Readers' Choice: Cheating the Causal Game

"The expression has the form of linear algebra rather than curvilinear geometry."

No difference between the two, John C., for a relativistic model. We know that space is mostly Euclidean and that curvilinear motion is constant. Some day, I am going to give up correcting the astounding lack of knowledge of people who continue to hold forth on relativity in this forum. Being the OC dyslexic I am, though, it's hard.

Tom

That's what I said, Tom. "Rather than" not different from.

If you take a great circle arc from GR and roll it out flat on the workbench you have a linear function which is the same relationship. Like a common bi-metal spring with the same energy content as would be necessary to apply to straighten it out. What Marcel points to is a linear projection which would resemble a spiral in energy distribution instead of a continuous curve.

Further, e=mc^2 @ c. 'Infinite mass' is the math line of reason to explain the limit of acceleration to classical mechanics which does not have interconvertability of mass and energy. Relativisticly at light velocity mass is no longer mass to be 'infinite', its energy. Don't need that much education to understand that, Sheldon.

John C,

From Marcel's post;

"But time, or more specifically its rate, is the cause for the ordering rather than just a silent metering partner."

What if time is not this primary cause, but is simply a form of measure? As I argued previously, the earth is not traveling some fourth dimensional Newtonian flow from yesterday to tomorrow. Tomorrow becomes yesterday because the earth rotates. Change creates time and time measures change.

Sequence is not causal, whether it's done by the observer, or by nature. Yesterday doesn't cause today. It is the sun shining on a spinning planet which causes this sequence of events called days. Just as one wave doesn't cause the next, but wind blowing across the water.

It is that we, as single points of perspective, experience action as an equally singular narrative and human civilization is largely a function of the fact we manage to remember the more notable experiences of that sequence of events. But the narrative and causality are only minimally related.

Contrary to Wheeler, causality is due to exchange of energy, rather than the descriptive qualities of information.

The issue then becomes how to explain gravity as something other than caused by a mathematical model in which the measure between events is somehow more foundational than the processes creating those events.

Regards,

john M

"Don't need that much education to understand that, Sheldon."

Well, I'm already in for a penny so I might as well be in for a pound. I'm afraid that one does need "that much education" to learn what the special and general theories of relativity allow and disallow, if one wishes to invoke those principles.

One of the disappointments in my years of participating in these FQXi forums, is that the affiliated experts -- some of them Nobel laureates at that -- stay away from the blog and forum discussions. It isn't hard to understand why -- once they give a proper explanation of solidly known physics, they are assaulted, bombarded, with all manner of nonsensical explanations for why "mainstream" physics has it all wrong. Who has time for that?

Although not a member of this group, Robert M. Wald is one such esteemed expert. I think the link evidences his talent as an educator as well -- he explains among other things, the common misapplication of linear algebra to general relativity. If I had my wish, every first year teacher of college physics would write his or her syllabus from Wald's outline, preferably for a two-semester course. At the top of his list of teaching resources is Einstein's classic, *Relativity: The Special and the General Theory*, which I have myself recommended several times in this forum. I deem it essential to understanding the more sophisticated material of Wald, Ellis, Hawking, Geroch, Thorne, et al.

Tom

Tom,

I, for one, am eternally grateful for your patience in taking the professional side of this argument. I can well understand why others in the field don't see it as worth the considerable time and effort. It is difficult to be in for a penny and not be in for a pound.

Only had the time to glance at that paper, as today is the day the child is to be dumped off at college.

I still see it as a situation where the intense focus has resulted in a form of myopia, to where some significant problems are being brushed aside, but eventually they will have to do a real bottom up review. If not this generation, then the next. As they say, change happens one funeral at a time. This amount of change might take a number of funerals.

Regards,

John M

Tom

Thanks for the link to Wald.

Thanks, John. I would like to say that my patience is a result of intellectual discipline rather than a mental infirmity. That's just the way it is, though.

I'm no physicist, and I know I make mistakes that no professional physicist is likely to make. I do read and research continually, though, and I try to keep up. And yes, leading edge knowledge and mathematical techniques do progress over the generations -- that's just more reason, in my opinion, to get fully grounded in the fundamentals of classical mechanics and field theory, up to relativity.

Best wishes for your daughter's college career. Hope it's not too hard on your wallet. :)

All best,

Tom

You're certainly welcome, John. It may be the least technical piece from Robert Wald that one will ever read. :-)

Tom

All

Perhaps it's in the more technical extensions that I'm not equipped to digest,

but in all my reading whether QM, S&GR, and Classic (Galilean to modern) I have never found a graphic representation of the structure of electromagnetic waveform, other than of Maxwell's equations plotted on perpendicular planes.

I think its important because without some physical structure I can't see how interference can occur in interferometers but not in spectrometers, and in mass spectrometry of distant sources the shift of absorption lines doesn't get filled in. Seems there would have to be a very distinct coherence. Any links?

Aristotilian logic yes, but please no neoclassic rays shooting out of my eyes.

Tom,

Mine probably has something to do with trying to overcome mental infirmity. Having run though my share of cat's lives, there have been a fair number of head bangs and when you have to put your own hard and software back in order enough times, the basics are on speed-dial, even if the complex all runs together.

The kid is a wiz in her own right. Full scholarship(per year) to Johns Hopkins. Wants to be a pediatric neurologist. (Nothing personal, but it really is nerd city down there. I find I'm becoming even more of a homebody up here on the farm.)

Regards,

John M

Tom,

While I've only given the paper by Wald one compete read through and a little reviewing, a few points;

Most of it is an entirely reasonable description of how to mathematically model complex actions; curvatures, vectors, tensors, etc. But then it breaks from this and doesn't clarify how one gets to ideas like block time, black holes, singularities, etc.

