Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie

Free Will & Absolute Motion

Options
  • 29-11-2020 8:52pm
    #1
    Registered Users Posts: 2,553 ✭✭✭


    Just thinking out loud here, but I was wondering if free will could be used to establish the existence of absolute motion?

    In a separate discussion, Fourier mentioned that the Kolmogorov embedding (I'm using that term as though I know what it means) demonstrates that free will is a necessary consequence/fundamental necessity in quantum mechanics?

    Could free will therefore be used to establish the existence of absolute motion, even if it remains impossible to actually determine which body is in a state of absolute motion?

    I'm thinking of two spaceships at rest relative to each other. The captain of one spaceship makes a decision to turn on their rockets which results in relative motion between the two spaceships. Could the asymmetry in the situation lead us to the conclusion that there must be absolute motion?

    Now, we still can't determine which of the two spaceships absolutely moves but for the spaceships to go from a state of relative rest to relative motion, one of the two spaceships would have to absolutely move, would they not?


«134

Comments

  • Registered Users Posts: 13 Goosius


    To me the idea that "free will" is necessary for any physical interaction, displays a kind of contempt for evolutionary biology. Because if we believe the theory of evolution, then people are essentially no more than evolved bacteria. Now, assuming that nobody is claiming a bacteria or virus has "free will", then in order to prove that human "free will" is a thing influencing our experiments, we would necessarily have to identify the specific point in our evolution where we went from being without the purportedly physics-manipulating attribute of free will (like a bacteria), to being granted that powerful attribute (like the purported human experimenters). This seems to me like a fairly comical errand.

    I think in the early years of quantum physics, people were much more caught up in the idea of the human mind having an effect on experiments, but these days I seem to see much less of that, and more around how the measuring apparatus "disturbs" the measured particles, causing decoherance, with no fundamental impact from human, mouse or bacterial free will.

    So in short, you probably couldn't use the idea of free will to prove absolute motion today, and before considering any future attempts, it would certainly be best (and probably critical too for the proof) to first carefully define and experimentally prove what free will actually is. (because right now that foundation is not solid).


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    Could free will therefore be used to establish the existence of absolute motion, even if it remains impossible to actually determine which body is in a state of absolute motion?
    No, there'd still be a reference frame in which the ship is at rest. The change of velocity, i.e. the acceleration, would be absolutely noticed in any frame. However the principle of relativity concerns velocity not acceleration.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    Goosius wrote: »
    I think in the early years of quantum physics, people were much more caught up in the idea of the human mind having an effect on experiments, but these days I seem to see much less of that, and more around how the measuring apparatus "disturbs" the measured particles, causing decoherance, with no fundamental impact from human, mouse or bacterial free will.
    Well the notion of "disturbance" is outdated in fact, having been laid to rest in Bohr's analysis of the "Heisenberg microscope" in 1927. We now know that quantum particles do not possess pre-existant properties independent of measurement (i.e. measurement is an "act of creation" as John A. Wheeler sometimes said).

    We also now know that in principle one cannot use quantum theory to explain how the measurement set-up came about, that seems to be outside the theory.

    Quantum Theory assumes:
    1. A given measurement set up. That is a particular classical system waiting to be affected by a quantum system
    2. A given quantum system, e.g. electron, superfluid

    It then describes the probability that the quantum system will have a particular effect on the classical system.
    However it does not describe:
    1. How the particular classical system got into the position of being able to be affected. It simply assumes the classical system is there. In an actual lab we choose the particular system. For example for light we might use a homodyne detector or a photo-detector. In which case quantum theory cannot tell you how the choice of homodyne vs photo-detector came about
    2. It does not describe the quantum system in and of itself. So for example only how an electron affects macroscopic objects is described, but not the actual nature of the electron itself.

    Decoherence is only a concept used to prove that some objects are classical like the theory requires, i.e. it's a consistency check.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    No, there'd still be a reference frame in which the ship is at rest. The change of velocity, i.e. the acceleration, would be absolutely noticed in any frame. However the principle of relativity concerns velocity not at
    acceleration.
    A frame in which the ship is at rest relative to what?


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    A frame in which the ship is at rest relative to what?
    Relative to that frame.


