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/
There are several new posts since I last visited this thread. I hope those that posted them will excuse me if I don't respond. Some are inappropriate, others not but there is a limit to what one can do.
However, I will briefly respond to Pentcho Valev, who on 19th September wrote:
"You heroically delete any critical comment, in accordance with your ethical principles, but I am going to ask my question again and again. Are absolute simultaneity and Einstein's 1905 light postulate both true according to Shape Dynamics?"
First, I deleted nothing; second, they are compatible according to Shape Dynamics.
With regard to the later post on 22nd September quoting my comments on the expansion of the universe, they are no longer to be taken as my position. I still find the expansion of the universe a most important issue but no longer think it can be understood along the lines suggested in Pentcho's quote.
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
Dear Julian,
An intriguing enjoyable and intriguing essay from an author I really respect. However I am not completely convinced that a holistic approach is always indispensable. Could one not argue, that if the result of the reductionist approach is a concept, idea or formula that is physically *very close* to nature then the whole would emerge from it on its own without further ado? As a minimalist example cellular automata interact according to a local rule and from it the whole emerges in due time.
Even so, perhaps I have implemented a species of Mach's principle in my Beautiful Universe Theory (BU) on which I based my fqxi essay Fix Physics! . My reductionist idea is that the Universe is made up of a lattice of just one type of building block. These blocks or nodes are discrete bundles of angular momentum rotating around their axes in units of (h) and the axes have various angular orientations in each timeless universal State. . Thus L =/= 0 in this scheme. Attached is figure 11 from my BU theory showing how a twist in the angular orientation of two nodes to lock into matter is caused by (or causes) the entire linkage of nodes throughout the universe to mimic the twist, and explaining why E=mc^2
I did not know about Mach's idea that time is emergent from motion. Interesting. I feel that the reductionist source idea in GR (space-time warping = gravity) is physically misleading. GR's Achilles heel is that it includes SR. Why should an observer-related physics enter in realms out there where it is only nature interacting with itself in the same inertial frame - for example light curving around the sun? Without SR, GR becomes very simple - gravity can be reduced to an optical density field, as Eddington proposed, and I have explained in BU.
Shape Dynamics (SD) sounds like a new concept that, at first sight, I wish I do not need to think about! - if there is a simple, local,causal explanation for gravity=acceleration=curvature I would be satisfied with that. In BU it is the curvature of the classical gravitational potential streamlines (or the orthogonal wavefronts) that defines this equivalence. You wrap SD in a probabilistic interpretation.
Quantum probability as a physically realistic phenomena is another of my bête noires . In BU I have shown how probability emerges naturally in the lattice interactions, and how the false point-photon idea made it seem that probability is an abstract interpretation of a dualistic particle-wave nature resistant to physical realism. Have you read the amazing experimental work of Eric Reiter reported in his current fqxi essay in which he proves that gamma rays are not point photons? In such a Nature where probability is the result of systematic, linear local interactions, entanglement can be understood simply and directly without resorting to further ingenious but perhaps complicating holistic ideas as SD.
Hope I have made some sense! I welcome your learned response to my rather qualitative and incomplete ideas.
With best wishes,
VladimirAttachment #1: 2_BUFIG11.jpg
If Mathematics, the tool of theoretical physics, can only describe becoming , then Mathematics of Becoming is Physics ?
I afraid there is no such thing as Mathematics of Becoming at all...
May be it is new philosophical abstraction or some kind of physical simplification of Calculus, and, If I understand, we cannot deduce any taking technical mathematical theorems seriously from Notion Mathematics of Becoming ( Similarly, from Einstein attempt to introduce a new kind of complex number in SR - please, see my FQXi 12 essay - we simply cannot deduce scientifically any taking physical time theory seriously )
I suppose, that Mathematics is not Tool, Language or Human subjectivity at all. It is independent perfectly working area of experimental science. Anybody can test for example, that, x^3 y^3 = z^3 cannot exist in Nature and in any version of Multiverse as well. Pure Mathematics is not Pure Physics.
