Jonathan,
The story of the twins is analogy. Everything is built up from quantum processes, from chemistry, to biology, to mechanical clocks, so if the quantum rate runs faster, as on gps satellites, then everything emerging from these processes runs faster as well, including metabolism, thus one twin ages faster.
I'm just not sure how my use of a common analogy disproves the observation that tomorrow becomes yesterday because the earth rotates.
If the twins pass each other in the street, walking in opposite directions, then as they pass, each is seeing the other in slow motion. That isn't consistent with your explanation. If the clues were such that they fitted your explanation, it would be a much, much easier puzzle. Now let's leave it, best wishes, JK
Jonathan,
No problem. Life is very complex and we all have varied and varying physical perspectives, both spatial and temporal, as well as the ideas to try to make sense of them.
I agree that one must define Time in terms of motion. Additionally, it seems reasonable to assume that similar physical results must have, at their base, common causes. That is the path I've taken in an attempt to determine the nature of Time. So, Gravitational Redshift, Cosmological Redshift, and doppler shifts must result from the same physical cause. To that end I prefer to look at the nature of spacetime for an answer. Since red and blue doppler shifts involve a change of wavelength caused by a position change of the emitter relative to the receiver, I conclude that some manifestation of spacetime must induce a change in wavelength for the other two types. To that end one very convenient model can be postulated wherein spacetime density increases in the presence of matter (along with a time change) For an emitted light ray leaving a gravitational field its wavelength increases as it exits the field(and enters less dense spacetime) The reverse obviously occurs when the ray enters the field. Time must then be a consequence of the relative spacetime density.
If this is valid then motion must be related to the interaction of matter with its local space. Acceleration must have the same common origin and the same common result in interactions with local spacetime. That is, if gravitational acceleration is caused by an increased spacetime density in the direction of motion, then this also implies that an accelerated object must induce an increased spacetime density ahead of itself.
This comes with a lot of ramifications for Physics! Mach's Principle as an explanation for inertia is only the first Foundational Leg to collapse. But, if that goes then what must be concluded about the FLRW model? Matter here cannot have any gravitationaal influence across the Universe!
As for the two apparent types of time, the entire Universe is in motion and matter densities (and spacetime densities) vary throughout the Universe depending whether one considers a perspective from the point of view inside a Void or within the bound nature of Matter Filaments. Time must be Relative according to ones' motion or relationship to local matter.
Hello Lloyd,
This isn't meant to be a platform for trotting out our theories, though you'd never know from looking at this site. For that reason, in my essay I've just said that I think we need a new interpretation for SR, and set out a rational argument that the existing one doesn't fit what we observe.
So I'm not going into discussions on theories that land here, unless the discussion relates to the general one. But I'll throw my Kent Brockman two cents back, in case it's of interest.
To me, you start with a principle that can be shown to be wrong, and then you don't go by it anyway. You say that similar results must have similar causes, and then you say that therefore all wavelength shifts must be caused by the same thing. But there are several kinds of redshift that are well understood, and they have different causes. There's the Doppler shift, refraction shift, and bremstrallung, for instance. We know their causes, and they're all different. So the general principle you start with doesn't look too good.
But then you don't go by it anyway, which actually helps. You then decide that the gravitational shift, because it must have the same cause as the Doppler shift, is caused by differences to the 'density of spacetime' - this is a completely different cause from that of the Doppler shift.
And it goes on - you don't define spacetime, but you need to not only because its density changes in your picture, but also because it has time in it, and you get time out of it the other side as well - "Time must then be a consequence of the relative spacetime density." So you need to define it early on.
If you want to talk about the general subject matter then do, you haven't so far.
Best wishes, Jonathan
Thanks Daryl,
sorry so late in replying. It has been a pleasure to discuss these things with you (mainly on Edwin Klingman's page), and I do respect your opinion, and your approach to physics in general.
Warm regards, Jonathan
Superdeterminism is delete all difference between past, present, future.
See my analogy book as Parmenides
PS I don't want you to feel you can't answer those points, I just mean we should keep to the general discussion generally... JK
I guessed that this post had been sent to more than one essay page, and found that it had. I also have trouble understanding it.
