Reductionist Doubts by Julian Barbour

Dear Julian:

I enjoyed reading your well-written and intuitive essay describing the weaknesses of the reductionist approach in representing the Natural physical reality.

My paper -" From Absurd to Elegant Universe" strongly vindicates the following conclusions of your paper especially related to the QM paradoxes and inconsistencies with GR -

"....it may be impossible to understand key features of the universe such as its pervasive arrow of time and remarkably high degree of isotropy and homogeneity unless we study it holistically - as a true whole. A satisfactory interpretation of quantum mechanics is also likely to be profoundly holistic, involving the entire universe. The phenomenon of entanglement already hints at such a possibility.."

The Reductionism literally means a pursuit of "Reduced" or truncated reality. The well-known Observer's Paradox of QM implies that the collapse of the wave function truncates the reality to the limits of the consciousness (or lack of it) of the observer. When this "Reduced" or truncated or incomplete view of reality is over-extrapolated to predict the universe or quantum behavior, paradoxes (multi-verses, multi-dimensions, black hole singularities, quantum gravity, quantum time, entanglement, dark matter, anti-matter, and dark energy etc.) and inconsistencies result leading to an Absurd universe.

My paper demonstrates that following a holistic approach wherein the whole universe is considered as a continuum of mass-energy-space-time, a very simple mathematical model of the missing physics (hidden variable) of the well-known spontaneous decay/birth of particles can be developed that explains the observed quantum as well as classical behaviors. The holistic model also successfully predicts the observed data at all scales from below Planck scale to beyond cosmological scales. The proposed model not only resolves black hole singularities but also the unresolved paradoxes of physics and cosmology. As you rightly said, the holistic model also explains the inner workings of QM and eliminates its paradoxes and inconsistencies with relativity. It also vindicates your conclusion that time is not a fundamental entity and is an illusion since the observed universe and galactic expansion can be predicted without any explicit consideration of a cosmic time.

I would greatly appreciate your comments on my paper. You can contact me at avsingh@alum.mit.edu.

Best Regards

Avtar Singh

You deleted all my comments because I did not read Shape Dynamics? The punishment is unproportional to the crime, Julian Barbour.

Pentcho Valev

You are "in the job of actually salvaging absolute simultaneity away from the clutches of Einstein", Julian Barbour. So Harvey Brown says. You confirm:

Aspects of Time, Julian Barbour, Warwick, August 24th 2011: "Was Spacetime Glorious Historical Accident? (...) ABSOLUTE SIMULTANEITY RESTORED!"

The problem is that, in textbooks, the relativity of simulteneity is derived from the principle of constancy of the speed of light (Einstein's 1905 light postulate). So if asked:

Can absolute simultaneity and the light postulate coexist in Einstein's relativity?

any textbook author would give a negative answer. Now my question:

Can absolute simultaneity and the light postulate coexist in Shape Dynamics?

Please don't delete the question, Julian Barbour. If your answer is "yes", then Shape Dynamics is a miraculous science, even more miraculous than relativity, and I promise to study it very carefully.

Pentcho Valev

Dear Mr Julian Barbour

Our intuition gives that Machian principle is foundation of physics, although it is not yet proved. Similar unproved intuition appears at fundamentality of consciousness and that gravitational force is different that other forces.

You wrote that time arrow is a holistic phenomenon. I wrote similarly in one old article: "Important time's arrow is also the cosmological time's arrow. It is very likely that all in our cosmos is connected, so it has the same direction of time's arrow. It is not possible to communicate with someone who travels in opposite time direction. Therefore, time's arrow at the collapse of a wave function can choose arbitrary plus or minus direction, but it is motivated by direction of time's arrow in the cosmos. (By the way, it is very likely that explanations of big-bang need improvement. For instance, why is entropy at big bang very low?! Low entropy does not happen spontaneously.) Hitoshi Kitada [15] wrote that absolute time of universe does not exist and that only time for local observers exists. This is true in principle, but time also exists as connection between local observers, local observers are connected and this gives one direction of time's arrow of cosmos."

I claim also that space-time is an emergent phenomenon caused by matter. Otherwise, interpretation of general relativity also claims, whether all matter is removed from universe, nothing remains - neither empty space. This is a holistic consequence of general relativity similarly as Machian principle is.

