Indefinite Causality

John,

You wrote, "Causality is energy transfer, not sequence." Your statement would only make sense if we didn't know that the transfer of heat energy from hot to cold causes water to boil. That's a definite ordered sequence of events.

In any case, you're missing the authors' point. They're talking about the transfer -- not of energy -- rather, of information contained in a disordered state, to a measurement of ordered, i.e., computable, results. A pot of water with a fire under it can be measured (with a thermometer) for energy content, and we have perfect knowledge of the ordered, covariant and continuous relation between the energy input and measurement output. What we don't know, is how the discrete states of observers inside the pot relate to the computable function we observe outside the pot. If Alice, in one region of the pot, sends Bob, in another region of the pot, a message about how fast she's moving, by the time Bob gets the message, any correlation between that information and Bob's state of motion will have been destroyed. As made clear in the article, even if Alice and Bob conspire in advance to send each other a message only when a set speed is achieved, their results will correlate -- at most -- only 75% of the time. Random correlations are limited to 50%.

What the authors propose is that the indeterminate information in a superposition of states can somehow be exploited such that a quantum "thermometer" -- i.e., the measurement output as a computable function -- can reach higher levels of information reliability, as the authors say, " ... the idea of indefinite causal structure brings the phenomenon of superposition into a new realm, the realm of the ordering of computational operations."

I approached the problem from a different perspective in my ICCS 2007 paper . Instead of superposition, I proposed applying the topological property of simple connectedness, and the complex systems property of self similarity: "3.7 The independence of time metrics in an n-dimensional system where time flows on a self avoiding random walk satisfies the multi-scale variety requirement. What we mean, is that the connectedness of the network is preserved in self-similar components that perform cooperative functions independent of the observed state of the system. Subsystems are self delimiting. Thereby, an analytically continuous complex system is tractable to analysis using the tools of discrete functions. This is an obvious crucial requirement for computability."

Tom

Tom,

I don't doubt we will continue to develop ever more effective methods of measuring and relating measurements on non-linear systems. Mine was a more general rant on the focus of measurement and not what is being measured, as in the two examples I gave, where both Barbour and Anderson clearly argue for a Machian, emergent view of time, then switch to describing it in terms of how best to measure intervals of time. That emphasizes sequence over causality. Obviously causality can be sequential, such as the little desk ornaments of steel balls, where swinging one on the end causes the one on the other end to bounce. That's because there is a direct transfer of energy. On the other hand, treating a sequence of events like days as causal is much more problematic, because these events and the sequence they form, are effects of a larger dynamic. My point is that sequence is an effect of causality, not synonymous with it. Time is sequence. As Mach, Barbour and Anderson point out, time is not fundamental. As I point out, therefore measures of such sequence are not foundational either. So while spacetime does a very interesting effort to correlate measures of distance and duration, using the velocity of light, it is not foundational cause. There is no more a "fabric of spacetime" anymore than there are giant cosmic gearwheels causing epicycles. One could just as easily use ideal gas laws to propose "temperaturevolume" and say the decrease in the temperature of the background radiation is what causes the universe to expand, just as it is said "spacetime" tells matter and energy what to do.

Now this might have some effect on how we model quantum behavior, if time is not an external, but emergent parameter, since it means particles and their actions cannot be fully differentiated and reality is more likely waves with particle like characteristics, rather than particles with wave-like characteristics and that might affect how well we can use quantum behavior to build digital computation functions, but that is another argument.

John, I don't know anyone who treats " ... a sequence of events like days as causal ..." I don't even understand what that could mean. Julian Barbour's view simply rests on what Einstein coined as "Mach's principle," meaning that every particle in the universe moves relative to every other particle. The critical difference between Mach's principle and general relativity is that GR disallows any causal connection between bodies that propagates faster than the speed of light ("All physics is local."). Local causality isn't a feature of pure relativity; i.e., Mach's mechanics.

"There is no more a 'fabric of spacetime' anymore than there are giant cosmic gearwheels causing epicycles."

Epicycles are caused by mathematics, not by anything physical. Spacetime is demonstrably physical. Be scandalized by the facts, if you must. However, if one speaks of changes in relations among mass points, one speaks of changes in relative points of spacetime. "Matter tells space how to bend; space tells matter how to move" (~ Wheeler). That doesn't settle the question of whether time is fundamental or whether space is fundamental -- it does, however, settle the question of whether spacetime geometry is fundamental. It is. And it does settle the question of whether information is fundamental. It is.

