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Absolute motion

roosh

This question comes from a discussion on here, and elsewhere, which involved the idea of absolute motion; I just wanted to see what peoples thoughts on the subject were.

Historically, the concept of absolute motion seems to have been thought of as motion relative to an absolute reference frame; where the absolute reference frame is, in practicality, undeterminable. This to me seems to be somewhat of a contradiction in terms, because it suggests that absolute motion is relative i.e. relative to an absolute reference frame.

My understanding of the term "absolute" is

Philosophy
a value or principle which is regarded as universally valid or which may be viewed without relation to other things:

OED - absolute

That is, what is absolute is not relative to something else; so absolute motion would be motion that is not necessarily relative to something else i.e. it is a kind of motion that is not relative. Absolute motion appears to be a perfectly suitable term in that regard.

In the real world
The above is all pretty theoretical, but I think it can be clarified by reference to real world scenarios, to try and give some contextual meaning.

Car
Imagine you are in a car on a long stretch of straight road; the car is stationary such that there is no relative motion between you and the road or the surrounding landscape.

Now, you start the car, put it into gear and press the accelerator, such that relative motion occurs between you and the road, and landscape. The question is, are you actually moving; does it make sense to you to ask the question, are you actually moving; is the rotation of your tyres propelling you forward?

This can be contrasted with the idea that your car is on a giant conveyor belt, and that when your tyres start rotating you actually remain stationary, and it is the road and surrounding landscape that is "doing the moving".

Would you agree that, in this scenario, even if we cannot determine which is actually "doing the moving", we can deduce that, at least, one or the other has to be actually "doing the moving"?

Escalator
Recall a time when you were on an escalator, or even try it the next time you are on an escalator - we'll say an escalator going up, for the sake of clarity.

As you stand on the escalator, are you actually moving; does the idea of "actually moving" make sense to you?

Would you say that you, and the escalator, are actually moving up, as opposed to the universe shifting around you in such a way as to give rise to the relative motion you would expect if you were "actually moving"?

Is it you and the escalator that are "doing the moving" or is it the entire universe?

If you couldn't determine which is the case, would you agree that, at least one of you has to actually be moving, in an absolute sense?

Walking down the road
As you walk down the road, is you that is actually moving, or are you walking on giant treadmill and it is the surrounding landscape that is actually moving? Do those questions make sense to you - even if you took it for granted what the answer was?

Active and Passive
I suppose the distinction I am trying to make is between active and passive relative motion.

When you drive down the road in your car, there is relative motion between you and the road; scientific principles suggest that we cannot determine the absolute nature of the motion of either object/observer, but can we deduce that the motion must be absolute - even if we can't determine who is absolutely moving?

When you walk down the road, relative motion manifests, but does it make sense to say that it is your active moving which is causing the relative motion to manifest, while the road is passively involved? That is, are you actually moving, or is it the road.

If we cannot determine, by experiment, which one is the true state, can we deduce that it must be one or the other?

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18AD

roosh wrote: »

While I would be inclined to agree, I'm not sure if "the science" would, because we supposedly cannot determine, by experiment, if we are moving or not; I'm not sure if this extends to proprioception, or if the equivalence principle would account for the feeling of moving.

But still, the conclusion that could be drawn from that is that either your train or the other train is actually moving - in the example you give above, assuming it doesn't contradict with scientific theory, the conclusion drawn is that your train is actually in motion.

The example I gave demonstrates that you are not the one that's moving, because you don't feel the exceleration of the train you're in. So you conclude it's the other one.

How would the observation of relative motion be accounted for in the context of Zeno's paradox?

I don't think it would be. It's all at rest. Perhaps a perceptual error? The greeks were fond of that.

roosh

Morbert wrote: »

All of those statements make reference to a frame of reference. For example, "It was actually the other train that was moving" is from the reference frame of the earth. "We are not moving" is from the reference frame of the train. Water and electricity flow in the reference frame of the circuit. "Traffic is moving freely" in the reference frame of the road/earth.

"The train is moving" is a statement about the absolute motion of the train, precisely because it doesn't make reference to a reference frame. It means that, regardless of what the train is moving relative to, it is the train that is actively "doing the moving", as opposed to the other object, relative to which it is moving.

Traffic is moving freely doesn't make reference to any reference frame either, it makes reference to the absolute motion of the traffic, because the statement is simply that it is the traffic that is moving - without qualification; this can be contrasted with the other possible cause of the relative motion, that the earth has changed its rotation, and is behaving like a giant conveyor belt/treadmill - akin to your spinning log analogy in another thread. That we cannot determine which is the case doesn't stop us from deducing that it is either one or the other.

To say that "we are not moving" is from the reference frame of the train, doesn't take into account the fact that the observers on the train can define their reference frame in such a way that labels the train as "moving". But, where they do label the train as being "at rest" the conclusion is simply reversed i.e. it is the earth and the surrounding landscape that is "doing the moving".

Reference frames
I think the constant recourse to reference frames might be obscuring the issue, because we are talking about absolute motion which isn't necessarily relative to anything; that we can define reference frames that labels one object as "moving relative to" another is essentially immaterial, because "absolute motion" isn't "moving relative to".

It might be helpful to do a field exercise, where you won't be using mathematical reference frames to define your movement; take a walk down the street, or a corridor, and notice the relative motion. First, notice the lack of relative motion as you stand at rest relative to the surface.

Then recall a time when you've been on a treadmill, and contrast it with a time when you've walked down the street. Now, ask yourself, what must occur for relative motion to occur between you and the area you are in - let's say it's a corridor.

Then start walking down the corridor towards a door; ask yourself, is it you that is moving towards the door while the corridor remains inertial, or are you remaining inertial while the corridor behaves like a treadmill and moves the door towards you?

Try not to get bogged down by the idea that we can define different reference frames which label it differently; because we can, and this isn't in dispute.

Morbert wrote: »

If by this you mean "There is no reference frame which labels both X and Y as stationary." you are correct. You cannot, however, extend this to "At least one of X or Y must be moving with respect to absolute rest." without implicitly assuming absolute rest exists.

If by this you mean that we can extend it to "at least one of X or Y must be moving, without the need to define it relative to absolute rest, because absolute motion is, by definition, not relative to anything", then you are correct.

There seems to be an attachment to the idea of absolute motion being relative to an absolute rest state; but this is a contradiction in terms, because it is saying that absolute motion is relative [to absolute rest]. The idea of absolute motion doesn't require absolute rest, because it is a simple "yes or no", "either, or" question.

When two things are moving relative to each other, it is a question of which one is "actually moving", or even if they are both "actually" moving, in an absolute sense, regardless of how they are labeled by an arbitrary, artificial co-ordinate labeling system.

It's not a question of "am I moving relative to something?", it is a question of "am I moving [full stop]." It can further be extended to the question "are you capable of movement? (without any qualification).

That we cannot tell if we are actually moving or not is immaterial, because where there is relative motion, something must actually be moving.

roosh

18AD wrote: »

The example I gave demonstrates that you are not the one that's moving, because you don't feel the exceleration of the train you're in. So you conclude it's the other one.

I would be inclined to agree with you 18AD, but the principle of relativity says that we cannot determine, by experiment, whether we are actually moving or not. I'm not sure if this extends to proprioception, or to factors that would affect our proprioception to make us think we are moving.

What would your thoughts be on the issue; would you say that absolute motion exist i.e. when you drive down the road are you actually moving, or is the road actually moving; or do you think it must be one or the other?

18AD wrote: »

I don't think it would be. It's all at rest. Perhaps a perceptual error? The greeks were fond of that.

18AD

roosh wrote: »

What would your thoughts be on the issue; would you say that absolute motion exist i.e. when you drive down the road are you actually moving, or is the road actually moving; or do you think it must be one or the other?

