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Does Special Relativity contain contradictions?

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Halc
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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 5:43 pm

Halc wrote:
October 5th, 2018, 3:25 pm
Tamminen wrote:
October 5th, 2018, 10:22 am
Reference https://www.physicsforums.com/threads/e ... on.810369/
I've learned not to get my physics from forum posts until I know the poster knows what he's talking about. This one cannot explain things for one, and the physics seems wrong.
I think I see what they're trying to describe, and yes, it is strictly SR putting clocks out of sync at front and back of rocket due to change of inertial frame. The frame change does it, not the acceleration. I would propose that they instead comment on my clock-in-a-centrifuge proposal.

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Re: Does Special Relativity contain contradictions?

Post by David Cooper » October 5th, 2018, 6:03 pm

Halc wrote:
October 5th, 2018, 5:34 pm
David interprets all such discussions with his own private definitions of the words, and is thus going to assert that the simultaneity lines do not correspond to his personal vision of an underlying reality, and so are wrong (as are all the clocks). He is utterly unwilling to read a description in the language defined by the author of that description. He's capable of it, but unwilling.
The underlying reality is revealed when two clocks are reunited after being separated. How things appear while they're apart can be highly misleading, and the claims generated from the two frames used during a trip are clearly not both providing good commentary on the underlying reality. If you take those claims at face value, you get a contradiction at the end because you say that your clock ran faster than the stay-at-home clock on both legs of your trip, and then at the end of the trip you get a claim direct from the two clocks that tells you the opposite. Why would you take seriously these in-transit measurements, at least one of which has now been shown to be false?

Are you trying to have your cake and eat it by having D>L and E>S as well, or do you recognise the mathematical impossibility of both of those being true at once?

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 6:34 pm

David Cooper wrote:It would be better to do it for experiment 4:-

Expt 4.
CD moves at speed -v relative to CE the entire time.
CD moves at speed -v relative to CL during leg 1.
CD moves at speed 0 relative to CS during leg 1.
CE moves at speed 0 relative to CL during leg 1.
CE moves at speed v relative to CS during leg 1.
CS moves at speed -v relative to CL during leg 1.
OK. Only leg 1 described. Initial relative positions not given. Relative speeds of 4 clocks given. So:

CD and CS are co-moving. So they're effectively the same. Call them A.
CL and CE are co-moving. So they're effectively the same. Call them B.
A and B are moving apart at speed v. A to the left. B to the right.

You're just describing two clocks moving apart from each other at speed v. See earlier explanations.
Halc wrote:You got it right, but not sure for whose benefit it was posted.
Mostly for mine as it's been quite a while since I've revised this stuff. It's interesting.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 7:01 pm

Halc wrote:David interprets all such discussions with his own private definitions of the words, and is thus going to assert that the simultaneity lines do not correspond to his personal vision of an underlying reality, and so are wrong (as are all the clocks). He is utterly unwilling to read a description in the language defined by the author of that description.
As I've said to him before, the underlying issue is that he and I disagree as to what physics is.
He's capable of it, but unwilling.
He may or may not also be capable of learning some of the background physics - the stuff that most people learn as the basis for the more advanced level physics of such things as Special Relativity, Quantum Mechanics, Statistical Mechanics etc. If someone is not willing to do something then it's not really possible to tell if they're capable of doing it. They may be. But the proof of the pudding is in the eating.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 8:07 pm

More detail:
David Cooper wrote:// Experiment 4
CD stands still relative to CA throughout .
CE moves at speed v relative to CA throughout.
CL moves at speed v relative to CA during leg 1 and at -v relative to CA during leg 2.
CS stands still relative to CA during leg 1 and moves at a speed much higher than v relative to CA during leg 2.
Leg 1: CL and CE co-moving. CD, CS and CA co-moving. So it's effectively just 2 clocks separating at speed v.

Leg 2: CD and CA are effectively the same clock throughout, so giving them separate names is superfluous. CA is a completely superfluous clock. So 4 objects moving at 4 different speeds relative to any given reference frame.
The tick rates during the first leg are as follows: D=S, L=E, ...
CD and CS are effectively the same clock. CL and CE are effectively the same clock. So obviously true.
... D>L, S>E.
Since, in leg 1, CD = CS (= CA) and CL = CE, the above is really just one inequality concerning 2 clocks separating at speed v. CD to the left. CL to the right. So you're simply claiming that there is some sense in which one of those clocks is ticking faster than the other. You've presumably tossed a coin and decided that it is the one that is moving to the left: CD.
That was because you changed frame between experiments, and changing frame is an illegal move if you're going to combine measurements from two frames.
Wrong. The reference frames that matter are those against which measurements are made, not the one against which we decide to describe relative speeds. What I did in the post to which you objected was to show that the relative movements of those reference frames are the same for all 3 experiments.