The remaining question is how continuous spacetime geometry relates to discrete quantum information.

Tom

Tom,

You and I have bumped heads over this for years and physics has bumped heads over how to connect GR and QM for longer than we have been alive, all without a meeting of the minds, so we may as well not get on that merry go round again.

I would have ask though, if every particle is moving relative to every other particle, how is the information of prior configurations of these particles being preserved? Isn't such information essentially being written over, as one would rewrite a computer memory? Which goes to the nature of time; Is blocktime physically real, or is time a measure of real change?

So we have the determinism of spacetime and the indeterminacy of quantum functions. Multiworlds must be real.

We're not bumping heads, John. We're talking about different things. I'm talking about the physics we know -- you're asking why physics doesn't answer all the questions you want to ask in the order you want to ask them. That's the difference between objective science and personal belief.

You ask, " ... if every particle is moving relative to every other particle, how is the information of prior configurations of these particles being preserved?"

Those are two mutually dependent (covariant) events. The discrete measurement of relative motion, and the continuous geometric record. Yes, the information of prior states is preserved in the geometry. Understand this, and you'll get closer to understanding Julian Barbour's program of shape dynamics, rather than just flailing against it without actually knowing what it is.

"Isn't such information essentially being written over, as one would rewrite a computer memory?"

What's meant by "writing over" is different from "erasing." Writing over means to randomize information, not rub it out. The information isn't gone, just difficult to recover, like a shredded document.

"Which goes to the nature of time; Is blocktime physically real, or is time a measure of real change?"

And then you introduce this nonsequitur. The nature of time -- whatever it is -- does not have a covariant relation to information, because time and space are not independent of each other in a relativistic theory. For all that we don't know about time, we know at least that much -- that is, physically real information and physically real spacetime are interactive, like any quantity that can be called physical " ... independent in its properties, having a physical effect but not influenced by physical conditions." (~ Einstein) George Ellis' theory of evolving blocktime exploits the interaction of information and spacetime by framing it in a complex system dynamic.

So your question -- "Is blocktime physically real, or is time a measure of real change?" -- is not even a true question, with an either-or alternative. It follows that if blocktime is physically real, time intervals are a measure real change, *and* vice versa.

Tom

Tom,

Truer words were never spoken; We are mostly talking past one another. A meeting of the heads maybe, but definitely not a meeting of the minds.

One of the points I've made here often, which you may not have noticed, is that information is inherently subjective. There is no God's eye, or Tegmark's bird's eye view. Without a particular frame, perspective, point of view, reductionist model, etc. ordered information doesn't exist. It's the old problem of everything equals nothing, in that it all cancels out. You might come up with some very basic piece of logic and say it is objective because it applies to all circumstances, but being reductionist it only applies to what is applicable and only describes a limited bit of information.GR and QM are good examples. They are limited models of reality which describe different contexts, that are not exactly compatible. You yourself have said that without the model, we have nothing. Ideals are not absolutes.

John, most of your statements are already falsified. That "... information is inherently subjective" is simply and demonstrably untrue. And you keep repeating the same error of nonsequitur -- that there may be no God's-eye or bird's-eye view does not imply that information is inherently subjective. That there is no privileged reference frame implies a fully relativistic universe, not a subjective one.

Your claim that ordered information doesn't exist "Without a particular frame, perspective, point of view, reductionist model, etc." which implies the primacy of consciousness, *may* be true, yet is irrelevant to generalized information theory. Self organized nature is also self limiting and self referential. Demonstrably so.

" ... the old problem of everything equals nothing," is not only not an old problem, it's actually a solution rather than a problem. That a linear equation sums to zero is what makes it algebraic.

Yes, we know that GR and QM are completely different things. *That's* a true problem -- of how or if the theories smoothly correspond. And yes, such correspondence could only be demonstrated in a mathematical model accompanied by a potentially falsifying experiment.