So the only real point of significance it makes is that General Relativity refutes the notion of simultaneity. Yet simultaneity is a notion, intuition if you will, based on the idea of a Newtonian universal flow of time, which really isn't applicable if we view time simply as an effect of action. There is no universal flow, as every action is its own clock. There is only the presence of a lot of activity and any measure of universal rate of change would be proximate or statistically averaging, at best.

So in order to refute a flawed intuition, we must be forced to accept that all events exist in some "blocktime" vector? One which is clearly, in Wald's exposition, only a modeling of action in the first place.

Earlier you seemed to agree that quanta are not just dimensionless points, but as specific amounts of energy, can expand, or contract. Now if you were to mathematically model the space described by masses of such quanta, then in areas where their volume is contracted and their energy correspondingly is elevated, the effect of gravity wouldn't be a "force," but the vacuum resulting from less volume/concentrated energy. Just as the pressure resulting from dispersed energy/expanded volume is not a force in its own right.

This would curve light just fine, as it is also composed of quanta, as well as explain why clocks run at different rates.

Would you have any source which does try to explicate exactly why this mathematical treatment of action requires physical blocktime? This one doesn't cover that and that is where my problem with the premise arises.

Regards,

John M

John,

I think Paul Davies is the best plain-language source to explain how physics treats time. The deep nature of time is still an open problem.

Best,

Tom

Tom,

If time is an open problem, then why are you so resistant to considering my observation that by primarily treating it as a measure of duration, physics only assumes and re-enforces the individual perception of a sequence from prior to succeeding events/past to future, rather than explore how these configurations come into being and are replaced/future becoming past, other than that I'm far less of a member of the club than you?

I realize it seems like an extremely trivial point, but that doesn't mean it and its consequences can't have been overlooked. If I throw a ball up in the air, knowing only the direction and momentum, where it lands can be fairly accurately predicted, but that doesn't have to mean the arc of its trajectory is somehow permanently etched in some eternal geometric configuration.

Regards,

John M

Considering that if I first spin around and then close my eyes before throwing it, the trajectory, according to QM, exists in some super position of all possible trajectories. ;-)

John,

It's interesting to me that you would associate your way of thinking with head bangs. I was already 60 years old before I found out that my dyslexia is probably the result of a traumatic automobile accident when I was three years old. Of the occupants of our vehicle -- my stepfather, mother, infant child and me -- all were seriously injured (baby killed) except I, who was thrown from the car and apparently suffered only a gash at the back of my head, which was closed in the emergency room with sutures. It was a hard blow, though, because I remember losing consciousness and recovering while rolling down the grassy highway embankment.

Up until that few years ago, I had no idea that dyslexia can be caused by head injury in childhood. The site of my injury, though, exactly corresponds to the right brain tasks that I have always had difficulty with, though less extreme as I have gotten older.

Off topic, so I'll keep it short.

Tom

" ... that doesn't have to mean the arc of its trajectory is somehow permanently etched in some eternal geometric configuration."

How do you know that?

Tom

Tom,

It ties into information theory. If the same information can be recorded on any medium, say a song on a vinyl record, cassette tape, or cd, then logically the same medium can be used to record different information. The vinyl repressed, the cassette or cd rerecorded.

The question is whether they can store different information at the same time. That does depend on how you define both the information and how it is accessed. Such as a holograph, where different angles form different images, but that is as much a function of how the information is perceived, as how it is recorded.

Now say the medium is me throwing a ball up in the air. Effectively the information of it leaving my hand is recorded over by it flying through the air, as that is recorded over by it hitting the ground, since the medium is the ball and it can only manifest one position, since it is only one ball. So in order to progress from one configuration to another, the prior must cease to exist.

Now like the holograph, different perspectives can yield different information. Say you are several hundred thousand miles away, with a very good telescope, watching me throw that ball. Given the finite speed of light, you will be seeing it leaving my hand, at about the same time as I'm watching it fly through the air. Yet just as I only see it at one position at a time, so do you, even though it is delayed by consequence of your more distant perspective. This does not mean the ball exists in some super-position, or is eternally extended along this trajectory, only that information is both a function of transmission and reception.

Otherwise I don't see any realistic physical explanation for how it can actually exist all along some time vector. If you have some explanation that sounds reasonable, I'm all ears, but just putting the math up on a pedestal and insisting it explains all, without showing how, doesn't count.

Regards,

John M

John,

"The vinyl repressed, the cassette or cd rerecorded."

Right. That doesn't mean the prior information is destroyed, though. Do you know how your computer hard drive memory works? -- overwriting with new information doesn't make the previous information disappear; it's just jumbled up and can be recovered by another algorithm. Now maybe you want to say that smashing the hard drive renders the information unrecoverable; however, that begs the question. In principle, software can run on any substrate, so whatever nature records is recoverable in principle -- that's what Hawking's solution to the black hole information paradox is all about.

"So in order to progress from one configuration to another, the prior must cease to exist."

To reemphasize: that's begging the question.

Best,

Tom

Tom,

As well as the trajectory of the ball can deduced from where it landed. The question isn't whether evidence of the past ceases to exist, but if the events of which the past consisted have been replaced by the fact the physical reality is now manifesting this present configuration. There is certainly lots of evidence of past events, but the very fact these traces do exist in the present means they are no longer as originally produced. Those layers and layers of historical evidence are proof time is a dynamic process, in which that evidence and memories continue to be altered, effectively pushing the events further into the past.

Regards,

John M