But best wishes, JK
Jonathan
What is your attitude to Gerard 't Hooft
Discreteness and Determinism in Superstrings ?
arXiv:1207.3612 (replaced) [pdf, ps, other]
Hello Yuri,
Thank you, it's fascinating, I'll read it again when I can. But ultimately the cellular automaton interpretation of quantum theory is still a mathematical interpretation, and I'm interested in truly conceptual interpretations, as I see the problems before us as conceptual ones. (John Wheeler thought the same - when asked what the best hope of progress for QT was, he said finding a conceptual basis from which QT could be rederived). And because an interpretation is needed for SR as well as QT, and ideally one should be found that reduces the problems of both, it seems that something very simple is needed. To me, although the CA interpretation is very simple mathematically, it's too complicated conceptually.
Also, I don't agree with his attempt to get out of non-locality. David Albert has argued that Bell's work means non-locality in inevitable in any interpretation of QT, not just in a hidden variables interpretation.
Best wishes, Jonathan
Have you read my essay?
http://fqxi.org/community/forum/topic/1413
Yes, will look at it again when I can. I liked your analogy of the book and the audio book - that describes exactly the two levels of time that I compare in my essay. But rather than look at the 'advantanges and disadvantages' of these versions of the universe, I've tried to relate them to the actual conceptual clues we have.
I'm amazed at how people ignore the conceptual clues, and look only at the mathematical clues. (I don't mean you, in fact your essay is refreshingly conceptual). Physics is detective work, and we can use logic to rule possibilities out, and to limit the possibilities about what kind of answer we might be looking for. But people are so absorbed in the mathematics, they can't see the wood for the trees. And yet to get to quantum gravity, it's almost certain that conceptual progress will be needed. The problems with time are in the conceptual department, and no mathematical advance alone would be likely to remove them.
Anyway, best wishes, Jonathan
Jonathan,
I very much appreciate the clarity and intelligence of your essay. And I agree that the "block time" concept is a major obstacle to a deeper understanding of physics -- but I don't think that Minkowski's spacetime is the problem.
As Stein pointed out back in the 60's, what the Rietdijk-Putnam argument disproves is the Newtonian notion of a single present moment "now" that applies to the entire universe simultaneously. It shows us that we shouldn't think of the universe as "moving through time" all at once, as a single vast object. But this has nothing to do with the physical "now" that can actually be experienced, from any particular point of view in spacetime.
This is one of the issues I dealt with in my essay ("An Observable World") -- unfortunately I tried to get way too much into that essay, so I'm afraid the arguments aren't very clear. But I tried to show (in Section 3) that Minkowski's geometry is completely different from that of a static, 4-dimensional "block universe". The problem is not with his geometry, but with our traditional way of theorizing about the physical world as if we could stand outside of it and describe it as an object.
I agree with you that physics needs to come to grips with the time as we experience it happening around us. What Minkowski's geometry shows us is not that this aspect of time is illusory, but that it's essentially local. It shows us that my "here and now" is not physically related to other places and times by means of any spacelike "time-slice" through a 4-dimensional block, but through a web of back-and-forth light-speed connections.
The deeper problem here is that we haven't yet learned to conceptualize the physical world that can actually be experienced, from inside. In many papers on time, the notion of a local present moment is just rejected out of hand, as "solipsistic" -- as if our physical location in spacetime were something "subjective". The main point of my essay was that physics needs to describe not only the objective structure of the world but also the internal structure of physical interaction through which information becomes observable, in specific local contexts.
So I don't think we should reject the "block universe" picture. It's entirely reasonable to spatialize time, to imagine it as if it were a 4th spatial dimension -- as we do in all our diagrams that put space on one axis and time on another. It's obviously helpful to visualize dynamics this way -- but we have to avoid confusing this picture with the more fundamental one given by Minkowski, representing the structure of spacetime that can actually be seen from inside.
