Gordon Watson wrote:In my [new] terms, pseudo-realism is the idea (understood and accepted by many working physicists) that physical systems have objective properties at all times, independent of interactions. This idea (akin to naive realism; the idea that an act of observation passively reveals what existed prior to observation) leads to the following strange conclusions under EPRB where Alice (Bob) is the mechanic maintaining polarizer-analyzer a-A (b-B):
So what has your pseudo-realism got to do with the definition of realism I mentioned above. I never said observation must be passive. That is naive realism.
(i) If a particle interacts with a polarizer-analyzer b-B (an observer) in such a way that a new property is created (e.g., the now-intrinsic property of being polarised UP in a specific direction, before the particle is absorbed in analyzer B), then the new property did not belong to the particle. Rather, it was an objective property of the “observer + particle” system.
Why do you choose to call that a new property instead of a pre-existing property that changed "value" after an interaction? Local Realism as I defined it allows for interactions to create new properties, but also for existing properties to change after interaction. Ownership of the property does not change simply because it's value changed. The momentum of a photon that changes after interacting with a mirror belongs to the photon, not the mirror + photon system. The definition I provided allows for such situations perfectly without any absurdity.
(ii) In the same way, since analyzer B also had a new intrinsic property (a red light was on): the red light was also a property of the “observer + particle” system.
The state of the light of the analyzer is not a new property. It simply changes "value" from OFF to ON after interaction. No absurdity here either.
(iii) We can remove analyzer B (in another run of the EPRB test) and know that a second particle (exiting polariser b) has the now-intrinsic property of being polarized UP. So this new property is an objective property of the “two particles + two polarizers + one analyzer” system.
(iv) Modifying (iii), we can remove polariser b in another run and know that a third particle has this extrinsic property: if it is tested by polarizer-analyzer bB, a red light will go on. This extrinsic property is a property of the particle.
I hope you now see where you are erring. My initial claim was that assigning properties from a larger system only to part of it leads to absurdities. Now you've gone to the other extreme classifying changes to existing properties as "new", thus erroneously increasing the scope of the system.
Seeking to resolve such issues, TLR uses Bell’s convenient term “beable” (an existent, an element of physical reality). Thus, under TLR, true realism recognises that beables have both intrinsic and extrinsic properties. Thus an electron has intrinsic properties like charge e, spin s =1/2; extrinsic properties like position, momentum; depending on the state preparation, intrinsic or extrinsic properties like polarization.
Hopefully you now see why those are non-issues so long as you consistently recognize the "physical system" that is said to "own" the "property", and distinguish between changes in "value" of an "existing property" and creation of "new properties". The definition of local realism I provided is perfectly consistent with intrinsic and extrinsic properties as is. NOTE: The definition I provided is also perfectly consistent with a situation in which the value of an existing property always changes at every attempt to observe it (in other words, if the only method available to observe a property involves an interaction that effectively changes the value of the property in the process). Note that in this case, the fact that the property had a definite "value" independent of observation, remains, even if we may never directly observe such a value. Naive realism does not allow this, hence my claim that you should not call what I defined "naive realism" or "pseudo-realism" as you did.
To be clear about the difference between intrinsic and extrinsic properties: all measured properties are taken to be intrinsic in classical mechanics whereas (under TLR and EPRB) some properties are extrinsic.
I think this is most probably wrong (cf thermodynamics), but irrelevant -- better not go down that rabbit trail ATM.
NB: Since ‘subjective’ as the generally accepted antonym of ‘objective’ can be misleading here: we might best use the antonym “nonobjective” to discuss what I believe is missing from your definition of “local realism”. Extrinsic properties are nonobjective (becoming objective via interactions). They are nonetheless real properties; like the property that particle q(λ) will spin UP when tested by polarizer b. Perhaps clearer if we use ACTUAL and POTENTIAL.
PS: Thanks again; this needs more work but I'm beginning to see more clearly what you mean about working on the definitions. My excuse (until now) being that it's all done for me via my notation and math.
Like I said, I'd better not go down the trail of "intrinsic" vs "extrinsic" because I don't agree with your use of those terms. I think the discussion can proceed without bringing them in. To me there is no difference between Non-objective and subjective. I like ACTUAL vs POTENTIAL but I don't think that needs to be involved in the definition of what Local realism means, since reality and thus "Local Realism" deals ONLY with actualities.