It's like this: Consider car A moving along road A at 60mph relative to that road. Consider car B moving along road B at 60mph relative to that road. If road A is road B, then the experiments are identical. If road A is moving at constant velocity relative to road B, then the experiments are identical. That is what you appear to be denying.
With experiment 4, it becomes easy to see why changing frame is cheating. Let's change frame and see what it does to experiment 4. The change of frame forces us to use CA2 instead of CA in order to maintain full symmetry (with CA2 being at rest in this new frame):-

// Experiment 4
CD moves at -v relative to CA2 throughout.
CE stands still relative to CA2 throughout.
CL stands still relative to CA2 during leg 1 and moves faster (negatively) than -v relative to CA2 during leg 2.
CS moves at -v relative to CA2 during leg 1 and at v relative to CA2 during leg 2.
The relative velocities of CD, CE, CL and CS are the same in both legs as they were before. Various other clocks, moving relative to these clocks in various ways, may or may not be present. They are irrelevant to our measurements.
The tick rates during the first leg are as follows: D=S, L=E, E>S, L>D.
OK, so as above CD = CS and CL = CE. So you have 2 clocks (CD and CL) separating at speed v, as before. You've tossed your coin again and this time you've decided that it's the one moving to the right that is, in some sense, ticking faster. What is it? Heads = left, tails = right?
The reason your frame change is an illegal move is that you're taking D>L from the first frame and S<E from the second.
No you are the one asserting relative tick rates here. As I've said, when we gather together all clocks that are co-moving and treat them as single clocks then it's simply 2 clocks separating at speed v in leg 1. You have arbitrarily decided that the left moving clock ticks fastest or the right moving clock ticks fastest with no physical difference between the two, accept for an irrelevant CA or CA2 (or any number of other irrelevant clocks) floating around.

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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 8:30 pm

Steve3007 wrote:
October 5th, 2018, 7:01 pm
As I've said to him before, the underlying issue is that he and I disagree as to what physics is.
OK, that as well.
He's capable of it, but unwilling.
He may or may not also be capable of learning some of the background physics - the stuff that most people learn as the basis for the more advanced level physics of such things as Special Relativity, Quantum Mechanics, Statistical Mechanics etc. If someone is not willing to do something then it's not really possible to tell if they're capable of doing it. They may be. But the proof of the pudding is in the eating.
I read him quite differently on this point.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 8:33 pm

Halc, look at my most recent post, in reply to David, and then tell me if you still think David is competent but merely using words in a different way. As I said in that post, we are considering a very, very simple situation of two clocks separating at speed v. David has got so confused and fixated by the idea of absolutes that he's driven to saying opposite things about precisely the same experiment, depending on the movements of some irrelevant other clock.

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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 8:51 pm

I read up on the acceleration thing, and the sites seem to say that acceleration itself does not dilate clocks. Clocks at the front and back of a rocket get out of sync due to being considered stationary in different frames, but that is just SR. The accelerated clocks might run faster even, depending on frame of choice.

The equivalence principle just says that there is no local test to distinguish resistance to gravity from acceleration. A clock at the top and bottom of a building is not a local test.

Time is dilated due to speed, and due to negative gravitational potential. Acceleration plays no role.

I didn't like the time-dilation-in-general-relativity article. It misrepresents things like this:
"Einstein’s principle of equivalence tells us that whatever is true for acceleration is true for a gravitational field."

The equivalence principle says that people on a planet or in an accelerating box make identical measurements over a short enough interval of space and time, they will get identical results; no local experiment will be able to distinguish the two. Time dilation cannot be locally detected. It is a relation with some other reference that is not local.