I don't know about absolute motion, since your body ignores motion you are with for a while. You don't notice whizzing through space on earth, the same way you don't notice being in a steady moving car.

But the change from one speed to another is defitely perceptible. To use the car example, you can feel the acceleration of your car. You can't tell if everything else is slowing down, it's simply not available information (except perhaps visually).

Also, if you're in a moving car you don't experience the world moving and yourself at rest. You could force the perception but then I'd say you're abstracting from perception.

roosh

18AD wrote: »

I don't know about absolute motion, since your body ignores motion you are with for a while. You don't notice whizzing through space on earth, the same way you don't notice being in a steady moving car.
.

Just to clarify, I meant absolute motion as opposed to inertial motion.

I would agree that accelerated motion is easier to determine, and that's why the example of two observers starting off at rest relative to each other is probably easier to imagine.

But if we take the example of walking down the road; it might be worth doing a little "experiment" the next time you're going for a walk.

Find a stretch of road where you will be walking straight for a reasonable distance; stop, so that you are at rest relative to the road and other objects at rest relative to the earth.

Ask yourself, what has to happen for relative motion to occur between you and the road. Would you agree that one of the following three scenarios would have to occur:

1) The Earth remains inertial, or continues either roating, orbiting, etc. as it is while you are at rest relative to it, and that your walking propels you forward, while the road remains passive.

2) The Earth has to behave like a giant treadmill, and the surrounding scenery has to behave as though on a conveyor belt linked to that treadmill, such that the relative motion results from you "walking on the spot" on a treadmill, while you remain inertial.

3) Both 1 & 2 above.

18AD wrote: »

But the change from one speed to another is defitely perceptible. To use the car example, you can feel the acceleration of your car. You can't tell if everything else is slowing down, it's simply not available information (except perhaps visually).

Also, if you're in a moving car you don't experience the world moving and yourself at rest. You could force the perception but then I'd say you're abstracting from perception

Would you agree though, that in a moving car, either your car is moving, or the world is?

Bearing in mind that the earth can be moving through space, and your car can, subsequently, move along the surface of the earth.

18AD

roosh wrote: »

Just to clarify, I meant absolute motion as opposed to inertial motion.

I would agree that accelerated motion is easier to determine, and that's why the example of two observers starting off at rest relative to each other is probably easier to imagine.

But if we take the example of walking down the road; it might be worth doing a little "experiment" the next time you're going for a walk.

Find a stretch of road where you will be walking straight for a reasonable distance; stop, so that you are at rest relative to the road and other objects at rest relative to the earth.

Ask yourself, what has to happen for relative motion to occur between you and the road. Would you agree that one of the following three scenarios would have to occur:

1) The Earth remains inertial, or continues either roating, orbiting, etc. as it is while you are at rest relative to it, and that your walking propels you forward, while the road remains passive.

2) The Earth has to behave like a giant treadmill, and the surrounding scenery has to behave as though on a conveyor belt linked to that treadmill, such that the relative motion results from you "walking on the spot" on a treadmill, while you remain inertial.

3) Both 1 & 2 above.

If you use your bodily experience to judge what is happening you will feel distinctly different effects if (1) you walk forward or (2) if the world behaves as a treadmill.

If you're just walking you propel yourself.

If the world moves you will have to compensate your balance. And you will feel that it is the earth that has moved. (Unless you have vertigo or something, in which case you might not be able to tell which of you is changing)

I think if you're seeing the world as moving as a treadmill you are abstracting from your experience, since you don't experience the world as moving as a treadmill, unless you force it. In which case I think you're privileging visual experience. (It can certainly look like the world is treadmilling)

Would you agree though, that in a moving car, either your car is moving, or the world is?

Bearing in mind that the earth can be moving through space, and your car can, subsequently, move along the surface of the earth.

As a theoretical point the car and the earth are both moving, flying through space.

From a phenomenological point you will be able to tell whether it is you or the world that is moving. (As in the case of the walking example above)

roosh

18AD wrote: »

If you use your bodily experience to judge what is happening you will feel distinctly different effects if (1) you walk forward or (2) if the world behaves as a treadmill.

If you're just walking you propel yourself.

If the world moves you will have to compensate your balance. And you will feel that it is the earth that has moved. (Unless you have vertigo or something, in which case you might not be able to tell which of you is changing)

I think if you're seeing the world as moving as a treadmill you are abstracting from your experience, since you don't experience the world as moving as a treadmill, unless you force it. In which case I think you're privileging visual experience. (It can certainly look like the world is treadmilling)

Don't get me wrong, I would be in agreement with you; personally I think it is our walking that propels us forward, although I might not have given a decent description of the world as a treadmill; it might be the case that the world is behaving like a treadmill when we are stopped, and we are going around with it, but when we start walking we then start walking against the conveyor belt.

The principle of relativity suggests that we cannot determine if we are actively "doing the moving", or if it is the conveyor belt earth that is actively "doing the moving" i.e. we cannot determine which one is actually moving.

Would you agree that those two options, or those two options combined, represent the only way in which the relative motion between you and the road can be accounted for, in a physical world?

Would you agree that, even if we cannot determine by experiment, whether we are actually in motion, or if the road is actually in motion, we could deduce that, at least, one of us has to be?

18AD wrote: »

As a theoretical point the car and the earth are both moving, flying through space.

From a phenomenological point you will be able to tell whether it is you or the world that is moving. (As in the case of the walking example above)

I would be inclined to agree with you, I think the earth is actually moving through space, and the car along with it; and that the car is subsequently actually moving again along the surface of the earth.

The principle of relativity suggests we cannot definitively say that this is the case; the earth could be at absolute rest, we just have no way of telling. We can also define reference frames that label the earth as stationary and everything else in the universe as in motion. But would you agree that, the fact that the sun and the earth move relative to each other means we can deduce that, at least one of them - and possibly both - is actually moving?

18AD

roosh wrote: »

Don't get me wrong, I would be in agreement with you; personally I think it is our walking that propels us forward, although I might not have given a decent description of the world as a treadmill; it might be the case that the world is behaving like a treadmill when we are stopped, and we are going around with it, but when we start walking we then start walking against the conveyor belt.

I don't think this analogy works. If walking means you walk against the treadmill of earth, then earth is effectively moving omnidirectionally because you can walk against the treadmill in any direction.

The principle of relativity suggests that we cannot determine if we are actively "doing the moving", or if it is the conveyor belt earth that is actively "doing the moving" i.e. we cannot determine which one is actually moving.

Would you agree that those two options, or those two options combined, represent the only way in which the relative motion between you and the road can be accounted for, in a physical world?

Would you agree that, even if we cannot determine by experiment, whether we are actually in motion, or if the road is actually in motion, we could deduce that, at least, one of us has to be?

If I could change the example a bit, just for my own sake. So there would be no experiment that could determine whether when I move my arm, whether it is my arm that I have moved or the entire universe has rotated around my arm?

As an aside: If we stay within the remit of phenomenology (which I'm trying to do) the experience of walking and the ground moving are experientially distinct phenomena. When I walk I am propelling myself, my senses tell me this. When the ground moves I have to adjust my balance, my senses tell me this (but I probably do it automatically). Regardless of experimental verifiability.

Whether either of us is absolutely moving or at rest is beyond the scope of this analysis.

roosh

18AD wrote: »

I don't think this analogy works. If walking means you walk against the treadmill of earth, then earth is effectively moving omnidirectionally because you can walk against the treadmill in any direction.

As far as im aware,that isn't an issue under the theory of reltivity;it is possible to define a reference frame where the Earth moves omnidirectionally.It wont necessarily state that the Earth is behving like a treadmill,but im not really aware of how relative motion could manifest otherwise.