  • Advertisement
  • Registered Users Posts: 13 Goosius


    Fourier wrote: »
    Well the notion of "disturbance" is outdated in fact, having been laid to rest in Bohr's analysis of the "Heisenberg microscope" in 1927. We now know that quantum particles do not possess pre-existant properties independent of measurement (i.e. measurement is an "act of creation" as John A. Wheeler sometimes said).

    Maybe I wasn't clear enough. I'm talking about a breakdown of the wave function as caused by the interaction of one particle with the large mass of the measurement device. (i.e. the disturbance of the particle by the device).

    This interpretation is described in wiki "/wiki/Objective-collapse_theory", and it is certainly not outdated. The wiki is explicit is noting that it is a growing area of research. QUOTE: "there is a growing number of experiments searching for spontaneous collapse effects."

    Thus the assertion that quantum particles do not possess pre-existing properties prior to measurement, is most certainly not something that we "know", as indicated by the a growing number of people working on finding out whether those same properties can emerge even without human measurement.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    Goosius wrote: »
    Maybe I wasn't clear enough. I'm talking about a breakdown of the wave function as caused by the interaction of one particle with the large mass of the measurement device. (i.e. the disturbance of the particle by the device).

    This interpretation is described in wiki "/wiki/Objective-collapse_theory", and it is certainly not outdated. The wiki is explicit is noting that it is a growing area of research. QUOTE: "there is a growing number of experiments searching for spontaneous collapse effects."
    Objective Collapse theories have been ruled out experimentally. Even for non-rel QM their parameters have been pushed into fine tuned regions and we have no-go theorems showing they won't work for relativistic theories like quantum field theory.
    Thus the assertion that quantum particles do not possess pre-existing properties prior to measurement, is most certainly not something that we "know"
    We do know it. It's a consequence of the Kochen-Specker theorem and other recent no-go theorems. The no-go theorems have led to a decline in people working on these things. Their heyday was the 50s-70s. They seem virtually unworkable now.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    Relative to that frame.
    In nature though, objects don't move relative to reference frames bcos reference frames are mathematical artefacts. If absolute motion exists it wouldn't be motion relative to a mathematical reference frame.

    Wouldn't the same would be true though, if absolute motion did exist; there would always be a co-ordinate "rest frame" for a body in absolute motion?


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    In nature though, objects don't move relative to reference frames bcos reference frames are mathematical artefacts. If absolute motion exists it wouldn't be motion relative to a mathematical reference frame.

    Wouldn't the same would be true though, if absolute motion did exist; there would always be a co-ordinate "rest frame" for a body in absolute motion?
    Reference frames can be modelled mathematically, but there not just mathematical constructs. You've made this point a few times as if certain things are just mathematics. The magnetic field for example is both a physical entity and is modelled mathematically with a two-form. Same with reference frames they have a physical nature which we then model with mathematics. The mathematics isn't just hanging free with no physical relevance nor is it an "artefact". This entire way of talking suggests little familiarity with how mathematics is actually used in physics.

    Have you read a proper account of what a reference frame is operationally?


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    Wouldn't the same would be true though, if absolute motion did exist; there would always be a co-ordinate "rest frame" for a body in absolute motion?
    The point would be that if the motion was absolute there would be some measurable physical effect distinguishing true absolute "at rest" from mere coordinate "at rest".


  • Advertisement
  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    Reference frames can be modelled mathematically, but there not just mathematical constructs. You've made this point a few times as if certain things are just mathematics. The magnetic field for example is both a physical entity and is modelled mathematically with a two-form. Same with reference frames they have a physical nature which we then model with mathematics. The mathematics isn't just hanging free with no physical relevance.
    I might be missing something in interpreting your statement about there being a reference frame in which the ship is always at rest.

    If we go back to the examples of two ships at rest relative to each other, which then start moving relative to each other. If we ignore every other physical thing in the Universe (or imagine a Universe in which there are only these two ships and spacetime). To say that there is always a reference frame in which the ship is at rest is effectively just saying that the ship is always at rest relative to itself, isn't it?

    This would be true for a ship in absolute motion also, wouldn't it?

    Fourier wrote: »
    Have you read a proper account of what a reference frame is operationally?
    I think I have. By that I mean I've read a lot of different accounts over the years and I understand the point you are making above.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    The point would be that if the motion was absolute there would be some measurable physical effect distinguishing true absolute "at rest" from mere coordinate "at rest".
    That would be the case if it we were trying to determine which of the two bodies was in a state of absolute motion, but we wouldn't need to determine which one is in such a state.

