Jesse,

Your example does NOT establish any inconsistency. I NEVER said "I'm pretty 
sure you've said before that you agree that if SR predicts two clocks meet 
at a single point in spacetime, their two readings at that point must be 
simultaneous in p-time)." That is NOT true. Only if there is no relative 
motion or acceleration is it true. I really wish you could just get the 
basics of the theory straight.

Let me just give you the general method for all cases and see if you can 
understand it:


If you are just trying to figure out the method of determining p-time 
simultaneity between any two observers in any combination of relativistic 
circumstances here it is.

The general case of determining p-time simultaneity between any two 
relativistic observers. Assume observers A and B, both accelerating 
relative to each other, with different rates of relative motion and in 
different gravitational fields. Assume all possible relativistic effects 
between A and B.


The method is trivially simple. I'll give two approaches:


1. Instantaneously pause all relativistic effects at any time t on A's 
clock and read the time t' on B's clock. These clock times are a point when 
A and B were/are in the same p-time current moment.

2. Do the same thing for any t you wish. The t' that corresponds will be 
the clock time in the same present moment of p-time as the t you paused at.

3. In general if you want to know what clock time t' of B occurred in the 
same p-time as any time t on A's clock, all you have to do is pause the 
experiment at t so that all relative motion ceases and just read t' on B's 
clock. 

Because this can be done at any point t on A's clock we can always 
determine what t' on B's clock occurred in the same p-time as that t simply 
by reading B's clock. 

Note this is exactly what happens when the twins meet up in the same p-time 
present moment and read each other's clocks to determine what clock times 
occurred at the same p-time, in that same common present moment. 


You can also do this with a calculation as well as by pausing the 
experiment.

1. Note there are two classes of relativistic effects in the general case:
a. Reciprocal temporary effects of relative motion in which A and B each 
see the other's clock slow by the same amount. These effects vanish when 
relative motion ceases and A and B do NOT agree on these effects because 
they are equal and opposite. No permanent actual age differences are 
produced by this type of effect.
b. Persistent and agreed effects of acceleration and gravitation in which 
one clock slows permanently relative to the other and both A and B agree on 
the amount of slowing. These effects persist after the relativistic 
differences vanish. They are permanent. And both A and B agree on these 
effects. These effects manifest as real permanent age differences.

2. At any desired time t on A's clock, identify, calculate and discard the 
effects of relative motion of type a. so that the only effects between A 
and B left are of type b., the actual real actual age differences up to 
point t on A's clock. We keep only the effects that would be/are permanent 
(type b. above) and disregard those that are not (type a. above).

This is effectively the same as pausing the experiment at any t, because 
that is just a simpler method of eliminating effects of type a.

Again all we have to do now is compare t and t' to see what t' of B 
occurred at the same p-time as t on A's clock. This will be the real age B 
is when A is t years old, which is the test of the same p-time. Both A and 
B agree on this age difference because it is real and persistent after all 
relativistic effects cease. 

3. This can be done either in A's frame for any t, or in B's frame for any 
t'.

4. This process is transitive between any number of arbitrary observers in 
any relativistic situation. We can always find the clock time t-values of 
each that occurred in the same p-time, the same present moment of p-time.

Edgar


On Tuesday, February 11, 2014 2:00:23 PM UTC-5, jessem wrote:
>
>
>
> On Tue, Feb 11, 2014 at 1:13 PM, Edgar L. Owen <edga...@att.net<javascript:>
> > wrote:
>
>> Jesse,
>>
>> Your condition C. was not example dependent. You just need to rephrase 
>> your condition C. as two observers with no relative motion AND in identical 
>> gravitational fields. Then it does hold and is consistent with conditions A 
>> and B. I already gave several examples.
>>
>
> But I gave a different example where it leads to inconsistent conclusions, 
> are you going to address that? In my example, Alice and Bob have no 
> relative motion and are both in identical gravitational fields (zero 
> gravitational fields, since this is an SR flat spacetime example). 
> Likewise, Arlene and Bart have no relative motion and are both in identical 
> gravitational fields (again, zero). The only comparisons I made between 
> members of different pairs were ones that involved their passing next to 
> each other and comparing clock readings at the same point in spacetime, so 
> their relative motion shouldn't be an issue (I'm pretty sure you've said 
> before that you agree that if SR predicts two clocks meet at a single point 
> in spacetime, their two readings at that point must be simultaneous in 
> p-time).
>
> Please just look over the Alice/Bob/Arlene/Bart example I gave at 
> https://groups.google.com/d/msg/everything-list/jFX-wTm_E_Q/pxg0VAAHJRQJand 
> tell me if you disagree with any of the numbered conclusions about 
> p-time simultaneity 1-4.
>
> Jesse
>
>

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