I would say not to get too bogged down in the analogy;just consider it in its simplest form and see id you agree with the deduction. if you're walking down the street,or a corridor might be easier to imagine,or even try; start at one end of the hall,don't walk for a few moments,just consider the scenario;note that there is no relative motion between you and the rest of the corridor. Ask yourself,what must occur for relative motion to manifest?

Would you agree that either you or the hall/universe has to actually move?

Would you agree that,either your walking has to move you towards the other end of the hall,or the hall has to behave like a conveyor belt and move the other end towards you,with your walking motion being akin to walking on a treadmill?

or both of these together i.e. like walking the wrong way down an escalator,but where yur pace is quicker than the escalator.

18AD wrote:

If I could change the example a bit, just for my own sake. So there would be no experiment that could determine whether when I move my arm, whether it is my arm that I have moved or the entire universe has rotated around my arm?

To my understanding,you could define a reference frame that labels your hand as at rest and labels everything else in the universe as "in motion" or moving;if there were a mini-observer on your hand,honey i shrunk the kids style,there is no experiment that either you or he could conduct to determine if it was your hand that moved,or the universe.

but,even assuming that to be the case,would you agree that we could deduce that either your hand actually moved,or the universe did?

18AD

roosh wrote: »

I would say not to get too bogged down in the analogy;just consider it in its simplest form and see id you agree with the deduction. if you're walking down the street,or a corridor might be easier to imagine,or even try; start at one end of the hall,don't walk for a few moments,just consider the scenario;note that there is no relative motion between you and the rest of the corridor. Ask yourself,what must occur for relative motion to manifest?

Would you agree that either you or the hall/universe has to actually move?

Would you agree that,either your walking has to move you towards the other end of the hall,or the hall has to behave like a conveyor belt and move the other end towards you,with your walking motion being akin to walking on a treadmill?

or both of these together i.e. like walking the wrong way down an escalator,but where yur pace is quicker than the escalator.

Ok.

Without saying anything about absolute motion or anything, the phenomenological approach says that you can tell whether either you or the hall moves. Whichever of you moves is experientially distinct.

So if you walk, you move.
If the hall moves, you will walk as well (or fall over) but you will experience it as the hall moving.

Although both may appear, visually, exactly the same, they are experientially distinct.

So yes, you can tell which is moving.

To my understanding,you could define a reference frame that labels your hand as at rest and labels everything else in the universe as "in motion" or moving;if there were a mini-observer on your hand,honey i shrunk the kids style,there is no experiment that either you or he could conduct to determine if it was your hand that moved,or the universe.

but,even assuming that to be the case,would you agree that we could deduce that either your hand actually moved,or the universe did?

Again, experientially, I actually move my hand. I move it, I can feel it moving, because I move it. I like to move it, move it.

This is wild. So if I move my hand it is conceivable that I'm actually rotating the entire universe around my hand, instead of just moving my hand? I think for this view to be believable you have to remove agency. Otherwise by will alone I shift the entire universe just to reach my glass of water. That would mean that my will permeates the entire cosmos. (Which it does, but that's a lesson for another day)
Or you could just be a determinist. But that's so dated these days. :pac:

Morbert

roosh wrote: »

"The train is moving" is a statement about the absolute motion of the train, precisely because it doesn't make reference to a reference frame. It means that, regardless of what the train is moving relative to, it is the train that is actively "doing the moving", as opposed to the other object, relative to which it is moving.

Traffic is moving freely doesn't make reference to any reference frame either, it makes reference to the absolute motion of the traffic, because the statement is simply that it is the traffic that is moving - without qualification; this can be contrasted with the other possible cause of the relative motion, that the earth has changed its rotation, and is behaving like a giant conveyor belt/treadmill - akin to your spinning log analogy in another thread. That we cannot determine which is the case doesn't stop us from deducing that it is either one or the other.

To say that "we are not moving" is from the reference frame of the train, doesn't take into account the fact that the observers on the train can define their reference frame in such a way that labels the train as "moving". But, where they do label the train as being "at rest" the conclusion is simply reversed i.e. it is the earth and the surrounding landscape that is "doing the moving".

Reference frames
I think the constant recourse to reference frames might be obscuring the issue, because we are talking about absolute motion which isn't necessarily relative to anything; that we can define reference frames that labels one object as "moving relative to" another is essentially immaterial, because "absolute motion" isn't "moving relative to".

It might be helpful to do a field exercise, where you won't be using mathematical reference frames to define your movement; take a walk down the street, or a corridor, and notice the relative motion. First, notice the lack of relative motion as you stand at rest relative to the surface.

Then recall a time when you've been on a treadmill, and contrast it with a time when you've walked down the street. Now, ask yourself, what must occur for relative motion to occur between you and the area you are in - let's say it's a corridor.

Then start walking down the corridor towards a door; ask yourself, is it you that is moving towards the door while the corridor remains inertial, or are you remaining inertial while the corridor behaves like a treadmill and moves the door towards you?

Try not to get bogged down by the idea that we can define different reference frames which label it differently; because we can, and this isn't in dispute.

What is in dispute is whether or not a statement like "John is travelling at 60 mph." implies a reference frame that is no more or less true than a reference frame where "John is stationary". That is the crux of the issue. You disagree with the postulate that no reference frame is more or less correct than any other. I suspect this is because you want to recover presentism from relativity.

If by this you mean that we can extend it to "at least one of X or Y must be moving, without the need to define it relative to absolute rest, because absolute motion is, by definition, not relative to anything", then you are correct.

I don't mean that. You must always define a reference frame when describing motion. To quote Einstein himself.

"Strictly speaking, one should not, e.g., say that the earth moves around the sun in an ellipse, since this statement presupposes a coordinate system in which the sun is at rest, … In the investigation of the solar system nobody will employ a coordinate system at rest relative to the terrestrial body, since that would be impractical. But in principle such a coordinate system is according to the general theory of relativity fully equivalent to every other system."

There seems to be an attachment to the idea of absolute motion being relative to an absolute rest state; but this is a contradiction in terms, because it is saying that absolute motion is relative [to absolute rest]. The idea of absolute motion doesn't require absolute rest, because it is a simple "yes or no", "either, or" question.

When two things are moving relative to each other, it is a question of which one is "actually moving", or even if they are both "actually" moving, in an absolute sense, regardless of how they are labeled by an arbitrary, artificial co-ordinate labeling system.

It's not a question of "am I moving relative to something?", it is a question of "am I moving [full stop]." It can further be extended to the question "are you capable of movement? (without any qualification).

That we cannot tell if we are actually moving or not is immaterial, because where there is relative motion, something must actually be moving.

If the answer to "Am I moving [full stop]?" is "no". Are they in a state of absolute rest? Any definition of "absolute motion" which encompasses a state of "absolute rest" or "absolute 0 motion" is not supported by relativity. That is the problem with your understanding of motion.

Morbert

18AD wrote: »

Ok.

Without saying anything about absolute motion or anything, the phenomenological approach says that you can tell whether either you or the hall moves. Whichever of you moves is experientially distinct.

So if you walk, you move.
If the hall moves, you will walk as well (or fall over) but you will experience it as the hall moving.

Although both may appear, visually, exactly the same, they are experientially distinct.

So yes, you can tell which is moving.

Special relativity says you can detect "non-uniform" i.e. accelerated motion. (This is how the twin paradox is solved) So you can detect if the hall accelerates, but you cannot detect, say, its 230 km per second motion of the hall with respect to the centre of the galaxy.

roosh

Morbert wrote: »

What is in dispute is whether or not a statement like "John is travelling at 60 mph." implies a reference frame that is no more or less true than a reference frame where "John is stationary". That is the crux of the issue. You disagree with the postulate that no reference frame is more or less correct than any other. I suspect this is because you want to recover presentism from relativity.

