Absolute motion

roosh wrote: »

The issue isn't that there is a single absolute rest frame implied, its that every mathematical reference frame implies it; when this is the case the conclusion is inevitable.

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And the hypothetical observer, or Albert, Henry, and Evelyn, to you and I, is treated as being at absolute rest.

I might not have been explicit enough when I stated above that we can change the thought experiment, remove the road behaving as if it were a giant treadmill and just use a giant treadmill instead.

Here we can phsysically distinguish between the three scenarios, as you have outlined above. We could of course physically distinguish between the original three scenarios using other physical phenomena, such as wind resistance, the movement of the walker, or the amount of fuel used in a car; the treadmill is much simpler though, because we can talk about it being "on" or "off".

This begs the question, what do the measurement correspond to; are they just an optical illusion; like when something appears smaller because it is far away; for examplem, like when people take pictures at the salt flats that look as if they are holding the sun, or standing on a wine bottle.

Or do the measurements correspond to physical objects in a way that isn't just an optical illusion i.e. is a clock measured to actually tick faster and slower than itself?

I did indeed read it.

As per the scenario we started with; the photon starts off traveling the perpendicular line between the midpoints of the mirror; the round-trip distance is 2d.

Acceleration or gravity pulls the photon off it's perpendicular trajectory; it has the exact same effect on the observer and the mirrors i.e. they are imparted with the same horizontal velocity as the photon, such that the photon will continue to travel between the midpoints of the mirrors, it just won't trace a perpendicular line.

The question is, how can the photon continue to travel between the midpoints of the mirrors if it changes from it's perpendicular trajectory?

roosh wrote: »

There is no express statement about intrinsic motion, as it is a tacit assumption. When we say that we can define a reference frame where the hypothetical observer has a velocity of 2kph, etc. we just shift the implicit assumption of absolute rest to the object with the zero velocity.

The implicit assumption of absolute rest can be deduced from the depicted behaviour of the photon in a light clock.

Also, when Evelyn " arbitrarily choose a reference frame to perform calculations" she calculates that her and Albert's clock is ticking slower than Henry's.

roosh wrote: »

Interesting that you should choose to make such bare assertions.

roosh wrote: »

Any arbitrary reference frame you construct will be independent of any expressed assertion of absolute rest, but the treatment of physical objects, such as a light clock, demonstrate the implicit assumption of absolute rest.

EDIT: this is the topic of the other thread though

In this thread we are discussing the three physically distinguished scenarios, which are logically necessary to account for relative motion; and, due to their logical necessity, establish the presence of absolute motion.

We are also discussing how a photon which has been pulled off it's perpendicular trajectory can continue to travel between the midpoints of the mirrors of a light clock.

We are also discussing how static world tubes, at angles to each other, can account for relative motion.

roosh wrote: »

That is a non-sequitir; the depiction of physical objects, such as light clocks, carry the implicit assumption of absolute rest.

The physicality of the three scenarios is entirely independent of any co-ordinate systems; take away the mathematical reference frames and the underlying physical scenarios remain. The physicial distinction of a treadmill being switched on and being switched off, and the movement of limbs, of a walker, are not dependent mathematical co-ordinates, in any way.

Furthermore, the logical necessity of one of the three, physically distinguished scenarios to account for relative motion allows us to conclude that absolute motion exists.

In the absence, that is, of an explanation of the extremely mysterious dynamics, which cause 4 dimensional world tubes at angles to each other, which are static in spacetime, to manifest in what we observe as relative motion; and which holds true for bars of steel and bars of smoke.

roosh wrote: »

In the case of the light clock thought experiments, the scenarios aren't actual physical scenarios which are being described, they're thought experiments.

The depiction of the light clocks demonstrates the implicit assumption of absolute rest.

The physical distinction between the scenarios isn't an artefact of co-ordinate systems, not least because co-ordinate systems aren't physical. The current running through the treadmill when the treadmill is switched on, as opposed to the absence of a current when the treadmill is switched off, is not dependent on mathematical co-ordinates, nor is the movement of a walkers limbs.