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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 10:43 pm

Steve3007 wrote:
October 5th, 2018, 8:33 pm
Halc, look at my most recent post, in reply to David, and then tell me if you still think David is competent but merely using words in a different way. As I said in that post, we are considering a very, very simple situation of two clocks separating at speed v.
I haven't been really following the example. I am trying to make sense of experiment 4, where speeds are sort of defined, but starting points are not. There are a lot more than 2 clocks. I have A E L S D at least.
L and S accelerate between legs, so those are the 'travelers' so to speak, out and back from A/D and from E respectively perhaps.
Steve3007 wrote:
October 5th, 2018, 8:07 pm
More detail:
David Cooper wrote:// Experiment 4
CD stands still relative to CA throughout .
CE moves at speed v relative to CA throughout.
CL moves at speed v relative to CA during leg 1 and at -v relative to CA during leg 2.
CS stands still relative to CA during leg 1 and moves at a speed much higher than v relative to CA during leg 2.
Leg 1: CL and CE co-moving. CD, CS and CA co-moving. So it's effectively just 2 clocks separating at speed v.

Leg 2: CD and CA are effectively the same clock throughout, so giving them separate names is superfluous. CA is a completely superfluous clock. So 4 objects moving at 4 different speeds relative to any given reference frame.
All this is true only if all 5 clocks are in the same location to begin with. Maybe they are, but that isn't yet stated here.
... D>L, S>E.
Since, in leg 1, CD = CS (= CA) and CL = CE, the above is really just one inequality concerning 2 clocks separating at speed v. CD to the left. CL to the right. So you're simply claiming that there is some sense in which one of those clocks is ticking faster than the other. You've presumably tossed a coin and decided that it is the one that is moving to the left: CD.
Yes, that statement lacks a frame reference. The beginning has references, but they're dropped here. I notice L is not declared to be stationary relative to E at first.
David wrote:That was because you changed frame between experiments, and changing frame is an illegal move if you're going to combine measurements from two frames.
Wrong.
I'm missing context of what David is talking about here. I don't see measurements being 'combined'.
David wrote:With experiment 4, it becomes easy to see why changing frame is cheating. Let's change frame and see what it does to experiment 4. The change of frame forces us to use CA2 instead of CA in order to maintain full symmetry (with CA2 being at rest in this new frame):-

// Experiment 4
CD moves at -v relative to CA2 throughout.
CE stands still relative to CA2 throughout.
CL stands still relative to CA2 during leg 1 and moves faster (negatively) than -v relative to CA2 during leg 2.
CS moves at -v relative to CA2 during leg 1 and at v relative to CA2 during leg 2.
This is different than the experiment 4 above. Maybe it should have got a new number. A and D were stationary relative to each other before.
It seems to be pretty much the same situation, except CA2 is different, which explains the '2' I guess. All relations seem described from A's perspective, so I'm betting that A is Ether, allowing David to appear to be talking in relative terms when he isn't.
The tick rates during the first leg are as follows: D=S, L=E, E>S, L>D.
Again, no frame reference, so the last two are meaningless outside of David's definitions.
The reason your frame change is an illegal move is that you're taking D>L from the first frame and S<E from the second.
This declaration is consistent with the absolute terminology that David uses. SR would just say D>L in one frame, and L>D in another frame, and L=D in yet another, and the only illegal move is to drop the frame references.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 6th, 2018, 3:12 am

Halc wrote:I haven't been really following the example. I am trying to make sense of experiment 4, where speeds are sort of defined, but starting points are not. There are a lot more than 2 clocks. I have A E L S D at least.
Yes, David defines A, E, L, S and D as the "tick rates" of 5 clocks. The terminology we've now adopted is to prefix with 'C' when referring to the clock. So, for example, CA is a clock. A is its proposed tick rate. David makes claims about relative tick rates and suggests that to deny those claims is to logically contradict oneself. This is the issue at hand.

