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Does Special Relativity contain contradictions?

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David Cooper
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Joined: April 30th, 2018, 4:51 pm

Re: Does Special Relativity contain contradictions?

Post by David Cooper » October 4th, 2018, 4:36 pm

Steve3007 wrote:
October 4th, 2018, 4:31 pm
What I'm rejecting is any idea that the speed of light relative to all observers is c.
As I've said, show me first that you understand why that was proposed in the first place, before rejecting it. If you can't do that simple thing, I'm afraid you can't be taken seriously.
You're the one who can't be taken seriously. You endorse maths riddled with contradictions. You're gone - credibility shot to pieces.

Steve3007
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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 4th, 2018, 4:38 pm

You can't do the maths. In any other context you could, but not here when Einstein's original SR model is destroyed by it. You simply refuse to accept reality.
If anything in the post to which I've repeatedly referred you is incorrect, please tell me explicitly what it is. (Not just general comments about my supposed personal failings.) And we'll take it from there.

Steve3007
Posts: 6053
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Location: UK

Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 4th, 2018, 4:39 pm

You're the one who can't be taken seriously. You endorse maths riddled with contradictions. You're gone - credibility shot to pieces.
I'll add this to the long, long list of content-free ad hominems. I'll let you calm down a bit and maybe talk some more tomorrow.

David Cooper
Posts: 224
Joined: April 30th, 2018, 4:51 pm

Re: Does Special Relativity contain contradictions?

Post by David Cooper » October 4th, 2018, 6:07 pm

Steve3007 wrote:
October 4th, 2018, 4:29 pm
When you talk here, and on your website, about your imagined necessity for this block to be somehow "generated", as it were, from the bottom up, you reveal (it seems to me) a deep misunderstanding of the purpose of models and theories in physics.
Spin. Theories are attempts to explain reality, and SR fails to do that. It should be thrown out, but you cling to it while rejecting a rational alternative theory that accounts for the facts without depending on magic. Physics isn't supposed to be doing magic.
I could speculate as to why that is. I could try to link it to your apparent very strange objectification of other non-physical concepts, like "hate", in other topics. These might indicate your inability to get your head around the idea of an abstraction - something that represents relationships between observables but isn't an observable itself. But then I'd be going down your route of repeated speculations as to the state of mind of my interlocutor. This is against the rules of the forum for good reason.
I've only discussed the state of your mind as a way of spelling out that I'm not making any claims about lack of intelligence on your part. That's important because I don't want it to be taken as an insult. You are falling to pieces on the maths not because you can't do the maths, but because you don't like what it says. As for the issue of "hate", I've simply used the word the way it's currently used - it refers to things which generate terrorism and other abuses. Ten thousand people were killed by people acting on hate in a holy text recently, but some people would rather defend that hate than defend the people who are murdered because of it. Note that I never attack the people who have bought into a religion which propagates hate - I simply condemn the hate and expect them to do likewise and to demonstrate that they oppose it by getting rid of it so that it stops generating more and more genocides. Is it wrong to think that this is the right way forwards for a peaceful world? God's hate should not be tolerated by anyone - if there was a God, he would expect his hate to be rejected by good people and be angry with them if they cling to it.
As I've said before, the reason why you alone concern yourself with "event-meshing failures" is that the concept represents your misunderstanding of what a 4D spacetime graph is and what the concept of a worldline means.
You're mixing models - in set zero models it's not an issue, but event-meshing failures occur in set 1 models. You won't discuss the different models though because you can see that proper, rigorous analysis destroys SR.
