[Rovelli's relational EPR.]{.underline}

Reply to GeorgeWeis@aol.com

Dear George,

Many thanks for sending Rovelli's paper "Relational EPR".

You ask me for comments upon it.

My overall impression is that it is moving in the opposite of the right

direction. It is kind of a continuation of the "search for certainty"

enterprise initiated by Descartes, in that makes it into an effort to
say the

*least* one can confidentially assert rather than the *most* that one
can usefully propose, as a way of understanding the scientifically
accepted data.

By proposing a rationally coherent model/theory with *more* specific
detail one achieves a *more* specific conception of nature and of our
place within it.

The issue of non-locality is an example.

The detailed information that confirms the predictions of QM in the EPR

type experiments (involving two-spacelike-separated-regions-R&L) is
available only in the later region C where the two experimenters get
together and compare notes. The proof of nonlocality given on the
penultimate (textual) page of Mindful Universe shows that if the
relationships entailed by QM between the outcomes experienced in R under
different choices made in R by the experimenter in R are independent of
the choices made in L by the experimenter in L about which of the two
alternative experiments he will perform in L, then the outcomes of
experiments performed in L, as reported in C, cannot be independent of
which experiment was chosen in R. That is, the outcomes in R and L,
*reported in C*, cannot both conform to the predictions of QM and be
independent of the choices made by the experimenters in the other
region. Because the facts/realities *in C* are facts about reports of
events occurring in R and L, they are physical realities within RQM. But
one cannot require, without logical contradiction, both, (1), the
validity of the predictions of QM and also, (2), the reported outcomes
in R and in L to be independent of the choices made by the experimenters
in the space-like-separated regions L and R, respectively.

This breakdown of the notion of "locality" is an interesting property
that is logically entailed by the predictions of QM about reports
reaching C. Insofar as Rovelli's relational approach obscures this
feature of QM, that approach is, in my opinion, deficient because it
hides a potentially important connectivity (wholeness) feature of
nature. Ultimately we want to know what the scientifically secure data
entails about us and our place in nature.

It is not clear that Rovelli's RQM does in fact allow one completely to
evade the inference of the existence of the wholeness feature of QM. One
must, of course, in considering the predictions of QM in EPR type
experiments, go to the region C where all the relevant fact are
available, and consider the reports that occur jointly there pertaining
to observations reportedly occurring in R and L. But then the
theoretical assumptions that the *reported* outcomes in R and L both (1)
conform to the predictions of QM and (2) are independent of the choices
made by the faraway experimenter, turn out to be logically compatible!

The description of "relational quantum mechanics" (RQM) given in terms
of a failure of "Einstein Realism", which is that:

"there exists a physical reality independent of substantiation and
perception."

In footnote 1 Rovelli notes that this statement does not do justice to

Einstein's position.

Rovelli begins to define RQM by saying that "In RQM physical reality is
taken to be formed by individual quantum events (facts^2^)..."

where footnote 2 recites Wittgenstein's dictum "The world is the
totality

of facts, not of things".

But his characterization of what is "real" applies to all "orthodox"
versions of quantum mechanics: all orthodox versions of QM feature
reduction/collapse events which specify the actual facts. In all
orthodox versions of QM the facts/realities are NOT "independent of
substantiation and perception."

So the issue, regarding RQM, as far as I am concerned, is not with
"Einstein Realism". It is with how the term "real" is best used within
an interpretation of quantum theory that accepts the idea that reality
is somehow created out of acts of "substantiation and perception".
Orthodox (von Neumann-Heisenberg) QM (insofar as it attempts to provide
an ontology) accepts the idea that the "actual" comes into being in
association with events that have both physically and psychologically
described aspects. The issue raised by RQM is to what extent is it
useful to regard these actualizations as *transpersonal*, rather than
merely personal. To what extent is it beneficial to

reject altogether the idea of a transpersonal "truth/reality/actuality",
and reduce truth to a something that is relative to the observer.

Given that we accept orthodox quantum mechanics we reject this "Einstein

Realism". Einstein Realism is not the issue. The issue is whether it is
beneficial to subscribe to the RQM view that "the reality of the
property of any given system S is only relative to a physical system A
that interacts with S and is affected by these properties". In terms of
the density matrix formulation the issue is whether one should say that
the "reality" of a system S is specified only relative to some observing
system A, and hence by a density matrix Rho(S\|A) instead of by von
Neumann's Rho(S)=Partial trace of the density matrix of the universe
over all variables other than those of S.

