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Free Will & Absolute Motion
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29-11-2020 8:52pm#1Just 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?0
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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).0 -
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.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?0 -
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).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.
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.0 -
A frame in which the ship is at rest relative to what?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.0 -
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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.0 -
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.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."
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.Thus the assertion that quantum particles do not possess pre-existing properties prior to measurement, is most certainly not something that we "know"0 -
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.Relative to that 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?0 -
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.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?
Have you read a proper account of what a reference frame is operationally?0 -
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".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?0 -
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I might be missing something in interpreting your statement about there being a reference frame in which the ship is always at rest.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.
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?
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.Have you read a proper account of what a reference frame is operationally?0 -
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.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".
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?0 -
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.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?
Unless you had a physical method to distinguish "relative x/y" from "absolute x/y" which there doesn't seem to be.0 -
Those are measurable properties, but my thinking is that they wouldn't necessarily exhaust the list of conclusions we can draw.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.
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.0 -
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.Measurement by its very nature is a relative process, so the idea that we might measure absolute motion would represent a contradiction in terms
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.0 -
Just out of curiosity as to what those particular theories say, bcos I am not familiar with them.
Is the absolute motion measured relative to something else?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.0 -
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.There would still be relative motion in a world where absolute motion exists0 -
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.0 -
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.we could potentially deduce it from relativity theory
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.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.
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".0 -
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.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.
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.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".
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.0 -
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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.0 -
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).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.
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.0 -
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'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.
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.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 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.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.
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.0 -
Maybe it's just a misunderstanding of the term 'absolute'. Is motion occurring? Absolutely. Is it absolute? No.0
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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.Quantum Erasure wrote: »Maybe it's just a misunderstanding of the term 'absolute'. Is motion occurring? Absolutely. Is it absolute? No.0 -
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.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.
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.
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.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.
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.
On a basic level, I'm just interested in what conclusions we can draw about the world we live in.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.0 -
Quantum Erasure wrote: »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.0 -
That's not what these models do though nor is it what I am discussing. They just have absolute motion.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.
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.This appears to go back to the initial issue of reference frames and their being mathematical artefacts
You've never shown how one does this though and we know from QFT that nothing will allow you to do this.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.
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.On a basic level, I'm just interested in what conclusions we can draw about the world we live in.0 -
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?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.0 -
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Not absolute velocity then?That's not what these models do though nor is it what I am discussing. They just have absolute motion.
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.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.
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.
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.You've never shown how one does this though and we know from QFT that nothing will allow you to do this.
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.
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.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.0 -
"Motion" is a vague pre-physical term.Not absolute velocity then?
The models have absolute velocity. From now on I'd ask you to only use velocity and acceleration to clearly distinguish which you mean when you say "motion".
Has to accelerate. Try phrasing all of this using only physical terms not everyday ones.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
One of us has to accelerate. And since acceleration is an absolute notion every frame would agree that there is some change in our relative velocities.
However this is not absolute velocity, but absolute acceleration.
My point is that all your ideas have the same format: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.
(a) Never learn the actual theories
(b) Never use precise language, but a vague mix of everyday and philosophical language
(c) Try to conclude old intuitive notions that have not been part of physics for over 400 years are still true0 -
The idea that you or I can move our hands or our bodies doesn't seem that vague or pre-physical. This is the idea that the hand is in "motion". The question of absolute motion then would be, is my hand really moving?"Motion" is a vague pre-physical term.
I'm not necessarily referring to either velocity or acceleration. I'm trying to get at something even more fundamental. The idea of movement that isn't relative to something. It's a question of whether or not things are actually moving.The models have absolute velocity. From now on I'd ask you to only use velocity and acceleration to clearly distinguish which you mean when you say "motion".
I know this isn't strictly the case, but rather than write the long form for the point, covering both sides, I'll make an affirmative statement that takes one side of it.Has to accelerate. Try phrasing all of this using only physical terms not everyday ones.
In order to accelerate, a body has to actually move, without actually moving there would be no accelaration. Or we might say that a body which undergoes acceleration must actually move.
