Sure, if one adopts an ontological perspective that says there is such a thing as absolute motion, rather than just relative motion, then one will have a problem. That seems a good reason not to adopt such a perspective.

I don't know what "absolute motion" would be, perhaps you mean absolute rest? In any case, it's a matter of a preferred perspective, the preferred rest frame. Do you agree that it's better to model the movement of the planets as movements relative to the sun as the rest frame, rather than as movements relative to the earth as the rest frame? If the preferred rest frame makes sense to you, then why not allow that there is an ideal, or best rest frame (absolute rest)?

If the preferred rest frame makes sense to you, then why not allow that there is an ideal, or best rest frame (absolute rest)? — Metaphysician Undercover

'Preferred' is a function of someone's mind - the person that prefers it. It is not ontological. For a given calculation there will often be a frame that makes the calculation simplest. Indeed, in GR, the biggest challenge is often in finding a frame that makes the calculations manageable. Again, that is a pragmatic, rather than an ontological consideration. There will be no universally preferred frame because a frame that is best for one purpose may be terrible for another. A laboratory-based frame is best for lab-based experiments. An Earth-centred frame is best for satellite management. A sun-centred frame is best for long-range space missions and predicting movements of solar system bodies other than the moon.

For a cabin attendant serving meals in a commercial jet, the preferred frame is that of the jet, but for an air traffic controller directing the flight paths for the jet and other planes, the preferred frame is that of the control tower. Neither would want to use the frame of the other.

'Preferred' is a function of someone's mind - the person that prefers it. It is not ontological. For a given calculation there will often be a frame that makes the calculation simplest. Indeed, in GR, the biggest challenge is often in finding a frame that makes the calculations manageable. Again, that is a pragmatic, rather than an ontological consideration. — andrewk

The point though, is that "rest" is an ontological principle. Therefore the reason why one rest frame is preferred over another ought to be ontological rather than pragmatic. In scientific endeavours we ought to choose the best in relation to determining the truth, rather than what makes the calculations easiest..

There will be no universally preferred frame because a frame that is best for one purpose may be terrible for another. A laboratory-based frame is best for lab-based experiments. An Earth-centred frame is best for satellite management. A sun-centred frame is best for long-range space missions and predicting movements of solar system bodies other than the moon. — andrewk

Now you base "best" in what "makes the calculations simplest" rather than true ontology. As I said, the easiest is not necessarily "the best". Your use of "best" here is not based in the intent of finding truth, but in the intent of making calculations easier.

For a cabin attendant serving meals in a commercial jet, the preferred frame is that of the jet, but for an air traffic controller directing the flight paths for the jet and other planes, the preferred frame is that of the control tower. Neither would want to use the frame of the other. — andrewk

In many of our day to day procedures we settle for less than the best, that is obvious. But science ought to strive for nothing less than the best understanding of nature, and that is the truth. This requires adherence to solid ontological principles rather than pragmatic principles.

The point though, is that "rest" is an ontological principle. Therefore the reason why one rest frame is preferred over another ought to be ontological rather than pragmatic. — Metaphysician Undercover

Your claim that it is an ontological principle is what creates your problem. That's why it is unhelpful to adopt an ontology that includes such a principle, and unhelpful to regard 'rest' as an ontological concept instead of a scientific one that is used for calculations and predictions.

"Rest" is not a scientific principle. What rest is, has never been demonstrated empirically. That "rest" is relative to a frame of reference is an ontological principle adopted by relativity theorists, for the purpose of ease in calculations (as you described). That this is what "rest" really is has never been scientifically proven and therefore it is false to claim that this is a scientific principle.

I didn't say it was a scientific principle. I said it was a scientific concept. Rest is a definition. We say an object is at rest relative to another if the displacement vector from the first to the second is constant over time.

Perhaps what you are challenging is whether it is ever possible for two objects to be perfectly at rest relative to one another. If so, fair enough. There will always e some tiny degree of relative movement, albeit imperceptible. All that matters in physics is whether such imperceptible movement can affect the predictions made by calculations based on an assumption that the object is at rest. In almost all cases, it doesn't.