You say that we need co-ordinates to specify the change in location of an object, implying that we need arbitrary mathematical co-ordinates; but that isn't necessarily the case; we can look at the world around us, without any mathematical co-ordinates - because they don't exist in nature - and observe the relative motion of objects; from that alone we can conclude that one of the relatively moving objects has to actually be in motion.

I think you might be struggling with cognitive dissonance; I don't doubt that you genuinely believe that you have addressed the issues raised, but you haven't. You've simply stated what spacetime is, and how objects are represented in spacetime diagrams, or how objects exist in spacetime; you haven't outlined the mysterious dynamics which cause static world tubes, at angles to each other, to manifest in what we observe as relative motion.

roosh wrote: »

And you can keep asserting the contrary for longer and the validity of it won't increase one iota.

And therein, again, lie the implicit assumptions of absolute motion.

It might be worth clarifying that we are talking about the motion of the observer to the treadmill, and the environment; not necessarily the treadmill to the environment; but I'll address the issue as you have formulated it.


Stationary environment
The "stationary environment" is a statement about the absolute motion of the environment; in this case, the absolute rest state of the environment. This is because it begs the question, relative to what is it stationary? It isn't stationary relative to the treadmill.

If you suggest that it is a non-physical "hypothetical observer", or a mathematical reference frame, then you are guilty of ascribing physical characteristics to a non-physical entity; but we don't need to make the observer hypothetical, we can introduce a physical observer at rest relative to the environment; this doesn't resolve the issue, however, because it simply introduces another object into the "stationary environment" which becomes part of "the environment", which is, as a whole, considered stationary.

Indeed, we don't need to worry about mathematical reference frames, because we're not looking to measure anything; we are simply talking about the observation of relative motion, and what can be deduced from it; we are not necessarily concerned with the relative velocity.

Still treadmill
To say the current is keeping the treadmill "still" is yet another statement about the absolute rest state of the treadmill, because, again, the question is begged, relative to what is the treadmill still? It isn't the environment. Hypothetical observers, or additional physical observers don't resolve the issue either, for the reason mentioned above.


Both are moving
When we consider only relative motion, then both are always moving, relative to each other; I don't see how you can cling to the idea that only relative motion makes sense when you suggest that "both are moving" is a distinguishable scenario from "one is moving" and "the other is moving".

Of course, in order to do this you need to introduce a third frame of reference, which isn't part of the original formulation; demonstrating that the three physically distinguished scenarios aren't just different ways of labeling the same scenario under Einsteinian relativity, because an additional observer needs to be added.

Root of the problem

That appears to be the root of the problem, you are confusing the three ways of labeling each physically distinguished scenario, with three physically distinguished scenarios, themselves. You are taking the possible conclusions that can be drawn from one of the three physically distinguished scenarios, to be the three different scenarios in and of themselves; this is a mistake however (unless absolute motion is assumed);

The three physically distinguished scenarios are:

Scenario 1
The treadmill is switched on and moving; the current is running through the treadmill; the observer is moving his/her limbs at a pace that exactly offsets the pace of the treadmill.; this gives rise to relative motion between the observer and the treadmill.

Possible Conclusions: the current is keeping the treadmill moving; the current is keeping the treadmill stationary.

Either the treadmill is moving, or the observer is; or both are. QED

Bear in mind that both are always moving relative to each other

Scenario 2
The treadmill is switched off, and not moving; there is no current running through the treadmill; the observer is moving his/her arms and limbs at the same rate as 1 above; this gives rise to the relative motion between the observer and the treadmill.

Possible Conclusions:the movement of the observers limbs is causing him to move; the movement of the observers limbs is causing him to remain stationary.

Either the observer is moving, or the treadmill is moving; or both are. QED

Bear in mind that both are always moving relative to each other

Scenario 3
The treadmill is switched on; there is a current running through the treadmill; the observer is moving his/her limbs at a rate that does not exactly offset the pace of the treadmill; this gives rise to the same measured velocity between the observer and the treadmill.

Possible Conclusions:the current is causing the treadmill to move; the current is causing the treadmill to remain still; the movement of the observers limbs are causing him to move; the movement of limbs is causing him to remain stationary.