This is written in my essay: "SR gives also that space-time is emergent so time exists only in matter [8], although, formally, every point in space in SR has attributed time. This is rarely mentioned, but it is very important. Namely, if all matter had been removed from our universe, there would not remain anything, not even space-time. Otherwise, this is given also by GR by its "diffeomorphism invariance" and by the "background free space-time" [9, p. 138]. Similar conclusions are given also by Markopoulou, namely that space-time arises as a consequence of relations between the elementary particles (or other elements of matter) [10]."

Maybe you should mentioned in introduction that quantum field theory is also holistic principle where field is more important than single particles.

My speculation: Maybe all universe has also properties of a particle. Otherwise, I am sure that black holes are elementary particles, maybe also universe is one particle, that means that it shows some properties of elementary particles.

Because of clarity it should be mentioned that Machian principle is also generalization of relativization: relations between objects are more important than location in one inertial system or in one coordinate system - similarly is at relativity principle.

Maybe You should explicitly mentioned that because angular momentum of universe is zero and because universe is finite, the Newton's bucket is so explained as not contradictory with Machian principle.

You replace time with time of universe. This is a cunning and something grounded idea, maybe it will show as good.

You mentioned that only six components of metric tensor is physically important, this means one volume and five angles. I do not understand what means which component? Can you explain this on three and two dimensional metric tensor and on a four dimensional example of Schwarzschild Black hole. Here non-diagonal components are zero, thus angles are only 90°? Do You think also about angles between coordinate axes?

You write also about dimensionless quantities. Do you see any advantage of using Planck's distance.

I suspect in my essay, that interior of black holes does not exist, similarly as tahions do not exist. Is this in any accordance with Your theory? Do You propose and novelty about Big Bang?

Otherwise You write very clearly.

Dear Julian

Original, thoughtful and well explained. But is reductionism a 'mutually exclusive' methodology? Should the real solution to the workings of the universe not be valid on a macro as well as micro scale, deriving observed reality from a consistent mechanism applicable to both ends of the 'known' scales, quanta to universe? (both ends of course yet unconstrained).

I now better understand your shape dynamics, but wonder where evolution from relative motion lies within it, as it seems not at the centre. Am I wrong? I found myself desperately hoping for a 'success' to hang this new set of beliefs on, but despite incisive analysis nothing materialised. May I offer an ADM based option.

You'd need to read my essay, but what this does is derive the effects we term SR from a quantum mechanism, and the mechanism from the morphology and evolution of universes. It may be seen as defining and creating the boundaries of closed three-geometries, each a mutually exclusive but nested inertial frame, defined by relative kinetic states. These have real evolving shapes, but size is immaterial. From the foundational structure of truth function logic an ontologial construct is described in the essay entirely from epistemological elements. A pre big-bang (not really a 'bang') state emerges as logically as local CSL.

I quite understand how improbable this seems, it is none the less the case. As Feynman said it does at first look wrong, so fails the test of 'beliefs' most use, but it has passed all falsification. I hope you may give it a stern test, and look forward to your critique. http://fqxi.org/community/forum/topic/1330

Interestingly, the physical reality of the boundary mechanism is shown and correctly interpreted in the experimental findings in Rich Kingsley Nixey's essay Fig.2.; http://fqxi.org/community/forum/topic/1448

Yours is a more clearly written essay than my own, with perhaps too dense an Architecture of the components, though I do add a little superficial theatre for fun.

Best wishes and good luck in the competition.

Peter

Dear Dr. Barbour,

I just read your essay. The idea of shape dynamics appears to be a form of Regge calculus. I watched a video presentation of yours on the FQXi blog. The time evaluated from the Jacobi variational principle

δt = sqrt{m_iδx_iδx_i/(E-V)}

is related to a proper time, or an interval. This got me thinking about how you could describe this in a completely non-time manner.

It dawn on me how one could think about this according to light rays. In this way there is no matter of time involved with the "motion" of a shape, for null rays have no proper time. I illustrate this with two diagrams I attach to this post. The first is a flat spacetime description. This is also pictured in 2-space plus 1-time spacetime in 3 dimensions. Two points on a spatial surface emit light pulses. These converge on three points on a subsequent spatial surface. These then define a triangle on that spatial surface. The two points then emit subsequent light pulses and map the triangle onto a third spatial surface. In Minkowsk spacetime this continues indefinitely.