    If the two bodies are at rest relative to each other, then they suddenly start moving relative to each other, because one of the captains freely chooses to start their engine, would this not lead us to conclude that [at least] one of the ships must have absolutely moved? We can't determine which one it is, but would we not conclude that one of them must have?


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    If the two bodies are at rest relative to each other, then they suddenly start moving relative to each other, because one of the captains freely chooses to start their engine, would this not lead us to conclude that [at least] one of the ships must have absolutely moved? We can't determine which one it is, but would we not conclude that one of them must have?
    We could conclude that the ship had changed velocity from x to y, but what those velocities were would depend on the reference frame. Thus the acceleration is absolute but not the velocities.

    Unless you had a physical method to distinguish "relative x/y" from "absolute x/y" which there doesn't seem to be.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    We could conclude that the ship had changed velocity from x to y, but what those velocities were would depend on the reference frame. Thus the acceleration is absolute but not the velocities.
    Those are measurable properties, but my thinking is that they wouldn't necessarily exhaust the list of conclusions we can draw.

    Measurement by its very nature is a relative process, so the idea that we might measure absolute motion would represent a contradiction in terms. Absolute motion would be a yes/no question e.g. is X moving?

    If we have two ships X and Y, at rest relative to each other in an otherwise empty universe, and they suddenly start moving relative to each other, my thinking is that we can deduce that [at least] one of the ships must have absolutely moved. If neither ship absolutely moves, then they would remain at rest relative to each other.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    Measurement by its very nature is a relative process, so the idea that we might measure absolute motion would represent a contradiction in terms
    Not really. There are physical theories were there is absolute motion that can easily be measured. Our world isn't described by them though. However the notion of measuring absolute motion isn't a contradiction in terms due to such models, e.g. Aristotelian spacetime modelled using fiber bundles.

    Since your example doesn't give an example of a measurable difference between "moving at velocity Y relative to frame F" and "moving absolutely" it's not an example with physical absolute motion.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Just out of curiosity as to what those particular theories say, bcos I am not familiar with them.
    Fourier wrote: »
    Not really. There are physical theories were there is absolute motion that can easily be measured. Our world isn't described by them though. However the notion of measuring absolute motion isn't a contradiction in terms due to such models, e.g. Aristotelian spacetime modelled using fiber bundles.
    Is the absolute motion measured relative to something else?


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    There would still be relative motion in a world where absolute motion exists
    Of course, I never said otherwise. The point is that there are theories where absolute motion is physically different from relative motion and this difference can be measured. The Free Choice aspect of QM doesn't convert QM into one of these theories thus there is no physical absolute motion.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    Of course, I never said otherwise. The point is that there are theories where absolute motion is physically different from relative motion and this difference can be measured. The Free Choice aspect of QM doesn't convert QM into one of these theories thus there is no physical absolute motion.

    I'm suggesting that we don't need an alternative theory, we could potentially deduce it from relativity theory.

    I was thinking that the free choice aspect would create a fundamental asymmetry between the two bodies moving relative to each other, but perhaps that isn't a necessity - I had a previous discussion with Morbert in mind, but I might be recalling it imperfectly.

    Essentially, my reasoning is that if X and Y are at rest relative to each other. For relative motion to occur between them, [at least] one of them has to move. If neither of them moves then there would be no relative motion.

    Note that, when one of them moves, both move relative to each other.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    we could potentially deduce it from relativity theory
    You can't. Relativity has no notion of absolute velocity, it's a concept that doesn't even make sense in its model of spacetime.
    roosh wrote: »
    Essentially, my reasoning is that if X and Y are at rest relative to each other. For relative motion to occur between them, [at least] one of them has to move. If neither of them moves then there would be no relative motion.

    Note that, when one of them moves, both move relative to each other.
    Yes but the "moving" here is acceleration. Somebody has to accelerate for them to go from relative rest to relative motion. And acceleration is absolute. The velocities however are not.

    You're analysing a change in velocities, i.e. an acceleration. This is never going to suggest absolute velocities in any sense.

    This just seems to be a confusion about how relativity works combined with not properly separating the intuitive "move" into the more precise and separate concepts of "velocity" and "acceleration".