Ok, I think I see where the issue lies; I'm not sure if I'll be able to illucidate it fully but hopefully, with some patience, on both our parts, I will be.

First, it is necessary to highlight that the implication of a preferred reference frame implied by the statement "John is travelling at 60mph", is not in dispute. I entirely agree that it is possible to define a reference frame which labels John as traveling at 60mph, as it is to define one where he is "at rest", just as one can be defined where his relative motion is that between him and the centre of the galaxy.

What is in dispute is the statement "John is moving", and whether or not this makes sense without reference to a reference frame; the contention is that, without this reference to a reference frame, the statement is a statement about John's absolute motion, precisely because it is a statement about John's motion without reference to a reference frame i.e. it is a statement about his state of motion, not what he is moving relative to.

The intention here isn't to try to find a way to recover presentism from relativity; this is entirely independent of the concept of presentism, and I'm not even sure if this concept of absolute motion will result in the conclusion of presentism. I personally think the universe is presentist, but that isn't something which plays a role in examining the relative motion between two bodies. This is simply a question of trying to develop a more accurate view of the world; this entails developing an understanding of what existing scientific theories say about the world and subjecting them to critical questioning.

The crux
The crux of the issue isn't so much whether there is a preferred reference frame, it's about what logical deductions we can make from about those reference frames. I see no issue with the idea of equally valid reference frames, so long as it is qualified with the idea that an observers instruments might be contracted by an amount unknown to themselves.

It comes down to something which doesn't seem to be illucidated by mathematical reference frames - that an observers instruments are contracted by an amount unknown to themselves is one such issue - to borrow 18ADs term, it comes down to a phenomenological description of the cause of the relative motion between two bodies.

Where there is relative motion between me and the street, either the earth has to be behaving like a giant treadmill, or spinning log as you mentioned elsewhere, or the earth is passive while I am actively "doing the moving", and my walking is propelling me forward.

The Earth can be moving relative to any other object in the universe, and us along with it, but the subsequent relative motion between us and the street has to be accounted for by one, or both, of the scenarios above. This offers three possible explanations as to how/why relative motion occurs between us and the street, one of which has to be correct. We can still define equally valid reference frames which label either as moving, but the three scenarios outlined have deductive consequences.

Morbert wrote: »

I don't mean that. You must always define a reference frame when describing motion. To quote Einstein himself.

"Strictly speaking, one should not, e.g., say that the earth moves around the sun in an ellipse, since this statement presupposes a coordinate system in which the sun is at rest, … In the investigation of the solar system nobody will employ a coordinate system at rest relative to the terrestrial body, since that would be impractical. But in principle such a coordinate system is according to the general theory of relativity fully equivalent to every other system."

I know that's not what you meant, but I'm pretty sure that, when you posted the same thing to me, you knew that that wasn't what I meant either.

You don't need a reference frame when discussing absolute motion, because absolute motion is a statement about the nature of the motion, as opposed to the measurement or qualification of it.

We can define a reference frame which labels the Earth as "in motion relative to the sun", the sun as "in motion relative to the Earth", and both are correct, there is no issue there; but where the sun and the Earth are moving relative to each other, either the sun has to actually be moving, or the Earth does, or both might actually be moving; in which case the instruments - or a light clock at least - of one of the observers will be contracted by an amount unknown to themselves.

Morbert wrote: »

If the answer to "Am I moving [full stop]?" is "no". Are they in a state of absolute rest? Any definition of "absolute motion" which encompasses a state of "absolute rest" or "absolute 0 motion" is not supported by relativity. That is the problem with your understanding of motion.

Did you not mention in the other thread that the state of absolute rest is perfectly compatible with relativity; you can either have it, or not have it?

I think this point, though, indicates a critical issue; the contention is that my "problem with [...] understanding motion" is that what I am saying doesn't agree with relativity, implying that, if it doesn't agree with relativity it can't be right; it almost seems like a conditioned attachment to "what relativity says" is the only way. The conditioning or training seems to be triggered at the first mention of "actually moving" or "absolute motion".

This isn't necessarily a negative thing, it's an entirely natural aspect of the human condition, but it can prevent us from looking at things more objectively. Of course, the same could be said for a belief in presentism, but both would depend on the level of sub-conscious attachment.

The answer to "am I moving [full stop]?" is "I don't know, but I'm either moving [full stop] or I'm not [full stop]."

Again, when you walk down the street and there is relative motion between you and the street, either the street is actively moving, behaving like a giant treadmill or spinning log, or the street is passive while it is you that is actively "doing the moving", or, of course, both could be the case.

All three scenarios have deductive consequences, which affect the path length of a photon in a light clock, and the conclusion that an observers instruments are contracted by an amount unknown to themselves; or at least, that time, for them, is dilated by an amount unknown to themselves.

Actually, this would still preserve the idea of relativity of simultaneity, depending on the assumptions made about the nature of time.

So it has little to do with presentism.

roosh

Morbert wrote: »

Special relativity says you can detect "non-uniform" i.e. accelerated motion. (This is how the twin paradox is solved) So you can detect if the hall accelerates, but you cannot detect, say, its 230 km per second motion of the hall with respect to the centre of the galaxy.

This is somewhat different to a statement about saying which one actually moves.

What does Special Relativity plus the equivalence principle say; does it allow you to say which one "actually moves" i.e. which one is absolutely moving?

Or does it say that we cannot tell which one actually moves, because the hall could be accelerating in a zero gravity region of space, or both you and the hall could be free-falling in a gravity well, and the felt acceleration could just be the hall coming out of free-fall to remain stationary in a gravitational well?

roosh

18AD wrote: »

As an aside: If we stay within the remit of phenomenology (which I'm trying to do) the experience of walking and the ground moving are experientially distinct phenomena. When I walk I am propelling myself, my senses tell me this. When the ground moves I have to adjust my balance, my senses tell me this (but I probably do it automatically). Regardless of experimental verifiability.

Whether either of us is absolutely moving or at rest is beyond the scope of this analysis.

Apologies, I had started replying to the post before you added this part.

I don't think the question of whether either of us is absolutely moving, or at rest, is beyond the scope of the analysis. I would say that we cannot determine which of us (us or the ground) is absolutely moving, but we can deduce that, at least one of us has to be.

As you mention, the experience of us walking and the ground moving are, at the very least, deductively different; I'm not sure if they are necessarily experientially different, because if we take the example of where the earth is always behaving as a treadmill, and you are being carried around with it, then you wouldn't be able to tell the difference; you're walking then would feel like normal walking; however, we can still deduce that they are different.

The question then becomes, what is "absolute motion"; "absolute" as I understand it means something which can be viewed without relation to other things i.e. something that is true, in and of itself. So absolute motion would be a state of motion which cna be viewed without relation to other things.

It would be a simple "yes or no", "either, or" question.

E.g. "Is X moving?" or "Is Y moving?", or "Is X or Y moving?"

On a more personal level it would be the question "Am I moving?", "am I moving, or is it the ground?", or "is our train moving, or is it the other train?".

Boil it down
I think we can boil it down to the following:

A and B start off at rest, relative to each other.

A and B start moving relative to each other.

A labels B as moving relative to A, while B labels A as moving relative to B; which is perfectly valid.

However, in order for relative motion to manifest between A and B, either A had to actually move, or B had to actually move; A and B can be you and the road as outlined above - this represents two different scenarios, with the same result.

However, we cannot determine whether it was A or B that actually moved.

We can deduce that it was either A or B, or both.

18AD

roosh wrote: »

Boil it down
I think we can boil it down to the following:

A and B start off at rest, relative to each other.

A and B start moving relative to each other.

A labels B as moving relative to A, while B labels A as moving relative to B; which is perfectly valid.

