Your distinction between "physical time" and "metaphysical time", upon which you base your claim that special relativity makes no metaphysical claims, is nonsense. The thing measured, "time" is the very same whether you're a physicist or a metaphysician.

Very well then. Your metaphysical view of time is in direct conflict with TOR then. Your theory makes empirical predictions that have been falsified.

I didn't think it did, but you seem to insist.

I don't know what you're talking about. All I have said is that special relativity is metaphysical. If this is my "metaphysical view of time", then perhaps my interpretation of the special theory of relativity is in direct conflict with your interpretation. But that's the thing with metaphysical theories, the same metaphysical theory is open to different interpretations.

Your theory makes empirical predictions that have been falsified. — noAxioms

My theory that special relativity is metaphysical entails which empirical predictions that have been falsified?

Why not? We travel forward in time, obviously, and that makes perfect sense. We also can orient and move in space in any directions, and space is just as "abstract" as time, isn't it? — SophistiCat

On a certain view of time, the present is all that exists. Time is simply the world undergoing change. As such, it would be impossible to construct a wormhole or whatever to jump to a previous or future point in time, since neither exists. I believe this is a version of the A-series notion of time, or presentism. I don't know how that's made consistent with Relativity, but I guess some of the concepts of spacetime in GR are rejected (replaced by presentist concepts), although not the experimental results.

HG Wells The Time Machine could not be written under a presentist view of time. A machine can't be traveling from the future to kill Sarah Conner or her son, and there is no parallel timeline/universe for Donnie Darko to save his family from the end of the world (or whatever he was doing).

I don't know how that's made consistent with Relativity, but I guess some of the concepts of spacetime in GR are rejected (replaced by presentist concepts), although not the experimental results. — Marchesk

It's easy to make it consistent with relativity theory, though it has its costs. One could simply define a foliation of spacetime as being the preferred one, or argue that one of the many foliations out there is the objective one. Empirically the worldview would be equivalent to both SR and GR so it would be like an alternative interpretation ala the interpretations of QM. The problem? There are too many foliations to choose from and we have no way of determining which one is correct without arbitrarily saying so, but this is not an insurmountable problem if one's motivations are strong enough. However, speaking of time travel, such a move would certainly not work if we are talking about spacetimes with time travel, like in Godelian Spacetimes with closed-timelike curves.

HG Wells The Time Machine could not be written under a presentist view of time. A machine can't be traveling from the future to kill Sarah Conner or her son, and there is no parallel timeline/universe for Donnie Darko to save his family from the end of the world (or whatever he was doing). — Marchesk

Haven't read the Time Machine, but I do believe that there can be some forms of time travel that are consistent with presentism. If we were to take time travel as a process of reversing the universe's history while the time traveller stays within a bubble for instance, in a manner similar to rewinding a cassette tape, then everything stays within a single 3D universe and we can visit 1850 and kill our ancestors without problem.

If we were to take time travel as a process of reversing the universe's history while the time traveller stays within a bubble for instance, in a manner similar to rewinding a cassette tape, then everything stays within a single 3D universe and we can visit 1850 and kill out ancestors without problem. — Mr Bee

I guess, if there was a mechanism for rewinding* the universe. One could be invented for a story. Surely there must be some stories out there with this. I can only recall stories about visiting existent future or past points in time, or parallel timelines. The ones involving the same timeline often allow changes from the past to ripple forward to the present (or future) somehow. Star Trek time travel was portrayed that way.

* Actually, Thanos and Dr. Strange did the rewinding events thing in the Marvel movies. It was on a local scale, though. But that would support presentism in those stories, except I think the comics have the other forms of time travel as well.

Anyway, the point of these time travel stories is that we can make a meaningful distinction between the different notions of time, and if physics/technology allowed us to, we could time travel in a similar fashion, depending on which view of time is true.

As you don't seem to understand, let me explain why the special theory of relativity is metaphysical. Einstein took the existing theory of relativity, which was a metaphysical theory concerning motions, and adapted it to be applicable to the motion of light. The classical theory of relativity stated that all motions are relative, and this is a metaphysical principle which denies the possibility of absolute rest. In Einstein's day, there was a problem in applying this principle to the motion of light. Classical relativity theory did not appear to hold in relation to the motion of light. According to classical relativity theory, the speed of light relative to various objects moving in relation to each other would have to be variable according to the various different motions of the objects. So, Einstein proposed that the classical theory of relativity be adapted such that the speed of light be understood as constant relative to the various moving objects. This is "the special theory of relativity".

So, the classical theory of relativity, which was a metaphysical theory excluding the possibility of absolute rest, was seen to be incompatible with the motion of light. Instead of rejecting relativity as wrong, which is what the observations of the relations between the motions of light, and physical bodies did, it proved classical relativity to be wrong, Einstein proposed adapting relativity theory to allow that the speed of light remains constant relative to moving bodies. Prior to classical relativity, absolute rest, was the metaphysical principle employed. Classical relativity was proven wrong by the motion of light. Instead of returning to absolute rest as the metaphysical principle, it was replaced with the speed of light, as the assumed constant. Since these are each different fundamental ontological assumptions, absolute rest, and the constancy of the speed of light, which are taken for granted, depending on which one assumes, each is a metaphysical principle.

