Dear Matthew Leifer,

Thank you very much for your comments. These are very helpful for me. In general I agree with your remarks but some points are to be discussed.

In general, it is clear that QM must be an applied probability theory and it is clear that this probability theory cannot be the Kolmogorovian probability theory.

1. The first…[Read more]

Dear Shan,

I have a comment and a critical remark to your argumentation.

I shall consider the property (C1) in the more complete formulation:
(C1x) the wave function of a physical system is a complete description of the individual system.
You write “The first approach is to deny the claim (C1), and add some additional variables …”.
I think…[Read more]

jiri soucek,

I am somewhat sympathetic to the view that quantum theory should be understood in terms of some sort of non-Kolmogorovian probability theory. However, there are a couple of problems with this.

First, it is not just since 2008 that this option has existed. There are currently a few dozen competing generalized probability theories…[Read more]

Hi Shan,

Turning back to your question in #3303, concerning randomness:

A central point of the paper I posted in this forum is that all of the probabilities in retrocausal quantum models can be classical/conventional in the sense that they all result from a lack of knowledge. But there are two different parts of this. First is the knowledge…[Read more]

Shan,

“In fact, the writing of this paper is mainly motivated by your words in your review paper. You said, “A straightforward resolution of the collapse of the wavefunction, the measurement problem, Schrodinger’s cat
and friends is one of the main advantages of psi-epistemic interpretations…. The measurement problem is not so much resolved by ps…[Read more]

Dear Matthew,

I have some comments

1) The very idea of the ontological models is based on the assumption that there exists only one probability theory – the standard Kolmogorov theory. But from 2008 there exist two probability theories – the Kolmogorov (linear) probability theory and the new quadratic probability theory published in…[Read more]

Dear Shan,

I am suprised that you consider the psi-epistemic view together with the idea that all observables have pre-existing values.
I understand the psi-ontic view as the standard assumption that each pure state represents the possible state of an individual system. For me the psi-epistemic view means that not all pure states represent the…[Read more]

Thnx for the reply, Yehonatan. You don’t need to concern yourself with the details of our approach, as you noted it doesn’t bear directly on your specific motives. I just wanted you to be aware of the fact that your 4D global perspective has company 🙂

Hi Matt,

Thanks for your interesting comments, some of which I basically agree.

But I think you misunderstood my paper. The paper does not aim to show the (realist) psi-epistemic view cannot solve the measurement problem. Rather, it only shows that the psi-epistemic view does not provide a straightforward resolution or a dissolution of the…[Read more]

Shan,

We have had so many discussions about this now that I am beginning to think that you are being deliberately obtuse, and trying to court controversy where there ought to be none.

Let me first note that not all ontological models solve the measurement problem, psi-epistemic or not. Some do and some don’t. Since Bohmian mechanics can be fit…[Read more]

Yehonatan, I read your paper. Is it published someplace, so we can reference it? Your approach shares many of the values found in the Relational Blockworld. See http://www.ijqf.org/wps/wp-content/uploads/2015/06/IJQF2015v1n3p2.pdf.

Shan, there is no superdeterminism in retrocausality with global constraints. Superdeterminism entails a time-evolved story per the Newtonian schema (NS), i.e., invoking a physical mechanism that “causes” the experimentalist to make certain choices. In Wharton’s Lagrangian schema (LS), the explanation is spatiotemporally holistic, e.g., Fermat’s…[Read more]

Shan, Thanks for the post. Here are a few thoughts.

1. You catch-out the ontogical models view at a weak point. For what they call “psi-epistemic” has to do with possible overlap of ontic states in the preparation of distinct state functions. But that has nothing to do with explaining collapse on measurement. In the earlier literature, as in…[Read more]

Mark: concerning “realist psi-epistemic view”. There’s no problem with the basic idea, so long as “realist” clearly modifies “view”. But a different parsing might make it seem that “realist” modifies “psi”, which would imply exactly the opposite of psi-epistemic (psi-ontic). That’s all I was getting at… 🙂

Shan: I’m not sure what you mean by “essential randomness”, or whether that would be ‘good’ or ‘bad’. But you are correct to imply that if there is some ‘special observable’ A in the real system that is perfectly correlated with the measurement B that we utilize on that system, then this correlation needs to be explained causally.

One option is…[Read more]

Ken, why do you think “realist psi-epistemic view” is “an interesting choice of words”? The title of our last RBW paper in IJQF was “Relational blockworld: Providing a realist psi-epistemic account of quantum mechanics” which we wrote after extensive correspondence with you.