On 2/16/2025 4:13 AM, John Clark wrote:
On Sat, Feb 15, 2025 at 6:59 PM Brent Meeker <[email protected]>
wrote:
*>> If what you say is true then quantum mechanics wouldn't
need probability, it could simultaneously make predictions
about momentum and position to any arbitrary degree of
precision, but quantum mechanics can't do that. Therefore I
must conclude that either quantum mechanics is wrong or you are. *
/> How does the HUP imply self-locating uncertainty?/
*There must be a fundamental reason why we can't make predictions
better than those allowed by HUP, and self-locating uncertainty is
that reason.
*
?? Most physicist think it's because conjugate operators don't commute.
Which has nothing to do with multiple different measurement results.
*>> Many Worlds and objective collapse make different
predictions, one says it happens the other says it doesn't.
Experiments are going on right now to determine who's right,
if they find objective collapse then Many Worlds will be
proven wrong.*
**
>How will they know it's "objective"? Every branch of MWI observes
objective collapse.
*According to Many Worlds nobody observes objective collapse because
objective collapse never happens. Many Worlds predicts that everything
follows Schrodinger's equation exactly, but Objective Collapse adds in
an additional term to the equation that is both nonlinear and randomly
determined. Experiments are going on right now in super cold systems
that are as isolated from the outside world as possible to look for
tiny amounts of spontaneous radiation or heating that Schrodinger's
unmodified equation and Many Worlds does not predict. If they find it
then Many Worlds is wrong and I will switch over and become an
Objective Collapse fan. I don't think that will happen, but I could be
wrong, it's certainly an experiment worth making. *
That's looking for *SPONTANEOUS* collapse.
/> //If it were merely subjective you'd need to explain how there
can be records and agreement on it. /
*If you make a record of which slit an electron went through in the
two slit experiment then you will not see an interference pattern on a
screen, but if you don't make a record of it then you will. And if you
make a record and place the screen a light year away from the slits
but erase that record one second before the electrons hit the screen
then you will see an interference pattern. This is certainly odd but
it poses no problem for Many Worlds.*
You only see the interference pattern after you know the identity of the
ones whose partner was erased. Otherwise you could use it for faster
than light signalling. But it's not subjective; the pattern is really
there for anyone to see.
/> One alternative to MWI is QBism which explicitly rejects
objective collapse and thereby disagrees with MWI. /
*All QBism is saying is that you should update your beliefs after
making a measurement, that's certainly good advice, you should do that
whenever you see the outcome of an experiment, not just those that
involve Quantum Mechanics; but QBism doesn't even try to explain what
is actually going on. QBism is just Shut Up And Calculate with a more
respectable name.*
It's curious that you criticize QBism because it's not explaining what's
"actually going on" but you like MWI versus spontaneous collapse. Yet
spontaneous collapse does explain what's "actually going on". Of course
explanations may be spurious.
Brent
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To view this discussion visit
https://groups.google.com/d/msgid/everything-list/2cb462a2-145b-4446-956f-d5701b122eda%40gmail.com.