It is the notion of absolute velocity which I'm suggesting is a contradiction in terms because it seeks to define absolute velocity as velocity relative to something - that would be relative velocity.One of us has to accelerate. And since acceleration is an absolute notion every frame would agree that there is some change in our relative velocities.
However this is not absolute velocity, but absolute acceleration.
Absolute motion is a question of which of the two things moving relative to one another is actually moving. If one of the bodies must undergo acceleration, then would we not deduce that the body that undergoes acceleration absolutely moves*?
*I expect the equivalence principle is relevant here.
I know that the theories say that absolute motion does not exist and why. It's just that the reasoning that's usually given doesn't seem to address certain very basic facts.My point is that all your ideas have the same format:
(a) Never learn the actual theories
(b) Never use precise language, but a vague mix of everyday and philosophical language
(c) Try to conclude old intuitive notions that have not been part of physics for over 400 years are still true
When I move my hand, that is neither vague nor pre-physical. It's a very clear, obvious and basic observation of the physical world.
The question "is my hand actually moving" is another pretty basic question which makes sense to all but those who seem to have rejected the idea based on [apparent] philosophical or scientific reasoning.
The reasoning appears to be, we cannot determine which body is actually moving, therefore absolute motion doesn't exist. That is a non-sequitir, however because we can deduce that where two bodies are in relative motion one of the bodies must be moving, in an absolute sense.0 -
Yes but physics divides motion into several different aspects and makes distinct claims about each aspect. Thus in just saying "motion" you are eliding all these differences and getting confused as to what physics is specifically saying.The idea that you or I can move our hands or our bodies doesn't seem that vague or pre-physical.
This is what's leading you down this rabbit hole as you seem to believe physics says there is no such thing as absolute motion, where as current physical theories say no such thing. They say there is no absolute velocity.
Thus if we take the motion of some body described by some function x(t) then knowledge of each of the derivatives of this function determine the function. Each derivative has been given a name:
First: Velocity
Second: Acceleration
Third: Jerk
Fourth: Jounce
etc
Physics makes different claims about each.
It says velocity has no absolute meaning. The rest do.
It says fundamental Forces only directly couple to acceleration
Recoil effects are proportional to Jerk
Physical stress limits are related to Jerk and Jounce...etc
Because we are dealing with a precise science, one has to deal with precise terms. You think you are being more "fundamental", you are actually just being more vague. No theory says motion in your vague sense is relative. Every derivative above velocity has an absolute sense. Relativity concerns velocity alone.
Thus this entire discussion is only a result of you not knowing physical terminology.
For the fourth time now. It is not a contradiction in terms because you can construct models in which absolute velocity exists and is well defined. I have given you their name. They are bundle models of Aristotelian physics. Please stop constantly repeating this, I have dealt with it four times nowIt is the notion of absolute velocity which I'm suggesting is a contradiction in terms because it seeks to define absolute velocity as velocity relative to something - that would be relative velocity
The point of physical models is that we have ruled out this model experimentally. Absolute velocity is not a part of our world. This was one of the advances of Newtonian-Galilean physics over previous ideas.
Newtonian-Galilean physics said velocity was relative but space and time were absolutely distinguished and simultaneity was absolute. This is where Special Relativity disagreed.
Thus modern theories say velocity and simultaneity are relative. No theory however has said that motion in general is not absolute.
No it's that you never take the time to actually learn the theories or the relevant terminology and thus have a massively incorrect notion of what is being said. I've counted at least eight physicists you've referenced in discussions I've seen where you've fundamentally misunderstood what they were saying since you don't the meaning of the precise words they use.It's just that the reasoning that's usually given doesn't seem to address certain very basic facts0 -
OK, so this is contrary to discussions I have had previously on here, where it was stated that absolute motion, specifically, is ruled out.Yes but physics divides motion into several different aspects and makes distinct claims about each aspect. Thus in just saying "motion" you are eliding all these differences and getting confused as to what physics is specifically saying.
This is what's leading you down this rabbit hole as you seem to believe physics says there is no such thing as absolute motion, where as current physical theories say no such thing. They say there is no absolute velocity.
I have no issues with the idea of absolute velocity being ruled out.
