What if Einstein's reference frames ( does anyone else get the credit for this 
term?) function because reality is what I call Virtuality? Its the old 
simulation argument, served up by myself, today. Someone who has worked 
arduously on this concept over the last, few, years, is mathematician, Brian 
Whitworth in New Zealand, and if anyone has the time, interest, and patience, 
to learn about his own theory of Virtual Reality (again, Virtuality) I will 
present it here. I believe it dovetails with the Block universe view of how 
spacetime works and is best measured. But it does take both special, and 
general, relativity as well as the quantum, in a very, different, direction. 
Here is his latest paper, dated, Jan 24, 2014. His earlier papers can be 
downloaded on ARXIV, of course, as well as his discussions on the FQXI.

Sincerely,

Mitch

http://brianwhitworth.com/BW-VRT1.pdf



-----Original Message-----
From: Edgar L. Owen <[email protected]>
To: everything-list <[email protected]>
Sent: Sat, Feb 22, 2014 3:03 pm
Subject: Re: Block Universes


Jesse,


I think the basic problem in our discussion, which seems intractable from you 
answers below, is your basic belief that time doesn't doesn't flow, that there 
is no such thing as a now in which you or the twins actually exist. >From your 
answers it seems clear that you can't even bring yourself to agree that you are 
actually some particular age right now, or were at any time in the past. If you 
don't even believe that I can't see any hope of agreement or having a 
meaningful discussion.


It's quite clear from all the numerous examples I gave that it is possible to 
determine a 1:1 correlation between the twin's actual ages in terms of their 
own clock time readings (what you call their proper times). This is their 'true 
actual age' because both twins agree on both actual ages and how their clock 
times correlate. They do this not by OBSERVING the other's age, but by 
calculating it from knowledge of how relativity works in both their frames. 
This is the frame independence I point out that is a fundamental (though 
unstated) assumption of relativity. It is only in this background notion of 
frame independence that frame DEPENDENCE of relativity makes any sense. But 
that concept remains beyond you....


But since you can't even bring yourself to admit the twins were actually alive 
with a particular actual age at every point on their world lines I see no 
useful way to continue the discussion. 


Thus the basic disagreement is not really about whether p-time is incompatible 
with relativity (it isn't) but that p-time is incompatible with block time, 
which for you seems a matter of faith which you are unable to set aside.


Best,
Edgar




On Wednesday, February 19, 2014 1:30:11 AM UTC-5, jessem wrote:




On Sun, Feb 16, 2014 at 9:40 AM, Edgar L. Owen <[email protected]> wrote:

Jesse,


OK, I'm back...


Let me back up a minute and ask you a couple of general questions with respect 
to establishing which past clock times of different observers were simultaneous 
in p-time....


The only clocks in this example are the real actual ages of two twins....




1. Do you agree that each twin always has a real actual age defined as how old 
he actually is (to himself)?


Yes or no?



Yes, in the sense that at each point on his worldline he has an "actual age" at 
that point, which is just the proper time between his birth and that point. But 
if you're suggesting a unique "true" actual age, as opposed to just each point 
having its own actual age, then I would have to change my answer to no.




 



2. Do you agree that this real actual age corresponds by definition to the 
moment of his actually being alive, to his actual current point in time? (As a 
block universe believer you can just take this as perception or perspective 
rather than actuality if you wish - it won't affect the discussion).

 



Yes or no?





If by "perspective" you mean that each point on his worldline takes his 
experiences at that point (including his age) to be the "current point in 
time", then yes.



 





Now assume a relativistic trip that separates the twins....


3. Do you agree that IF, for every point of the trip, we can always determine 
what ACTUAL age of one twin corresponds to the ACTUAL age of the other twin, 
and always in a way that both twins AGREE upon (that is frame independent), 
that those 1:1 correspondences in actual ages, whatever they are, must occur at 
the same actual times? That this would give us a method to determine what 
(possibly different) actual ages occur at the same actual p-time moment in 
which the twins are actually alive with those (possibly different) actual ages?


Yes or no?



IF we had a method to determine a unique 1:1 correspondence in ages for 
separated twins, then yes, that could reasonably be interpreted as a 
demonstration of absolute simultaneity, telling us which ages "occur at the 
same actual times". But I don't believe you can find any such method for 
determining a unique frame-independent 1:1 correspondence in relativity.


Since I am answering your questions, are you willing to answer mine? In the 
post that you are responding to I requested that you respond to my questions at 
https://groups.google.com/d/msg/everything-list/jFX-wTm_E_Q/xtjSyxxi4awJ , 
especially the part at the end about the meaning of "same point in spacetime" 
(i.e. whether two events happening at the same space and time coordinates in a 
single coordinate system automatically implies that they satisfy the 
operational definitions of "same point in spacetime" I had given, and whether 
you'd agree that this means they must have happened at the same moment in 
p-time). You ignored that request in your response. I'll even narrow it down to 
a single question I asked in that post:


'If we have some coordinate system where relativity predicts the event of 
Alice's clock reading 30 happens at exactly the same space and time coordinates 
as the event of Bob's clock reading 40, do you agree or disagree that this 
means relativity automatically predicts these two events would satisfy the 
various operational meanings of "same point in spacetime" I gave at 
https://groups.google.com/d/msg/everything-list/jFX-wTm_E_Q/AZOhnG04__AJ , 
regardless of whether Alice and Bob had synchronized their clocks in the past 
or not? Please give me a clear agree/disagree answer to this question'



For example, say that in some particular coordinate system Alice's coordinate 
position x as a function of coordinate time t is x(t)=80, i.e. she is at rest 
at position coordinate x=80, and her age T (proper time since birth) as a 
function of coordinate time t is T(t)=t+10. Meanwhile Bob's coordinate position 
as a function of coordinate time is x(t)=68+(0.6c)*t, i.e. at t=0 he is at x=68 
and he is moving in the positive x-direction at 0.6c, and his age T' as a 
function of coordinate time t is T'(t)=24+0.8*t. Then at t=20 in this 
coordinate system, they will both be at position x=80, and Alice's age will be 
T=20+10=30 while Bob's will be T'=24+0.8*20=24+16=40. So the question above is 
asking whether, in an example like this one, you'd agree that their reaching 
these ages at the same space and time coordinates implies they must actually 
meet at the "same point in spacetime" when Alice is 30 and Bob is 40, according 
to the operational definitions I gave earlier (like the one involving bouncing 
light signals back and forth and noting when the time for them to bounce back 
approaches zero).


Jesse




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