If you want to show me I'm wrong, you need to write a program to simulate the same simple event that my simulation covers and show how you avoid event-meshing failures while generating the block. You won't manage it because it's impossible.
I could write a program to demonstrate more clearly, using animation, where you're going wrong in our considerations of the "twin paradox" involving 4 clocks. It would illustrate that each of the 3 experiments transforms into the other, without changing the relative velocities within the experiment, by changing the frame from which the experiment is considered. This is what I've previously explained in words.
You would just reproduce the same cheating models as everyone else, using LET as a mechanism, but changing frame whenever it suits you and pretending that events unhappening and rehappening isn't a problem. And you won't produce event-meshing failures unless you make the program run all clocks at the same ticking rate, so you're not even talking about the right thing here - changing frame doesn't change anything in set 1 models because they're Lorentz invariant, which leads to the exact same event-meshing failures in all frames.
But I'd probably write it in C# using MS Visual Studio. It would be quite a bit of work for me to write it in a form that I could easily share with you. And I'm almost certain that it would do no good. So the effort doesn't seem worthwhile.
It would do no good because you've already explained how you would cheat. The simulation needs to show how to grow a block universe in order of causation, and to avoid event-meshing failures you either have to apply different rates for causation on different paths using an absolute frame mechanism or you end up with a model generating contradictions.
The speed of light as measured by all observers is a constant.
But the speed of light relative to them is not a constant.
I've described, briefly, how this was arrived at empirically elsewhere.
It isn't disputed. It simply isn't the answer to the right question.
if the speed of light is measured to be the same by observers who are moving relative to each other, something interesting must be happening to distance and time.
Nothing exotic is happening to either. Moving clocks simply run slow and their atoms settle closer together in the direction of travel (and the components of atoms do likewise).
If you start with the arena's frame and an object at rest in it, when you switch to a frame moving at 0.99c relative to the arena, you now assert that the speed of light relative to that same object as 0.01c in one direction and 1.99c in the opposite direction.
We assert no such thing. This is where you keep going wrong.
I know you don't assert such a thing, but that's where you go wrong. You reject all frame measurements of the speed of light relative to objects that aren't at rest in that frame. You simply deny them because you've been brainwashed into thinking that's the right way to do things.
The invariance of the physical constants which represent the observed strengths of the electric and magnetic forces leads directly to the invariance of the physical constant that is 'c', via a very simple mathematical relationship. So the invariance of 'c', as measured by any observer is a direct result of the invariance of these other constants as measured by any observer.
You aren't talking about the speed of light relative to them. (Or if you are, then you're making a serious error.)
Now we look at the logical consequences of this. The empirical validity of Maxwell's Equations (demonstrated by such things as Faraday's experiments) means that we cannot assert that anyone will measure the speed of light to be anything other than 'c'.
Not disputed, but not relevant either.
So, logically, we have to examine more carefully the elements of the concept of speed - change in position divided by change in time. And what logically comes out of that is that there is no single, universal "Newtonian" time.
No - that comes out of it illogically. Not logically. It's a belief system based on blind assumption.
Without ever clearly defining your concept of "underlying reality".
You go on a trip away and back and measure your clock to be ticking faster than a stay-at-home clock at all times, but when you get home you find that your clock has run slower than the stay-at-home one. That tells you that your measurements while you were travelling were misleading. The final result reveals the truth about the underlying reality of what happened during your trip.
If you stick to the business of physics and follow the logical consequences of observations you have no contradictions.
Asserting that repeatedly does not overcome the mathematical problem that you are faced with.