This contradicts the argument you make in your first section, that we have to choose one or the other view of time. I think both are equally important in understanding physics, though not equally fundamental. I realize this view is unusual, and I've struggled to find ways to express it. I hope you'll find time to look at my essay and let me know if it makes any sense to you.
Thanks again for your excellent work -- Conrad
Hello Conrad,
thank you very much for what you say, I really appreciate it. I'll read your essay.
I have two points to make - the first is that I don't think you understand why the Rietdijk-Putnam argument rigourously rules out any possibility of motion through time existing at all (if Minkowski was right). You sound surprised that people talk as if our position in time is subjective, but according to Minkowski spacetime, it unavoidably has to be. I haven't read Stein, but it sounds like he was writing immediately after the shocking discovery in the '60s, and trying to cushion the blow. But since then it has been worked through and understood, and without at least some adjustment to Minkowski spacetime, you simply get motion through time not exisitng.
The reason is straightforward - it's that the difference between past and future is entirely observer-dependent in some situations. That means it has to be perception-based, and has no reality outside the observer.
But as you quite rightly say, SR leads to local time rates, which can't be connected up at all. I'm saying that this local aspect makes the very long distance simultaneity required for the Rietdijk-Putnam argument questionable. But if simultaneity at a distance only applies within the light cone, block time then no longer applies at all, removing the confusion about time that we have nowadays, and allowing what we observe to be real.
Incidentally, I've shown on George Ellis' page that the kind of adjustment he tries to make in his EBU (emerging block universe) approach doesn't work, because this observer-dependence for the difference between past and future still arises. There's a need to remove block time in any form.
I hope this makes sense, best wishes,
Jonathan
Hello thinkers,
It is relevant indeed these cellular automatas. So, if I am understanding well, all the forms can be created under a specific continuity with this method. The strings seem relevant for the 2d and the convergences with the 3D. The cellular automata are relevant. I ask me how the predictions can be purely deterministic considering the finite groups.
The strings in 2d more the datas and informations can be encoded under a specific spherical universal automata of convergences.
We could simulate the universal sphere and its spheres.Considering the central sphere like the most important volume. The universal spherical fractal of uniqueness appears. So the holographic automata can be a reality.furthermore this architecture permits tocreate all 3d pictures furthermore. If the number is known, between 1 and x, so we have the finite group, and so the serie of uniqueness. My equations so permit to converge and to quantize furthermore. The gravitation is porportional with rotating spheres.
Maths and physics are linked, universally linked, unified in the spherization in fact.
Regards
Hi Jonathan,
Thanks for your thoughtful comments on my essay forum page. They are appreciated. I've been sidelined by unexpected responsibilities, but I expect to get caught up on reading and comments soon - now that things are back to normal (more or less). I'll read and comment on your essay as soon as I can, and I'll respond to your comments back on my essay page if it seems appropriate.
All the Best,
Jonathan
Dear Jonathan,
I think your essay is right on target, and it rates very high in my opinion. Let me make a few remarks. First, let me say that I don't believe the manifold structure of spacetime persists to arbitrarily small scales, but this in of itself is hardly a radical position anymore.
1. I agree that one ought not to begin with mathematical models of time (or anything else!), but ought to begin with physical concepts, and then use whatever mathematics is necessary to get the job done. This may lead to mathematics that is "less convenient," but so be it! Choosing mathematically convenient but physically dubious models has caused too many problems in physics to even begin to list.
2. An excellent point you make: "Often more than one conceptual picture is described by similar mathematics." Likewise, there is often more than one choice of mathematical formalism to use in attempting to make a physical idea precise. Often the differences among these conceptual pictures or formalisms involve physical issues at the periphery of what is being considered when the theory is first developed. Only later are the distinctions recognized as important, and by this time it has often become "common knowledge" that a particular marriage of concept and formalism is the "only way to go."
3. You say "And then other physical laws, which also depend on there being a timeline (or rather, many), and behind them fundamental principles like cause and effect, which also depend on a timeline." Now, this is something I have thought about a great deal. Do cause and effect depend on a timeline, or does time depend on cause and effect? Or are they two ways of talking about the same thing?