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    You can't. Relativity has no notion of absolute velocity, it's a concept that doesn't even make sense in its model of spacetime.
    I'm not suggesting the idea of absolute velocity though. To my mind, velocity must always be relative to something. That would, again to my mind, make the idea of absolute velocity a contradiction in terms.

    Fourier wrote: »
    Yes but the "moving" here is acceleration. Somebody has to accelerate for them to go from relative rest to relative motion. And acceleration is absolute. The velocities however are not.

    You're analysing a change in velocities, i.e. an acceleration. This is never going to suggest absolute velocities in any sense.

    This just seems to be a confusion about how relativity works combined with not properly separating the intuitive "move" into the more precise and separate concepts of "velocity" and "acceleration".
    As mentioned above, I'm not suggesting the idea of an absolute velocity. I think such a concept would be a contradiction in terms bcos velocity is necessarily a relational property.

    If we take the real world example of being on a train at rest relative to another train when suddenly they start moving relative to each other. For a moment, we might wonder if it is our train or the other train that is moving.

    Even if we cannot determine which train is absolutely in motion, to my mind, we can deduce that [at least] one of them must be. It's not a question of velocity because it would be true for any relative velocity. It is more a question of which train is actually moving or which one is doing the moving.


  • Advertisement
  • Registered Users Posts: 13 Goosius


    Fourier wrote: »
    Objective Collapse theories have been ruled out experimentally. Even for non-rel QM their parameters have been pushed into fine tuned regions and we have no-go theorems showing they won't work for relativistic theories like quantum field theory.

    Ok no problem. Since the relevant wiki page ("Objective Collapse") today contains no reference to them being "ruled out", since the page actually states that the number of experiments is growing, and since I have seen a few recent interviews of scientists who support this line of investigation, then we will disagree.

    I won't be posting any more replies on that topic.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    Goosius wrote: »
    Ok no problem. Since the relevant wiki page ("Objective Collapse") today contains no reference to them being "ruled out", since the page actually states that the number of experiments is growing, and since I have seen a few recent interviews of scientists who support this line of investigation, then we will disagree.

    I won't be posting any more replies on that topic.
    Wikipedia doesn't keep up with current research and isn't an academic source. Actual monographs about Objective Collapse theories mention what I was saying (I'm not even sure if you've read the wiki page as it mentions what I have said).

    The recent experiment by Donadi et al ruled out the chunk of parameter space left free by previous tests.

    Are you disagreeing based on any actual knowledge or just half reading a wiki page?

    Some people espouse objective collapse but they are very small in number and it seems experimentally ruled out. There used to be a bit more activity in it twenty years ago but very few in the last ten years and virtually none now given recent experimental tests.

    It sounds like you evaluate scientific ideas in unscientific ways. If you're trying to submit to a journal then referencing wikipedia to back your understanding seems like a bad way to go. It seems like you've submitted a paper on entanglement without fully understanding entanglement or current research.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    I'm not suggesting the idea of absolute velocity though. To my mind, velocity must always be relative to something. That would, again to my mind, make the idea of absolute velocity a contradiction in terms.
    It's not as there are well-defined theories with absolute velocity. They're experimentally wrong, but the notion isn't a contradiction in terms.
    As mentioned above, I'm not suggesting the idea of an absolute velocity. I think such a concept would be a contradiction in terms bcos velocity is necessarily a relational property.
    I've said this a few times now, it's not necessarily a relational property. It turned out to be, but there are self-consistency models where it is not.

    If I'm taking the time to answer and explain can you please not repeat this habit of just constantly claiming something is true when I have described to you literal proofs that something is wrong. I said above that Aristotelian bundle models have absolute motion. It's a completely well defined notion since these models exist, thus it is just pointless to keep saying "absolute velocity is a contradiction in terms".
    roosh wrote: »
    Even if we cannot determine which train is absolutely in motion, to my mind, we can deduce that [at least] one of them must be. It's not a question of velocity because it would be true for any relative velocity. It is more a question of which train is actually moving or which one is doing the moving.
    What is "absolute motion" distinct from absolute velocity? To my mind absolute motion means you can absolutely, i.e. in all frames, determine they are in motion which means you can determine at least that they have non-zero absolute velocity.