Tom

Tom,

Whether you call it relativistic or subjective doesn't make information permanent. Consider a rainbow; It exists because light traveling through the edge of a cloud is bent. If it were permanent, than the light would have to freeze, yet if the light stopped, there would be no rainbow. Given that the reality we experience is such energy in motion, it follows that without motion, nothing would exist, but with motion, nothing exists forever. Now you say it exists somewhere in that blocktime geometry and has been proven, yet nothing of the sort has been proven, other than the paths of light and mass curve relative to the presence of other masses. There is no physical geometric record, because the energy to manifest it in the first place is also the very same energy that alters it. No time travel, no wormholes etc. have ever been discovered. All we can really observe about black holes is that they do radiate prodigious amounts of energy, likely as much as they consume.

It's not about consciousness. A radio tuned to a particular signal will receive a far more clear and nuanced amount of information than one simply responding to all frequencies and amplitudes. Similarly a camera set at a particular aperture and speed will take a far more clear and detailed picture than one with a fully open aperture and long speed. There is no theoretical method, other than an all-knowing god and spacetime geometry, to record all past and future information. It quickly goes to white noise.

Consider just the camera speed; The interval it is left open is the time vector and the longer it's open, the more the motion of what is being recorded blurs, because information requires energy to manifest and energy is dynamic, while information is static, so it gets disrupted and over-written by the recording mechanism. So how does this time vector store information?

A good example, consciousness based, is this conversation. Each of us is coming at the question of the nature of reality from different perspectives and we are effectively speaking different languages. As I see it, your criteria is what is accepted by the established physics community, while mine is simply a coherent understanding of the reality I inhabit. So you see me as having a personal bias, while I see you as having an institutional bias. To the extent we meet on this forum, I suppose I have a bottom up view, while you have a top down view. You see me as having a very limited field of knowledge, while I see you as being completely dependent on a structure where the plaster and paint are covering more cracks than anyone within cares to admit. I'm certainly willing to admit I do have a very limited amount of information to go on, though I don't see that as a complete weakness, since "too much information" does create chaos and the aforementioned white noise. Are you willing to admit the current physics establishment should consider a deep examination of its foundations, as the recent contest proposes?

Eckard : Your "well defined space-time in which we live" is also the past, the pre-existing time in our memories.

The most little time scale is untill now the "Planck-time", that is the indication of the frequency of our reality.

This frequency is not percepible to our senses, so we are aware of a smooth time (in our memories).

Wilhelmus

John,

I'm afraid that what you mean by "existence" and "permanent" have no physical meanings. Physical information is real -- that's why it's called physical information. It exists " ... independent in its physical properties, having a physical effect but not itself influenced by physical conditions." If one doesn't understand what that means, one has not stepped on, much less crossed, the threshold of physical science. "Permanent" is also not a concern of physics, unless one denies the 2nd law of thermodynamics.

And your statements regarding curved spacetime and black holes completely misunderstand and contradict the known physics. I can't see any profit in continuing the dialogue.

Tom

Tom,

We have reached the usual impasse.

"Physical information is real -- that's why it's called physical information. It exists " ... independent in its physical properties, having a physical effect but not itself influenced by physical conditions."

This does step off the edge for me. To me, information is an effect of physical conditions. If there are no physical conditions, there is no information. The existence of information requires physical manifestation, so the term "physical information" is redundant. There is no platonic realm. Principles arise with the actions and effects they describe. If some effect is repetitive, it isn't because there is some law governing it, but because the underlaying process has been repeated.

Possibly you are referring to something similar to Ellis' top down effects. The reality there is that top down and bottom up are complimentary. To the extent you have one, the other exists as well, like opposite sides of the same coin. Energy manifests information. Information defines energy.

The "known physics" is currently exploring multiverses.

Hello thinkers,

The second law, I love it! The thermodynamics and heat are so essential with the finite groups!!!

John and Tom, a little beer from Belgium and hop you are friends...

Ps the information is physical and this information is bosonic or fermionic, it is so the energy, so the light.The entropy is relevant in its general fractalization. You can ask to Kelvin and Planck ;) they agree.

Regards

Hello Eckard,Wilhelmus,

You know Eckard, we learn all days :) how is it possible to understand and to discover all the entire secrets of our Universal Sphere, it seems so far of us this immensity. This 3D sphere. The quantum scale also is in the same logic. The singularities are far of us.

The universal sphere is fascinating in fact.