Either the observer is moving, or the treadmill is; or both are. QED.

Bear in mind that both are always moving relative to each other

Overall conclusion
All three of these, physically distinguished scenarios will give rise to the observed relative motion between the observer and the treadmill; one of these scenarios is a logical necessity to account for the relative motion between the observer and the treadmill; each scenario implies absolute motion, therefore absolute motion is a logical necessity.

You seem to have an odd habit of assuming that you have adequately addressed issues that you haven't. Any of the "corrections" you have proffered have been challenged; the challenge to that particular point is the question on the mysterious dynamics that cause stationary world tubes to give rise to relative motion. Your response to this is, as below, related to the kinematics of the system.

Your mistake is in assuming that this adequately addresses the issue.

"A well defined hyperbolic geometry" simply states what spacetime is; it doesn't explain how static world tubes give rise to relative motion.

Space, time and Einstein

Kinematics - wiki

A-level phyiscs - wikibooks

Saying what spacetime is doesn't address the question of how static world tubes give rise to relative motion; Kinematics is a description of motion, not an explanation as to what causes it.

So, in the absence of an explanation of the exceptionally mysterious dynamics, which outlines how static world tubes give rise to relative motion, we are left with a theory about relativity which not only can't account for the observation of relative motion, but logically should preclude it.

In the absence of an explanation of such dynamics, we are left with the logical necessity of absolute motion to account for relative motion.

roosh wrote: »

And we can take that back up in the other thread.

A person walking on a treadmill which is either on or off; very convoluted indeed.

There are a number of issues with what you say; again, statements such as "the treadmill is stationary", "the environment is stationary" and "both are moving" are statements about the absolute nature of motion of the aforementioned objects.

When we consider the relative motion between the treadmill and the environment, we cannot say that "one is moving, while the other is stationary" because the treadmill and the environment are always moving relative to each other.

If we say it is relative to a non-physical, hypothetical observer then we are ascribing physical characteristics to something which is non physical. We can, though, make that hypothetical observer represent a physical observer; for example, an observer who is at rest relative to the environment; again, however, this doesn't resolve the issue, because that physical observer simply forms part of "the environment" which is deemed to either be "stationary" or "moving".

Again, these are statements about the absolute motion of the objects, because when considering the relative velocity of the two systems, both are always moving relative to each other; neither is stationary.

The issue, as somewhat outlined above, is that by considering the motion of objects relative to a non-physical, hypothetical observer we are ascribing physical characteristics to something which is non-physical; it implies that mathematical co-ordinates exist a priori in nature; and it means that our use of reference frames don't accurately correspond to the physical world.

When we take the hypothetical observer correspond to the physical world, then the reference frames carry implicit assumptions about absolute motion and rest; because we label the observer as "stationary" when he/she is in fact moving relative to something. When we say that he/she is "stationary" relative to a non-physical, mathematical reference frame, we ascribe physical characteristics to something non-physical.

If we don't make the hypothetical observer correspond to the physical world, then the implications of absolute rest and motion do indeed disappear; but what we get instead are certain conclusions, namely reciprocal contractions, which don't correspond to the physical world, and are simply mathematical artefacts, like our hypothetical observer and his mathematical reference frame. This is because we consider the motion relative to something which is not physical, but mathematical.

What we have is an explanation of the observations which leads to the conclusion that objects exist as 4-Dimensional world tubes, in spacetime. Hyperbolic geometry explains why relatively moving objects would result in the given observations, it doesn't offer a "get-out-of-jail-free" card to explaining how relative motion arises from those 4-Dimensional world tubes in the first place.

Indeed, we could say that the kinematical explanation explains the observations, but we don't observe 4-Dimensional world tubes, or how those 4-Dimensional world tubes contrive to manifest as the relative motion we do observe; but this is an unavoidable aspect of the kinematical explanation.


The issue remains, that there must be something extremely mysterious at play to make the kineamtical explanation work; something exceptionally mysterious to make 4-Dimensional world tubes, which are at rest in spacetime, manifest as relative motion.