As you don't seem to understand, let me explain why the special theory of relativity is metaphysical. Einstein took the existing theory of relativity, which was a metaphysical theory concerning motions, and adapted it to be applicable to the motion of light. The classical theory of relativity stated that all motions are relative, and this is a metaphysical principle which denies the possibility of absolute rest. — Metaphysician Undercover

A principle yes, more than a theory, and a local one at that. You putting a label of 'metaphysical' on everything doesn't make it thus.

In Einstein's day, there was a problem in applying this principle to the motion of light. Classical relativity theory did not appear to hold in relation to the motion of light. According to classical relativity theory, the speed of light relative to various objects moving in relation to each other would have to be variable according to the various different motions of the objects. So, Einstein proposed that the classical theory of relativity be adapted such that the speed of light be understood as constant relative to the various moving objects. This is "the special theory of relativity".

I think I object to 'be understood as'. SR was born of empirical evidence of constant local speed measurement, not an adjustment of understanding about it. The theory was a reaction to that evidence that did not fit current models. All of SR follows from constant light speed.

So, the classical theory of relativity, which was a metaphysical theory excluding the possibility of absolute rest, was seen to be incompatible with the motion of light.

The principle says the laws are the same in any frame, and thus no test can be devised to determine absolute rest. It never asserted the impossibility of it. There are always exceptions. Speed of sound in a particular medium is relativistic, but only locally. I can talk to the person ahead of me in a supersonic jet, but I cannot hear the aircraft behind us. Sound has a medium, and light was initially supposed to have one. SR threw that out, and GR sort of brought it back.

Instead of rejecting relativity as wrong, which is what the observations of the relations between the motions of light, and physical bodies did, it proved classical relativity to be wrong, Einstein proposed adapting relativity theory to allow that the speed of light remains constant relative to moving bodies.

Well, relative to stationary bodies. Light does not travel at c relative to a body that is moving in a given frame.

Prior to classical relativity, absolute rest, was the metaphysical principle employed. Classical relativity was proven wrong by the motion of light. Instead of returning to absolute rest as the metaphysical principle, it was replaced with the speed of light, as the assumed constant. Since these are each different fundamental ontological assumptions, absolute rest, and the constancy of the speed of light, which are taken for granted, depending on which one assumes, each is a metaphysical principle.

I disagree that there is any ontology asserted one way or another by any theories. Constant light speed is an observation, not an assumption, and GR shows that speed of something is undefined if not local, so light has speed different than c when not local, and depending on how speed is defined. Those definitions might indeed be metaphysics, but GR doesn't depend on them.

You asserted that metaphysical time is the same as physical time. The latter is that which is measured by clocks, but since clocks in relative motion do not measure the same value, they are not measuring metaphysical time (the actual age of the universe, a concept denied by spacetime metaphysical model). There is no device that can measure that. Best one can do is assume an objective foliation as perhaps suggested by GR and use that, but one still cannot express the unitless rate of it. If the universe suddenly aged at half the pace it did before, nothing physical could detect that change. That's why metaphysical time and physical time are not the same.

I think I object to 'be understood as'. SR was born of empirical evidence of constant local speed measurement, not an adjustment of understanding about it. The theory was a reaction to that evidence that did not fit current models. All of SR follows from constant light speed. — noAxioms

It is exactly this "constant local speed measurement" which makes SR a ,metaphysical assumption rather than empirically proven. It has only been empirically proven In "local speed" which is a very small portion of all possible speeds, yet it is claimed as a constant for all speeds.

Constant light speed is an observation, not an assumption... — noAxioms

The human capacity for observations of this is very limited. A large percentage of the various existing situations are not directly observable by a human being, and that light speed remains constant in these situations, is an assumption which is not empirically proven.

You asserted that metaphysical time is the same as physical time. The latter is that which is measured by clocks, but since clocks in relative motion do not measure the same value, they are not measuring metaphysical time (the actual age of the universe, a concept denied by spacetime metaphysical model). — noAxioms

I don't see how you draw this conclusion. The "actual age of the universe" does not equate to "metaphysical time". Metaphysical time is the passing of time as we experience it, and this is what clocks measure. If clocks in relative motion do not measure time in the same way, then I suggest that people in relative motion do not experience time in the same way. So there is no difference between metaphysical time and physical time. The claimed "actual age of the universe" is calculated from principles and models. If the models are wrong, then so is the "actual age of the universe".

