On Wednesday, 7 September 2022 at 13:35:50 UTC+2, richali...@gmail.com
> On Monday, September 5, 2022 at 12:03:11 AM UTC-5, ju...@diegidio.name
> > On Sunday, 4 September 2022 at 19:54:28 UTC+2, richali...@gmail.com
> > > On Saturday, September 3, 2022 at 7:15:37 PM UTC-5, ju...@diegidio.name
> > > but the wave function calculated is not real.
> > That *depends* on your ontological stance: and your choice,
> > which is the standard one, is the one that is *most* problematic.
> This clarifies a difference of opinion between us. I don't understand
> why you say that is *most* problematic? Can you elaborate? I'm
For the reasons I have hinted at upthread: 1) saying "the wave function
is not real" means a plain hole in a theory's ontology (you may think our
physical theories are full of these "holes": they aren't, and the problem
here is in fact quite serious), and in this respect the standard interpretation
is the weakest of the lot, i.e. as compared to pilot-wave theory or even
many-worlds ("multiverses"); 2) "collapse" of the wave function is indeed
an externally added postulate that simply has no place in any physical
theory proper (under the least-action over a state space paradigm that is);
and, 3) with collapse we break "reversibility", which is really the nail in the
coffin as far as that theory is concerned. So... "shut up and calculate."
Indeed, note that many-worlds was born exactly as an attempt to solve
the problems of the standard interpretation: there is no "collapse" but
rather "branching" in many-worlds, and, while ontologically that remains
quite unjustified (as long as there is no way to probe the existence of
these branches), it at least saves reversibility.
While, as for pilot wave theory, that is fine ontologically and otherwise,
indeed (as I get it) it is the best quantum theory we could have, but it's
simply been "cancelled". Sure, it's dualistic, just as in Yin and Yang...
but this is another story.
> For what it is worth, I distinguish the physics of QM from the math of
> QM. The math is a model of our understanding that may be imperfect. I
> believe there is a reality where the actual physics happens.
No, you are quite not precise enough. Physics already *per se* has two
dimensions, theoretical and applicative (experimental), where the
theoretical part is where you find the (physical!) models: and the more
we probe into realms that we cannot directly experience, the more the
theoretical part becomes relevant and needs to be solid. As for maths,
that is simply a tool, it provides a formal language and algebra, but that's
all about it, it certainly does not dictate anything properly physical.
That said, the belief you express above I agree with (how couldn't I), but
now you are getting into the properly philosophical issue of what one
believes about cosmos: physics per se just needs a solid ontology and
then it is proper physics, whether or not the whole cosmos is somebody's
dream or else... but this too is another story and only marginal to our topic.
> Seriously, isn't collapse a part of reality, or required by reality?
Nope, "collapse" is a postulate and then a requirement of *that
theory* to somehow manage to use it at all. Conversely, the fact that
we "measure things" does not per se entail the need for "collapse".
> For example, back to the photon detected in the two slit experiment,
> once the photon is detected there is now a new reality that differs from
> the previous wave function.
You are being *very* imprecise there. Indeed this is my last reply in this
thread: at this point I think if you want more or even just more confirmation,
you should rather start looking into some course material...
> It sounds like you may follow the many worlds concept.
I thought I had to made clear that I am quite unhappy about that, too.
> Thanks Julio for responding, this is clarifying these ideas for me.
Fascinating topics. Best luck to you,