However, in order for relative motion to manifest between A and B, either A had to actually move, or B had to actually move; A and B can be you and the road as outlined above - this represents two different scenarios, with the same result.

However, we cannot determine whether it was A or B that actually moved.

We can deduce that it was either A or B, or both.

To look at the experience, yes, one has to actually move. If you are on the train you will only be able to tell either:

Your train has moved. You can't tell if the other one has.
Your train has not moved. You can tell if the other one has.

So if A moves, B is indeterminate.
If not A then B moves.

roosh

18AD wrote: »

To look at the experience, yes, one has to actually move. If you are on the train you will only be able to tell either:

You're train has moved. You can't tell if the other one has.
You're train has not moved. You can tell if the other one has.

So if A moves, B is indeterminate.
If not A then B moves.

I would slightly amend that, to reflect scientific principles, perhaps:

if you are on a train and relative motion arises;

You can't tell if your train has moved
You can't tell if the other train has moved

You can tell that either your train or the other train has moved.

18AD

roosh wrote: »

I would slightly amend that, to reflect scientific principles, perhaps:

if you are on a train and relative motion arises;

You can't tell if your train has moved
You can't tell if the other train has moved

You can tell that either your train or the other train has moved.

Well that makes you a bad phenomenologist. :pac:

Morbert

roosh wrote: »

Ok, I think I see where the issue lies; I'm not sure if I'll be able to illucidate it fully but hopefully, with some patience, on both our parts, I will be.

First, it is necessary to highlight that the implication of a preferred reference frame implied by the statement "John is travelling at 60mph", is not in dispute. I entirely agree that it is possible to define a reference frame which labels John as traveling at 60mph, as it is to define one where he is "at rest", just as one can be defined where his relative motion is that between him and the centre of the galaxy.

What is in dispute is the statement "John is moving", and whether or not this makes sense without reference to a reference frame; the contention is that, without this reference to a reference frame, the statement is a statement about John's absolute motion, precisely because it is a statement about John's motion without reference to a reference frame i.e. it is a statement about his state of motion, not what he is moving relative to.

The intention here isn't to try to find a way to recover presentism from relativity; this is entirely independent of the concept of presentism, and I'm not even sure if this concept of absolute motion will result in the conclusion of presentism. I personally think the universe is presentist, but that isn't something which plays a role in examining the relative motion between two bodies. This is simply a question of trying to develop a more accurate view of the world; this entails developing an understanding of what existing scientific theories say about the world and subjecting them to critical questioning.

The crux
The crux of the issue isn't so much whether there is a preferred reference frame, it's about what logical deductions we can make from about those reference frames. I see no issue with the idea of equally valid reference frames, so long as it is qualified with the idea that an observers instruments might be contracted by an amount unknown to themselves.

It comes down to something which doesn't seem to be illucidated by mathematical reference frames - that an observers instruments are contracted by an amount unknown to themselves is one such issue - to borrow 18ADs term, it comes down to a phenomenological description of the cause of the relative motion between two bodies.

Where there is relative motion between me and the street, either the earth has to be behaving like a giant treadmill, or spinning log as you mentioned elsewhere, or the earth is passive while I am actively "doing the moving", and my walking is propelling me forward.

The Earth can be moving relative to any other object in the universe, and us along with it, but the subsequent relative motion between us and the street has to be accounted for by one, or both, of the scenarios above. This offers three possible explanations as to how/why relative motion occurs between us and the street, one of which has to be correct. We can still define equally valid reference frames which label either as moving, but the three scenarios outlined have deductive consequences.

If I understand this correctly, you are saying the existence of a preferred reference frame (i.e. a reference frame that reflects the "true" motion of an object). The problem is you are begging the question. To reiterate, your line of reasoning is:

1) Two observers are moving, relative to each other.
2) Therefore at least one of the observers must have an absolute velocity, and one of their reference frames, on a metaphysical level, must be incorrect.
3) Therefore absolute velocities exist.

I am saying 2) does not follow from 1) unless you assume 3). You are implicitly assuming the very thing you are trying to show. Instead, relativity only permits us to say

1) Two observers are moving, relative to each other.
2) Therefore there is absolutely motion between the two observers.

To say/deduce anything else requires more assumptions.

Did you not mention in the other thread that the state of absolute rest is perfectly compatible with relativity; you can either have it, or not have it?

I did indeed. Which is why I said "is not supported" rather than "contradicted". You are not merely saying "absolute motion, in the sense of an absolute velocity, may or may not exist". You are saying it can be shown to necessarily exist, based on our current understanding of motion. I am saying our current understanding of motion does not support the notion of an absolute velocity.

I think this point, though, indicates a critical issue; the contention is that my "problem with [...] understanding motion" is that what I am saying doesn't agree with relativity, implying that, if it doesn't agree with relativity it can't be right; it almost seems like a conditioned attachment to "what relativity says" is the only way. The conditioning or training seems to be triggered at the first mention of "actually moving" or "absolute motion".

This isn't necessarily a negative thing, it's an entirely natural aspect of the human condition, but it can prevent us from looking at things more objectively. Of course, the same could be said for a belief in presentism, but both would depend on the level of sub-conscious attachment.

In the other thread, you make the argument that relativity implicitly assumes absolute motion, and I figured you were doing the same thing here. Can I assume you no longer believe relativity says absolute motion, in the sense of absolute velocity, exists?

The answer to "am I moving [full stop]?" is "I don't know, but I'm either moving [full stop] or I'm not [full stop]."

I assume by "moving" you mean absolute motion. If this is the case, "I am not [full stop]" has two interpretations. It means either I have an absolute velocity of 0, or it means absolute velocity, and hence absolute motion, does not exist.

<snipped redundant exchanges>

roosh

Morbert wrote: »

If I understand this correctly, you are saying the existence of a preferred reference frame (i.e. a reference frame that reflects the "true" motion of an object). The problem is you are begging the question. To reiterate, your line of reasoning is:

1) Two observers are moving, relative to each other.
2) Therefore at least one of the observers must have an absolute velocity, and one of their reference frames, on a metaphysical level, must be incorrect.
3) Therefore absolute velocities exist.

I am saying 2) does not follow from 1) unless you assume 3). You are implicitly assuming the very thing you are trying to show. Instead, relativity only permits us to say

1) Two observers are moving, relative to each other.
2) Therefore there is absolutely motion between the two observers.

To say/deduce anything else requires more assumptions.

OK; I think this is probably where the confusion lies. The contention isn't necessarily that there exists a preferred frame of reference, which reflects the true motion of objects. The contention is that we can deduce that at least one of two relatively moving bodies must be in absolute motion.

The existence of an absolute reference frame isn't a necessary assumption, because we are talking about the underlying physical process which the mathemeatical reference frames attempt to describe. We are talking about the nature of motion, as opposed to it's measurement.

The problem probably lies in the historical concept of what "absolute motion" means; it was taken to mean motion relative to an absolute reference frame; but that, of course, would be a contradiction in terms; because what is absolute is not, by definition, relative. So there is no necessity for an absolute reference frame to exist.

"Absolute motion" is a statement about the nature of motion of an object, which is not necessarily a measurable quantity, but it does have deductive consequences. "Absolute motion" is a "yes or no", "either, or" question:
"Is X moving?"
"Is Y moving?"
"Is X or Y moving?"

It is also unqualified statements such as "I am moving" or "I am not moving".

Physical processes
Absolute motion is probably easier to interpret using contextual examples; like the example of the observer walking along the earth. As you mentioned in another thread, the observer cannot determine if it is they that is moving, or if the earth is behaving like a spinning log. Here we have two deductively different scenarios which both account for the relative motion between an observer and the road - actually we have three, where the earth is behaving like a spinning log and the observer is walking at a pace that doesn't exactly offset the rotation of the log.