    I don't understand what motion without velocity is here?

    Surely if you are undergoing absolute motion then you are moving with respect to the absolute time and absolute space and thus have a rate of change of absolute space with respect to absolute time and thus have an absolute velocity.

    Regardless nothing you have presented shows one train is absolutely in motion since there's a frame where train A is stopped and B is moving and another where B is stopped and A is moving. There doesn't seem to be any absolute motion here.

    I also don't really understand what this interest in absolute motion is. It's not been part of physics for over 400 years and it has no evidence. It's like constantly trying to find evidence for the primal elements of Greek theology.


  • Registered Users Posts: 8,472 ✭✭✭Quantum Erasure


    Maybe it's just a misunderstanding of the term 'absolute'. Is motion occurring? Absolutely. Is it absolute? No.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    Maybe it's just a misunderstanding of the term 'absolute'. Is motion occurring? Absolutely. Is it absolute? No.
    Yeah in every frame the two objects are moving with respect to each other. So in all frames there is relative motion between them. But in some frames one of them will be at rest.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    It's not as there are well-defined theories with absolute velocity. They're experimentally wrong, but the notion isn't a contradiction in terms.


    I've said this a few times now, it's not necessarily a relational property. It turned out to be, but there are self-consistency models where it is not.

    If I'm taking the time to answer and explain can you please not repeat this habit of just constantly claiming something is true when I have described to you literal proofs that something is wrong. I said above that Aristotelian bundle models have absolute motion. It's a completely well defined notion since these models exist, thus it is just pointless to keep saying "absolute velocity is a contradiction in terms".


    What is "absolute motion" distinct from absolute velocity? To my mind absolute motion means you can absolutely, i.e. in all frames, determine they are in motion which means you can determine at least that they have non-zero absolute velocity.

    I don't understand what motion without velocity is here?

    Surely if you are undergoing absolute motion then you are moving with respect to the absolute time and absolute space and thus have a rate of change of absolute space with respect to absolute time and thus have an absolute velocity.
    The contradiction in terms is in the definition of something absolute as being relative to something. To define absolute velocity as velocity relative to an absolute reference frame is to define absolute velocity as relative velocity.

    Absolute motion would be prior to any measurement of the relative velocity. It would be a yes/no question as opposed to a question of quantity.

    Fourier wrote: »
    Regardless nothing you have presented shows one train is absolutely in motion since there's a frame where train A is stopped and B is moving and another where B is stopped and A is moving. There doesn't seem to be any absolute motion here.
    This appears to go back to the initial issue of reference frames and their being mathematical artefacts. When we say there is a frame where train A is stopped, the consequence of this is that the frame and the train are something different and train A is not in motion relative to the reference frame.

    But, when we take the reference frame as being the model of the train itself, then the statement is simply that train A is at rest relative to itself. This is true in a world where there is absolute motion also.

    A point that might be worth reiterating is not that it can be demonstrated that one of the trains is absolutely in motion, it seems to be the case that it cannot, but rather we can deduce that one of them must be and thereby conclude that there is absolute motion.
    Fourier wrote: »
    I also don't really understand what this interest in absolute motion is. It's not been part of physics for over 400 years and it has no evidence. It's like constantly trying to find evidence for the primal elements of Greek theology.
    On a basic level, I'm just interested in what conclusions we can draw about the world we live in.


  • Registered Users Posts: 2,553 ✭✭✭roosh


    Maybe it's just a misunderstanding of the term 'absolute'. Is motion occurring? Absolutely. Is it absolute? No.

    If a police officer tries to apprehend a suspect and the suspect starts running away. Did the suspect move or was it the police officer?

    In both frames they are moving relative to each other, and in their respective frames each is at rest relative to themselves or their "frame". But without one of them moving, in an absolute sense, there would be no relative motion between them - they would remain static relative to each other.