Thanks Fourier, I am familiar with the first and second derivatives but not the subsequent ones.Thus if we take the motion of some body described by some function x(t) then knowledge of each of the derivatives of this function determine the function. Each derivative has been given a name:
First: Velocity
Second: Acceleration
Third: Jerk
Fourth: Jounce
etc
Physics makes different claims about each.
It says velocity has no absolute meaning. The rest do.
It says fundamental Forces only directly couple to acceleration
Recoil effects are proportional to Jerk
Physical stress limits are related to Jerk and Jounce...etc
I see. Thank you. This does appear to be contrary to what I've encountered in other discussion where I have made the same distinction between absolute velocity and absolute motion.Because we are dealing with a precise science, one has to deal with precise terms. You think you are being more "fundamental", you are actually just being more vague. No theory says motion in your vague sense is relative. Every derivative above velocity has an absolute sense. Relativity concerns velocity alone.
Apologies, I must be misinterpreting your previous statements. Here are the comments in order:For the fourth time now. It is not a contradiction in terms because you can construct models in which absolute velocity exists and is well defined. I have given you their name. They are bundle models of Aristotelian physics. Please stop constantly repeating this, I have dealt with it four times nowThe 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.Not absolute velocity then?"Motion" is a vague pre-physical term.
The models have absolute velocity.
These models have absolute velocity but the velocity is not measured relative to something, is that correct?
To clarify the point I was making, defining absolute velocity as velocity relative to an absolute reference frame would be a contradiction in terms because it defines absolute velocity as relative velocity.
If there are theories that define absolute velocity in another way i.e. not relative to something else, then this would not be a contradiction in terms.
There is some confusion here because I never stated that it was.The point of physical models is that we have ruled out this model experimentally. Absolute velocity is not a part of our world. This was one of the advances of Newtonian-Galilean physics over previous ideas.
In presentist interpretations of relativity, wouldn't simultaneity be absolute; with the "relativity of simultaneity" being akin to local time in the Lorentzian interpretation?Newtonian-Galilean physics said velocity was relative but space and time were absolutely distinguished and simultaneity was absolute. This is where Relativity disagreed.
Thus modern theories say velocity and simultaneity are relative. No theory however has said that motion in general is not absolute.
I appreciate your correcting me along the way. As with here, where I was under the misapprehension that it was absolute motion that was ruled out of physical theories when in fact it was absolute velocity.No it's that you never take the time to actually learn the theories or the relevant terminology and thus have a massively incorrect notion of what is being said. I've counted at least eight physicists you've referenced in discussions I've seen where you've fundamentally misunderstood what they were saying since you don't the meaning of the precise words they use.
I'm not sure why my example caused such an issue though, if we can say that [at least] one of the trains is in absolute motion.0 -
If this refers to discussions with Morbert I think he took your "motion" to mean velocity. He was just trying to disambiguate the term and made a guess.OK, so this is contrary to discussions I have had previously on here
They have absolute velocity not relative to anything.If there are theories that define absolute velocity in another way i.e. not relative to something else, then this would not be a contradiction in terms.
I'm just explaining Newtonian-Galilean physics to make it clear how it advanced over previous notions so you can see the progression of ideas. It's not meant to be a counterpoint to anything you said.There is some confusion here because I never stated that it was.
No absolutely not.In presentist interpretations of relativity, wouldn't simultaneity be absolute
The issue was one of confusion since you weren't being precise.I'm not sure why my example caused such an issue though
I said a few times the acceleration was absolute but the velocity wasn't. From your posts it was hard to tell if by motion you meant velocity or something more general. You then introduced further confusion (reference frames are artefacts, absolute velocity is a contradiction in terms).
My taking of "motion" to mean velocity is exactly what happened with Morbert, since from our perspective if you meant motion in general it wouldn't even be worth pointing out. Since you were presenting it as contrary to usual physics the natural assumption is that by motion mean you mean velocity. Confusing two people because you try to discuss subjects without ever bothering to learn them and their terminology and then describing that as them confusingly "having an issue" is lazy.