Regards

Quote:"One of the biggest obstacles has been that general relativity and quantum mechanics treat time very differently. In the former theory, time is another dimension alongside space and can bend and stretch, speed up and slow down, in different circumstances. Quantum theories, however, usually assume that time is set apart from space and ticks at a set rate. Theories of indefinite causality tackle this mismatch head-on, by questioning what time is at a fundamental level." From the article 'cheating the Causal Game'.

This is nux of various problems. Understanding -Why that difference- in how time must be treated, is helpful in seeing the direction from which a solution to a number of problems must come.There are two different things going on simultaneously. Atoms are interacting and giving a causal order of events in the material Object reality and EM potential sensory data is being generated with the potential to give a different apparent order of events in time because of data transmission and processing delays.

It was interesting to read about this promising research. I don't know exactly what they are doing from such a brief article but I wonder if considering the mismatch of causality at the quantum level and apparent causality at the macroscopic level will give the gravity solution. I will outline why I think it may not.

In GR the observer is assumed to be static. That is just a subjective view. It is built into the curved space-time hypothesis and model. However the observations with which curved space-time fit, seemingly verifying the model, might instead be due to curvature of light paths resulting from disturbance of the Object reality environment, through which they pass, by motion of the body within it and through it. The description of that motion within the 3n+1 space-time construct is bizarre, not because the motion is bizarre, but that the observer-subjective construct has not been constructed in such a way that it allows illustration of what is happening. I.e. As the observer is assumed to be static, when it is not, the necessary motion can not occur within the subjective observed space but occurs instead along the time dimension. Each new observation is conducted from within a new objective space from which data is received and from which the image of the universe is constructed.

A stationary observer on the Earth is not static at all but moving with all of the Earth's movements, over many scales of possible consideration. With the galaxy, with the solar system around the sun, around its axis and with geological movements. A change in the movement of the Earth over those different scales could give a change in the apparent expansion of the Image universe if it gives a increase in the rate of movement away from the origin source of the sensory data from which the universe Image is constructed. Such changes could occur as a result of the changing motion of the material solar system or Earth due to altering, rather than permanently fixed, relationships and that will alter the 'selection' of the potential sensory data received, giving not just the affect of expansion due to the motion but increasing expansion if change in the motion is also occurring.

At the smallest scales of consideration the vibration of the particles becomes significant. The affect of that upon the environment will mask any minute gravitational interaction that might otherwise possibly be detected; and the larger scale (Object) universal movement is not included in consideration. Though subatomic particles too must be moving with the motion of the laboratory on the Earth's surface and so along with the Earth's total Object universal motion. The subatomic scale of matter is not separate from the macroscopic scale of matter but contained within it and it all moves together. That's what unites gravity over different scales IMHO.

SciAm publishes an article by David Tong,based on his FQXi contest entry, from the digital vs. analog contest and it doesn't get a mention, let alone an article or blog post????

John, the article was already published in november 2011, I also gave (then) a post on the thread. Indeed it is strange that even george Musser could not get mre attention, but a reason might be that at the moment the essays are coming in everybody is sticked to his own trick on FQXi, which is logical.

Wilhelmus

Hi John and Wilhelmus,

We'll follow this up soon, don't worry!

In the meantime, here's the link to David Tong's Is Quantum Reality Analog After All?

Thanks Zeeya. Should be interesting.

Hi

My reaction to this new research about reordering causality went something like this: "Oh No! Here is another group of talented imaginative young physicists who have found another aspect of probability to play with - are we in for another half century of multiverse-type thinking, this time around featuring micro-scrambled-time universes?" Doubtless clever mathematics can twist 'reality' around and make the outcome appear to follow experimental results. This may even lead to interesting computational methods, but does QM and general relativity need more bells and whistles to 'explain' their results?.

Should not effort be now rather directed to develop revisionist ideas that say probability itself is emergent, and can result from an ordered, linear, causal universal lattice, such as the one I described in my Beautiful Universe Theory ? Or Eric Reiter's experimental results showing that Einstein's photon is not the point quantum he thought it was - in my opinion that is the root mistake that created the particle-wave duality and made the probabilistic interpretation necessary. By the way it was sad that Eric's name for his theory 'Unquntum' was used in the title of David Tong's Scientific American article without any justification, or reference to the original source: Eric Reiter's home-page unquntum.net

Best to all,

Vladimir