On Aug 23, 2011, at 6:45 PM, Paul Zielinski wrote to RS:
Aren't you confusing "evidence" with "proof"? I would say a physical theory can have empirical support -- be supported by "physical evidence -- short of "proof". Where "proof" is evidence sufficiently compelling to (eventually) establish a professional consensus. Which is a historical process. According to the Duhem-Quine principle, from a purely logical standpoint any theory can be made to agree with any given finite set of empirical observations, by floating the required auxiliary hypotheses that are limited only by the theorist's creative ingenuity. So in order to justiour theory choice decisions we have to go beyond mere logical consistency to the naturalness and conceptual economy of the comparative theoretical explanations of the observed phenomena. Are you seriously arguing that the Machian explanations for the instantaneity and isotropy of inertial reaction are more natural than the anti-Machian explanations? After all, even Wheeler thought that Hoyle-Narlikar was a can of worms.
On Aug 23, 2011, at 6:25 PM, Paul Zielinski wrote:
On 8/23/2011 5:43 PM, Ron Stahl wrote:
Jack,
RS: If I understand what Paul was saying correctly, it is that warrant for belief in the Machian explanation for the origin of inertia is less than or equal to, other explanations such as ZPF and this is plainly not so.
PZ: It doesn't have to involve the ZPF specifically. Currently there is a whole raft of condensate models for the vacuum under active consideration which might naturally account for inertial reaction forces in an anti-Machian manner.
JS: To make sure we are on the same page here, by the translational "inertial reaction force" I mean, in terms of Einstein's equations (SSS for simplicity)
{Levi-Civita Connection}^rtt ~ (external non-gravity force)^r/(rest mass of test particle)
this would be the "weight" of the test particle clamped to the Local Non-Inertial Frame (LNIF).
That's what I mean.
This inertial reaction force (measured as "weight" - e.g. standing on a scale clamped to Earth, or clamped to a hovering rocket etc, a hovering helicopter etc) is completely contingent of no fundamental interest - not needing Mach's Principle to explain.
I don't know what any of you mean by that key term.
RS: First of all, we have the still unopposed logical argument Jim made several weeks ago, that comes to the conclusion that if we grant GR, we must grant M-E. That is an extremely powerful argument when it comes to assessing warrant for belief, because few are going to want to sacrifice GR.
PZ: Didn't I just make a counterargument? To wit, that natural interpretations are available for GR in which gravity represents physical modification of a pre-existing inertial guide field, as accounted for in Einstein's 1916 geometric model by the objective gravitational deformation of the spacetime geodesics?
JS: This is a rare moment when I agree with Z. ;-)
PZ: In this view, what is left unexplained is the pre-existing inertial guide field, that as Woodward has correctly pointed out, is put into SR "by hand". If this pre-existing guide field is conceived as a property of the physical vacuum (not necessarily the ZPF), and this can be made to work under some deeper model for said vacuum, then as far as I can see there would be no need to abandon GR as a geometric model for gravity.
JS: Trite problem. Curvature explains it. End of story. Almost "nuff said" If you like you can view curvature as topological disclination defect density in a 4D world crystal lattice (Hagen Kleinert), but then you need to explain the nodes - the lattice points of that lattice.
PZ: If GR implied a generalization of Einstein's Machist 1905 relativity principle, the situation might be different; but the modern consensus is that 1916 GR does not actually support such a generalized relativity principle. As Woodward says, 1916 GR has strong anti-Machian features (as famously argued by de Sitter in early conversations with Einstein).
JS: This is obviously a proof for miracles, for God's immanence since again I agree with Z! ;-)
I was today with a person close to the Vatican Astronomers who told me funny stories of Hawking and others in debates with the Arch-Bishop of Vienna over Hawking's recent book poo poohing God's necessity.
PZ: Now Jack is saying that there is no need for a deeper explanation for inertial motion, which surprises me since Jack is working on a condensate model for the gravitational vacuum.