Perhaps what you are challenging is whether it is ever possible for two objects to be perfectly at rest relative to one another. If so, fair enough. — andrewk

Yes, that's the issue, the inertial frame of reference is essentially arbitrary. Yet it is extremely important because inertia under Newton's first law represents the temporal continuity of existence, i.e. things that do not change as time passes. Newton's concept assumes that there is such a thing as an object with no forces acting on it, and this object will continue in time to be as it was. This a completely unrealistic assumption.

The opposite perspective (which I believe is more realistic), is that the temporal continuity of existence requires an acting force (traditionally that would be God). So the law of inertia, upon which the "scientific" definition of rest is based, takes what had been attributed to the act of God, the temporal continuity of existence (things which stay the same as time passes), for granted. This taking inertia for granted, assumes that the temporal continuity of mass is necessary (cannot be otherwise), requiring no forces, while the opposite perspective assumes that a force is required for temporal continuity. But if the temporal continuity of mass is not necessary, (and there may be good evidence that it is not, in QM), then this so-called "scientific" definition of rest is completely off track. And so we would need to assume some force to fill the place of "the Will of God", in order to account for what we observe as rest.

The opposite perspective (which I believe is more realistic), is that the temporal continuity of existence requires an acting force (traditionally that would be God). — Metaphysician Undercover

That is a metaphysical perspective, not a physical one, and what you refer to as a force there is completely different from what a force means in physics.

What you describe is Aquinas' belief that objects require a constant act of will to sustain their existence. I have no objection to that belief, but it is a belief that some hold and some do not, and that cannot be proved or disproved. Further, the act of will to which it refers is nothing like what Newton means by a force.

That is a metaphysical perspective, not a physical one, and what you refer to as a force there is completely different from what a force means in physics. — andrewk

The two distinct perspectives of temporal continuity, which I described, are both metaphysical perspectives, that's the point. That "inertia" is the one adopted by physics doesn't make it any less metaphysical.

The primary one is the philosophical interpretations of time: presentism and eternalism. The former was always the default until relativity gave equal if not better footing for the latter, but scientifically (empirically), the two are not distinct. SR does not assert a block universe even if the assumption of one makes the calculations simpler. Hence the difference is philosophical. — noAxioms

I agree it's interesting what historical philosophical trends changed moving from Galilean to Einsteinian relativity.

I wouldn't go as far as to say presentism and eternalism are philosophies that are impacted in anyway. Both philosophies predate any mathematical physics at all, and we can view Newtonian physics as a block universe just as easily as SR, just wasn't the habit.

I would agree that lot's of people build philosophies with an (generally completely unfounded) belief SR, GR, QM and/or QFT* supports their ideas. I find it philosophically relevant to refute such arguments (at least the part connecting to modern science).

However, I don't see how SR, or GR and QM for that matter, displacing Newtonian physics had a big impact on presentism and eternalism, the debate pre-existed both and continues.

Though I agree there is impact on historical trends, I don't think anything's resolved. Even for questions such as the start of the universe, we can posit eternal inflation and similar (non-refutable) ideas that provide an eternal universe compatible with GR. Though it was a shock, to Einstein and others, that our universe as we see it isn't stable, in the end every philosophy requires only trivial updating to account for the new sciences.

*Special Relativity, General Relativity, Quantum Mechanics, Quantum Field Theory (for anyone unfamiliar with these abbreviations).