"I will constantly argue against scientific theories and never learn them. Please recognise my own imprecisions as quickly as possible while educating me for free. Any misunderstandings resulting from my odd stance are issues on your end"0 -
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I'm pretty sure that isn't the case. He was arguing against the idea that one of two bodies actually moves, with the term actually being the point of contention.If this refers to discussions with Morbert I think he took your "motion" to mean velocity. He was just trying to disambiguate the term and made a guess.
I see, thank you.They have absolute velocity not relative to anything.
Thanks. I'm familiar with that from my discussions with Morbert. It seems as though the confusion is arising from the idea of absolute velocity. I outlined the interpretation of absolute velocity I was referring to.I'm just explaining Newtonian-Galilean physics to make it clear how it advanced over previous notions so you can see the progression of ideas. It's not meant to be a counterpoint to anything you said.
This is my understanding, based on discussions with Morbert.No absolutely not.
If there is a universal now, which is true for all observers, then, as a matter of necessity simultaneity must be absolute.
The relativity of simultaneity contradicts this idea, saying that there is no universal now for all observers.
A consequence of RoS is that the past and future of every observer is as equally real as their present - if only their present were real, then we would have absolute simultaneity, as above.
The following is from more recent discussions:
If an observer's future is as real as their present it means that their choices are pre-determined/deterministic. This would contradict the principle of free will.
I think a contributory factor was that you were assuming I meant something other than what I had said.The issue was one of confusion since you weren't being precise.
And I clarified that defining absolute velocity relative to an absolute reference frame is a contradiction in terms because it defines relative velocity as absolute velocity.I said a few times the acceleration was absolute but the velocity wasn't. From your posts it was hard to tell if by motion you meant velocity or something more general. You then introduced further confusion (reference frames are artefacts, absolute velocity is a contradiction in terms).
The question of reference frames as mathematical artefacts stems from the statement that there is always a frame in which Train A is at rest. This begged the question, relative to what is Train A at rest, given that it was specified from the beginning that we were talking about an otherwise empty universe, save for the two trains.
If the answer to the question, relative to what is train A at rest, is "its reference frame", this implies, in an otherwise empty universe, that the train is at rest relative to a set of mathematical coodrindates.
If by "reference frame" we mean introducing measuring rods and synchronised clocks which are always at rest relative to the train, then we are simply modifying the problem. The scenario is no longer that of two trains moving relative to each other but two trains and their associated rods and clocks moving relative to each other.
This means that the statement about the train being at rest in a given frame doesn't make the point that you think it is making - or perhaps that addresses the question - bcos the frame can be treated as an extension of the train - given that they are always at rest relative to each other.
That wasn't the nature of my discussion with Morbert.My taking of "motion" to mean velocity is exactly what happened with Morbert, since from our perspective if you meant motion in general it wouldn't even be worth pointing out. Since you were presenting it as contrary to usual physics the natural assumption is that by motion mean you mean velocity. Confusing two people because you try to discuss subjects without ever bothering to learn them and their terminology and then describing that as them confusingly "having an issue" is lazy.
The question at hand can be illustrated using a very simple and easy to grasp example."I will constantly argue against scientific theories and never learn them. Please recognise my own imprecisions as quickly as possible while educating me for free. Any misunderstandings resulting from my odd stance are issues on your end"
Two students sitting in a classroom. The teacher has to leave the room and tells them not to move. Whoever moves will be punished. The teacher leaves and returns and notices that there is a bigger distance between the two students than when he left.
The teacher deduces that there are only two possible scenarios:
1) One of the students moved.
2) Both of the students moved.
Note, we're not talking about acceleration or velocity here, we're talking about something more basic or fundamental. Acceleration and velocity are not necessary in this question - they may indeed have occurred, but they are not necessary for the teachers conclusion.
To say that there is always a frame in which each student was at rest makes no difference. We conclude that [at least] one of the students actually moved [in an absolute sense].
In my discussions with Morbert, he would have argued that we cannot conclude that one of the students actually moved for the same reason you have given previously - because there is a frame in which each student is always at rest.0 -
[edit] - posted before seeing the other pages of this thread. Deleting0
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I'm pretty sure that isn't the case. He was arguing against the idea that one of two bodies actually moves, with the term actually being the point of contention.
