special, many things
happen, everything that is not forbidden happens.
You have no answer to that question other than
"because it is".
*
The only thing special about is that it's the one
that happened. If everything not forbidden happens
then you're going to need to explain what
probabilty means.
/> I can write an equation for the toss of
die that shows that the probability of each
face is 1/6. That equation is
deterministic. It determines probabilities.
And probabilities tell you that some things
happen and some don't. Not that every face
of the die comes up on every throw./
*Schrodinger's equation producesa complex-valued
wave that evolves in time, the square of the
absolute value of the amplitude of that wave
determines probabilities.You just take the Born
Rule as a given because experimenters tell you
that it works. Many Worlds can tell you _why_ it
works and why you need it.
*
So you say. But all attempts to derive it,
assuming MWI, have failed. I look forward to your
paper.
*And unlike Schrodinger's Equation your dice
equation directly determines a probability*
Not as directly as Schrodinger's equation
determines QM proability amplitudes.
*; classical physics doesn't have or need a
counterpart to the Born Rule (although the square
of the absolute value of an electromagnetic wave
is proportional to its energy). Classical physics
can provide us with an excellent approximation of
how the orientation of the die will change in
time, so why do we need to use probability? The
reason for that is practical not fundamental,
sometimes in classical physics tiny changes in
initial conditions lead to exponentially
diverging trajectories over time, and you're
never going to know the initial conditions
exactly, and even if you did you don't have the
computing capacity to use them.*
/> And you have no answer to what probability
means, until you resort to "uncertainty of
self-location",/
*Resort to? If I'm not allowed to give the
correct answer then my answer is going to be
wrong. Many Worlds says everything always obeys
Schrodinger's equation including the observer,
therefore there will always be self-location
uncertainty, it can't be avoided. *
And how does that result in uncertainty, when you
are located in every branch. It's just the
problem of what does probability mean when
everything happens. You're just pushing the
problem around.
Brent,
The problem isn’t that "everything happens"—it’s *how
often* different things happen from the perspective of
an observer. Probability in MWI doesn’t mean "some
branches exist and others don’t" but rather that an
observer finds themselves in certain branches
*proportionally* to their measure.
Saying "you’re just pushing the problem around"
ignores that probability in any framework is about
*expectations for future experience* based on
structure. In a single-world view, you justify
probabilities by appeal to hypothetical ensembles or
repeated trials that never actually happen. In MWI,
the structure of the wavefunction provides the
ensemble *within* reality, and measure determines
where most instances of an observer exist.
Also, I’m not specifically advocating for MWI. I lean
more towards *a computational theory of reality*,
where measure and probability emerge from an
underlying informational structure. But I do favor
frameworks where *everything happens* rather than a
single unique history set in stone forever.
*Then you'll like this: *
*In a horse race, according to the MWI, multiple worlds
come into existence for all possible winners in a
particular race. But for one given race, are there are not
multiple worlds, possibly countably infinite, which come
into existence for every possible way in which the winner
wins, while retaining the finishing order of the losing
horses? I think so, and is the reason I find the MWI and
its devotees, lacking in discrimination. But for a
discerning eye, it's in the eye of the beholder, of
Schrodinger's equation. AG *
AG,
That’s exactly the point, MWI doesn’t just split for the
winner, it splits for every possible microscopic detail of the
race, including variations in how each horse crosses the
finish line, fluctuations in the crowd, air molecules, and so
on. The number of branches isn’t just countably infinite; it
follows the continuous evolution of the wavefunction.
But calling that "lacking in discrimination" misses the core
idea. It’s not about choosing which worlds are "important",
it’s about unitary evolution preserving all possible outcomes.
The structure is dictated by Schrödinger’s equation, not by
human intuition about what "should" count as a distinct event.
If you think that level of detail makes MWI unreasonable, you
should also reject classical probability, where every possible
dice roll, coin flip, or weather pattern is part of a notional
ensemble. The only difference is that MWI doesn’t assume
unrealized outcomes "disappear" without explanation.
Quentin
*
*
*So every wiggle of your finger or toe results in perhaps
uncountable worlds coming into existence, as well as every random
turn of a flying insect? It just doesn't pass the smell test. AG *
AG,
Yes, every quantum interaction leads to branching—whether it’s a
photon reflecting off your skin or an insect flapping its wings. But
the mistake is thinking of this as “new worlds popping into
existence.” MWI doesn’t add anything extra, it simply follows unitary
evolution, where all possible outcomes exist in superposition.
What doesn’t pass the smell test is the idea that only one history is
mysteriously “chosen” while the rest, dictated by the same Schrödinger
equation, vanish without explanation. If you accept quantum mechanics,
you already accept that reality operates in a way that defies
classical intuition. Rejecting MWI because it feels excessive is just
favoring one form of weirdness over another.