If the universe suddenly aged at half the pace it did before, nothing physical could detect that change. That's why metaphysical time and physical time are not the same. — noAxioms

This is meaningless nonsense. The "aging of the universe", as I described, is calculated from principles and models. It's nonsense to suggest that the universe could age at a pace different than that represented by the models, unless you are proposing that the models are wrong. Then it's not the case that nothing physical could represent that change, it is simply the case that the models don't properly represent that change. This is not due to the change itself being undetectable, it is due to a lacking in the capacities of the human beings, to understand and model the physical universe.

Relativistic mass is rarely discussed in the same breath as space-time, even though it is 1/3 of Special Relativity. The result is a 2-D illusion called relative reference and/or no preferred reference.

The way to demonstrate this is to have two references, each with a different mass; M and 2M, with a relative velocity V. If reference was relative and neither reference is preferred, and each references assumes the other has all the motion, than each will predict a different total system kinetic energy; 1/2MV2, and a different system momentum MV. One reference will be twice the energy of the other. Both cannot be true at the same time and maintain energy conservation. One of the relative references is creating or taking away energy.

The twin paradox tries to disguise this by using twins. Twins have the same mass, therefore kinetic energy and momentum will be the same for both references. This is how the system was gamed. If you use different masses, the energy conservation problem appears when you assume relative references and no preferred reference.

We can easily measure energy and we can see red/blue shifts in energy with standard tools. However, we can't measure mass or relativistic mass, directly. We have to infer rest mass from changes in energy; GR, with energy a relationship in distance and time, but not in mass.

Consider the classic example of someone on a train looking out the window at someone standing at the train station. They see each other moving with a relative velocity V. They both see relativistic changes in distance and time. If the mass of the train and the mass of the train station are not the same, and we know how much energy; diesel fuel, was used to achieve this system motion, then you can infer who has to be moving and who has to be stationary. It is no longer relative but an absolute hierarchy appears.

Dark energy and dark matter can be explain as an artifact of the relative reference illusion. If we assume no preferred reference, in a system with different masses in each reference, and if we assume the wrong reference as the baseline for observation, this can add or take away energy from the universe. The violation of energy conservation will eventually appear as anomalies, with something needing to be added to close the energy balance.

A person on a train, looking out the window will appear to see the landscape moving at velocity V, If they assume they are stationary; train is stopped. It looks this way to the eyes but they just added energy to the universe, since the landscape what more mass. However, other observations will not support this, so they may need to add invisible negative energy to close the energy balance. Using 2 out 3 variables in SR is metaphysics.

Why not? We travel forward in time, obviously, and that makes perfect sense. We also can orient and move in space in any directions, and space is just as "abstract" as time, isn't it? The question of why we cannot (easily) travel backwards in time both makes sense to ask and not trivial to answer. — SophistiCat

Interesting thought.

What does it mean actually, to travel backwards in time?

I think our sense of time is stuck to space, as we commonly understand it.

Our conception of time standing still or stopping is when all physical change ceases - like when we pause a movie. Am I wrong?

If I'm correct then traveling backwards in time would mean to revert all phsyical change to a state that once occured.

If so, then I can easily travel backwards in time. Take a room as an example. On Sunday all objects in it are at a particular position. As the days pass the objects get moved to different locations and we ''move'' through time. On Saturday I put all objects back to their original positions, as they were on Sunday. Now, I can't distinguish the room on Sunday from the room on Saturday. For all practical purposes, as far as the room is concerned, Sunday = Saturday. Have I traveled back in time? Or is our notion of time in error?

What do you think?

It is exactly this "constant local speed measurement" which makes SR a ,metaphysical assumption rather than empirically proven. It has only been empirically proven In "local speed" which is a very small portion of all possible speeds, yet it is claimed as a constant for all speeds. — Metaphysician Undercover

There is no 'local speed'. Local means 'inside a limited size box', like one drawn around the galaxy. They've tested small clocks moving at .98c and higher, just so you know.

Your post seems to attempt to throw doubt on SR, like it does indeed threaten your position. Interesting that you feel the need to attack it when you say it is a metaphysical theory.

The human capacity for observations of this is very limited. A large percentage of the various existing situations are not directly observable by a human being, and that light speed remains constant in these situations, is an assumption which is not empirically proven.

Again an attack, and dragging 'human' into it. You think light speed is different for humans than for other things?

Metaphysical time is the passing of time as we experience it, and this is what clocks measure.

Thing is, if time did not flow at all, we'd experience it exactly the same way. So what we are experiencing is not the metaphysical flow rate. You experience physical time, the same thing clocks measure. Your interpretation of that as flow is indeed a metaphysical interpretation, but relativity theory renders no opinion on which interpretation is correct. You seem to think otherwise as you seem to feel the need to cast it into doubt in your above posts, like there is empirical evidence against your view.

If clocks in relative motion do not measure time in the same way, then I suggest that people in relative motion do not experience time in the same way.

