Ben,
Thanks for the interest and the post! I am going to have to re-read your paper before I can any comments on it, but I will post them to your paper at the earlist opportunity.
As far as objective realism, we need to frame this question in terms of Einstein's apparent view on this subject, since this is at the center of EPR's paper (as highlighted in the first paragraphs of the paper). It is important that we recognize that they didn't bother to provide a full definition of objective reality. This is significant because a lack of definition in a paper that is arguing that objective reality is the means by which we should grade theories should be viewed as flawed from the start.
So we are left grasping as to what is actually meant by the term.
In posterior construction, we have to note that Einstein was heavily influenced by both Mach and Boltzmann. Einstein never met Boltzmann, but he did meet Mach, and on page 164 of Walter Isaacson's book Einstein: His Life and Universe [1] we see the following exchange:
"Einstein wanted to convince Mach of the reality of atoms, which the old man had long rejected as being imaginary constructs of the human mind. "Let us suppose that by assuming the existence of atoms in a gas we were able to predict an observable property of this gas that could not be predicted on the basis of non-atomistic theory" Einstein asked. "Would you then accept such a hypothesis?"
"If with the help of the atomic hypothesis on could actually establish a connection between several observable properties which without it would remain isolated, then I should say this hypothesis was an 'economical' one," Mach grudginly replied.
It was not a full acceptance, but it was enough for Einstein."
So we see that Einstein was deeply influenced by Boltzmann's ideas, and presumably his ideas of objective reality. So then we have to examine what Boltzmann meant. It turns out that there is a collection of Boltzmann's philosophical discourse. The book Ludwig Boltzmann, Theoretical Physics and Philosophical Problems, Edited by Brian McGuinness; contains a paper entitled "Objective Existence in Inanimate Nature". What is interesting is that as Boltzmann first builds an argument where he must start which the subjective observations before he can talk about objective things. This is effectively an argument where the objective *emerges* from subjective roots, then we get to page 65 of the the book where Boltzmann says this:
"It would of course be absurd to prove or disprove the objective existence of matter."
then
"Rather, it will be the case of giving further reasons why it would be inappropriate constantly to remind ourselves of the fact stated earlier, namely that we denote matter as not objectively existing, although we should always remain clearly aware of this fact."
and further
"To fix the concept of objective existence we earlier appealed to the common judgement of all."
Boltzmann's objective is to then show start with the other point of view, starting with objective inanimate matter. This argument is a little harder to follow but one part of the argument stands out on page 70:
"It is simply that, for our subjective feelings, that is fine and lofty which advances and raises our species: objectively these concepts do not exist."
Here is the man, Boltzmann, who Einstein admired enough as to propose his world view to his other hero, Mach, basically pointing out that objective existence can only be built upon a foundation of collected subjective interpretation. Since the latter can not *emerge* from the former. He is basically arguing that we are mechanisms, and essentially everything that we identify with individuality is purely non existent.
This is the argument as it stood for 100 yrs. It is also the view that quantum mechanics says is completely wrong. It is also disproved by Godel's Incompleteness Theorem in the sense that existence built on discrete material objects is simply incapable to explain the universe, or even people (we have to differentiate from the discreteness found in QM, which is a discreteness in hilbert space).
Ok, now onto path integrals.
First we have to recognize that the wave-particle duality that is frequently discussed is different from the wave-simple harmonic oscillator duality. Particles, as we identify them in nature, most are not simple entities. The are composite entities, they are composed of waves. Even the simple photon itself is a composite entity, as highlighted in the dual slit experiment, it interferes with itself. A simple wave, like a sine wave, extends throughout all of space, however, it has a dual representation as a simple harmonic oscillator. There is nothing contradictory in saying that a composite particle, like the electron, when it is in a potential well, behaves as a simple harmonic oscillator. However, is it conversely true to argue that a simple harmonic oscillator is a particle? I would argue that it isn't.
Why I discuss this is that it is important to understand that Feynmann's path itegral approach has a dual Hamilitonian approach, as highlighted in most QFT books, but specifically I refer to A. Zee's book QFT in a Nutshell. Essentially it says that recursive evolution (hamiltonian evolution) is functional equivalent to the spacetime filling path representation. So at some level one can see the analogy of oscillator-path to simple harmonic oscillator-wave duality.
So what about Feynmann diagrams, and there use of particles? What about strings? Are these not real objects?
The simple answer is no. If we reference Diagrammatica by Veltmann, we find an interesting quote:
"Feynman rules have a true physics content,and the physicist must understand that."
The point as emphasized in the book, is the strength of the theory has nothing to do with the concept of particles, it is the development of rules to govern how we derive a result. Does it matter whether there is a point or a string in the diagram, not really except that we can attach additional variability to our mental image of a string. The string is simply a more evolved collection of oscillators.
I hope that answer isn't too long, I just thought it was better to give more detail about my thoughts on this than less.
Harlan
[1]http://books.google.com/books?id=cdxWNE7NY6QC&pg=PA164&lpg=PA164&dq=einstein+met+mach&source=bl&ots=1w4yuUfxpK&sig=EH0OwvnLqNXoWiAn3qjWCQkIkAQ&hl=en#v=onepage&q=einstein%20met%20mach&f=false