In the curved spacetime situation null rays are curved. Since the metric

ds^2 = g_{00}c^2dt^2 - g_{ij}dx^idx^j

is such that for ds = 0 we can have

U^iU^j = (g_{00}/g_{ij})c^2dt^2

And the optical path change due to curvature has a c^2 term. Hence we can assume the triangles on the spatial surface are flat. The deformation of null rays will then map the first triangle on the second diagram I attach into the second. The picture here is then completely described by null rays which have no proper time.

The time computed by the Jacobi variation is then an "emergent" or computed quantity. This is a parameter which emerges from the "motion" of the triangle, or the map from the first to the second.

On another vein I am not convinced that time is a complete illusion. Maybe I will go into this later, but I think that in quantum spacetime it may be that if you only have space then time is not defined. Conversely, if time is defined you have no space. I suspect the two are complements.

Cheers LCAttachment #1: light_rays_and_triangles.JPGAttachment #2: null_rays_and_triangles_in_curved_spacetime.JPG

This post above is mine; I forgot to include my name. My essay is on a different path.

Cheers LC

Lawrence Crowell wrote: "On another vein I am not convinced that time is a complete illusion. Maybe I will go into this later, but I think that in quantum spacetime it may be that if you only have space then time is not defined. Conversely, if time is defined you have no space. I suspect the two are complements."

How can one qualify this without facing deletion? "Not even wrong" seems to be a suitable euphemism. Brendan Foster? Is "not even wrong" too rude? Are you going to delete this comment?

Pentcho Valev

here is what I wrote and got deleted without the link. do you think it is prime for deletion.

"The standard physics has failed to really tell us what reality is, your theory as non-standard is the most interesting one in my opinion. My theory QSA confirms your hypothesis as to the nature of time and is close to other aspects of your theory. It is also the most direct description of reality and it is a natural outcome of the mathematical universe hypothesis. My theory just like yours says that each point carries the information about the rest of the points in the universe; as a matter of fact that is how interaction is described (or brought about). My theory ties space (time indirectly), energy, matter, forces in one concept based on the line. The theory spits out the mass of the electron from purely random numbers, the first theory to naturally predict the mass of the electron. Moreover, the non-local behavior also naturally appears as an automatic consequence of invariance. Many other results are obtained including the amazing formulas."

Hi Julian,

I am always impressed with your commitment to relativity in its purest form.

I fail to understand, however, that you admit this barrier:

"I have given what I believe is the correct definition of Mach's principle [5] and argued that if the universe is closed up in three dimensions like the earth's surface in two then GR does implement Mach's principle [5]. If the universe is spatially infinite, the answer is equivocal. It is Machian however far you can imagine, but infinity is unreachable, and one can never establish a complete sense in which the whole determines the part."

Surely there are solutions to GR in an open universe that do not contradict Mach's principle. The conventional "finite and unbounded" interpretation of GR as finite in time (bounded at the singularity of creation) and unbounded in space, closed up like a 3-ball as you say -- suffers no loss of generality when transposed to a model finite in space and unbounded in time. This latter interpretation requires topology to implement global boundary conditions, and it agrees with your angle-preserving evolution of shapes without regard to the length-preservation inherent in ordinary geometry.

As always, thanks for a masterful presentation, and best wishes in the contest. (I hope you get a chance to visit my own essay site, "The Perfect First Question.")

Best,

Tom

Dear Julian

Freeman Dyson described reductionism in physics as the effort "to reduce the world of physical phenomena to a finite set of fundamental equations".

Please read my 2 essays

http://www.fqxi.org/community/forum/topic/946

http://fqxi.org/community/forum/topic/1413

It is a real triumph of reductionism.

No doubt about reductionism...

All the best

Yuri

Dear Julian

Freeman Dyson described reductionism in physics as the effort "to reduce the world of physical phenomena to a finite set of fundamental equations".

Please read my 2 essays

http://www.fqxi.org/community/forum/topic/946

http://fqxi.org/community/forum/topic/1413

It is a real triumph of reductionism.