They both measure/experience physical time, and in the same way. Principle of relativity says you can't notice the dilation, but you would if you were experiencing a century of flow in only 10 years of high absolute speed travel. Indeed, nobody has tested this. It assumes that experience is a physical process, and you suggest it is a metaphysical process, that humans are metaphysically different than the rest of matter. Even your presentism doesn't assert this, but you seem to feel the need to add this to it. Yes, SR then would be a threat to your position.

So there is no difference between metaphysical time and physical time. The claimed "actual age of the universe" is calculated from principles and models. If the models are wrong, then so is the "actual age of the universe".

I'm not talking about the age of the universe from a point of view. I'm talking about the objective age of it, which doesn't exist except in some metaphysical views, my own not included.

Your problem is that you understand only one metaphysical interpretation and process all my comments with only that interpretation in mind, so you can't separate the parts that are different between the various metaphysical views. Einstein's work is compatible with both of them, and is thus not disproving one view or the other, but you don't see that because you don't see which parts are metaphysical differences. This would be easy if you understood the alternate view like Minkowski spacetime, the very concept that is the subject of this forum topic. That is a metaphysical view, and one that renders the relativity equations so much simpler, but relativity also works in a 3D model (at a massive expense of complexity) so doesn't assert those metaphyiscs. If it did, then yes, you are correct to attack relativity because it would indeed disprove your position. This is why I said that you have been empirically falsified when you said physical time is the same as metaphysical time.

Relativistic mass is rarely discussed in the same breath as space-time, even though it is 1/3 of Special Relativity. The result is a 2-D illusion called relative reference and/or no preferred reference. — wellwisher

I think I replied to most of this in my post 4 days ago.

The twin paradox tries to disguise this by using twins. Twins have the same mass, therefore kinetic energy and momentum will be the same for both references. This is how the system was gamed. If you use different masses, the energy conservation problem appears when you assume relative references and no preferred reference.

There is no suggested energy conservation in the hypothetical experiment. We have a rocket blasting energy and momentum all over the place. Are you attempting to deny the twin experiment? It is hard to tell, but you say 'how the system was gamed' like the description is faulty in some way.

However, we can't measure mass or relativistic mass, directly.
We have to infer rest mass from changes in energy; GR, with energy a relationship in distance and time, but not in mass.

Relativistic mass is a relational concept, not a property. Rest-mass is a property and can be directly measured. Not sure what you consider 'mass' to be if different from both rest mass and relativistic mass.

If the mass of the train and the mass of the train station are not the same, and we know how much energy; diesel fuel, was used to achieve this system motion, then you can infer who has to be moving and who has to be stationary.

No. This is just wrong. Mass comes not into play with the concepts being illustrated with this example. "Bigger-thing is the stationary one". Relativity does not support that.

A person on a train, looking out the window will appear to see the landscape moving at velocity V, If they assume they are stationary; train is stopped. It looks this way to the eyes but they just added energy to the universe, since the landscape what more mass.

They did not add kinetic energy to the universe. It was always there. The landscape/universe was always moving at V in that frame.

That is a metaphysical view, and one that renders the relativity equations so much simpler, but relativity also works in a 3D model (at a massive expense of complexity) so doesn't assert those metaphyiscs. — noAxioms

To be clear, both the 3D and 4D interpretation use the same mathematical equations, so one approach mathematically isn't any more or less complex than the other. In other words, physicists will calculate the same results in the same way regardless of their metaphysical views. This is why they are empirically equivalent to one another, since the only difference lies in the interpretation and not in the equations themselves.

To be clear, both the 3D and 4D interpretation use the same mathematical equations, so one approach mathematically isn't any more or less complex than the other. — Mr Bee

Well, those equations describe a 4D model, even if a 3D interpretation is assumed. To do it in 3D, each experiment must adjust for inaccuracies of measured mass, length and time since all these are dilated if one is moving. The train thought experiments assume a non-absolute definition of space, which is incorrect in the 3D model. Incorrect conclusions of event simultaneity are drawn.

Well, those equations describe a 4D model, even if a 3D interpretation is assumed. — noAxioms

The equations are the equations. Whether they describe a 4D or 3D world is what is up to interpretation.

To do it in 3D, each experiment must adjust for inaccuracies of measured mass, length and time since all these are dilated if one is moving. — noAxioms

Of course, if one assumes a preferred order of events, then every other order that people find in other reference frames will be considered false. But to my mind there is no difference in the scientific approach for someone who has different interpretations of relativity, which is what you seemed to have stated earlier. Like with QM, the equations remain the same regardless of your metaphysical views and the maths aren't any different.

The train thought experiments assume a non-absolute definition of space, which is incorrect in the 3D model. Incorrect conclusions of event simultaneity are drawn. — noAxioms

The train thought experiments are a demonstration of the relativity of simultaneity, describing a situation where two or more observers have differing views on the ordering of events. The presentist version of this situation would certainly describe it differently, as it will take one or more of these observers as being incorrect in their assessments.