D = S
L = E
D > L
Therefore S > E

But you want it to be E > S. Your position is bonkers.
You haven't defined what you mean by a "normal person" but is seems clear that you mean a person using common sense and instinct. Common sense is derived from human-scale surface-of-the-Earth experience. It has fooled people for many years. That is why Aristotle's physics was replaced by Newton's.
A normal person is someone like any competent mathematician who declares that S > E in the above rather than E > S.
Any person who is capable of following a logical argument, and thinking very, very carefully about precisely what is being done when we measure/observe things, can see that there are no contradictions in Special Relativity.
E > S in the above context is your contradiction. Are you blind?
...but you've been hypnotised into not being capable of seeing them.
More state-of-mind speculations.
You are denying a contradiction that's sitting in plain sight right before you. Do you expect people not to wonder about how you can fail to see it? No one here would believe for a moment that it's down to stupidity because you're clearly very capable, and yet you trip over this every single time. Why? I'm trying to get you to ask yourself why you're rejecting sound maths. I'm trying to break the hypnotist's spell.
Given your strange comments here, and your strange comments about the concept of "hate" in a different topic (seemingly trying to objectify it into an unambiguously measurable quantity), I could come up with my own theories as to your state of mind. But I don't do that. I stick to the substance of the argument. Please do likewise.
Hate is perfectly measurable. We can see it in Nazi literature and the devastating impact that it had on the people who were exposed to it, demonising and dehumanising particular groups to the point where people could slaughter them and think of them as nothing more than vermin. You find it strange that I don't want to see that being repeated again and again forever with a never-ending series of genocides? I want a peaceful world, but you're trying to make out that that makes me weird. It may have escaped your notice, but hate speech is now being banned in a great many places and people can end up in court for posting it. There is an imbalance though on which hate is classed as hate and which is excused on holy grounds, and I object to the difference because it enables any amount of genocidal hate to be protected by tying it to an imaginary God.
The "underlying reality" is that which is invariant for all observers - the things that do not change when we change observers. It is the thing that all observations have in common. The business of physics is to discover it. The thing which is invariant between all observers is the laws of physics. That's the whole point of them. The speed of light, as measured by any observer/experimenter, either by measuring the strengths of the electric and magnetic fields or more directly, occurs as a constant in the laws of physics. Therefore the speed of light is constant as measured by all observers.
That's a good start, but some of the underlying reality is never revealed, as are the asymmetries between frames. The physics appears the same to naive physicists, but it is actually different.
No. To be clear: they calculate each other to be running slow based on their respective measurements during the trip. When re-united they observe that the travelling clock has ticked fewer times than the clock that stayed at home. This doesn't mean that anything was misleading.
It does - it means that the measurements indicating that the travelling clock was ticking faster than the non-travelling clock were misleading. The only measurement that can be trusted is the final one when the clocks are reunited.
It is a simple consequence of the fact that the travelling observer switched between two different inertial reference frames. Halc and Tamminen have already spelled this out with a numerical example. I have now repeated that example with more detail.
Voodoo. You're changes of frames are done to change the physics, asserting a new speed of light relative to any companion of the travelling clock who keeps going when the clock turns back.
I'll stick to describing what is actually empirically observed and what abstract models and theories can be logically constructed to describe and predict those observations. Rather than just citing model numbers.
You'll go on mixing incompatible models so that you can pick and choose as it suits you, failing to see that every single one of the possible SR models is broken.
The static eternal block models don't run time but rely on magical creation.
A meaningless statement to make about a mathematical model.
It isn't meaningless at all. The set zero models don't contain time at all - instead, they have a "time" dimension which is nothing more than a space dimension with a requirement that all objects are infinitely long in that dimension. That's all it is - a ridiculous mathematical abstraction which eliminates the contradictions by eliminating time.
The models that run time without clocks running slow always create event-meshing failures.
There is no such thing, in this context, as an event meshing failure.
Denial of a logical necessity.
See the descriptions elsewhere of what happens when the travelling observer changes inertial reference frames.
If D > L, S > E. That's a mathematical necessity in the models in question.
If you change the reference frame from which you are considering the relative movements of the clocks/observers in the experiment you do not change those relative movements. Changing the way that you view the experiment does not changes the facts of the experiment - the relationships between its participants. This is what you seem not to be able to get your head around.
I understand that in full, but my understanding of what's happening goes beyond that into an area where you refuse to go, which means that you don't see the asymmetries that are there. You just produce a contradiction instead, but deny it.
Your concept of there being "no running time" is physically meaningless. You keep forgetting that a 4 dimensional graph of the worldline of an object is an abstract mathematical construction.
I'm very aware that it's an abstract mathematical construction - it has no time in it at all. It's an extreme contrivance designed to hide the contradictions, but it comes at the cost of depending on magical (irrational) generation.
Fact B: it is mathematically impossible for that clock to have run slower than the stay-at-home clock on average without ticking slower than the stay-at-home clock on one or other of those legs.
No it isn't, because you are not considering what is observed by the two clocks during the transition between reference frames of the travelling clock and (apparently) not carefully considering the difference between what each clock directly observes of the other clock, and what each clock infers from those observations from the point of view of a particular reference frame.
Fact B is a fact. One of the clocks ran slow, and if it didn't run slow during one leg of its trip, it must have run slow on the other. If you can't even accept that though, you've already parted company with mathematics even before you try to insist that D > L and E > S.
I think it's best to look at Halc's and Tamminen's description of this, with specific numbers used, and then look at the more explicit description that I will post later, using those same numbers.
No, I think it's best to look directly at the simple maths of it and to remember that we are not allowed to mix models here - finding a way out that uses a set zero model does not save a set 2 model from this attack.
That is for rational people an undeniable asymmetry. This conditional truth means exactly what it says, and no amount of establishment voodoo can override it.
Symmetry means invariance through transformation. We all learn about it in the context of geometry when we're at school, considering geometrical transformations - rotations and reflections.
If you want symmetry through transformations, then you have the following symmetry:-