The von Neumann definition gives a powerful unity to the whole system
that is technically useful. It does entail a nonlocality property: the
density matrix undergoes "quantum jumps" RhoP Rho P , and such a jump,
associated with a projection operator P that act locally, say in
someone's brain. But the new state can then be extended over all
space-time via the Schroedinger equation. The action of P eliminates the
strands of potentialities that are incompatible with P, and this alters
the effective past---the past that determines potentialities for the
future\-\--and this produces some completely understandable effects in
the faraway region. The whole is completely understandably tied together
into a whole quantum universe. I see no technical or logical advantage
in suppressing the use of this powerful theoretical conception of
nature, and of our dynamical role within it. The

relational/relative conception of truth certainly has devastating moral
implications, which must be accepted if is truly the implication of the
scientifically secure data. But the rejection of transpersonal truth is
in no way foisted upon us by a rational analysis of the scientific data.

Rovelli defines "locality" as the principle that *two spatially
separated objects cannot have instantaneous mutual influence.*

This is quite obscure, in a world that is the totality of facts, not
things!

\-\--in a world consisting of events!

The meaning of "locality" normally used in the analysis of
EPR-Bohm-Bell-Hardy type experiments is the non-dependence of outcomes
(of events) in one space-time region upon choices of experiments
performed in a space-time region that is space-like separated from the
first.

This idea of locality is central not only to the Bell-type theorems but
to the

EPR arguments itself. It is the basis of the EPR argument at its final
crucial step: "This makes the reality of P and Q depend upon the process
of measurement carried out on the first system, which does not disturb
the second in any way."

The Rovelli analysis does not, it seems to me, really get to the core of
the nonlocality issue, which is the failure in QM of the notion that the
free choice made by the experimenter in one region should not affect the
outcome that appears in the other region, which is spacelike separated
from the first.

Rovelli does emphasize the fact that one must go to the region C in
order to have *in hand* the facts that that the pertinent predictions of
QM refer to. But it seems to me that once the two observers have met and
compared notes, both have the reports about what choices were made and
what outcome appeared (earlier) in the space-like separated regions R
and L. They can confirm that the relevant predictions of QM are
satisfied, and can carry out logical analyses and determine that logical
contradictions occur if one assumes that the choices made in the two
regions can be treated as locally inputted free variables, and that the
registered and reported outcomes in each region are independent of the
faraway free choice. It does not appear to me that orthodox (von
Neumann) quantum mechanics "requires the existence of a hypothetical
super-being that can simultaneously measure the state of A and B."
(Rovelli, p. 4 of ArXive copy) On the other hand, it is true that one
*can* form a rationally coherent conception of an evolving universe with
well defined transpersonal facts at each stage of the evolutionary
process.

Any claimed virtue of RQM, such as the dissolving of the need for
effective faster-than-light transfer of information\-\--which, however,
can be rationally achieve via reductions that change potentialities
globally in the orthodox way\-\--is, I believe, overshadowed by the
difficulty of explaining\-\--strictly within an RQM framework that
allows no FTL transfer of the information inputted by the "localized
free choices" by experimenters in R and L\-\--the apparent logical
contradictions found by rational quantum physicists located in region C.
I regard that difficulty as evidence for the existence of an
interpersonal (non-relational, non-relative) truth/reality. Also, I do
not see in what I have read about RQM the all-important process-1
choices that logically precede the stochastic process-3 events. How do
Rovelli's "systems" make these choices, which appear to be un-caused by
any of the known quantum laws? The notion that these choices are "free"
and "localized" is the basis of all EPR-type arguments.

In the RQM formulation the observers must themselves be quantum systems.

Thus they themselves, in making the difficult decision as to whether to
do experiment 1 or experiment 2 can be presumed to be, before choosing,
in a quantum mixture of states corresponding to the two possibilities.
The core problem in quantum theory is the relationship between mind and
matter, and this naturally goes over to the issue of the connection
between the contents of our streams of conscious experiences and the
processes going on in our brains. This is where the issue of the origin
of the process-1-related conscious choice comes to a head. What chooses
which of the process-1 physical probing actions will occur, when the
observing system is in a mixed state? This is the core question in the
interpretation of QM, but RQM seems not to address it. If RQM accepts
the usual quantum idea that this is a localized free choice, then the
rational quantum physicist situated in region C are faced with a logical
quandary that seems irresolvable within a restricted RQM ontology that
forbids faster-than-light and backward-in-time transfers of the
information inputted in R and L by the experimenters' free choices.

Within the more orthodox quantum ontology that permits interpersonal

(objective) truth/reality, one can consider the stage of the objective
process

where the regions associated with the events that have already (in
process time) filled up the portion of space-time up to the space-like
surface σ.

The process-1 events \[ρPρP + P'ρP'\] leave all "Traces" unaltered.

Consequently, the process-1 events can occur simultaneously at an
infinite collection of disjoint parts of σ: there is no interference
between them. Then the process-3 reduction can occur simulteously

(in process time) at all of these locations, or at any subset of them,

in accordance with the statistical constraints of QM. In this
"objective"

model the "present" is a space-like surface, rather than a constant time
surface, as it is in the non-relativistic version. But truth/reality can
be objective without any violation of the empirical conditions demanded
by the theory of relativity.