Of course, if one assumes a preferred order of events, then every other order that people find in other reference frames will be considered false. — Mr Bee

And all measurements of time and distance are false as well only if you consider them to describe the 3D metaphysical interpretation.

But to my mind there is no difference in the scientific approach for someone who has different interpretations of relativity, which is what you seemed to have stated earlier. Like with QM, the equations remain the same regardless of your metaphysical views and the maths aren't any different.

That's right. The equations are scientific ones that describe what will be observed. The reality of the universe as 4D or 3D is a metaphysical difference with no empirical implications, so the equations describing empirical expectations need not change depending on your metaphysical view. The equations are not metaphysical.

The train thought experiments are a demonstration of the relativity of simultaneity, describing a situation where two or more observers have differing views on the ordering of events. The presentist version of this situation would certainly describe it differently, as it will take one or more of these observers as being incorrect in their assessments.

It is an interesting exercise to do just that. Assume that the train is the thing stationary, which helps one see past the bias that the platform is always the stationary thing. The platform observer detects the two events at once and is equidistant from the marks left by the events. Why is he wrong in concluding simultaneity?

And all measurements of time and distance are false as well only if you consider them to describe the 3D metaphysical interpretation. — noAxioms

With the exception of the absolute frame measurements. Other than that, the rest will be distorted due to a certain degree and will have to be adjusted, but they will all find the speed of light to be constant.

It is an interesting exercise to do just that. Assume that the train is the thing stationary, which helps one see past the bias that the platform is always the stationary thing. The platform observer detects the two events at once and is equidistant from the marks left by the events. Why is he wrong in concluding simultaneity? — noAxioms

Cause he is operating from the incorrect frame of reference. Assuming that the absolute rest frame is the correct one, then the events are actually ordered according to the train observer. The speed of light being measured the same in all frames would lead the platform observer to deduce the wrong set of simultaneous events.

With the exception of the absolute frame measurements. — Mr Bee

Keep in mind that the absolute frame is not an inertial one, nor accelerated or anything else. All the things you can do with a frame are not valid even in this absolute non-frame.

Other than that, the rest will be distorted due to a certain degree and will have to be adjusted, but they will all find the speed of light to be constant.

I thought about it, and light speed is constant only in an absolute sense. Of course light speed is constant, just as is sound in a stationary medium. But if you are moving at 1/2c, delta real light speed in one direction is .5c, and it is 1.5c in the other. The subjective moving observer will not notice that since he's perhaps measuring round trip, not one direction.. So he puts a mirror 300000 km away (they have these), and it takes 0.666 real seconds one way and 2 seconds the other way, which is 2.66 seconds round trip. But his clock runs slow and the mirror appears to be 346000 km away, so it says 2.3 seconds have elapsed and hides the fact that light in one direction moved slower than the other way.
I probably screwed up the maths somewhere, but it was my shot at it. This is what I mean by more complicated to do it in 3D. In 4D, it is just 2.3 seconds for a 692000 round-trip with everything being stationary in its frame.

Interestingly, the first light speed measurements were done in one direction by putting a clock very far away and then syncing a local clock to our image of it as its light arrives here at (unknown at the time) lightspeed. Now you move that distant clock even further away and notice the amount that it gets out of sync. You move it closer again and it appears to catch back up. In this way, light speed was measured by dividing the increase in separation distance by the amount of time the two clocks appeared to get out of sync. No compensation for relativistic implications (all unknown at the time) of accelerating clocks, but good enough for the precision they were after.

I bring this up because it would again be an interesting exercise to express that one-way measurement in absolute terms.

Your post seems to attempt to throw doubt on SR, like it does indeed threaten your position. Interesting that you feel the need to attack it when you say it is a metaphysical theory. — noAxioms

SR doesn't threaten ,my position at all. I don't know why you keep saying such things. It's just another metaphysical principle which ought to be doubted like any other, and that's why I throw doubt at it, like I do any other metaphysical claim. I'm a metaphysician, and that's my business, to analyze metaphysical theories looking for strengths and weaknesses.

Again an attack, and dragging 'human' into it. You think light speed is different for humans than for other things? — noAxioms

It was you who claimed "empirically proven", so you are the one dragging "human" into it. What I am saying is that "empirical observations" are human observations. To say that SR has been "empirically proven" in a situation where a human being couldn't possibly observe, is simply false. So to say that it has been empirically proven that the speed of light is still constant at .98c, is simply false.

Thing is, if time did not flow at all, we'd experience it exactly the same way. — noAxioms

I don't see how this makes any sense to you. You are saying that if time wasn't passing, we would still experience time in the exact same way that we do. Are you serious?

You seem to think otherwise as you seem to feel the need to cast it into doubt in your above posts, like there is empirical evidence against your view. — noAxioms

The only "view" I am proposing is that SR is metaphysical. It is your claim that it is not metaphysical, and that's what I am casting doubt on, this claim of yours.

