Intriguing Cosmology Paper By GFR Ellis

http://arxiv.org/abs/1407.7243

Title: The Evolving Block Universe and the Meshing Together of Times

Author George F.R. Ellis

I have just started this paper but in the first sections the author is
seriously questioning the rationale for the idealistic assumptions of
reversibility, unitarity and dissipationless dynamics (Hamiltonian).

This putting of fundamental assumptions on the cold examination table
and scientifically dissecting their merits, or lack thereof, is
something we have not seen much of for decades.

Open-minded discussion that minimizes overt and covert agenda is
solicited by this poster. Is this the future of cosmology or a less
useful excursion into speculation?

[Mod. note: reformatted -- mjh]

In article , "Robert L.
Oldershaw" writes:

I have just started this paper but in the first sections the author is
seriously questioning the rationale for the idealistic assumptions of
reversibility, unitarity and dissipationless dynamics (Hamiltonian).

You use "idealistic" disparagingly.

Others, such as Penrose, have also questioned unitarity. The question
is in what regime. Even if it breaks down somewhere, that doesn't mean
it is invalid everywhere. GR almost certainly breaks down near the
Planck length, but that doesn't mean it is not the correct theory to
analyze the orbital dynamics of pulsars.

This putting of fundamental assumptions on the cold examination table
and scientifically dissecting their merits, or lack thereof, is
something we have not seen much of for decades.

George Ellis (along with others) has been writing similar papers for the
last 50 years or so.

On Friday, August 1, 2014 3:27:25 PM UTC-4, Phillip Helbig---undress to reply wrote:

You use "idealistic" disparagingly.

------------------------------------

Over the last 100 years or so physics has adopted certain assumptions
that made analyses much simpler mathematically. A brief and partial
list might include cosmological homogeneity/isotropy, reversibility
(especially in the microcosm), unitarity, absolute scale, cut-offs to
nature's hierarchy, etc.

Most of these assumptions did involve idealizations and were initially
acknowledged as such. Unfortunately, as de Vaucouleurs argued, the
repetition of the assumptions and their use over decades of time
allowed them to subtly morph from assumptions into accepted "facts of
nature". At least they became treated as if they were well-proven
facts.

Perhaps we are approaching a point in the development of science when
we can begin to seriously question these assumptions and explore
alternative assumptions. Possibly the new paper by Ellis will catalyze
a broad and sincere reassessment of assumptions by the entire physics
community. Many individuals have questioned individual assumptions
over the last 100 years, but they have not made much headway against
the prevailing winds. A more concerted effort might lead to new and
interesting developments in physics.

[Mod. note: reformatted -- mjh]

In article , "Robert L.
Oldershaw" writes:

On Friday, August 1, 2014 3:27:25 PM UTC-4, Phillip Helbig---undress to reply wrote:

You use "idealistic" disparagingly.

------------------------------------

Over the last 100 years or so physics has adopted certain assumptions
that made analyses much simpler mathematically. A brief and partial
list might include cosmological homogeneity/isotropy,

Was an assumption; isn't anymore.

reversibility
(especially in the microcosm),

Not really an assumption; assuming non-reversibility would be an
assumption.

Most of these assumptions did involve idealizations and were initially
acknowledged as such. Unfortunately, as de Vaucouleurs argued, the
repetition of the assumptions and their use over decades of time
allowed them to subtly morph from assumptions into accepted "facts of
nature". At least they became treated as if they were well-proven
facts.

Getting back to George Ellis, he has written dozens of papers
questioning the cosmological assumptions. He is one of the pillars of
the cosmological community. I see no evidence for your conspiracy.

On Saturday, August 2, 2014 5:33:10 AM UTC-4, Phillip Helbig---undress to reply wrote:

Was an assumption; isn't anymore.

Not really an assumption; assuming non-reversibility would be an

assumption.


the cosmological community. I see no evidence for your conspiracy.
------------------------------------

The assumption of cosmological homogeneity/isotropy, when we are
talking about the *entire* cosmos, is still an assumption that is
vigorously debated within the astrophysics community, at least by
thoughtful members who demand scientific standards and avoid
faith-based beliefs.

Your comment on the putative distinction between
reversibility/irreversibility assumptions is a false statement whose
falsity is evidenced everywhere in the scientific literature over the
last 100 years.

One cannot make someone see what he/she is blind to, i.e., what he/she
genuinely believes to be an absolute impossibility.

On 8/2/2014 11:33 AM, Phillip Helbig---undress to reply wrote:
In , "Robert L.
writes:
...
Over the last 100 years or so physics has adopted certain assumptions
that made analyses much simpler mathematically. A brief and partial
list might include cosmological homogeneity/isotropy,

Was an assumption; isn't anymore.

This remark is ambiguous, Phillip! :-)

For clarity: you mean it is not believed to be true
anymore? (We have true-vacuum bubbles and inflating
regions, homogeneity only within each region?)

--
Jos

In article , "Robert L.
Oldershaw" writes:

The assumption of cosmological homogeneity/isotropy, when we are
talking about the *entire* cosmos, is still an assumption that is
vigorously debated within the astrophysics community, at least by
thoughtful members who demand scientific standards and avoid
faith-based beliefs.

Obviously, if by "entire cosmos" you mean those parts from which,
perhaps by definition, we have no information, then perhaps you have a
point. However, it is not "vigorously debated" as most people would see
nothing tangible to debate here.

You define someone who agrees with you as thoughtful, demanding
scientific standards and avoiding faith-based beliefs. You would be
more believable if you wouldn't criticize (often ad-hominem) those who
disagree with you and praise those who (you think) agree with you in
some fashion.

Your comment on the putative distinction between
reversibility/irreversibility assumptions is a false statement whose
falsity is evidenced everywhere in the scientific literature over the
last 100 years.

If it is "evidenced everywhere in the scientific literature over the
last 100 years", why did Ellis even mention it?

One cannot make someone see what he/she is blind to, i.e., what he/she
genuinely believes to be an absolute impossibility.

I'm sure all readers here agree with this statement, and are aware of
the fact that evidence for it regularly shows up in this newsgroup.

In article , Jos Bergervoet
writes:

On 8/2/2014 11:33 AM, Phillip Helbig---undress to reply wrote:
In , "Robert L.
writes:
...
Over the last 100 years or so physics has adopted certain assumptions
that made analyses much simpler mathematically. A brief and partial
list might include cosmological homogeneity/isotropy,

Was an assumption; isn't anymore.

This remark is ambiguous, Phillip! :-)

For clarity: you mean it is not believed to be true
anymore? (We have true-vacuum bubbles and inflating
regions, homogeneity only within each region?)

What I meant was that yes at one time the universe (defined here as
"that which is described by the Friedmann-Lemaitre equation") was ASSUMED
to be homogeneous and isotropic. As observations improved, the
(visible) universe was shown to be more and more isotropic; the CMB is
very much so. Together with the idea that we are not at a special
place, this implies that homogeneity exists everywhere. (Obviously, in
both cases this applies above a certain scale in a statistical sense,
but this scale is much smaller than the universe.) However, Ellis and
co-workers have even been testing the CONCLUSION (not assumption) of
homoegeneity by measuring the CMB temperature at other places.

In other words, I didn't mean that it is no longer believed to be true,
but rather that it is now not an assumption but a fact.

Of course, if you think of the multiverse, then no-one has ever claimed
that it is homogeneous and isotropic.