Frame 1: D = S, L = E, D > L, S > E
Frame 2: L = E, D = S, E > S, L > D

That's your symmetry. However, you want D > L and E > S, and you can't have that in a single frame. Reality also bans you from having it in the underlying reality, because to try to have D > L and E > S, you'd have to deny that D = S and L = E, but we know for certain that D = S and L = E.
A measurement which is accurately made has the same status as any other measurement, by any other observer, that is also accurately made.
A measurement of the relative ticking rates of two clocks moving relative to each other where they don't start together and end together is less reliable than a measurement of the relative ticking rates of two clocks where they do start together and end together. One of these measurements proves the others to be misleading, so you're inventing an equal status for them which is not only not justified in science, but which goes directly against what science should be saying. One measurement is clearly superior.
We take them all at face value and then try to find what they have in common. The thing that they have in common is referred to as the laws of physics. It is a set of abstract concepts that describe patterns (commonalities) between observations. That's it's job.
When they're shown to be misleading, it's the job of physics to accept that they merely describe the appearance of what's going on but that they do not always describe the underlying reality accurately.
The existence of the underlying reality is revealed by a clock running slow after going on a journey and returning. It runs slow on average, but you switch frame between making measurements and believe that it's always running at full speed while all other clocks are magically running slower unless they're co-moving with yours. You are incapable of recognising the mathematical necessity for your clock to run slower than the stay-at-home clock on at least one of the two legs of your trip,...
TODO
Having trouble with that bit? I don't wonder why you had to leave it till later.
I assert no such superiority. As already explained, a measurement which is accurately made has the same status as any other measurement, by any other observer, that is also accurately made. We take them all at face value and then try to find what they have in common. The thing that they have in common is referred to as the laws of physics. The laws of physics are, if you insist on using this term, the proposed "underlying reality".
There is a clear superiority of this measurement because all communication delays have been eliminated, so we can't be fooled by it - one of the clocks actually ran slow. The measurement(s) that suggested that it was running faster than the other clock when it was actually running slower than it is/are misleading.
The point is exactly as I stated earlier. If my clock is ticking faster than Lorentz's during the first leg of his trip, your clock is ticking faster than Einstein's on the fist leg of your trip. Alternatively, If your clock is ticking more slowly than Einstein's on the first leg of your trip, then my clock is ticking more slowly than Lorentz's on the first leg of his trip. Either way, its asymmetrical. You are incapable of accepting these mathematical necessities,...
See various other comments. You've failed to grasp what is observed, and what is inferred from those observations by the observers, when an observer changes inertial reference frames.
Changing frame is cheating. We have D=S, L=E, D>L, S>E for one frame, and D=S, L=E, E>S, L>D for the other. You want D>L and E>S, but you can't have it without destroying the D=S and L=E. You fail this maths test every single time.
...and that's why you're doing religion rather than physics.
Irrelevant comment.
Not at all - you're rejecting what mathematics tells you, and in doing so you are no longer doing physics. You're disqualifying yourself from physics.

David Cooper
Posts: 224
Joined: April 30th, 2018, 4:51 pm

Re: Does Special Relativity contain contradictions?

Post by David Cooper » October 4th, 2018, 6:15 pm

Steve3007 wrote:
October 4th, 2018, 4:38 pm
You can't do the maths. In any other context you could, but not here when Einstein's original SR model is destroyed by it. You simply refuse to accept reality.
If anything in the post to which I've repeatedly referred you is incorrect, please tell me explicitly what it is. (Not just general comments about my supposed personal failings.) And we'll take it from there.
I've shown you your error repeatedly, but all you do is point back to your error while making out that it resolves itself. It doesn't. You change frame, and when you take D > L from one frame and E > S from a different frame, you break the known facts that D = S and L = E.
Steve3007 wrote:
October 4th, 2018, 4:39 pm
You're the one who can't be taken seriously. You endorse maths riddled with contradictions. You're gone - credibility shot to pieces.
I'll add this to the long, long list of content-free ad hominems. I'll let you calm down a bit and maybe talk some more tomorrow.
If you're going to say things like "If you can't do that simple thing, I'm afraid you can't be taken seriously", expect your attack to be reflected straight back at you. You have rejected a simple piece of mathematics which destroys your position.

Steve3007
Posts: 6053
Joined: June 15th, 2011, 5:53 pm
Favorite Philosopher: Eratosthenes
Location: UK

Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 3:07 am

The current post will just deal with this:
David Cooper wrote:D = S
L = E
D > L
Therefore S > E

But you want it to be E > S. Your position is bonkers.
Clearly, in the above, if these letters represent numerical quantities, S > E and I would indeed be bonkers to claim otherwise. So let's look back at our previous posts to see what you're telling me those variables physically represent (or if they are actually variables), to see if that really is what I'm claiming and to thereby figure out whether I am, in fact, bonkers.

Some relevant posts for reference, in cronological order:
viewtopic.php?p=320716#p320716
viewtopic.php?p=320720#p320720
viewtopic.php?p=320758#p320758
viewtopic.php?p=320773#p320773
viewtopic.php?p=321014#p321014

I decided to refer to the clocks as C1, C2, C3 and C4 and to the starting line as SL. (You refer to the SL frame as "the arena". Fair enough. What's in a name? A rose by any other would smell as sweet.) In one of the above posts I set out the relative speeds of all of these objects in legs 1 and 2 of experiments 1 to 3. Although those relative speeds were accurately set out, there are reasons why you consider the facts set out there to be irrelevant, so I'll leave that for now.

In an earlier post, I summarized the situation with the first 2 clocks like this:

1. You stand still throughout. I move away from you and then turn around and come back. At speeds v and -v relative to the Earth frame and you.

2. You move at speed v relative to the Earth frame throughout. I move at speed 2v, then I stop and wait for you to catch up.