Principle of relativity says you can't notice the dilation, but you would if you were experiencing a century of flow in only 10 years of high absolute speed travel. Indeed, nobody has tested this. It assumes that experience is a physical process, and you suggest it is a metaphysical process, that humans are metaphysically different than the rest of matter. Even your presentism doesn't assert this, but you seem to feel the need to add this to it. Yes, SR then would be a threat to your position. — noAxioms

None of this makes any sense to me at all. What you say I claim is not what I've claimed at all.

I'm not talking about the age of the universe from a point of view. I'm talking about the objective age of it, which doesn't exist except in some metaphysical views, my own not included. — noAxioms

What are you talking about, as "objective age" of the universe? How can there be such a thing? "Age" is a function of the principles used to measure. There cannot be an objective age of the universe, that's nonsense, the "age" is dependent on the standard of measurement.

I never said anything about 'the age of the universe", these are your terms. And now when I interpret your terms you say that's not what you're talking about, and you try to assign this "objective age" to me. You're so confused it's starting to confuse me.

Your problem is that you understand only one metaphysical interpretation and process all my comments with only that interpretation in mind, so you can't separate the parts that are different between the various metaphysical views. — noAxioms

I have to say, that you've already assigned about three different metaphysical views to me already, presentism, absolute rest, and "objective age of the universe", none of which I hold, and now you claim I only understand one metaphysical interpretation. I really think that you are metaphysically lost.

If it did, then yes, you are correct to attack relativity because it would indeed disprove your position. — noAxioms

I am not "attacking" relativity. I am describing it as what it is, metaphysics. It is you who is attacking my description, as if this description is somehow a threat to you. Why?

Keep in mind that the absolute frame is not an inertial one, nor accelerated or anything else. All the things you can do with a frame are not valid even in this absolute non-frame. — noAxioms

I was operating from SR at that point. In GR we don't have inertial frames, but there can be a preferred foliation, which serves the same function with respect to this conversation as an absolute frame that describes the correct order of events in the universe's history.

I thought about it, and light speed is constant only in an absolute sense. Of course light speed is constant, just as is sound in a stationary medium. But if you are moving at 1/2c, delta real light speed in one direction is .5c, and it is 1.5c in the other. The subjective moving observer will not notice that since he's perhaps measuring round trip, not one direction... So he puts a mirror 300000 km away (they have these), and it takes 0.666 real seconds one way and 2 seconds the other way, which is 2.66 seconds round trip. But his clock runs slow and the mirror appears to be 346000 km away, so it says 2.3 seconds have elapsed and hides the fact that light in one direction moved slower than the other way.

I probably screwed up the maths somewhere, but it was my shot at it. This is what I mean by more complicated to do it in 3D. In 4D, it is just 2.3 seconds for a 692000 round-trip with everything being stationary in its frame. — noAxioms

The differences you describe appear to be purely conceptual. Under the 3D view, time dilation and length contraction is a real effect on moving objects whereas in the 4D view it arises from moving through space-time. The results and the mathematical work used to get them are the same in both cases for both observers however, which again restates my point that it is not the equations that are different (so one cannot be more complicated than the other) but the metaphysical framework with which we interpret them.

Interestingly, the first light speed measurements were done in one direction by putting a clock very far away and then syncing a local clock to our image of it as its light arrives here at (unknown at the time) lightspeed. Now you move that distant clock even further away and notice the amount that it gets out of sync. You move it closer again and it appears to catch back up. In this way, light speed was measured by dividing the increase in separation distance by the amount of time the two clocks appeared to get out of sync. No compensation for relativistic implications (all unknown at the time) of accelerating clocks, but good enough for the precision they were after. — noAxioms

Hmm, you have a reference for this? The best example that comes to mind is Galileo's proposed experiment which involved lanterns but not clocks.

A person on a train, looking out the window will appear to see the landscape moving at velocity V, If they assume they are stationary; train is stopped. It looks this way to the eyes but they just added energy to the universe, since the landscape what more mass.
They did not add kinetic energy to the universe. It was always there. The landscape/universe was always moving at V in that frame. — noAxioms

Let me expand on this to make my point. We start with these two references; train and landscape. I place a person in each reference. Before the experiment begins, I place each person in a seal container so they can't see or feel what I am about to do.

I use 1000 gallons of diesel fuel to propel the train. This fuel defines our two reference system energy balance. Lastly, I let each person out of their sealed container and tell each to do an energy balance from the POV of their relative reference.

The person who thinks the landscape is in relative motion will assume more energy was added than was in reality. It will take more than 1000 gallons of diesel fuel to move that mountain. He will add imaginary energy due to assuming reference is relative and no reference is preferred. The experiment was designed on an absolute hierarchy, since only the train gets the energy. The other is an illusion.

The way this is normally done; in space, is we don't have an energy balance up front. We are not able to compare references to see who is closer, like in my experiment. This makes anything one says seem to appear valid. It is a magic trick, due to using space-time or distance and time, but not including relativistic mass as a way to do an energy balance on the fly.