In all cases, the nature of motion ascribed to each object is different, but all result in the same relative motion. We cannot determine which of the three scenarios is the true one, but we can deduce that one of them has to be, because otherwise there would be no relative motion.

Just to reiterate, absolute motion is not relative i.e. it is not necessarily motion relative to an absolute rest frame, so such an assumption isn't necessary.

Morbert wrote: »

I did indeed. Which is why I said "is not supported" rather than "contradicted". You are not merely saying "absolute motion, in the sense of an absolute velocity, may or may not exist". You are saying it can be shown to necessarily exist, based on our current understanding of motion. I am saying our current understanding of motion does not support the notion of an absolute velocity.

I'm not necessarily saying that there exists an absolute velocity, because that would imply some measurable quantity; and measurement, by its very nature, is relative, not absolute.

I'm not so sure that I would say that absolute motion can be deduced from our current understanding of motion, becaues the idea of "our current understanding of motion" is somewhat vague; what is being said is that based on the observation of relative motion - not necessarily contemporary interpretation of that observation - we can deduce, in general, three different scenarios that can account for the relative motion between bodies; each of these scenarios, necessarily, distinguish between the nature of motion of the bodies involved, that is, they make reference to the motion of the body in a manner that isn't necessarily relative i.e. in an absolute manner.

We cannot determine which of the three scenarios is the true one, but we can deduce that one of them has to be, and therefore that at least one of the bodies must absolutely be in motion.

Morbert wrote: »

In the other thread, you make the argument that relativity implicitly assumes absolute motion, and I figured you were doing the same thing here. Can I assume you no longer believe relativity says absolute motion, in the sense of absolute velocity, exists?

No, I would still maintain that.

Morbert wrote: »

I assume by "moving" you mean absolute motion. If this is the case, "I am not [full stop]" has two interpretations. It means either I have an absolute velocity of 0, or it means absolute velocity, and hence absolute motion, does not exist.

Again though, we can outline three general scenarios to account for the relative motion between two bodies, each of which makes reference to the absolute motion of one or the other bodies i.e. by making a statement about the movement of the body, that isn't necessarily relative. So this determines that absolute motion does exist.

There might be some confusion being caused by the conflation of absolute velocity with absolute motion, where the former referes to a measurable quanity, while the latter refers to the nature of motion, which isn't necessarily measurable.

So, absolute velocity doesn't necessarily exist, because it implies some measurable quantity, and measurement is by nature relative, not absolute. Theoretically, if we could determine an absolute reference frame we could possibly perform a measurement which we could label "absolute velocity", even though it would technically be velocity relative to a body at absolute rest; but we cannot determine whether or not a body is at absolute rest or not.

Absolute rest
The issue of absolute rest is somewhat different, and you would be right in saying that it is possible that an absolute rest frame doesn't exist, but this in itself would have two interpretations; firstly, that mathematically constructed reference frames don't have phyiscal existence; and secondly, that an absolute rest frame doesn't exist because there is no object in the universe that is at absolute rest; that is, everything in the universe is absolutely in motion.

roosh

18AD wrote: »

Well that makes you a bad phenomenologist. :pac:

I should probably have looked up the meaning of the word first

Morbert

roosh wrote: »

OK; I think this is probably where the confusion lies. The contention isn't necessarily that there exists a preferred frame of reference, which reflects the true motion of objects. The contention is that we can deduce that at least one of two relatively moving bodies must be in absolute motion.

The existence of an absolute reference frame isn't a necessary assumption, because we are talking about the underlying physical process which the mathemeatical reference frames attempt to describe. We are talking about the nature of motion, as opposed to it's measurement.

The problem probably lies in the historical concept of what "absolute motion" means; it was taken to mean motion relative to an absolute reference frame; but that, of course, would be a contradiction in terms; because what is absolute is not, by definition, relative. So there is no necessity for an absolute reference frame to exist.

"Absolute motion" is a statement about the nature of motion of an object, which is not necessarily a measurable quantity, but it does have deductive consequences. "Absolute motion" is a "yes or no", "either, or" question:
"Is X moving?"
"Is Y moving?"
"Is X or Y moving?"

It is also unqualified statements such as "I am moving" or "I am not moving".

Physical processes
Absolute motion is probably easier to interpret using contextual examples; like the example of the observer walking along the earth. As you mentioned in another thread, the observer cannot determine if it is they that is moving, or if the earth is behaving like a spinning log. Here we have two deductively different scenarios which both account for the relative motion between an observer and the road - actually we have three, where the earth is behaving like a spinning log and the observer is walking at a pace that doesn't exactly offset the rotation of the log.

In all cases, the nature of motion ascribed to each object is different, but all result in the same relative motion. We cannot determine which of the three scenarios is the true one, but we can deduce that one of them has to be, because otherwise there would be no relative motion.

Just to reiterate, absolute motion is not relative i.e. it is not necessarily motion relative to an absolute rest frame, so such an assumption isn't necessary.

I'm not necessarily saying that there exists an absolute velocity, because that would imply some measurable quantity; and measurement, by its very nature, is relative, not absolute.

I'm not so sure that I would say that absolute motion can be deduced from our current understanding of motion, becaues the idea of "our current understanding of motion" is somewhat vague; what is being said is that based on the observation of relative motion - not necessarily contemporary interpretation of that observation - we can deduce, in general, three different scenarios that can account for the relative motion between bodies; each of these scenarios, necessarily, distinguish between the nature of motion of the bodies involved, that is, they make reference to the motion of the body in a manner that isn't necessarily relative i.e. in an absolute manner.

We cannot determine which of the three scenarios is the true one, but we can deduce that one of them has to be, and therefore that at least one of the bodies must absolutely be in motion.

No, I would still maintain that.

Again though, we can outline three general scenarios to account for the relative motion between two bodies, each of which makes reference to the absolute motion of one or the other bodies i.e. by making a statement about the movement of the body, that isn't necessarily relative. So this determines that absolute motion does exist.

There might be some confusion being caused by the conflation of absolute velocity with absolute motion, where the former referes to a measurable quanity, while the latter refers to the nature of motion, which isn't necessarily measurable.

So, absolute velocity doesn't necessarily exist, because it implies some measurable quantity, and measurement is by nature relative, not absolute. Theoretically, if we could determine an absolute reference frame we could possibly perform a measurement which we could label "absolute velocity", even though it would technically be velocity relative to a body at absolute rest; but we cannot determine whether or not a body is at absolute rest or not.

Absolute rest
The issue of absolute rest is somewhat different, and you would be right in saying that it is possible that an absolute rest frame doesn't exist, but this in itself would have two interpretations; firstly, that mathematically constructed reference frames don't have phyiscal existence; and secondly, that an absolute rest frame doesn't exist because there is no object in the universe that is at absolute rest; that is, everything in the universe is absolutely in motion.

This thread is beginning to repeat what has already been said in the other thread. My response to this would be the same as my response here.

Namely, the motion of an object is reference frame dependent. If two objects are in motion with respect to each other, then there is no reference frame that labels both as at rest (Though each has a reference frame where they are at rest, as you acknowledge in your post above). This does not establish any form of "intrinsic" motion independent of reference frames.

To put it another way:

roosh wrote:

In all cases, the nature of motion ascribed to each object is different, but all result in the same relative motion. We cannot determine which of the three scenarios is the true one, but we can deduce that one of them has to be, because otherwise there would be no relative motion.

Relativity says all three scenarios are true.

roosh

Morbert wrote: »

This thread is beginning to repeat what has already been said in the other thread. My response to this would be the same as my response here.