Dear Julian Barbour,
I appreciate that you are a busy man and there are more essays in this competition than any individual can be expected to read thoroughly and comment upon. However I would be very grateful indeed if you could take a look at my essay. If you are able to comment on it as well that would mean a great deal to me. I have received very little feedback from the members over the years and I do admire your essay writing and other very clear and sensible explanations of your work. I have tried to improve my writing from last years inadequate entry, making it more readable. I will certainly respect your opinion, even if you dislike what I have produced and can find no merit in it.
Again, there are some posts that are inappropriate or too difficult for me to understand, but I will comment on three:
Vladimir Tamari wrote:
"Could one not argue, that if the result of the reductionist approach is a concept, idea or formula that is physically *very close* to nature then the whole would emerge from it on its own without further ado? As a minimalist example cellular automata interact according to a local rule and from it the whole emerges in due time."
I think that is reasonable position and certainly a reductionist starting point can lead to a holistic picture. However, even with cellular automata there is an holistic element. The individual elements must be tied together since otherwise what happens at one element could not affect what happens at its neighbour. A chain is an holistic concept.
Michael Popov seems to have inverted what I said. I said mathematics can only describing Being. I did not say it could only describe Becoming.
Pentcho Valev again challenges me on the issue of simultaneity and the speed of light. I twice invited him to look and my papers or talks on the web, but he has twice declined the invitation. Perhaps a simple analogy will help. Imagine a very smooth landscape with a single valley running through it.If you look at only a very small part of the landscape, it will appear flat, both at the bottom of the valley as well as elsewhere. In very small regions, no directions on the surface will be distinguished. This is almost exactly analogous to the absence of a distinguished definition of simultaneity in special relativity.However, in the bottom of the valley, there is clearly a distinguished direction, along the valley, even though on the smallest scales it cannot be detected. This is by no means a perfect analogy for what happens in Shape Dynamics, but it does show how what happens on the smallest scale may be misleading about large-scale structure.
Dear Julian!
An excellent analysis in your essay and hypotheses. But the «Alpha» and «Omega» is not enough. To search Protostructure (Superstructure, "the missing structure" by Umberto Eco) requires synthesis of "Alpha" and "Omega". This can be done "Delta" with its deep OntoTopoLogical Interpretation. Ontological framework of the country Platonia - it is also an ontological framework of the world (univerce), represented as the natural (absolute) coordinate system. .
From a country of eternal forms helps to get the time - the memory structure at a certain level of its holistic existence. Time is the burden of becoming. This - the price of becoming. Its outcome - asymmetry. Sincerely, Vladimir
Dr. Barbour,
I did not find in your first essay that you showed how newton's notion of an independent absolute time can be derived from motion. As far as I can tell, Newton was attempting to define the best clock, not absolute time, and used motion for that purpose of defining a most useful measure of duration. More to the point of your present essay, your example in part 1 of reductionism does not appear to be an example of reductionism. It appears to be an example of applying your 'holistic' concept in a piecemeal fashion.
Reductionism is the ability to trace evolution step by step through its development. Those steps will not be small repeated images of the whole. They will however, reveal at every step during evoluion, from beginning to end, the same unity that makes the holistic result possible. I accept that your professional view is different from my unprofessional view.
I will though take this opportunity to state my view that neither time nor space undergo changes of velocity. For this reason there is no empirical evidence to tell us about motion involving either space or time. Motion tells us only about effects endured by objects. We do not learn the natures of 'cause' in either of its two forms, force and mass. The still unknown natures of the universe, restricting this to the mechanical concepts employed by theoretical physics, are those of force, mass, space, and time.
Should you find it worthwhile to offer corrections to what I have said, I would welcome them. Thank you.
James
Julian/Pentcho
It is the concept of simultaneity, as defined, that is wrong. Any given physically existent state occurred at the same time as any other, if that was at the same point in time. Timing being an extrinsic measuring system which enables the comparison of disparate changes. It has nothing whatsoever to do with light, etc, etc. Now, in the assessment of whether that occurred, and if the sense being utilised is sight, the speed of light is, obviously, a factor. But whatever occurred, did so, independently of the sensing thereof, and occurrences either happened at the same point in time, or they did not.
The speed of light always starts at the same speed because it is the result of an atomic reaction, and like anything else, it will then continue at that speed unless impinged upon. There is nothing mysterious about this. But, 1905 presumed light was in vaccuo and everything else was not, hence the two could not co-exist (so it was not a cohesive theory and is not SR). Later, SR presumed a purely theoretical circumstance where everything was in vaccuo (in order to reconcile the mis-match of 1905). While GR is the real world, and so light is affected by the physical circumstances encountered in its travel.