It is my belief that as one gradually accelerates and approaches the speed of light a person on board that space ship they will be flattened and pressed back into their chair. The ship length will be compressed and it will require more and more thrust to continue to accelerate to the speed of light. Eventually the human brain will not be able to function because the electrons in their brain will no longer be able to move forward in the direction of motion that the ship is traveling." — ↪MrCypress

So this is completely wrong. Again, it uses the concept of a property of speed. There is no such thing. In the frame of the ship, the occupant will notice nothing and his brain works just fine. There is no contraction at all since the occupant is stationary in this frame. He is not going fast at all, but the stuff outside the window certainly is, which accounts for its red and blue shifts. — noAxioms

The reasoning you are using to claim what I said is wrong is not consistent. Of course the property of speed is correct. There is evidence that objects moving through space is everywhere you look. Inertia is evidence that objects possess the property of speed. This is already common knowledge known to all. Further more if an object is moving relative to some other object then it has a speed. You can tell it is moving relative to the other object because its clock will move slower than the object you are comparing to. This is more evidence that objects are moving through space. The speed at which your clock ticks is real hard evidence that you have motion within space. The action is really not about ones relative motion to some other thing in space. It's really about the relationship of the moving object and its interaction with the space it is moving through. This is especially true when the motion is accelerated. Surely you believe in General Relativity. When a spaceship accelerates, inertia is demonstrated. Are you proposing that the accelerating object does not possess the property of acceleration which is a 2 dimensional representation of speed. All the evidence supports what I am saying. It's time for you to wake up and smell the coffee.

Here are some of the evidences that proves that all objects have a property of motion through space.

. Clocks on orbiting satellites move slower
. Atomic clocks on planes move slower
. Michelson-Morley experiment - Proves the constancy of light independent from the emitting source.
. Muon particles decay more slowly while falling
. The fact that particle accelerators work the way they do is evidence that speed of an object is a real thing that can be measured and has effects. When scientists have tried to apply more energy to the particles in the accelerator they will not move beyond the speed of light. The question is, What is holding the particles back? Obviously, the particles must be interacting with something. The only thing the particles can interact with is the space they are moving within. So space in someway is impeding the acceleration of the particles beyond the speed of light.

The point is that there is a huge pile of evidence that supports the concept that particles moving through space possess a real absolute speed not only as it relates to other moving frames of reference but to the stationary background of space itself. In all honesty there is no evidence that supports what you are saying when you say this. "

I can only have speed relative to an arbitrary reference. — noAxioms

That statement is the classic incorrect assumption about Special Relativity. That is what needs to be fixed in the realm of the current scientific community. If you have a speed relative to one arbitrary reference then by default you now have a speed relative to all other moving frames of reference including the stationary substance of space. This is an inescapable conclusion that has to be arrived at. The alternative is to assume an inconsistent unsupported notion that speed only exists relative to something else we compare to. This is a very limited point of view.

Clearly the best example of absolute motion is light. It has a speed that is the same to all other moving frames of reference. That is a real speed and a property of light. Light possesses autonomous motion and that is a real absolute velocity that can be compared to everything else.

I wonder if you could be made to move at 99% the speed of light using just thrust power without the protection of a spatial bias drive and you could see for yourself the effects of moving at that speed would you then accept that the spaceship has a real absolute speed? Would you believe it's true when when you arrive at 99% the speed of light and you find its impossible to get up out of your chair? Would you believe it's true when you look out the front window of your spaceship and see nothing but blackness because all of the starlight is blue shifted and is now no longer visible? Would you believe it's true when you look at the clock on the control panel and see that it has stopped counting? You will believe then but by then it will be too late. There won't be a thing you can do to slow down and if the rockets are still accelerating your ship things will only get worse.

We have been tricked into believing that we would not notice anything different because in our frame of reference within the spaceship while traveling at relatively slow speeds compared to the speed of light we cannot perceive a difference. This is a folly. This belief system is similar to when scientists believed the earth was flat and the earth was the center of the Universe.

I would agree that lot's of people build philosophies with an (generally completely unfounded) belief SR, GR, QM and/or QFT* supports their ideas. I find it philosophically relevant to refute such arguments (at least the part connecting to modern science). — boethius

Your choice of QM interpretation most definitely go with certain philosophical stances and not others. It seems important to be compatible. But I agree that I don't see this with relativity.

However, I don't see how SR, or GR and QM for that matter, displacing Newtonian physics had a big impact on presentism and eternalism, the debate pre-existed both and continues.