Namely, the motion of an object is reference frame dependent. If two objects are in motion with respect to each other, then there is no reference frame that labels both as at rest (Though each has a reference frame where they are at rest, as you acknowledge in your post above). This does not establish any form of "intrinsic" motion independent of reference frames.

Indeed, we are repeating ourselves, and the point raised above has been addressed several times in this thread alone. The measurement of relative motion is frame dependent; the nature of motion isn't.

When you talk about motion being frame dependent, you are talking about relative motion, not absolute motion; absolute motion pertains to the nature of motion of an object, and isn't necessarily a measurable quantity, and hence doesn't require a reference frame to define it. As said before, it is a "yes or no", "either, or" question.

The observation of relative motion, as opposed to the measurement of relative velocity, allows us to determine three physically distinct scenarios which all ascribe the nature of motion to the relatively moving objects, in deductively different ways.

In each scenario, the implication is that the "intrinsic" motion of each object is different from the other scenarios.

Morbert wrote: »

To put it another way:

Relativity says all three scenarios are true.

The three scenarios are physically different, with different deductive consequences; they can't all be simultaneously true.

Morbert

roosh wrote: »

Indeed, we are repeating ourselves, and the point raised above has been addressed several times in this thread alone. The measurement of relative motion is frame dependent; the nature of motion isn't.

And as I have responded, the nature of motion that is absolute is the relation between objects that persist in all reference frames, and not some notion of intrinsic absolute velocity.

When you talk about motion being frame dependent, you are talking about relative motion, not absolute motion; absolute motion pertains to the nature of motion of an object, and isn't necessarily a measurable quantity, and hence doesn't require a reference frame to define it. As said before, it is a "yes or no", "either, or" question.

"Am I moving?" Is frame-dependent. What ever frame-independent questions you can construct, that question will always be frame-dependent.

The observation of relative motion, as opposed to the measurement of relative velocity, allows us to determine three physically distinct scenarios which all ascribe the nature of motion to the relatively moving objects, in deductively different ways.

In each scenario, the implication is that the "intrinsic" motion of each object is different from the other scenarios.

The three scenarios are physically different, with different deductive consequences; they can't all be simultaneously true.

These scenarios are physically identical. That is the entire revelation of relativity: The physical indistinguishability of reference frames. Perhaps you mean metaphysically distinct. Again, this is only true if you tacitly assume frame-dependent statements are actually "absolute" statements.

roosh

Morbert wrote: »

And as I have responded, the nature of motion that is absolute is the relation between objects that persist in all reference frames, and not some notion of intrinsic absolute velocity.

The problem is you are conflating absolute statements, about the relative motion between two objects, with statements about the absolute nature of motion of an object.

"I am moving relative to X" is an absolute statement about the relative motion between two objects; while, "I am moving" is an absolute statement about the intrinsic motion of an object.

Morbert wrote: »

"Am I moving?" Is frame-dependent. What ever frame-independent questions you can construct, that question will always be frame-dependent.

We can see how the question "Am I moving?" pertains to the intrinsic motion of an object, by considering the example of the two trains at rest, relative to each other in a train station, when the trains start moving relative to each other.

The question "am I, or is our train, moving; or is it the other train that is moving?" clearly pertains to a question of absolute motion; the reason being, there is absolute no doubt whatsoever about the fact that both trains are moving relative to each other, nor is there any doubt that the observer is at rest relative to their train.

The question is asking, which train is actually moving i.e. the intrinsic motion of which train changes?

Morbert wrote: »

These scenarios are physically identical. That is the entire revelation of relativity: The physical indistinguishability of reference frames. Perhaps you mean metaphysically distinct. Again, this is only true if you tacitly assume frame-dependent statements are actually "absolute" statements.

I think you might mean that they are mathematically identical, which of course doesn't mean that they are physically identical. I am talking about physical scenarios, which are deductively different from each other. I'm not sure which term best applies, but whatever it is, I'm talking about the physical world, not mathematical reference frames.

Donnielighto

Light moves in absolute terms under certain conditions and can be used as reference for everything else. Stuff moves in relative terms but also in absolute terms, it just takes more effort ti figure out the numbers.

Morbert

roosh wrote: »

The problem is you are conflating absolute statements, about the relative motion between two objects, with statements about the absolute nature of motion of an object.

I have been saying that such a conflation is the problem. I.e. You have been showing that it is logically true that one object must be moving relative to the other. You have been arguing for absolute statements about relative motion. But you then confuse absolute statements about relative motion with statements about "absolute motion".

"I am moving relative to X" is an absolute statement about the relative motion between two objects; while, "I am moving" is an absolute statement about the intrinsic motion of an object.

And you must show that intrinsic motion is a logical necessity. I am saying it is not a logical necessity. We are perfectly consistent in stating that absolute motion, in the sense of "I am moving" is meaningless, and only "I am moving, relative to X" is needed.

We can see how the question "Am I moving?" pertains to the intrinsic motion of an object, by considering the example of the two trains at rest, relative to each other in a train station, when the trains start moving relative to each other.

The question "am I, or is our train, moving; or is it the other train that is moving?" clearly pertains to a question of absolute motion; the reason being, there is absolute no doubt whatsoever about the fact that both trains are moving relative to each other, nor is there any doubt that the observer is at rest relative to their train.

"My train is moving." and "The other train is moving." are both correct answers, provided the appropriate frame is referenced. You are saying one must be less correct, due to intrinsic motion, but you have not established intrinsic motion.

I think you might mean that they are mathematically identical, which of course doesn't mean that they are physically identical. I am talking about physical scenarios, which are deductively different from each other. I'm not sure which term best applies, but whatever it is, I'm talking about the physical world, not mathematical reference frames.

They are mathematically different. They are physically identical. If they were not, we could tell them apart by looking at their physics. You yourself have acknowledged this point.

roosh

Morbert wrote: »

I have been saying that such a conflation is the problem. I.e. You have been showing that it is logically true that one object must be moving relative to the other. You have been arguing for absolute statements about relative motion. But you then confuse absolute statements about relative motion with statements about "absolute motion".

Indeed it is the probelm.

You are conflating an absolute statement about the relative motion between objects - "I am moving relative to X" - with a statement about the absolute nature of motion, of an object - "I am moving".

"I am moving" is a statement distinct from "I am moving relative to X"; and it is a statement about the absolute nature of motion, precisely because it doesn't relate the motion to anything else; it is a statement about the intrinsic motion of an object.

3 scenarios
The three scenarios outlined, are three distinct cases, where the intrinsic motion of the objects is ascribed differently; in each scenario, the object that is "doing the moving" is different, and hence, the statement about the absolute nature of motion, in each case is different i.e. "I am moving" doesn't apply to all three scenarios, it only applies to two.

On the other hand, the absolute statement about the relative motion of the objects applies in all three cases.

Morbert wrote: »

And you must show that intrinsic motion is a logical necessity. I am saying it is not a logical necessity. We are perfectly consistent in stating that absolute motion, in the sense of "I am moving" is meaningless, and only "I am moving, relative to X" is needed.

This is precisely what the three scenarios do; they provide the three distinct scenarios that can account for the relative motion; each one is deductively different, and each one carries different implications about the absolute nature of motion of the objects involved.

While we cannot determine which of the three scenarios are true, it is a logical necessity that one of them must be, otherwise there would be no relative motion to account for.

The logical necessity of one of the scenarios means we can deduce that the nature of motion must be absolute, or that the objects must have some intrinsic motion.

Morbert wrote: »

"My train is moving." and "The other train is moving." are both correct answers, provided the appropriate frame is referenced. You are saying one must be less correct, due to intrinsic motion, but you have not established intrinsic motion.

Again, the logical necessity of one of the three scenarios, to account for the observation of relative motion, establishes intrinsic motion; because one of them has to be correct.