Dark energy can't be seen in the lab, but it is needed for the universal energy balance. It is very possible that dark energy is a relative reference illusion, fix, needed to close the energy balance. The need to add dark energy would suggest that our earth reference original underestimated the energy of the universe using relative references. One explanation is earth is at higher energy in the hierarchy of the universe. However, we had assumed we are stationary and/or going slower. We may have higher relativistic mass than expected.

In the twin experiment, only the twin who was given motion, based on rocket fuel, shows permanent time dilation; ages slower. His change is connected to the energy balance slanted in his favor. Relative reference does not allow both to age at the same rate, even if both see the same relative velocity. Relativistic mass is what leverages time, just as rest mass does in GR.

I was operating from SR at that point. In GR we don't have inertial frames, but there can be a preferred foliation, which serves the same function with respect to this conversation as an absolute frame that describes the correct order of events in the universe's history. — Mr Bee

Yes, agree.

The differences you describe appear to be purely conceptual. Under the 3D view, time dilation and length contraction is a real effect on moving objects whereas in the 4D view it arises from moving through space-time.

Yes, the differences are metaphysical, and the equations are not, so there is no need to perform them the difficult way like that unless you are computing metaphysical values for things like which point on Pluto is the center of the side that is objectively facing us right now, and even this is not computable without an unverifiable assumption that comoving foliation is the same foliation as 'the present'. The only evidence of that is that there seems to be only two choices available: That one or anything else.

Hmm, you have a reference for this? The best example that comes to mind is Galileo's proposed experiment which involved lanterns but not clocks.

That lantern thing was an early attempt, but yielded no results. They might have measured sound speed with such a setup, but the distances were too small for the limited precision of the timing methods.

The clock was the moons of Jupiter or Saturn, and the distance to that varied mostly from Earth moving back and forth every half year. You could see the eclipses down to almost the second, so it made a pretty good clock. Observations on the increased delay of those eclipses vs. distance yielded the first reasonably accurate light speed measurements. The difference could be over 15 minutes, well within the precision of the clocks of the day.

I'm a metaphysician, and that's my business, to analyze metaphysical theories looking for strengths and weaknesses. — Metaphysician Undercover

So your username suggests.

You are saying that if time wasn't passing, we would still experience time in the exact same way that we do. Are you serious?

To be unaware of this view (or for that matter, the name of the view that you do hold) seems pretty inexcusable for someone who makes metaphysical interpretations (they're not theories) their business. Look up Eternalism. Spacetime is an eternalist model if you take it as metaphysical, which you seem to.

Let me expand on this to make my point. We start with these two references; train and landscape. I place a person in each reference. Before the experiment begins, I place each person in a seal container so they can't see or feel what I am about to do. — wellwisher

Newton's laws are enough for the acceleration concepts you are describing. Relativity doesn't seem to come into play at all. You are about to accelerate the train observer. He'll notice that from inside a box. It is a local effect.

I use 1000 gallons of diesel fuel to propel the train. This fuel defines our two reference system energy balance. Lastly, I let each person out of their sealed container and tell each to do an energy balance from the POV of their relative reference.

As I said, the kinetic energy observed (of everything except the train) was always the same from that post-acceleration inertial reference frame (IRF). An accelerated person is the thing that changed, and the thing that gained or lost kinetic energy in one IRF or another. The fuel represents entropy. It could be done with a hill without change of entropy.

The person who thinks the landscape is in relative motion will assume more energy was added than was in reality.

No. He detects the acceleration and knows it is himself that is now in a different IRF, one where the landscape was always moving. You can make him not know that (by sleeping say), but that just forces him to forget a knowable objective fact: that he is the thing that accelerated. There is no symmetry going on here.

It will take more than 1000 gallons of diesel fuel to move that mountain. He will add imaginary energy due to assuming reference is relative and no reference is preferred. The experiment was designed on an absolute hierarchy, since only the train gets the energy. The other is an illusion.

Well, momentum was transferred to the landscape per Newton's third law, in proportion to their relative masses. Momentum is conserved whether fuel or a hill is used to get things up to speed.

The part below is relevant to relativity, unlike the part above:

In the twin experiment, only the twin who was given motion, based on rocket fuel, shows permanent time dilation.

Due to acceleration, not due to motion (which is frame dependent, not absolute), and not due to fuel consumption, which can be avoided if different means are used like springs and trampolines and such. A frictionless clock pendulum ages slower than a stationary one, all without fuel consumption, and does so because it accelerates more than the non-swinging pendulum. To be precise, it is the moment of acceleration (acceleration times leverage distance) that determines the magnitude of the dilation. Two things can both accelerate equally but age differently if the moment is different.