Without such an explanation, what we've got is a theory about relative motion, which can't account for relative motion.

roosh wrote: »

We can probably make progress on two fronts. With regard to the points raised above, we can leave those to the thread intended to be a discussion on the implicit assumptions of Einsteinian co-ordinate labels

With regard to the deduction of absolute motion, from relative motion, the points raised about how the scenarios are just the same scenario labeled differently, under Einsteinian relativity, are not necessarily material.

Essentially, what we have, or rather what we should have, are two possible explanations for relative motion; the concept of absolute motion is one such explanation.

You're suggesting that Einsteinian relativity says that "the 3 scenarios" are just the same scenario labelled differently; that is fine, as Einsteinain relativity doesn't include the concept of absolute motion. Einsteinain relativity, however, leads to the conclusion that objects exist as absolute, and static, 4D worldtubes; what we don't have though is an explanation for how these world tubes manifest as the relative motion we observe.

That ER is a kinematical explanation of the observations doesn't mean that an explanation isn't required, it simply means that it doesn't give one.

It isn't the idea that objects exist as 4D world tubes which is mysterious; indeed, I have an understanding of that, albeit a limited one. What is mysterious is how these world tubes manifest as the realtive motion that we observe.

What you have essentially done here, as you have done before, is stated that the idea, that objects exist as 4D world tubes, is clear, concise, well established, rigorous and precisely described; it's just a restatement of the idea that objects exist as 4D world tubes, and that this concept is well understood. That much isn't in question; what is in question is, how do these 4D world tubes manifest as the relative motion that we observe?

That is what is mysterious, because, logically they should actually preclude relative motion; unless there is something very mysterious which causes them to manifest as the relative motion we observe.

In the absense of such an explanation, the concept of absolute motion is a logical necessity to account for relative motion.

I'm not suggesting anyone is wrong for adopting the postulates of relativity; I think the manner in which it has come about is entirely understandable, I just think there are issues with it, in terms of the logic. As there appears to be with Lorentzian relativity.

In the context of this particular discussion though, we are looking to see what we can deduce from relative motion; the question appears to come down to either a) absolute motion; or b) 4D world tubes manifesting as relative motion.

The idea that absolute motion can give rise to relative motion makes perfect sense to me; how static 4D world tubes give rise to relative motion, doesn't.

Logically, an explanation is needed for the latter; or at least an alternative to absolute motion is required to imply that it isn't a logical necessity; stating that objects exist as 4D world tubes, and that this well understood, doesn't provide such an explanation.

roosh wrote: »

I think we can separate it out from this line of discussion, but we can resume it in the thread on that topic.



I'm not sure the shape of the world tubes makes much difference; a conical world tube has the same issues. The question is still begged, how does the light-cone structure of events give rise to the relative motion that we obvserve, given that the past and future of light cones are extended eternally in spacetime?

With regard to the need for an explanation of the kinematics, it is probably worth highlighting that it isn't really necessary to explain why the kinematics is the way it is; what is necessary is an explanation for how relative motion manifests. Kinematics doesn't offer such an explanation. Taking all theories together, absolute motion can account for the observation of relative motion; in the absence of an alternative explanation for the cause of relative motion, it would certainly seem that absolute motion is a logical necessity.

roosh wrote: »

The issue isn't the relation between the observations of relative motion and the 4D structure of spacetime; the issue is the cause of relative motion; the kinematical model, which is the 4D structure of spacetime, doesn't provide such an explanation. Given relative motion, and certain other assumptions, the 4D structure of spacetime is the conclusion.

This conclusion, however, necessitates that objects exist as world tubes in spacetime; the question which arises from this is, how do those world tubes, which are static in spacetime, manifest as the relative motion we observe, when, logically speaking, they should preclude the manifestation of relative motion.

This represents a pretty fundamental assumption, and requires a very exotic explanation, which doesn't appear to exist. In the absence of such an explanation we are left with a theory about relative motion which, not only can't account for relative motion, but should actually preclude it's manifestation.


The absence of such an explanation would also mean that absolute motion is a logical necessity to account for relative motion. Indeed, even in the advent of such an explanation, occams razor might favour absolute motion anyway.

