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by **Jarek** » Mon Dec 23, 2019 10:21 pm

What is crucial here is time/CPT symmetry of physics e.g. in Lagrangian formalism (from QFT to GR), unitary evolution.
In contrast we try to enforce our time asymmetric intuition like in Euler-Lagrange evolution, but maybe we should be more careful.

Here are some symmetric ways to choose a solution:
1) The least action principle: solution is chosen as action optimizing one based on state in past and future ... but state when exactly? Can be minus plus infinity.
2) Path ensemble e.g. Feynman's of paths from minus to plus infinity. Boltzmann path ensemble ( https://en.wikipedia.org/wiki/Maximal_E ... andom_Walk ) already has e.g. Anderson localization e.g. rho~sin^2 in [0,1], Born rules, which can lead to Bell violation constructions.
3) Path ensemble is naturally transformed into propagator, allowing to imagine the current moment as effect of meeting of two propagator: from minus and plus infinity as in https://en.wikipedia.org/wiki/Two-state ... _formalism

Accepting time/CPT of physics - that physics has chosen solution we live in in symmetric way like in the 3 ways above, the current state was already chosen to be compatible with all future measurements - as in superdeterminism.

Having solution chosen in symmetric way, we can switch to compatible asymmetric perspective, e.g. least action principle -> Euler-Lagrange evolution.
More arguments: https://arxiv.org/pdf/0910.2724

by **local** » Mon Dec 23, 2019 7:48 pm

Who's to say "we need to fix it somewhere far in the past e.g. in Big Bang, and somewhere in the future e.g. Big Crunch, infinity etc."? Your argument is circular.

by **Jarek** » Mon Dec 23, 2019 6:09 am

In the least action principle ( https://en.wikipedia.org/wiki/Principle_of_least_action ) you fix values in past and future, getting evolution between them as the one optimizing action.
From Universe perspective, we need to fix it somewhere far in the past e.g. in Big Bang, and somewhere in the future e.g. Big Crunch, infinity etc..

Now having chosen such action optimizing history of the universe, we can switch to standard forward in time evolution using Euler-Lagrange equation, which is mathematically equivalent (if already having a solution).
It uses information only e.g. in current moment, but not only value e.g. of a field, but also of time derivatives.

If physics works accordingly to the least action principle (or other time/CPT-symmetric formulations like path ensembles), then this hidden Euler-Lagrange internal state was already chosen to be compatible also with all future measurements.

by **local** » Mon Dec 23, 2019 5:40 am

I don't see how an action principal must entail superdeterminism.

by **Jarek** » Sun Dec 22, 2019 2:38 pm

Please elaborate what exactly do you see incoherent in considering assumption of physics working accordingly to the least action principle?

by **local** » Sun Dec 22, 2019 12:23 pm

Jarek, as an unbiased observer, I have to say that you are sounding incoherent.

by **Jarek** » Sat Dec 21, 2019 2:19 pm

Jarek wrote:- assume you have a source of prepared identical states,

I deliberately emphasized identical states there - so that selection for various measurements does not matter.

This "free will" selection is not a problem here.
The problem is understanding Born rule: probability of alternative of exclusive events is proportional to squares of sums of their amplitudes, what disagree with standard probability axioms.

by **Joy Christian** » Sat Dec 21, 2019 2:09 pm

***
Here is another quote regarding the conspiratorial nature of superdeterminism from Abner Shimony, Michael Horne and John Clauser, Epistemological Letters, 13, 1 (1976):

Abner Shimony, Michael Horne and John Clauser wrote:
In any scientific experiment in which two or more variables are supposed to be randomly selected, one can always conjecture that some factor in the overlap of the backward light cones has controlled the presumably random choices. But, we maintain, skepticism of this sort will essentially dismiss all results of scientific experimentation. Unless we proceed under the assumption that hidden conspiracies of this sort do not occur, we have abandoned in advance the whole enterprise of discovering the laws of nature by experimentation.

***

by **Jarek** » Sat Dec 21, 2019 1:52 pm

I am not introducing anything, only reminding 18th century principle of least action - do you see it controversial or a part of theology?

Assumption that physics works accordingly to this principle is stronger than just determinism - state in a given moment is literally chosen accordingly to both past and future situation there - similarly as in superdeterminism.

I only accept assumption of this principle here.

by **Joy Christian** » Sat Dec 21, 2019 1:40 pm

***
You are the one who is introducing theology into science. Superdeterminism is a conspiratorial theology, not science.