3. You move at speed v relative to the Earth frame throughout. I stand still for a while then start moving and catch you up by travelling at speed 2v, relative to the Earth frame.

(Where "You" = C1; "I" = C2)

You seemed more happy with that. Perhaps because I used less "relative language". I said such things as "You stand still throughout". I could of course have said "You stand still throughout relative to SL" or "You stand still throughout relative to 'the arena'". But then I'd presumably be moving towards a form of words that you would tell me makes my remarks suddenly irrelevant. But, no, I understand. You're telling me that the speed of the whole shebang relative to "the arena" affects the results of experiments.

OK. You then decided to equate your clock with C3. So "You" is no longer C1. It is C3. Fair enough.
I'm going to stay in the same place in the arena throughout, so my clock will tick along with clock 3 throughout.
You also decided to give C4 an extra name - "Einstein".
Einstein is going to move away from me at v, so he will accompany clock 4 throughout.
Fair enough. A rose by any other... Finally you introduce the character of "Lorentz".
Lorentz will initially travel with Einstein but then he'll turn round and come back to me. So Lorentz and I are doing experiment 1 while you and Albert are doing experiment 3.
Now, here is where those letters start to come in - the ones that you treat as variables and claim that I'm making logically contradictory (bonkers) claims about.
(Ticking rates during the first leg: D = My clock, L = Lorentz's clock, E = Einstein's clock, S = your clock.) Your mathematical skills are absolutely woeful.
(Bonkers and woeful!)

OK, so:
C3 = You = D.
C4 = Einstein = E.
C2 = Me = S.
(The labels "you" and "me/I", of course, add the slight extra complication of having a meaning that is dependent on the identity of the speaker. That's why I tried to drop them.)

So now you continue with your analysis:
You change frame to analyse the S and E part of it separately from the D and L part, but D and S are co-moving during the first leg and L and E are co-moving during the first leg too, so your analysis is borked, generating the utterly moronic claim that D>L and E>S during the first leg even though we know that D=S and L=E.
(Bonkers, woeful, borked, moronic.)
I was suggesting to you that you consult a mathematician and run this past him/her, then get his/her agreement for you to post his/her name along with an endorsement of D>L and E>S and D=S and L=E. None of them will give you permission to make them look so stupid. Are you claiming that Bertrand Russell endorses D>L and E>S and D=S and L=E?
(Bonkers, woeful, borked, moronic, stupid.)

Here's where the labels attached to our clocks suddenly, in your language, become variables. That eminent mathematician is going to want to know what quantities those variables represent before signing his/her name. So I'm going to have to guess. I am going to guess that they represent the speeds of those objects. Am I right? If so, speeds relative to what? Relative to the SL/Arena? For the benefit of a stupid moron, could you please set out again, succinctly, using a single label for each clock, the relative movements of all the clocks in legs 1 and 2 of experiments 1 to 3.

Thanks.

OK. I'll leave all that for you to clarify before continuing after you've commented.

A final aside for this post:
That doesn't equate to you being an idiot.
(Bonkers, woeful, borked, moronic, stupid. not idiot.) Good.

Steve3007
Posts: 6053
Joined: June 15th, 2011, 5:53 pm
Favorite Philosopher: Eratosthenes
Location: UK

Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 3:59 am

Further to the above post: I often find that gathering together the relevant information from various posts, summarising them and reading them back makes things clearer, to a person of very little brain, like me. Having read back my previous post it's clear that the variables represent the tick rates and that a proposition like, for example, S > E proposes that clock 2 is ticking faster than clock 4.

Good. Clarified.

I'll start by referring to this post:

viewtopic.php?p=321015#p321015

about what we mean when we say these things, and take it from there in my next post.

Steve3007
Posts: 6053
Joined: June 15th, 2011, 5:53 pm
Favorite Philosopher: Eratosthenes
Location: UK

Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 6:48 am

OK, so now I have the summary information to refer to, rather than scrolling back through several pages of posts, I can perhaps do what I've asked you (David) to do and summarise the 2 legs of the 3 experiments. Here goes. (For clarity of logic I've borrowed some of the syntax of the C++ programming language.)

// Things that are true in all 3 experiments

// The class encapsulating a clock, observer and reference frame.
class Clock;
float Clock::TickRate(Clock &other_clock);

// The names of clock objects, of observers travelling with those clocks and of the reference frames WRT which they are stationary.
Clock SL = the starting flag frame = "the arena";
Clock C1 = Clock 1;
Clock C2 = Clock 2 = Steve; // Me
Clock C3 = Clock 3 = David; // You
Clock C4 = Clock 4 = Einstein;
Clock C5 = Clock 5 = Lorentz;

// Tick Rates during the first leg.
float D = C3.TickRate(other_clock);
float E = C4.TickRate(other_clock);
float S = C2.TickRate(other_clock);
float L = C5.TickRate(other_clock);

The first thing to note is that the number returned by TickRate() cannot just be a function of a single clock object. As a clock, I can only assign a numerical value to my tick rate relative to a reference tick rate. Hence, the function takes another Clock as a parameter. Obviously you can say that SL is the default value for that parameter if you like, such that TickRate() is the same as TickRate(SL). That's fine. I have no problem with that.