Yes, starting points are not defined here. Only relative speeds are. But starting points are not relevant to establishing relative tick rates. Two clocks that have zero velocity relative to each other (are stationary WRT the same inertial reference frame) can be agreed to have the same tick rate WRT each other. Therefore, for the purposes of making statements about relative tick rates (as David does), two clocks that are co-moving in this way can be regarded as the same clock. Hence, in the first leg of the experiment there are, for the purposes of considering tick rates, just 2 clock receding from each other at speed v. It is for leg 1 that David makes his statements about relative tick rates, for now.
L and S accelerate between legs, so those are the 'travelers' so to speak, out and back from A/D and from E respectively perhaps.
Yes. But since David's claims about tick rates apply specifically to leg 1, this is not relevant for now. It is only relevant when clocks meet again and the conversation moves on to the "twin paradox", the explanation for which we've both discussed. For now, it's David's claims for tick rates during leg 1, and his claims about people who deny those claims, that are being assessed.
All this is true only if all 5 clocks are in the same location to begin with. Maybe they are, but that isn't yet stated here.
As I say, it's true for the purposes of analyzing David's claims about relative tick rates.
Yes, that statement lacks a frame reference. The beginning has references, but they're dropped here. I notice L is not declared to be stationary relative to E at first.
CL is declared to be stationary relative to CE during leg 1 by stating that they both move at speed v relative to CA during that leg. Hence CL and CE can be regarded as effectively the same clock during leg 1, for the purposes of assessing tick rates.
This is different than the experiment 4 above. Maybe it should have got a new number. A and D were stationary relative to each other before. It seems to be pretty much the same situation, except CA2 is different, which explains the '2' I guess.
The relative movements of CL, CE, CD and CS are the same as they were before. The difference is that CA has been removed and CA2 has been added. None of David's claims about relative tick rates refer to CA or CA2. Therefore those clocks are irrelevant.
All relations seem described from A's perspective, so I'm betting that A is Ether, allowing David to appear to be talking in relative terms when he isn't.
What David appears to be claiming is that replacing CA with a clock that is moving differently from CA, relative to the other 4 clocks, (CA2) changes the things that he can say about those other 4 clocks' relative tick rates. He further claims that not saying those things constitutes us stating mathematical contradictions. This is the root of his "you SR people claim that 1=2" claim. This is why, in my opinion, he cannot simply be said to be saying the same thing but in different language. If either speaker accuses the other of a logical contradiction, then this is not a function of their respective languages. Either they are or they aren't.

When we've distilled experiment 4, leg 1, down to a consideration of 2 clocks separating at speed v (with, or without, another clock, CA/CA2, flying around) David's claim is that there is some objective sense in which one of those clocks ticks faster than the other, or vice versa, and which depends on the movements of that other (A) clock relative to the clocks being considered. And his further claim is that those who deny this are effectively saying that 1=2. Perhaps there's some way that he can get away with the first claim by (as you suggest) somehow associating the A clocks with the ether. But there is no way that the second claim can stand, regardless of any language disagreements.

Changing the languages in which we each speak does not alter the fact that 1 is not 2. Unless we're changing the meanings of the symbols '1' and '2'. Whatever other words we may disagree as to the definition of, we're not doing that!
Again, no frame reference, so the last two are meaningless outside of David's definitions
As I said, for reasons given above, I propose that David's claims are not merely meaningless outside of David's use of language. They are wrong in any language. He, of course, makes the same claim about us if we dispute what he says. And therein lies the dispute.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 6th, 2018, 3:20 am

So, Halc, bearing in mind the above, when David asks you this:
David Cooper wrote:Are you trying to have your cake and eat it by having D>L and E>S as well, or do you recognise the mathematical impossibility of both of those being true at once?
what are your thoughts as to the answer?

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 6th, 2018, 4:04 am

Just to try to put this whole thing to bed and move on with life (and possibly remove any lingering doubts that I'm a bit of a sad obsessive) here is a diagram illustrating the two legs of experiment 4. The top of the diagram shows the movements of CD, CE, CL and CS relative to CA. The bottom of the diagram shows the movements of CD, CE, CL and CS relative to CA. As a reminder they're defined here:
Clocks.png
Clocks.png (8.13 KiB) Viewed 734 times
David Cooper wrote:// Experiment 4
CD stands still relative to CA throughout.
CE moves at speed v relative to CA throughout.
CL moves at speed v relative to CA during leg 1 and at -v relative to CA during leg 2.
CS stands still relative to CA during leg 1 and moves at a speed much higher than v relative to CA during leg 2.
David Cooper wrote:// Experiment 4
CD moves at -v relative to CA2 throughout.
CE stands still relative to CA2 throughout.
CL stands still relative to CA2 during leg 1 and moves faster (negatively) than -v relative to CA2 during leg 2.
CS moves at -v relative to CA2 during leg 1 and at v relative to CA2 during leg 2.

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 6th, 2018, 4:05 am

(Error above, second CA should read CA2.)

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Re: Does Special Relativity contain contradictions?

Post by Tamminen » October 6th, 2018, 4:09 am

Halc wrote:
October 5th, 2018, 8:51 pm
The equivalence principle just says that there is no local test to distinguish resistance to gravity from acceleration. A clock at the top and bottom of a building is not a local test.