To be unaware of this view (or for that matter, the name of the view that you do hold) seems pretty inexcusable for someone who makes metaphysical interpretations (they're not theories) their business. Look up Eternalism. Spacetime is an eternalist model if you take it as metaphysical, which you seem to. — noAxioms

Eternalism does not deny that the human subject experiences the passing of time. It just does not provide an explanation for this experience. It appears like the human subject's experience of the passing of time is unimportant to the eternalist.

Why is it inexcusable for me not to name the view of time that I hold? It is the capacity to understand and to describe time which matters, not the name.

Eternalism does not deny that the human subject experiences the passing of time. — Metaphysician Undercover

Since there is no passing of time, the eternalist denies that it is what is experienced. So closer to say that humans interpret their experience as the passage of time.

It just does not provide an explanation for this experience.

Natural physics explains this, not metaphysics. Biological creatures naturally interpret their experience as the passage of time, else they'd not be fit. The rational part might realize otherwise (as Einstein did).

So yes, I am serious. The interpretation is a metaphysical difference only, and has no implications for empirical experience. The experience in both views must be the same.

It is the capacity to understand and to describe time which matters, not the name.

Yes, and the above post makes me question that capacity. I'm not telling you that your interpretation is wrong, but you seem to think the alternate interpretation (if it were the case) would result in a different experience, and that points to a lack of capacity to understand, and to distinguish physics from metaphysics.

References are not relative, unless you ignore the conservation of energy. In SR, conservation of energy is where relativistic mass comes in. However, relativistic mass is not as easy to measure, compared to time and distance. As such, relativistic mass is often left out and/or lumped into space-time. The result is an illusion.

The train and diesel fuel example above, was not about sensing motion or acceleration. Rather it was about viewing two study state references after all the acceleration is done. Both parties go into the final references, blind to any energy balance. This allows both references can apply the relative reference assumption in good conscience.

However, since a third party knows the energy conservation answer before the two references tell us what their reference appears to say, we have a way to prove if their assumptions are true or an illusion. If we did not know how much fuel was used such that the energy balance was left open ended, then the illusion would work.

The train and landscape may not be a good example, since rational common sense would say the landscape can't move, unless the entire earth was moved, which is unlikely due to the energy needed. So we could do this with two trains or two rockets, to avoid second guessing, what you appear to see, in terms of the relative reference assumption.

When we look at the universe , we do not have an accurate energy balance. The idea of no preferred reference or center of the universe tells us that. We know the Conservation of energy applies, but we don't have a hard starting number. The illusion will work, if nobody is able to impose a hard energy balance.

I not saying SR is not real, only that relative reference is an illusion that can be seen through it we include energy conservation.

In terms of acceleration, acceleration has the dimensions of d/t/t. It is one part distance and two parts time. It is space-time plus time. SR applies to velocity, which is d/t, or one part distance and one part time, just like space-time. Acceleration is different due to the extra time acting on space-time.

In the case of gravity, the extra time for acceleration comes from gravity which comes from mass. Mass has a connection to the second time. Relativistic mass also has a connection to the second time that impacts space-time. Dark matter might be relativistic mass.

One difference between mass and relativistic mass is mass can generate pressure, whereas relativistic mass does not generate pressure, or else a space ship would implode at extreme velocity and change material phases. The only impact is on space-time.

OK, I think I understand what you are arguing now. You are saying that some metaphysicians such as presentists, claim that human beings experience the passing of time. Others. like eternalists claim that what human beings experience and call "the passing of time" , is not really the passing of time, it's something different.

Further, you have already claimed that there is something called "the passing of time", which physicists measure with clocks.

So your argument appears to be that what metaphysicians refer to as "the passing of time" is something completely different from what physicists refer to as "the passing of time". The former refers to the human experience, and the latter refers to the activities of an inanimate clock.

My opinion, is that this distinction you make is unwarranted. I think that what a metaphysician refers to as "the passing of time" is the exact same thing as what the physicist refers to as "the passing of time". The two, the metaphysician, and the physicist, just utilize different measurement techniques, one the human experience, the other a physical clock. This is very clear from the fact that human beings synchronize their experience with the clock, in our day to day life. That the physicist employs a more accurate measurement technique than the metaphysician is irrelevant to the fact that the two are measuring the very same thing.

Therefore, your claim that "physical time" is different from "metaphysical time", is completely ungrounded. The two are just different ways that human beings relate to the very same thing, the passing of time. One is how we measure it within ourselves, as experience, the other how we measure it with clocks. Furthermore, that claim of yours, that these two are fundamentally different, is itself a metaphysical claim. And, since it is evident that there are multiple ways to measure the same thing, different parameters, different properties, etc., the decisions concerning the best way to measure a thing, and the relevance of different ways of measuring the same thing, are metaphysical decisions. These are decisions concerning good and bad, correct and incorrect. So I argue that whether or not the physicist's way of measuring time is the best way for a particular application, is a metaphysical decision. Therefore when Einstein stipulated that this is the way that physicists ought to measure time, this was a metaphysical decision.