I think relativity moved a lot of people (those who thought about such things and understood it) to the less intuitive camp of eternalism. It certainly did for me, even if I continue to defend the opposite stance as not being in contradiction.

I have though of my own 'proof' of presentism being wrong, but I think it is invalid like the attempts others have made. If time on Earth is dilated (running slow) due to its motion and gravity well, how much faster does time actually flow? If my Earth clock says a million seconds went by, how many seconds actually went by as measured by a clock measuring absolute time, stationary and at zero gravitational potential? Gravitational potential is negative, so zero is 'in no gravity well', as high as one can possibly be.

The complete lack of an answer to this in the absolutist web sites (like conspiracyoflight.com for example) seems to be my evidence against their position. They avoid it, like it's embarrassing or something.

Suppose an object is moving relative to space, and some sort of ether occupies this space. Suppose also that the object is emitting light, and the movement of the light is a property of the space (ether). Wouldn't is be possible to track that object's movement relative to the ether based on the wave patterns?

You're being ironic, yes? Michelson-Morley?

Have you read MrCypress' posts?

Unfortunately because of the misinterpretation of the null result of the Michelson & Morley experiment he came to believe that you cannot sense motion relative to it. Einstein said, "But this ether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it." The confusion about this was created by the failure to detect the ether wind. The design of this experiment was incorrect. Looking for a difference in the motion of light will never be detectable relative to the emitting source motion. This is true because light moves autonomously relative only to the medium it is moving within. The density and tension of the medium is what determines the maximum velocity. — MrCypress

What I think is that there must be detectable motion of the emitting source of light, relative to the medium (ether).

This explanation should help clarify my position:

The observer in Special Relativity inertial frame of reference is fooled into thinking that nothing has changed because the changes at speeds well below the speed of light are undetectably small for the observer in the inertial frame of reference. This fact has been used to completely misinterpret Special Relativity.

The flaw in our current day understanding of Special Relativity comes from this postulate: “the laws of physics are invariant (i.e. identical) in all inertial systems.”

* An inertial frame of reference in classical physics and special relativity is a frame of reference in which a body with zero net force acting upon it is not accelerating; that is, such a body is at rest or it is moving at a constant speed in a straight line.

* https://en.wikipedia.org/wiki/Inertial_frame_of_reference

The flaw imbedding is subtle. There needs to be a distinction made in the concept or definition of what an inertial system is. I believe that if there is an “ether medium” then the laws of physics will be different when a body is at rest relative to the ether and when it is moving at a constant speed in a straight line relative to the “ether”. This makes sense because these are two different states of motion. If in fact the ether did not exist then the statement would be correct as is. But the evidence from experiments proves there is an ether medium. When you increase the velocity of an object through space its clock slows down. If the ether did not exist a change in velocity would have no effect on the speed at which the clock ticks. It would have no effect because we would be accelerating through a non-existent medium. Accelerating through nothing will have no effect on the rate of the ticking clock. Why? It would have no effect because the accelerating object would have nothing to interact with. It’s just that simple.

The evidence for the ether is strong and it comes from experimental verification of Special Relativity.

* Special relativity implies a wide range of consequences, which have been experimentally verified, including length contraction, time dilation, relativistic mass, mass–energy equivalence, a universal speed limit, the speed of causality and relativity of simultaneity.
* https://en.wikipedia.org/wiki/Special_relativity

In particular the verification of the existence of an ether comes from length contraction, time dilation, relativistic mass increase and Universal speed limit.

General Relativity also supplies evidence of the existence of an ether as General Relativity was built upon special relativities length contraction principle. Einstein’s happiest thought which explains the origin of mass.

I believe that if there is an “ether medium” then the laws of physics will be different when a body is at rest relative to the ether and when it is moving at a constant speed in a straight line relative to the “ether”. — MrCypress

Doesn't the Michelson-Morley experiment show that if there is an ether, bodies do not move relative to the ether? This would mean that possibly bodies are a function of the ether, and their movements are changes in the ether.