// The Individual Experiments

// Experiment 1
C1 stands still relative to SL throughout.
C2 moves at speed v relative to C1 during leg 1 and then at speed -v relative to C1 during leg 2.
C3 = C1. Stands still relative to C1 throughout.
C4 moves at speed v relative to C1 throughout.
C5 = C2. Stands still relative to C2 throughout.


// Experiment 2
C1 moves at speed v relative to SL throughout.
C2 moves at speed v relative to C1 during leg 1, then at speed -v relative to C1 during leg 2.
C3 moves at speed -v relative to C1 throughout.
C4 = C1. Stands still relative to C1 throughout.
C5 stands still relative to C1 during leg 1, then at speed -xv relative to C1 during leg 2.


// Experiment 3
C1 moves at speed v relative to SL throughout.
C2 moves at speed -v relative to C1 during leg 1, then at speed v relative to C1 during leg 2.
C3 moves at speed -v relative to C1 throughout.
C4 = C1. Stands still relative to C1 throughout.
C5 stands still relative to C1 during leg 1, then at speed -xv relative to C1 during leg 2.

---


David, do you agree that all of the above is factually correct, as you have described these experiments? I realize that some of it looks like this post:

viewtopic.php?p=320758#p320758

and that you objected to that post on the grounds of irrelevance. But all the information is there for you to work out the relative speed between SL and each other clock, if you want to. In other words, all the information is there for you to keep your concept of absolute speed (i.e. speed relative to the arena), if you want to. If you object to the fact that I've pointed out that the relative speeds of C1, C2, C3 and C4 (but with the roles of C3 and C4 switched between expt 1 and expt 3) are the same in all 3 experiments, and you regard that fact as irrelevant, then just feel free to ignore that fact.

OK, you say that during the first leg:
D = S
L = E
D > L
Therefore S > E
In other words, you've said, for the first leg:

C3 ticks at the same rate as C2.
C5 ticks at the same rate as C4.
C3 ticks faster than C5.
Therefore C2 ticks faster than C4.

Do you agree that this is what you've claimed? I presume so. The maths is the same.

---

What actually happens, during leg 1, with the clocks you've mentioned above, in the order that you mentioned them.

Expt 1.
C3 moves at speed -v relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed 0 relative to C4 during leg 1.

Expt 2.
C3 moves at speed -xv relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed 0 relative to C4 during leg 1.

Expt 3.
C3 moves at speed 0 relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed -v relative to C4 during leg 1.

Do you agree with the above (regardless of whether you think it relevant or not)? If so, I may be wrong, but I think you'll find you've made a mistake in your proposed relationships between the tick rates of these clocks. Once that's been sorted out, I think we can then talk about the difference between directly measured tick rates and calculated tick rates, as discussed in more detail in a post of mine that I cited earlier (which itself referenced a conversation between Halc and Tamminen.)

Steve3007
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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 7:05 am

Typo in the last line for experiment 2. Correction:

Expt 1.
C3 moves at speed -v relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed 0 relative to C4 during leg 1.

Expt 2.
C3 moves at speed -xv relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed v relative to C4 during leg 1.

Expt 3.
C3 moves at speed 0 relative to C2 during leg 1.
C5 moves at speed 0 relative to C4 during leg 1.
C3 moves at speed -v relative to C5 during leg 1.
C2 moves at speed -v relative to C4 during leg 1.

Steve3007
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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 8:01 am

In an effort to pre-empt future arguments as much as possible, I'd like to try to hammer home this point about the difference between the direct observations of pairs of moving observers and the calculations of those observers, based on the definition of simultaneity, discussed here:

viewtopic.php?p=321015#p321015

Here's a bigger version of that Minkowski diagram:
MD.png
MD.png (20.67 KiB) Viewed 626 times
The red and blue lines are lines of simultaneity from the point of view of the two reference frames between which B switches. The black dots on those lines illustrate graphically the fact that observer B calculates observer A's clock to be running slower than his own. The black dots on those lines in a similar diagram from the point of view of B would illustrate graphically the fact that observer A calculates observer B's clock to be running slower than his own. As I said, this is not the same as the raw data received by each observer.

If somebody thinks I've got this wrong, please tell me! I'd be interested to know.

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Re: Does Special Relativity contain contradictions?