Summary
So what we now require are the following explanations (although one might cover both):
- How do static world tubes manifest as relative motion
- How is time experienced as passing, while also remaining static.


To many these would just appear to be paradoxes, inherent in the theory.

roosh wrote:

It's probably worth highlighting that the two scenarios aren't analagous, because, of course, we do experience the thoughts of the "identical twin" i.e. the thoughts of our former self, and future self; I experienced the thoughts of my 8yr old self, and every manifestation of myself in between.

We can also offer an explanation, in terms of world tubes, for why we don't experience the thoughts of an identical twin; we can say it's due to the fact that the world tubes are spatially separated i.e. they are separate world tubes; but this doesn't explain how both twins experience an ever changing present moment.

We can take it as an explanation for how we don't experience the thoughts of our future and former selves, but that much isn't in question. What is required, in addition to how static world tubes manifest as relative motion, is how there is this experience of growing older, of transitioning from moment to moment, when all moment, supposedly co-exist. It requires an explanation for how my 8yr old self experienced the transition to the age I am now, while eternally remaining 8yrs old; how do we transition from moment to moment along our world tubes, while not transitioning from moment to moment i.e. when all moments co-exist eternally?

It might be easier to try and put into words using the redundant concept on which it is based; the theory requires an explanation of how time is experienced as passing, while time doesn't pass.

Masteroid wrote: »

Really? Are you saying that we would get younger rather than older? That what we perceive as 'effects' in this universe would be perceived as 'causes' in an area where the 2nd law was reversed?

This would require a physics that could account for, for example, how thoughts could spontaneously appear in the mind giving rise to neural responses that cause the hammer in the ear to vibrate against the timpanic membrane resulting in the generation of a pressure wave which increases in intensity as it travels until it arrives at a vocal chord which transduces the wave into a neural impulse in a process that causes the loss of knowledge.

Surely you don't suppose that a reversal in the direction of time would result in the creation of the past?

In terms of determinism though, or 'presentism', if you will, even if the 2nd law were reversed, the direction of time would be unaffected, i.e. change would take place as a result of deterministic processes.

And don't forget that in the event that the 2nd law was reversed then my digital watch would not start counting backwards, it would stop working altogether. This might be considered trivial when it is realised that the mechanisms that give rise to the beating heart wouldn't work either. No, if the 2nd law were reversed, we wouldn't get younger, we would die horribly as existence as we know it decomposes into energy and through deterministic processes reorganises and evolves new structures which are under the constraints of deductable laws of physics.

And change continues to take place.

Anyway, if the 2nd law were reversed, wouldn't the universe be contracting and isn't there a coordinate system which can treat the universe as being a process of condensation and that could be reconciled with observation?

Masteroid wrote: »

In other words, doesn't the 2nd law demand certain phyical laws? Isn't it the case that by treating certain laws of physics as being absolute we have forced modern physics upon ourselves? Aren't we guilty of making the 'questions' fit the 'answers'? ER is so elegant it must mean something, right?

Masteroid wrote: »

Until it's wrong.

Masteroid wrote: »

But I digress. My point is that the 2nd law, reversed or not, intrinsically implies a 'directional' component to all energy which gives rise to motion.

Masteroid wrote: »

Matter is composed of energy which means that no electron, proton or neutron continuously occupies the same space. Not a single photon does. Nothing is still. To exist is to be in motion. So isn't it safe to assume that there is no absolute rest as that would mean 'non-existence'?

Masteroid wrote: »

Although ER and LR 'get around' the problem of absolute rest versus absolute motion by not addressing it, a complete physical theory cannot.

Masteroid wrote: »

But we can ask, What does it mean to be at absolute rest, can't we? We can imagine an object, a piece of apparatus perhaps, as continually occupying the same space, motionless, with all motion being relative to it. We can then say that any other object that is motionless relative to that apparatus is also at absolute rest. We can try to arrange the whole universe in a static configuration, no relative motion, absolute rest but before long things like gravity and the expansion of space begin to introduce relative motion.

Masteroid wrote: »

Surely physics can discount the notion of absolute rest and therefore assume absolute motion even though ER or LR can make predictions that are not dependent on such an assumption?