JS: No need for a deeper explanation of the shape of geodesics outside Einstein's GR - curvature explains it.
At a deeper level, my macro-quantum coherent condensate model shows how the tetrad fields emerge from the Higgs-Goldstone fields post-inflation as a low-energy effective c-number field theory. The phases of the vacuum field are distorted by Tuv. Tuv includes both real and virtual particles. However, real particles are only 4% of the whole. 96% of Tuv are virtual particles inside the vacuum.
Dark energy = random plasma of virtual bosons - dominant negative ZPF pressure creates the repulsive anti-gravity accelerating our universe.
Dark matter = random plasma of virtual fermion-antifermion pairs - dominant positive ZPF pressure creates attractive gravity
RS: Honestly, if you want to examine the argument and see whether the form is valid and the premises are factual, that would be a great idea; but until someone finds some holes, I think we HAVE to say the Machian explanation obtains, or at least presently seems to obtain, on solid logical grounds.
PZ: More like quicksand!
JS: RS's remark shows how a little bit of knowledge is a dangerous thing. ;-)
PZ: It's certainly news to me that there is an airtight argument to the effect that either we accept a Machian model for inertia, or we will be forced to abandon GR. I don't think even Woodward himself is claiming this. Correct me if I'm wrong.
JS: Again I agree with Z!
PZ: Of course this depends at least in part on how GR is physically interpreted.
RS: Second is the physical evidence which every person on the planet judges differently.
PZ: There are a number of persuasive empirical argument in favor of an anti-Machian model for inertia.
JS: By inertia I mean rest masses of the elementary particles, leptons, quarks (Higgs) ---> hadrons (QCD).
that's what I mean. I don't know what you guys mean.
PZ: The criteria for theory choice are not limited to purely logical empirical agreement; one must also take into account the naturalness of the explanations within the theoretical context.
JS: Again I agree with Z. Pure logic is over-rated. Of course, we don't want our arguments in physics to be logically inconsistent. However, there are many logically consistent models of the world that are wrong - don't fit the facts.
RS: Most of Jim's experiments are showing low thrust figures and I'd suppose this is why you're saying the physical evidence is "marginal at best". That's fine to say, but those thrusts have always been a couple decades above the resolution of the measurement apparatus and in particular, Jim has always used the proper scientific controls to weed out spurious sources. This makes the experiments complex to analyze, so in order to make a real appraisal of the experiments, one needs to look carefully at them, which most are not willing to do. This single fact is the main reason the physical evidence is most often generalized as "marginal."
PZ: But you have to show that such observations have no satisfactory explanation within any competing anti-Machian theory.
JS: Right again Z!
1) Jim's data may not be real. May be a systematic error? I am not saying that is a fact, only outlining the logical possibilities.
Like much of parapsychology - marginal data is hard to interpret. If Jim's "thrust" can't be scaled up to make something fly in vacuum then like Gennady Shipov's torsion propulsion it's not of practical interest. Remember Shipov also has a working machine with marginal propulsion on film - though it does not fly yet.
2) Even if Jim's data is real as you say it may have a perfectly mundane natural explanation.
3) I find Jim's concept of Phi = c^2 totally incomprehensible even if Sciama also first wrote it down. Therefore, if Jim's data is explained by Jim's equation for Phi I will also find that incomprehensible and not of any serious interest until he has a flying model - even a small drone will do.
Of course if someone shows me that Jim's Phi is a limit of Einstein's GR then I can understand it.
PZ: Where is your argument?
RS: Then also there are tests like the Rotator, which don't generate thrust at all, but merely demonstrate the Mach Effect. In this instance, the magnitude of the signal doesn't matter--what matters is the signal is found at all, and it is! Perhaps I ought not say the magnitude doesn't matter at all, the magnitude is still important to demonstrate scaling as per theory, and this is just what was found. So IMHO; I would not judge the physical evidence as "marginal" simply because most often it is in the uN region rather than the commercial mN region, nor neglect things like the proof-of-science rotator experiment simply because it doesn't generate useful force. I would however, agree that MUCH more needs to be done to validate or repeat these tests. The issue then is one of validation, not that the test results are marginal.