But, "my train is moving" is a statement about the intrinsic motion of the train, because it doesn't make reference to any relatively moving object. The same applies for the statement "the other train is moving". They don't require a reference frame to define the movement, because they are statements about what object is "doing the moving".

You are saying that "my train is moving" and "the other train is moving" are both correct answers, provided the appropriate frame is referenced; what this is effectively saying is that "my train is moving relative to the other train" - appropriate frame is referenced - and "the other train is moving relative to my train" - appropriate frame is referenced; this of course is true, but these are absolute statements about the relative motion of two objects.

You are effectively just repeating what has been said before, that "I am moving" is not a valid statement without saying "relative to X"; but this is conflating absolute statements about relative motion with statements about the absolute nature of motion of an object - of which, "I am moving" is one.

Again, the three scenarios distinguish between the intrinsic motion of the objects, and by logical necessity, one of the three scenarios must be true, because otherwise there would be no relative motion.

Morbert wrote: »

They are mathematically different. They are physically identical. If they were not, we could tell them apart by looking at their physics. You yourself have acknowledged this point.

I think this is where the confusion lies; the erroneous conclusion that all three must be the same, because we cannot distinguish between them by means of a scientific experiment; I think this more highlights the limitation of experiments in determining absolute properties, than it does anything about the absolute nature of objects.

Of course, while we may not be able to distinguish between them experimentally, we can deduce that they each carry different logical implications; and thus, we can determine that they must be physically different.

Essentially, it is a question of, is there a physical difference between walking on a treadmill and walking down the road?

Morbert

roosh wrote: »

Indeed it is the probelm.

You are conflating an absolute statement about the relative motion between objects - "I am moving relative to X" - with a statement about the absolute nature of motion, of an object - "I am moving".

"I am moving" is a statement distinct from "I am moving relative to X"; and it is a statement about the absolute nature of motion, precisely because it doesn't relate the motion to anything else; it is a statement about the intrinsic motion of an object.

3 scenarios
The three scenarios outlined, are three distinct cases, where the intrinsic motion of the objects is ascribed differently; in each scenario, the object that is "doing the moving" is different, and hence, the statement about the absolute nature of motion, in each case is different i.e. "I am moving" doesn't apply to all three scenarios, it only applies to two.

On the other hand, the absolute statement about the relative motion of the objects applies in all three cases.

This is precisely what the three scenarios do; they provide the three distinct scenarios that can account for the relative motion; each one is deductively different, and each one carries different implications about the absolute nature of motion of the objects involved.

While we cannot determine which of the three scenarios are true, it is a logical necessity that one of them must be, otherwise there would be no relative motion to account for.

The logical necessity of one of the scenarios means we can deduce that the nature of motion must be absolute, or that the objects must have some intrinsic motion.

Again, the logical necessity of one of the three scenarios, to account for the observation of relative motion, establishes intrinsic motion; because one of them has to be correct.

But, "my train is moving" is a statement about the intrinsic motion of the train, because it doesn't make reference to any relatively moving object. The same applies for the statement "the other train is moving". They don't require a reference frame to define the movement, because they are statements about what object is "doing the moving".

Again, the three scenarios distinguish between the intrinsic motion of the objects, and by logical necessity, one of the three scenarios must be true, because otherwise there would be no relative motion.

You are implicitly assuming intrinsic motion to argue that the three scenarios are different. You are then arguing that intrinsic motion is a logical necessity because the three scenarios are different. This is circular reasoning.

Relativity says the three scenarios are just different ways of labelling the same scenario.

You are saying that "my train is moving" and "the other train is moving" are both correct answers, provided the appropriate frame is referenced; what this is effectively saying is that "my train is moving relative to the other train" - appropriate frame is referenced - and "the other train is moving relative to my train" - appropriate frame is referenced; this of course is true, but these are absolute statements about the relative motion of two objects.

You are effectively just repeating what has been said before, that "I am moving" is not a valid statement without saying "relative to X"; but this is conflating absolute statements about relative motion with statements about the absolute nature of motion of an object - of which, "I am moving" is one.

I am not conflating anything. I have been very precise about what I mean. "I am moving, relative to X." is an absolute statement. "I have an absolute velocity/intrinsic motion." is a metaphysical statement, an untestable assumption, and in no way logically necessary.

I think this is where the confusion lies; the erroneous conclusion that all three must be the same, because we cannot distinguish between them by means of a scientific experiment; I think this more highlights the limitation of experiments in determining absolute properties, than it does anything about the absolute nature of objects.

Of course, while we may not be able to distinguish between them experimentally, we can deduce that they each carry different logical implications; and thus, we can determine that they must be physically different.

That intrinsic motion exists a priori in nature is an assumption that is in no way supported by relativity. Again, you must show that intrinsic motion is a logical necessity. So far, all you have shown is absolute statements about relative motion can be made.

Essentially, it is a question of, is there a physical difference between walking on a treadmill and walking down the road?[/QUOTE]

Morbert

roosh wrote: »

Indeed it is the probelm.

You are conflating an absolute statement about the relative motion between objects - "I am moving relative to X" - with a statement about the absolute nature of motion, of an object - "I am moving".

"I am moving" is a statement distinct from "I am moving relative to X"; and it is a statement about the absolute nature of motion, precisely because it doesn't relate the motion to anything else; it is a statement about the intrinsic motion of an object.

3 scenarios
The three scenarios outlined, are three distinct cases, where the intrinsic motion of the objects is ascribed differently; in each scenario, the object that is "doing the moving" is different, and hence, the statement about the absolute nature of motion, in each case is different i.e. "I am moving" doesn't apply to all three scenarios, it only applies to two.

On the other hand, the absolute statement about the relative motion of the objects applies in all three cases.

This is precisely what the three scenarios do; they provide the three distinct scenarios that can account for the relative motion; each one is deductively different, and each one carries different implications about the absolute nature of motion of the objects involved.

While we cannot determine which of the three scenarios are true, it is a logical necessity that one of them must be, otherwise there would be no relative motion to account for.

The logical necessity of one of the scenarios means we can deduce that the nature of motion must be absolute, or that the objects must have some intrinsic motion.

Again, the logical necessity of one of the three scenarios, to account for the observation of relative motion, establishes intrinsic motion; because one of them has to be correct.

But, "my train is moving" is a statement about the intrinsic motion of the train, because it doesn't make reference to any relatively moving object. The same applies for the statement "the other train is moving". They don't require a reference frame to define the movement, because they are statements about what object is "doing the moving".

Again, the three scenarios distinguish between the intrinsic motion of the objects, and by logical necessity, one of the three scenarios must be true, because otherwise there would be no relative motion.

You are saying that "my train is moving" and "the other train is moving" are both correct answers, provided the appropriate frame is referenced; what this is effectively saying is that "my train is moving relative to the other train" - appropriate frame is referenced - and "the other train is moving relative to my train" - appropriate frame is referenced; this of course is true, but these are absolute statements about the relative motion of two objects.

You are effectively just repeating what has been said before, that "I am moving" is not a valid statement without saying "relative to X"; but this is conflating absolute statements about relative motion with statements about the absolute nature of motion of an object - of which, "I am moving" is one.

I think this is where the confusion lies; the erroneous conclusion that all three must be the same, because we cannot distinguish between them by means of a scientific experiment; I think this more highlights the limitation of experiments in determining absolute properties, than it does anything about the absolute nature of objects.

Of course, while we may not be able to distinguish between them experimentally, we can deduce that they each carry different logical implications; and thus, we can determine that they must be physically different.

That intrinsic motion exists a priori in nature is an assumption that is in no way supported by relativity, nor is it a logical consequence of relativity. Again, you must show that intrinsic motion is a logical necessity. So far, all you have shown is absolute statements about relative motion can be made.