I don't remember all the details of the convo butJust 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?
I would echo this. We can reject absolute velocity as a physical property without also rejecting assertions about relative velocity. I can't remember if I made distinction between actual and absolute in the context of a previous convo but if I did feel free to show it to me.If the answer to the question, relative to what is train A at rest, is "its reference frame", this implies, in an otherwise empty universe, that the train is at rest relative to a set of mathematical coodrindates.
Yes. There is no sense of the train being at absolute rest.0 -
Just having a quick read back over this thread and I think I've misremembered some details myself - not all, but some.I don't remember all the details of the convo but
Just in case I am misremembering details of our other discussions - although this one I'm pretty sure I'm not - am I right in saying that the Relativity of Simultaneity is contradictory to presentism; and as such, implies that past and future exist ala the Block Universe?
I was misremembering that you did initially emphasise the point about absolute velocity. I'm not sure if we talked past each other somewhat on that because I was trying to emphasise that I wasn't talking about absolute velocity. We did move on from that, somewhat, to the idea of "intrinsic" motion.I would echo this. We can reject absolute velocity as a physical property without also rejecting assertions about relative velocity. I can't remember if I made distinction between actual and absolute in the context of a previous convo but if I did feel free to show it to me.
PostMorbert wrote:This does not establish any form of "intrinsic" motion independent of reference frames.
In general this was the discussion about which of two relatively moving bodies is actually moving. Or in the example above, with the Garda and the criminal, who is it that does the moving.
This was an issue that arose in the previous discussion also. We can forget about the idea of absolute rest altogether bcos that isn't my contention.Yes. There is no sense of the train being at absolute rest.
To my mind, there is an issue with saying "there is a frame in which train A is always at rest". The reason being, we can specify from the outset that the Universe is empty other than for the two trains.
This then begs the question, relative to what is train A at rest? It isn't train B, since train A and B are moving relative to each other.
If the answer to this is "the co-ordinate reference frame", the issue is that co-ordinate reference frames are mathematical artefacts relative to which bodies do not move, in the [physical] Universe.
We can of course theoretically construct the physical analog of the co-ordinate frame, using synchronised clocks and measuring rods but:
a) we have specified at the outset that the Universe is empty other than for the two trains.
b) if we do "construct" the physical analog of the co-ordinate reference frame, then we have only slightly changed the scenario. The physical analog of the co-ordinate reference frame can be viewed as an extension of the train - since they are always at rest relative to each other. We are still left with the question of relative to what is train A at rest (given the rods and clocks can be affixed to the train without an consequence).
Alternatively, our scenario simply becomes one where train A and its clocks and rods are moving relative to train B and its clocks and rods.0 -
If the answer to this is "the co-ordinate reference frame", the issue is that co-ordinate reference frames are mathematical artefacts relative to which bodies do not move, in the [physical] Universe.
This wouldn't be an issue. Relative velocity can be understood as a choice of description. It might be better in this context to call it a co-ordinate velocity. So e.g. "The co-ordinate velocity of train A is 0" can be understood as "Upon application of this co-ordinate system, the quantity dx/dt of the train is 0"0 -
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This would remain true for train A if it were in a state of absolute motion*.This wouldn't be an issue. Relative velocity can be understood as a choice of description. It might be better in this context to call it a co-ordinate velocity. So e.g. "The co-ordinate velocity of train A is 0" can be understood as "Upon application of this co-ordinate system, the quantity dx/dt of the train is 0"
*Note, I'm not talking about absolute velocity here.
Is your position still the same with regard to presentism and relativity? Am I remembering the following conclusion correctly?roosh wrote:the Relativity of Simultaneity is contradictory to presentism; and as such, implies that past and future exist ala the Block Universe?0 -
This would remain true for train A if it were in a state of absolute motion*.
I was specifically addressing the issue "co-ordinate reference frames are mathematical artefacts relative to which bodies do not move, in the [physical] Universe." re/ describing train A as at rest. We can apply a co-ordinate frame and describe train A as at rest without needing to worry about conjuring up some ancillary system that justifies this description.