Time is dilated due to speed, and due to negative gravitational potential. Acceleration plays no role.
Halc wrote:
October 5th, 2018, 8:51 pm
The equivalence principle says that people on a planet or in an accelerating box make identical measurements over a short enough interval of space and time, they will get identical results; no local experiment will be able to distinguish the two. Time dilation cannot be locally detected. It is a relation with some other reference that is not local.
Yes, I understand now. A good summary of the situation. I had just come to the same conclusion myself. Takes time. Much confusion with this on the net.

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Re: Does Special Relativity contain contradictions?

Post by Halc » October 6th, 2018, 8:53 am

Steve3007 wrote:
October 6th, 2018, 3:12 am
Yes, David defines A, E, L, S and D as the "tick rates" of 5 clocks. The terminology we've now adopted is to prefix with 'C' when referring to the clock. So, for example, CA is a clock. A is its proposed tick rate. David makes claims about relative tick rates and suggests that to deny those claims is to logically contradict oneself. This is the issue at hand.
It isn't a logical contradiction without at least one unstated assumption, that it is meaningful to speak of the tick rate of a clock. Given that assumption (and he assumes it, and you don't), his contradiction is sound logic.
Yes, starting points are not defined here. Only relative speeds are.
The example seemed to get no further than leg 1, and starting points seemed irrelevant. It all seems to hinge on these 'tick rates'.
For now, it's David's claims for tick rates during leg 1, and his claims about people who deny those claims, that are being assessed.
People making and denying the same claims make different unstated assumptions. I read through what David posted and it is quite consistent. I saw no mistakes, except for the lack of explicit statement of that unstated assumption.
Yes, that statement lacks a frame reference. The beginning has references, but they're dropped here. I notice L is not declared to be stationary relative to E at first.
CL is declared to be stationary relative to CE during leg 1 by stating that they both move at speed v relative to CA during that leg.
David does not say this. He never compares CL to CE. All references are to CA, which apparently represents reality. CL has the same velocity as E, yes, but never does he use wording that CA is stationary relative to CE.
None of David's claims about relative tick rates refer to CA or CA2. Therefore those clocks are irrelevant.
They all refer to clocks L and E that are stationary along side CA2, so they're still references only against that one frame. Perhaps that's why extra clocks are needed: to obfuscate the fact that all references are to CA2's frame. Never a relation relative to something not stationary in that frame. That would be an inconsistency in David's definitions of all the terms.
All relations seem described from A's perspective, so I'm betting that A is Ether, allowing David to appear to be talking in relative terms when he isn't.
What David appears to be claiming is that replacing CA with a clock that is moving differently from CA, relative to the other 4 clocks, (CA2) changes the things that he can say about those other 4 clocks' relative tick rates.
Wow, I didn't get that at all. You're interpreting his words using your own definitions of the terms. CA and CA2 are the same clock, and its all the other ones that changed, despite not getting their names changed.
This is the root of his "you SR people claim that 1=2" claim.
He makes the same mistake then, interpreting SR using different definitions of the terms than was meant by the author of SR.
If either speaker accuses the other of a logical contradiction, then this is not a function of their respective languages. Either they are or they aren't.
So you say that this swan is white and not black, but David says that it is black, not white because he labels the colors differently, and thus your statement is a contradiction. The mistake is David using his labels for the colors in interpreting your words, and your mistake is using your definitions of those colors when interpreting David's words. Contradictions only appear when not using the language of the author of the statements made. I found no contradictions in the experiment 4's as described in David's post.
When we've distilled experiment 4, leg 1, down to a consideration of 2 clocks separating at speed v (with, or without, another clock, CA/CA2, flying around) David's claim is that there is some objective sense in which one of those clocks ticks faster than the other, or vice versa, and which depends on the movements of that other (A) clock relative to the clocks being considered.
David does not say this. The two experiments 4 and 4-2 are entirely separate experiments (I see now why they're both called 4) and there is no relation between CA and CA2 since they don't both appear in any one experiment.
Again, no frame reference, so the last two are meaningless outside of David's definitions
As I said, for reasons given above, I propose that David's claims are not merely meaningless outside of David's use of language.[/quote]He's referring to tick rates absent a frame. That is pretty meaningless in the way the two of us define the terms.
They are wrong in any language.
How are they wrong in his language? The terms have meaning there, and L>D is true in the 4-2 experiment, and it would indeed contradict with D>L. In our language, L and D are undefined meaningless values, so statements made about them are meaningless and cannot contradict.

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