Jesse, Yes, but what you are saying here is just that it is impossible to unambiguously OBSERVE that the proper ages are the same. I agree. But it is possible to unambiguously DEDUCE and CALCULATE that they MUST be the same, which is all my theory says.

If we can use calculation and deduction with respect to an invariant notion of proper ages that we CANNOT unambiguously observe, why can't we use calculation and deduction with proper age simultaneity as well? Edgar On Saturday, March 1, 2014 5:51:37 PM UTC-5, jessem wrote: > > > > On Sat, Mar 1, 2014 at 5:35 PM, Edgar L. Owen <edga...@att.net<javascript:> > > wrote: > > Jesse, > > Let me ask you one simple question. > > In the symmetric case where the twins part and then meet up again with the > exact same real actual ages isn't it completely logical to conclude they > must also have been the exact same real actual ages all during the trip? > > If, as you claim, the same exact proper accelerations do NOT result in the > exact same actual ages all during the trip then how in hell can the twins > actually have the exact same actual ages when they meet up? > > > > It's not that I'm claiming that there's an objective truth that they DON'T > have the same ages during the trip. I'm just saying that as far as physics > is concerned, there simply IS NO OBJECTIVE OR "ACTUAL" TRUTH ABOUT > SIMULTANEITY, and thus there is neither an "actual" truth that they are the > same age or an "actual" truth that they are different ages. These things > are purely a matter of human coordinate conventions, like the question of > which pairs of points on different measuring-tapes have the "same y > coordinates" in any given Cartesian coordinate system. Similarly, questions > of simultaneity reduce to questions about which pairs of points on > different worldlines have the "same t coordinate" in any given inertial > coordinate system, nothing more. > > > > > What is the mysterious mechanism you propose that causes twins that do not > have the same actual ages during the trip to just happen to end up with the > exact same actual ages when they meet? > > > Again, I do not say there is any objective truth that they "do not have > the same actual ages", I simply say there is no objective truth about which > ages are "actually" simultaneous in some sense that is more than just an > arbitrary coordinate convention. But if you're just asking about how things > work in FRAMES where they don't have the same actual ages during the trip, > the answer is that in such a frame you always find that the answer to which > twin's clock is ticking faster changes at some point during the trip, so > the twin whose clock was formerly ticking faster is now ticking slower > after a certain time coordinate t, and it always balances out exactly > ... -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.