No doubt about reductionism...

All the best

Yuri

Dear Dr. Barbour,

You kindly deleted the following comment of mine but I find it important so let me repost it.

You are looking for a no-expansion explanation of the Hubble redshift:

JUlian Barbour: "The greatest need is for an EXPLANATION OF THE HUBBLE RED SHIFT THAT DOES NOT RELY ON EXPANSION OF THE UNIVERSE. (...) The estimates of section 7 show how readily the scale-invariant potential energy can increase if the universe becomes more clumpy. Scale-invariant gravity must, in the first place, yield a cause of the Hubble red shift. The only plausible candidate that I can see is this change in the 'potential' of the universe induced by such clumping. It is suitably great and, according to the standard model, has been happening since the end of inflation. Therefore, the conjecture has to be that somehow the change in potential causes the Hubble red shift. This is not inherently impossible. We know that differences in the gravitational potential give rise to a gravitational red shift."

But the speed of light VARIES with the gravitational potential, according to both general relativity and Newton's emission theory of light. So perhaps the redshifted light coming from distant celestial objects has a speed lower than c? What does Shape Dynamics say?

Sincerely yours, Pentcho Valev

Hi Julian,

Take a look at: http://digitalwavetheory.com/DWT/22_Classical_Gravity.html

and: http://digitalwavetheory.com/DWT/21_Self-Gravity.html

It may give you some ideas on how to get a red shift without expansion. It is possible that the red shift may come from increased gravity and not increased speed.

OH, and if you get a chance check out my entry: http://www.fqxi.org/community/forum/topic/1403

Greetings from a fellow Machian.

Don L.

The computer and the universe

John Archibald Wheeler

Abstract

The reasons are briefly recalled why (1) time cannot be a primordial category in the description of nature, but secondary, approximate and derived, and (2) the laws of physics could not have been engraved for all time upon a tablet of granite, but had to come into being by a higgledy-piggledy mechanism. It is difficult to defend the view that existence is built at bottom upon particles, fields of force or space and time. Attention is called to the "elementary quantum phenomenon" as potential building element for all that is. The task of construction of physics from such elements is compared and contrasted with the problem of constructing a computer out of "yes, no" devices.

Preparation for publication assisted by the University of Texas Center for Theoretical Physics and by National Science Foundation Grant No. PHY78-26592.

http://www.springerlink.com/content/ck753337h0515573/

Julian Barbour wrote:

"First, I deleted nothing..."

Then I apologize. But my comments - 7 or 8 perhaps - all disappeared so... Brendan Foster, what are you doing?!?

"...second, they [absolute simultaneity and Einstein's 1905 light postulate] are compatible according to Shape Dynamics."

But, Dr. Barbour, in textbooks the relativity of simultaneity is directly deduced from the light postulate - see pp. 9-10 in David Morin's text. In other words, according to special relativity, absolute simultaneity and Einstein's 1905 light postulate are incompatible.

I think you should explain this contradiction between Shape Dynamics and special relativity.

Pentcho Valev

Dear Pentcho, Dear Julian,

thank you for clarifying your positions, so i can see more clearly.

Stefan

Pentcho

Has it ever struck you to ask what the speed at which any given photons happen to travel has got to do with anything? Except that is, the timing relationship between the incidence of observation and the occurrence of the reality which affected the state of those photons.

The whole issue of the supposed relationship between the speed of light and simultaneity is based on simple mistakes (section 1 1905). Unless they occurred in immediate proximity(!), the point in time when two events occurred simultaneously was deemed to have a relationship with the distance between them. This is nonsense. Either events occurred at the same time, or they did not, distance is irrelevant.

Distance was then expressed in terms of duration of light travel, which is irrelevant as such, in that the distance AB is one distance, however expressed. The next mistake was confusion over timing and duration. So the point in time at which both events occurred was defined as being when the time (ie duration) for light to travel in one direction equalled the time (ie duration) to travel back. Although nonsense anyway, this was then incorrectly expressed. Hence: when t(b) - t(a) = t'(a) - t(b), a duration of time has been confused with a point in time, ie this involves the concept of 'and then' back. Following on from this, the constant velocity of light is derived as: 2AB/ t'(a) - t(b).

Paul