Post by Tamminen » October 5th, 2018, 10:22 am

Halc wrote:
October 3rd, 2018, 6:40 am
Tamminen wrote:
October 3rd, 2018, 4:02 am
To apply the equivalence principle, isn't this the same as the situation where the rocket is standing on the ground and a clock at the bottom runs slower than the clock at a top because of the difference in gravity?
The rocket on the planet is in a non-uniform field, so the bottom is deeper in the well than the top, so is dilated more, yes.
I don't see the equivalence between that and a rocket accelerating out in nowhere. Is the nose not accelerating as much as the tail? The thing keeps a fixed length in its own accelerating reference frame. In any inertial frame, the length is contracting or expanding as it accelerates, so there is a tiny variation on that front, but the difference could be either way depending on if the acceleration is in the same direction as its velocity. Alice and Bob experience the exact same acceleration (G-force), which is not true of the rocket sitting on the ground.
Another claim for acceleration causing time dilation:
Consider two people: one is standing on the surface of the Earth, the other is standing at the top of a tall tower directly above the first. If each of them have sufficiently accurate clocks, and they exchange light signals, they will be able to confirm that the clock of the one at the bottom of the tower is running slower; for example, they can verify that there are fewer ticks of the bottom clock between two successive round-trip light signals than there are ticks of the top clock. This is what is actually meant by the common pop science statement that "gravity slows down time".

And in this sense of the statement, it is true that "acceleration also slows down time". For example, consider two more people, inside a spaceship far out in space that is accelerating at 1 g. One is at the rear of the ship; the other is at the front. By similar measurements to those the first pair made (exchaging round trip light signals and counting ticks of each one's clock between successive signals), they can verify that the rear clock is running slower than the front clock, and if the length of the ship is the same as the length of the tower, the difference in clock rates will be the same in both cases.
Reference https://www.physicsforums.com/threads/e ... on.810369/

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Re: Does Special Relativity contain contradictions?

Post by Steve3007 » October 5th, 2018, 10:56 am

I think it's definitely true that the GR Equivalence Principle says that an accelerated reference frame is identical to a non-accelerated reference frame that is in the presence of a uniform gravitational field. And that means there is no experiment that could distinguish between the two. And that means that gravitational time dilation applies to accelerated reference frames, in at least some sense.

The issue that Halc has with it (as I understand him) is the part about it being a uniform gravitational field - i.e. a vector field in which all the vectors are the same size and point in the same direction. The acceleration at the top of an accelerating rocket is equal to that at the bottom so the vector field is uniform in this way. But in a gravitational potential well, gravity is non-uniform. The vectors are radial.

This is an issue that I'm still trying to get my head around too. It's something I haven't looked at for a very long time. I cited an article about it earlier that Halc looked at. I still haven't got around to properly going through the maths in that article so as to be able to properly understand what it is claiming and whether it seems right. It's on my TODO list!

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Halc
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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 3:25 pm

Tamminen wrote:
October 5th, 2018, 10:22 am
Another claim for acceleration causing time dilation:
Consider two people: one is standing on the surface of the Earth, the other is standing at the top of a tall tower directly above the first. If each of them have sufficiently accurate clocks, and they exchange light signals, they will be able to confirm that the clock of the one at the bottom of the tower is running slower; for example, they can verify that there are fewer ticks of the bottom clock between two successive round-trip light signals than there are ticks of the top clock. This is what is actually meant by the common pop science statement that "gravity slows down time".
This is standard gravitational dilation, as per GR, but not as per SR, which only predicts the upper clock to run slower due to it moving faster.

Not sure what the measurement method is, this round trip exchange of light signals. The quote here doesn't explain it at all. I can illustrate the dilation with a single signal sent at the start and another a day later, but that doesn't seem to be what they're envisioning here. I think you didn't include the context for that.

It talks about a light signal making a round trip, like I send a beam up to the top and hit a mirror there and time the round trip. That measures distance to the mirror and not so much the dilation of the environment with the mirror up there. I've done pretty much exactly that experiment. Somehow I think they have something else in mind, but I cannot figure it out from this brief 'exchange signals' and 'successive round trips'. My description only involved one clock, not the one at the top.
And in this sense of the statement, it is true that "acceleration also slows down time". For example, consider two more people, inside a spaceship far out in space that is accelerating at 1 g. One is at the rear of the ship; the other is at the front. By similar measurements to those the first pair made (exchaging round trip light signals and counting ticks of each one's clock between successive signals), they can verify that the rear clock is running slower than the front clock, and if the length of the ship is the same as the length of the tower, the difference in clock rates will be the same in both cases.
This seems nonsense. The two in the building will get hours off if they wait long enough. Not so the two in the rocket, who are accelerating identically. Their clocks will get out of sync due to being stationary in a different inertial frame, but that isn't dilation. Their clocks will never be more out of sync than the magnitude of their separation.
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.