PZ: Your argument amounts to claiming that such marginal observations, if confirmed, cannot be accounted for within any anti-Machian model for inertia.
If that is your view, how can you be so confident about that?
JS: Precisely. Z you are on a roll today. ;-)
RS: Opinions will differ, especially about how to generate warrant for belief from the physical evidence, but what was Paul comparing the Machian explanation for the origins of inertia to? To models and theories that have NO physical evidence and NO logical proof in support.
PZ: I think that is simply false.
Are you seriously claiming that instantaneous and isotropic inertial reaction forces do not constitute powerful empirical support for anti-Machian theories of inertia?
JS: Again my local anti-Machian formula for translational inertial reaction force is simply
{Levi-Civita Connection}^rtt ~ (external non-gravity force)^r/(rest mass of test particle)
PZ: If so, why?
And what about the Higgs mechanism? Isn't that inherently anti-Machian?
Z.
I have to disagree. I think at the current time, M-E theory has no peers.
best,
Ron
On Tue, Aug 23, 2011 at 8:06 PM, JACK SARFATTI <
Ron, I don't think top guns in relativity will agree with your statement. What do you mean exactly? I don't think even Jim would agree with you if you are thinking only of his data - still marginal at best unless I am mistaken.
On Aug 23, 2011, at 4:57 PM, Ron Stahl wrote:
"And I don't see how, as things stand, one could reasonably argue that the various "Machian" models for inertia are
any less speculative."
Paul, the Machian model has ten years of physical evidence in support. I'd say that makes a difference. :-)
On Tue, Aug 23, 2011 at 7:43 PM, Paul Zielinski <
These kinds of questions are not hard to answer if it is assumed that we start in Minkowski SR with a "flat" inertial guide field, and
then interpret the covariant "warping" of spacetime in GR as the objective physical modification of the pre-existing gravity-free
inertial trajectories resulting from the influence of gravitating matter. Then the GR geodesics naturally serve as local dynamical
references for forced motion in a 4D geometric model for gravity.
Exactly what physically maintains the motion of free test objects along the spacetime geodesics in a flat or a curved spacetime is
an interesting question, but since we now accept the reality of the "physical vacuum", it seems natural to suppose that a deeper
theory of gravity and inertia will explain this in terms of local interactions between moving matter and the gravitationally distorted
vacuum.
I would say that the Higgs mechanism of the Standard Model could provide some clues, if gravity is conceived as a physical
modification of the "flat" (gravity free) inertial guide field (modeled geometrically in GR in terms of 4D spacetime curvature).
I think we are way beyond the point where where one could plausibly dismiss such ideas as the "idle metaphysics" of Newtonian
absolute space. And I don't see how, as things stand, one could reasonably argue that the various "Machian" models for inertia are any less speculative.
On 8/23/2011 3:08 PM,
I suspect that Rovelli might not agree with you that inertial reaction forces are produced by the local gravitational field when external forces are applied to objects in geodesic motion. The problem here is: what is the local gravitational field? The sorts of calculations of local fields, as mentioned before, calculate the geodesics that result from local concentrations of matter (the Earth, Sun, whatever). In these calculations a boundary condition of flat spacetime at infinity is ASSUMED. (This is why the geodesics cannot be said to be meaningfully global. No account of cosmological conditions other than this assumption is built in to the calculations.) The gravitational action of the Earth, or Sun, or Galaxy, or other local object by itself cannot account for inertial reaction forces. (If the assumption of asymtotic flatness for local solutions is taken to have cosmological dynamical consequences, though, you might be able to finesse this.)
What to make of Jim Woodward's Machian Engine? 8-23-2011
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