Re/ Presentism etc. It has been a while since I have thought about the issues. I do not think relativity is a priori incompatible with presentism as a metaphysical property of the world, but I have also seen little motivation/success re/ introducing it to physical models.*Note, I'm not talking about absolute velocity here.
I don't know what you mean by this. I also don't know what you mean when you describe the co-ordinate system as an artefact.0 -
Thanks Morbert, I understand that. I'm saying we could do this also if train A were in a state of absolute motion.I was specifically addressing the issue "co-ordinate reference frames are mathematical artefacts relative to which bodies do not move, in the [physical] Universe." re/ describing train A as at rest. We can apply a co-ordinate frame and describe train A as at rest without needing to worry about conjuring up some ancillary system that justifies this description.
In the example of our empty universe with the two trains, at rest relative to each other. When the trains start moving relative to each other, the observer in the train has that split second question of, is it my train that is moving, or is it the other train? They obviously know that their train is moving relative to the other train, but the question points to a more fundamental, absolute aspect of motion.
As far as I am aware, the mathematics of relativity are not incompatible with presentism. I believe Lorentz's competing Ether Theory was predicated on the notion of absolute simultaneity. From what I can gather, neo-Lorentzian relativtiy is a more modern interpretation that has removed any vestiges of the ether and is empirically equivalent to Special Relativity. The last I had read though, there had been no successful attempt to generalize neo-Lorentzian relativity. But it does, I believe, demonstrate that the mathematics of relativity is compatible with absolute simultaneity.Re/ Presentism etc. It has been a while since I have thought about the issues. I do not think relativity is a priori incompatible with presentism as a metaphysical property of the world, but I have also seen little motivation/success re/ introducing it to physical models.
Absolute simultaneity would be a particular signature of presentism in that presentism is the position that only the present moment exists, which is the same for all observers. In my best attempt to use the appropriate terms, it is the position that there exists only a single foliation* of spacetime, a single simultaneity hypersurface* or "slice".
Relativity of Simultaneity (RoS) then, would be contradictory to the notion of absolute simultaneity. A consequence of RoS, as you were patient enough to explain to me, is that past and future states of the Universe are equally as real as present states - a model colloquially known as "the Block Universe".
This would appear to make RoS incompatible with free will, if I'm not mistaken.
*I've butchered those terms haven't I?0 -
Thanks Morbert, I understand that. I'm saying we could do this also if train A were in a state of absolute motion.
In the example of our empty universe with the two trains, at rest relative to each other. When the trains start moving relative to each other, the observer in the train has that split second question of, is it my train that is moving, or is it the other train? They obviously know that their train is moving relative to the other train, but the question points to a more fundamental, absolute aspect of motion.
I don't know what you mean by motion here, absolute or otherwise. On the same note, the observer in the train should ask a more precise question. One like "What is the co-ordinate velocity of my train?" Or "Is my train undergoing proper acceleration?"0 -
I suppose I mean it in the same sense that, when you move your arm, your arm is in motion i.e. it is your arm that is moving and not your body.I don't know what you mean by motion here, absolute or otherwise. On the same note, the observer in the train should ask a more precise question. One like "What is the co-ordinate velocity of my train?" Or "Is my train undergoing proper acceleration?"0 -
I suppose I mean it in the same sense that, when you move your arm, your arm is in motion i.e. it is your arm that is moving and not your body.
We could e.g. construct a co-ordinate frame that labels your body as at rest and your arm with a co-ordinate velocity v or co-ordinate acceleration a such that ||v(t)|| > 0, ||a(t)|| > 0.
Or if we wanted some invariant quantity like proper acceleration we could compute that easily enough.
"Motion" could be ascribed to any of these quantities. We could in a sense call the latter absolute but not I suspect in a sense suitable for your purposes re/ establishing presentism.0 -
I understand this and I'm not questioning it. But here, as with the train example, you are making the statement that the train is labelled as "at rest". This simply begs the question, relative to what is the train labelled as "at rest"?We could e.g. construct a co-ordinate frame that labels your body as at rest and your arm with a co-ordinate velocity v or co-ordinate acceleration a such that ||v(t)|| > 0, ||a(t)|| > 0.