4. You say, "Within the light cone, where events are in range of each other, there's a clearer sequence - one can say an event happens before another if it can influence it by getting a light signal there in time. This short range way of relating events has meaning, based on causality. But it doesn't mean there are long range time links across space, as in Minkowski spacetime." This, in my opinion, is the crucial point. The physical order is the causal order, and the "time-orders" given by choices of reference frame are not physical. They represent extra, noncanonical information added for mathematical convenience and should be given no weight when discussing issues of existence.
5. Continuing from 4, I believe another aspect of this false assumption is the "symmetry interpretation of covariance." Covariance in special relativity is, conceptually speaking, the statement that different inertial frames are "equally valid," and the usual way of making this precise is to invoke the symmetry group of Minkowski space (the Poincare group). I do not think this is the best interpretation, especially when one generalizes the discussion from special relativity to general relativity and then to the fundamental structure of "spacetime." I think a better interpretation is in terms of order theory. The causal order on Minkowski space is defined in terms of the light cones, and an event E is simply unrelated to events outside its light cone in terms of the causal order. Imposing a time order on Minkowski space refines the causal order by artificially relating E to most of the events outside its light cone (all those outside the same "spatial section.") Different frames of reference, then, are different refinements of the causal order. However, it is obvious that such a refinement carries no canonical physical meaning. The physical information is contained in the causal order, which does not imply a block universe.
6. These topics are a major focus of my essay, On the Foundational Assumptions of Modern Physics. Since you have evidently thought about these issues deeply, I would be grateful for any further thoughts you might have on the subject. I think that "spacetime" is essentially a way of talking about cause and effect, and that geometry is a very good approximation to this at currently observable scales.
Congratulations on an excellent contribution! Take care,
Ben Dribus
Jonathan,
You wrote (on Giovanni's page): "Pentcho, briefly, you and I have already discussed this question at length on my page, and I have shown you to be wrong, in a way that even you eventually didn't argue back about. The reason we call it "the spacetime interpretation" is because it's an interpretation. It's untested - unlike SR, which is extremely well confirmed by experiment. People often imply that spacetime is an unavoidable consequence of SR, but no-one will actually say that it is, because it isn't."
Then you wrote (on my page): "Hello Pentcho, we can find out the answer to what we've been discussing. I thought I'd got it across, was trying to help to get to what's underneath the picture they imply, which sometimes can be false. Maybe you want to email John Baez, (baez@math.ucr.edu), or some other relativist, with the question 'is Minkowski spacetime an unavoidable consequence of SR, and the only possible interpretation?'. I'd be surprised if any relativist said yes to that. Anyway, please discuss it, if there's any further need to, on my page rather than on Giovanni's page. (Let me know what they say, if you email them.)"
Here is a text where Minkowski spacetime is referred to as an useful diagram allowing one to get "an overall intuitive picture of a setup". Note that "if you want to produce exact numbers in a problem", special relativity is enough:
David Morin: "Minkowski diagrams (sometimes called "spacetime" diagrams) are extremely useful in seeing how coordinates transform between different reference frames. If you want to produce exact numbers in a problem, you'll probably have to use one of the strategies we've encountered so far. But as far as getting an overall intuitive picture of a setup goes (if there is in fact any such thing as intuition in relativity), there is no better tool than a Minkowski diagram."
In my view, if you want to prove that Minkowski spacetime is more than a useful diagram, you will have to find an example where Minkowski spacetime produces "exact numbers in a problem" that special relativity does not produce. I think there is no such example.
Pentcho Valev
Dear Jonathan,
Your essay is well written, accessible, interesting and defends valuable fundamental points. I am sure it will do well! I was glad to see your defence of real change, and hence of things existing wholly in the present and causal powers being real factors in explanation-building. In our essay Julie and I argue that the concept of energy commits us to a view of material things as capable of changing, and link this to the ability to build scientific explanations. If this on the right track then the block universe model cannot be a realistic view, just as you so clearly argue.
I greatly enjoyed reading your essay, and hope you will find ours interesting too. Good luck in the competition!
Best regards,
David