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Re: Does Special Relativity contain contradictions?

Post by David Cooper » October 5th, 2018, 4:55 pm

Steve3007 wrote:
October 5th, 2018, 6:48 am
Clock C2 = Clock 2 = Steve; // Me
Clock C3 = Clock 3 = David; // You
Clock C4 = Clock 4 = Einstein;
Clock C5 = Clock 5 = Lorentz;
If you have C3 staying at rest in the arena throughout, C4 moving at a constant v through it, C5 moving with C4 for a while and then moving back to C3, and C2 staying with C3 for a while before racing after C4 at >v, then that's fine. It would certainly make things clearer to use the letter C in the names to avoid using D, S, L and E both as clock names and as tick rate values for them.
// Tick Rates during the first leg.
float D = C3.TickRate(other_clock);
float E = C4.TickRate(other_clock);
float S = C2.TickRate(other_clock);
float L = C5.TickRate(other_clock);
However, it's clearest to name the clocks CD, CS, CL and CE to avoid remembering which numbers relate to which letters, and this is preferable because the names with numbers in them do different things in different experiments. We have moved on to experiment 4, and this combines experiments 1 and 3 in a single experiment. We can also call your SL clock CA (the clock of the arena frame).

// 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.

The tick rates during the first leg are as follows: D=S, L=E, D>L, S>E.
David, do you agree that all of the above is factually correct, as you have described these experiments?
I didn't check it all as it's unnecessarily complicated - the changing roles of clocks in the different experiments makes it hard to understand what's meant by their names, but all that complication that can be avoided by sticking to using experiment 4 instead (where Lorentz and Einstein were introduced), thereby saving a lot of time and providing everything we need.
and that you objected to that post on the grounds of irrelevance.
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. 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 tick rates during the first leg are as follows: D=S, L=E, E>S, L>D.

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. In doing this, you destroy the D=S and L=E parts which we know we aren't allowed to break - these are our best two measurements (primary facts) and must be maintained. This means that if D>L, then S>E. It also means that if E>S, then L>D. You simply can't have D>L and E>S. It's a mathematical impossibility.

In set zero models, that illegal move of changing frame and taking measurements from each appears to be legal for the simple reason that all the tick rates are zero - there are no ticking clocks at all, so you have D = S = L = E = 0.

In set 1 models, again it appears to be legal for the simple reason that all the clocks tick at the same rate at all times, so you have D = S = L = E = 1.

It's only in set 2 and set 3 models that we have ticking clocks where some of them run slower than others, and as soon as you introduce a ">", you show up a conditional asymmetry. It is still a symmetry in that it works the same way both ways: for every "if" here there's an equivalent "else". The reason there's a conditional asymmetry though is that only one of the conditions can be true: if D > L, then E > S is false. If E > S, then D > L is false. If both of these are true (D > L && E > S), you have a contradiction. Set 2 models produce an infinite number of such contradictions.
OK, you say that during the first leg:
D = S
L = E
D > L
Therefore S > E
In other words, you've said, for the first leg:

C3 ticks at the same rate as C2.
C5 ticks at the same rate as C4.
C3 ticks faster than C5.
Therefore C2 ticks faster than C4.

Do you agree that this is what you've claimed? I presume so. The maths is the same.
That looks right, but it's hard to remember what the clock numbers mean as they do different things in different experiments, whereas D, S, L and E do not change what they're doing.
What actually happens, during leg 1, with the clocks you've mentioned above, in the order that you mentioned them.

Expt 1.
...

Do you agree with the above (regardless of whether you think it relevant or not)?
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.

The above applies to both frames. If you want to include the superfluous arena clocks for the two frames:-

CA moves at speed 0 relative to CD at all times.
CA2 moves at speed 0 relative to CE at all times.
If so, I may be wrong, but I think you'll find you've made a mistake in your proposed relationships between the tick rates of these clocks.
I haven't, but you'll find it much easier to hold the details in your head by getting rid of the complications. In experiment 4 we have versions of experiments 1 and 3 combined into one, and this gives us a single, consistent story for each of the four clocks.

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Re: Does Special Relativity contain contradictions?

Post by Halc » October 5th, 2018, 5:34 pm

Steve3007 wrote:
October 5th, 2018, 8:01 am
If somebody thinks I've got this wrong, please tell me! I'd be interested to know.
You got it right, but not sure for whose benefit it was posted.
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.

On the other hand, it seems to illustrate the example that Tamminen and I have been working with, so perhaps we're the audience, but the posts above it suggest you're attempting to educate David. He know his stuff and is in need of no such education. He's a presentist apologist and will not consider an alternate description using its own definitions of the terms.

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