The answer appears to be "relative to the co-ordinate frame". But the co-ordinate frame does not exist in nature and so the train cannot be at rest relative to it, in any physical sense.
We could of course have two observers on the train each using a different co-ordinate frame, where one labels the train as "at rest" while the other labels it with a co-ordinate velocity. Both perfectly valid and useful. Again however, these co-ordinate frames do not exist in nature and so the train cannot be at rest or in motion relative to it, in any physical sense.
When the trains start off at rest relative to each other and then start moving relative to another, they move relative to each other in a physical sense. When relative motion occurs between two bodies previously at rest, it must be because at least one of them was moving in a physical sense and not just in the sense of relative to the co-ordinate frame.
The principle of relativity together with the equivalence principle says that we cannot determine which of the two is actually moving, but we don't need to be able to determine which is actually moving to conclude that, at least, one of them must be.
The question of presentism is separate to the question of absolute motion, although they may be related, I'm not actually sure."Motion" could be ascribed to any of these quantities. We could in a sense call the latter absolute but not I suspect in a sense suitable for your purposes re/ establishing presentism.
To my mind, and I am certainly open to correction on this, the necessity of free will in quantum mechanics effectively (re)establishes presentism because the alternative is not compatible with free will.
If past and future states co-exist with present states, in a "block-like" structure, it means that there are no free choices for experimenters because the "choosing event" (and its outcomes) co-exists with the birth of the experimenter in the "block universe". It is set in stone even as the experimenter is born.
This appears to be the necessary consequence of the relativity of simultaneity meaning it would be incompatible with free will, which appears to be a necessity of quantum mechanics.0 -
I understand this and I'm not questioning it. But here, as with the train example, you are making the statement that the train is labelled as "at rest". This simply begs the question, relative to what is the train labelled as "at rest"?
The answer appears to be "relative to the co-ordinate frame". But the co-ordinate frame does not exist in nature and so the train cannot be at rest relative to it, in any physical sense.
As I mentioned before, this wouldn't be an issue. Relative velocity can be understood as a choice of description. It might be better in this context to call it a co-ordinate velocity. So e.g. "The co-ordinate velocity of train A is 0" can be understood as "Upon application of this co-ordinate system, the quantity dx/dt of the train is 0".
Therefore, no question is begged.0 -
If we plug this back in as the response to the statement about moving an arm, where it was said that, when I move my arm, it is my arm that is actually moving and not my body:As I mentioned before, this wouldn't be an issue. Relative velocity can be understood as a choice of description. It might be better in this context to call it a co-ordinate velocity. So e.g. "The co-ordinate velocity of train A is 0" can be understood as "Upon application of this co-ordinate system, the quantity dx/dt of the train is 0".
Therefore, no question is begged.
we can indeed apply a co-ordinate system which labels the dx/dt of the arm as 0, or we can apply one which labels it as >0. This is just a way of measuring the relative velocity between the two "bodies" and the tautological value for the relative velocity of an object to itself.
This doesn't mean that the arm isn't actually moving. When I move my arm, it is still the arm that is still actually moving and not the body.
The same is true for the trains. An observer on a train, which is at rest relative to another train, can employ a co-ordinate system which labels the dx/dt of both trains as 0. Then, something happens, and the dx/dt of both trains is no longer 0. That observer can apply a frame which labels his dx/dt = 0 and the other train as >0; or even vice versa.
For the relative velocity between both trains to go from 0 to >0, something has to happen. That something is that at least one of the trains has moved or is moving - both are moving relative to each other, but one of them had to move for there to be relative velocity between them in the first place.0 -
Since you were presenting it as contrary to usual physics the natural assumption is that by motion mean you mean velocity. Confusing two people because you try to discuss subjects without ever bothering to learn them and their terminology and then describing that as them confusingly "having an issue" is lazy.
I was reading back over a few posts and this point struck me. Now, I know you may have been moving relative to Morbert and I at a sizeable fraction of the speed of light and so the order of events may have been different :pac:, but it was actually the case that usual physics was presented as contrary to what I had been saying.0 -
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