Paul
Julian
Many including I have had the courtesy to read your essay and comment on it in your thread. Here we are, as last year, side by side, but, as last year, you still don't speak. We are all busy, but some would consider it a courtesy implicit on entering to read and comment on others essays. The word 'arrogant' has been used here, and you may perhaps wrongly be giving that impression.
Perhaps my post, or even my essay, was among those you referred to as 'too difficult to understand'. I wouldn't be surprised as I identify a multiple set of associated assumptions, and explain a complex ontological construction. The ontology does however derive the SR postulates (inc. CSL) direct from a known quantum mechanism, (which Roger Penrose termed the 'Holy Grail' of physics). It may be wrong, but is falsifiable and is so far unfalsified. I've given the model it the most stringent tests, and hope you also may study it.
I do hope you are able. I think if I can understand yours you should be able to unravel the layered depths of mine. There's even a little contemporary theatre and a sonnet! I'm personally suffering a bit of eye strain, but there is much excellent quality work here you seem to be missing.
And very best wishes in the competition.
Peter
Ooops! That was me. The system logged me out again.
Peter
Julian
You essay is just splendid -- clear, compelling, captivating, and revelatory. I think your work is going to change the shape of our paradigm! It is great to see clear-headed philosophical thinking put to such immediately effective use in the service of good physics (and good education) -- this is exactly how philosophy and empirical science should integrate to bring progress in our understanding of what exists and how it works. I think your position that 'the angles are the fundamental things', provides a surprising but exact way of giving mathematical expression to the intuitive notions of holism and of concrete properties being determined by context.
Julie and I argue, from very different grounds, but largely on philosophical grounds too, for a similar vision of the nature of the world in our essay. We approach it from the quantum vacuum side rather than the SR side, but our philosophical trail led to a highly congruent world-view. Our difference is that we infer a fundamental concrete world in which 'becoming' is a primary attribute (I guess we could have called it Energeia?), thus providing a foundation for the evolution of the platonium (sorry I couldn't resist) that you associate with instants of being. Either way leads to a world in which 'holistic change' is the primary observed quality of the phenomenal world.
I think the Shape Dynamics formalism will turn out to be seminal for Systems Philosophy. So glad to have read your work!
With admiration and best wishes,
David
I see you have embraced entanglement instead of seeing through its illusion. A simple solution is the long abandoned loading theory. The reason everyone is going through such acts of desperation to explain quantum irrationality is that they were baboozeled by their textbooks and much biased coverage. If you look at original data of famous experiments one can see that the loading theory fits just fine.
Please look at what I have on the loading theory: Revealing the coverup, experimental verification for matter and light, theory, history, analysis of famous experiments, predicting new working experiments, first failure of quantum mechanics. What more does one need?
So please give my essay a good rating. Even better, please take actions toward my essay falling in the top 35 in your contest. I suggest a note at the beginning of this contest of my essay being news. It is the only essay that I know of describing an experiment doing fundamental things. I made a note of this idea in B Fosters blog on the essay contest. Another place to visit is my website unquantum.net.
There are two problems: (1) everyone is invested in their pet theory, and (2) my message is hard to take because other experimental physicists need to witness the gamma-ray splitting. However, you can see experimental verification yourself. Any physics lab can read pulse height spectra of Cd-109 gamma-rays or Am-241 alpha-rays. There is an anomalously large pile-up count in the pulse height spectrum at 2x(characteristic pulse height). At this part of the spectrum the coincidence rates exceed chance, killing quantum mechanics. I explain why this effect is not always visible from other radiation sources or detectors.
Begging for mercy already. It has bee 10 years since my experimental breakthrough.
Eric Reiter. Essay: A Challenge to Quantized Absorption by Experiment and Theory
Hi Julian
I'm glad to see you flying the Machian flag, and also taking a stand against infinity. I'm with you in both cases.
I find shape dynamics intriguing, and agree with the basic premise that the gravitational degrees of freedom are conformal. I'm struggling with whether they are 3-d or 4-d conformal. I tend to the latter position, but am willing to learn.
Best wishes
george