    This is where I was thinking free will might be used to conceptually establish which of the two is absolutely moving, although the equivalence principle might preclude concluding which of the two are absolutely moving.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    The contradiction in terms is in the definition of something absolute as being relative to something. To define absolute velocity as velocity relative to an absolute reference frame is to define absolute velocity as relative velocity.
    That's not what these models do though nor is it what I am discussing. They just have absolute motion.
    This appears to go back to the initial issue of reference frames and their being mathematical artefacts
    But they're not mathematical artefacts. As I've said this thing of just repeating your own convictions endlessly is tiring. Get a basic book on college physics and you'll see how they are a mathematical model of a physical set up. This is something that's come up a few times and where your lack of knowledge of the mathematics means you don't really understand what the mathematics is doing in a physical theory. Saying "a reference frame is a mathematical artefact" is like reading a book about plants and saying that "ecosystem is a linguistic artefact". Mathematics is just the language in which you speak about physics.
    A point that might be worth reiterating is not that it can be demonstrated that one of the trains is absolutely in motion, it seems to be the case that it cannot, but rather we can deduce that one of them must be and thereby conclude that there is absolute motion.
    You've never shown how one does this though and we know from QFT that nothing will allow you to do this.
    On a basic level, I'm just interested in what conclusions we can draw about the world we live in.
    But we already know this. We know what you are trying to establish doesn't exist. If you were simply interested in what we could conclude you'd just learn the current theories. Why try again and again to see if you are able to reintroduce 400 year old notions? There's no reason.


  • Registered Users Posts: 10,558 ✭✭✭✭Fourier


    roosh wrote: »
    In both frames they are moving relative to each other, and in their respective frames each is at rest relative to themselves or their "frame". But without one of them moving, in an absolute sense, there would be no relative motion between them - they would remain static relative to each other.
    This is where you are tripping up. Just because they are in relative motion with respect to each other does not mean one is absolutely moving. You've never described the experimental protocol that shows one is absolutely moving. What quantity can I measure to conclude this?


  • Advertisement
  • Registered Users Posts: 2,553 ✭✭✭roosh


    Fourier wrote: »
    That's not what these models do though nor is it what I am discussing. They just have absolute motion.
    Not absolute velocity then?

    Fourier wrote: »
    But they're not mathematical artefacts. As I've said this thing of just repeating your own convictions endlessly is tiring. Get a basic book on college physics and you'll see how they are a mathematical model of a physical set up. This is something that's come up a few times and where your lack of knowledge of the mathematics means you don't really understand what the mathematics is doing in a physical theory. Saying "a reference frame is a mathematical artefact" is like reading a book about plants and saying that "ecosystem is a linguistic artefact". Mathematics is just the language in which you speak about physics.
    If I walk through my reasoning, you might be able to identify where I am falling down. I don't think I am, but it may make any incorrect assumptions more apparent.

    The issue, as I see it, stems from statements such as "there's a frame where train A is [at rest] and B is moving". I've changed the word "stopped" to "at rest" here. With this statement, the obvious question is, relative to what is train A at rest? Bear in mind, that we are talking about a universe that is otherwise empty, except for train A and train B.

    You mentioned previously that reference frames are not mathematical artefacts rather they are "they are a mathematical model of a physical set up". In this case, the physical set up is the two trains. This would make each reference frame a mathematical model of each train.

    In this context, the statement that "there's a frame where train A is [at rest] and B is moving" is simply the statement that train A is at rest relative to itself. This is of course always true of train A, even if it were absolutely in motion.

    Now, we can seek to expand the physical set-up to include rods and synchronised clocks, spread throughout the Universe, relative to which train A always remains at rest, but we can treat these as extensions of the train itself. The slightly changes the question because now train B is suddenly moving relative to train A and those rods and clocks. We would then deduce that either train A and the rods and clocks started moving, or train B did.

    Fourier wrote: »
    You've never shown how one does this though and we know from QFT that nothing will allow you to do this.
    Nothing will allow us to determine which of the two trains is absolutely moving, but I think we can still deduce that one of them must be, which would be sufficient.

    Let's say that you and I are standing face to face, at rest relative to each other. What would be required for relative motion to occur between us? [inert joke here]. It would take for one of us to move. As soon as one of us moves, we are both moving relative to each other. But one of us has to move. I was thinking that free will play a role here, but we might arrive at the same conclusion without it.
    Fourier wrote: »
    But we already know this. We know what you are trying to establish doesn't exist. If you were simply interested in what we could conclude you'd just learn the current theories. Why try again and again to see if you are able to reintroduce 400 year old notions? There's no reason.
    I'm familiar with the idea that our current theories say there is no such thing as absolute motion but my reasoning makes me inclined to believe that there must be.


Advertisement