***

by **Jarek** » Sat Dec 21, 2019 1:23 pm

So how would test/violation of Pr(A=B) + Pr(A=C) + Pr(B=C) >=1 look like?
- assume you have a source of prepared identical states,
- for some you measure AB, for others AC, for others BC,
- estimate the probabilities from these measurements and calculate Pr(A=B) + Pr(A=C) + Pr(B=C).

Where exactly do you need "free will" assumption here?
If nowhere, please let's not mix physics with theology - leave "free will" arguments for the latter.
The difficulty is understanding Born rule, which already can be seen in Malus law in EM - the question is how to take it e.g. to spins?

by **Joy Christian** » Sat Dec 21, 2019 12:40 pm

***
Ok, I give up. You are not going to get it.

***

by **Jarek** » Sat Dec 21, 2019 12:23 pm

The problem pointed by Bell is existence of inequalities which are satisfied by standard probabilistics, but can be violated by QM formalism.

E.g. 3rd probability axiom ( https://en.wikipedia.org/wiki/Probability_axioms ) says that
probability of alternative of exclusive events is sum of their probabilities.
what e.g. allows to conclude for binary variables A, B, C that:
Pr(A=B) + Pr(A=C) + Pr(B=C) >=1
however, quantum formalism allows to violate it ( https://arxiv.org/pdf/1212.5214 ).

It says that QM allows for statistics essentially different than standard probability axioms.
It can be seen in Born rule: probability of alternative of exclusive events is proportional to squares of sums of their amplitudes. - which allows to violate above inequality.

The problem of Bell theorem does not regard free will of observers, but understanding nonintuitive correlations of QM, especially the Born rule ... which is natural for time symmetric models like the least action principle.

by **Joy Christian** » Sat Dec 21, 2019 11:49 am

Jarek wrote:
We use Lagrangian mechanics from QFT to GR - if physics use it through the principle of least action, then everything is predetermined - including what you have written.
Yes, just using this principle, I don't know what's conspiratorial about it.

Then you don't understand Bell's argument (which is often called a "theorem"), as I have always suspected. Think about the question I asked and you answered in "Yes."

Here is a quote from Zeilinger that makes the problem with superdeterminism very transparent [Dance of the Photons, Farrar, Straus and Giroux, New York, 2010, p. 266]:

Anton Zeilinger wrote:
[W]e always implicitly assume the freedom of the experimentalist... This fundamental assumption is essential to doing science. If this were not true, then, I suggest, it would make no sense at all to ask nature questions in an experiment, since then nature could determine what our questions are, and that could guide our questions such that we arrive at a false picture of nature.

***

by **Jarek** » Sat Dec 21, 2019 11:35 am

We use Lagrangian mechanics from QFT to GR - if physics use it through the principle of least action, then everything is predetermined - including what you have written.
Yes, just using this principle, I don't know what's conspiratorial about it.

by **Joy Christian** » Sat Dec 21, 2019 11:28 am

Jarek wrote:
What conspiratorial do you see in the principle of least action?
https://en.wikipedia.org/wiki/Principle_of_least_action

I see its irrelevancy for the question I asked and you (I think) answered in Yes.

***

by **Jarek** » Sat Dec 21, 2019 11:09 am

What conspiratorial do you see in the principle of least action?
https://en.wikipedia.org/wiki/Principle_of_least_action

by **Joy Christian** » Sat Dec 21, 2019 10:50 am

***
I take it that this is your longwinded way of answering my question affirmatively. In that case, you believe in a conspiratorial world. I don't. And we don't have to.

***

by **Jarek** » Sat Dec 21, 2019 10:19 am

Assuming e.g. the least action principle is the way physics works, everything is predetermined, superdetermined.

This way we can imagine that our universe was fixed in the past in Big Bang and in the future e.g. in Big Crunch, and physics has chosen action optimized history of the universe between them.

This philosophy of just traveling through already chosen spacetime is called (Einstein's) block universe, eternalism: https://en.wikipedia.org/wiki/Eternalis ... hy_of_time)
Alternative is presentism - spacetime does not exist, only the current moment: https://en.wikipedia.org/wiki/Philosophical_presentism

So which philosophy of time is the proper one?

by **Joy Christian** » Sat Dec 21, 2019 9:47 am

Jarek wrote:
Superdeterminism does not need any conspiracy, only accepting time/CPT symmetry of nearly all physics we use - that the history of the universe was chosen by e.g. the least action principle, hence shifting to Euler-Lagrange perspective its state was chosen also accordingly to all future measurements.

Answer this question: Are the choices of the settings made by the experimenters in any EPRB experiment predetermined by the initial state of the spin system? Yes, or No?

***

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