Hello everyone ! I want to ask you something and I hope you think your answer and not just reply with an orthodox foundation. I'm not another Einstein's enemy, I believe in SR but sometimes I just can't imagine some situations... Look at this: I will use the famous twin paradox because it is known for all... but I won't answer who is younger at the end, we know "Earth-Twin" is older, now... WHEN "Traveler-Twin" get this difference? was it during his acceleration? was it during his inertial movement (outbound or inbound travel?). Even more... let me modify our paradox: Now the "Traveler-Twin" never returns to the Earth. Does he remain younger? And if we don't know WHO accelerates? who is younger? I hope you can understand my doubt. To me, THERE is the real paradox... and I don' think relativity of simultaneousness solves it... Someone told me once: If nobody is accelerating and nobody turns back, then, they cross at maximum ONE time, and then is not relevant who is younger... I can understand that answer in a practical way, but I think it's not acceptable from a theoretic point of view. I think SR, with the current interpretation, can't solve this. But look at this: I we assume there's a preferential frame of reference, if we assume the nature of universe is NOT the same for all inertial observers, BUT: every physical theory should look the same mathematically to every inertial observer, and the laws of the universe are the same regardless of inertial frame of reference, so, we left the equations of our SR unbroken, and we save our "logic", because now, like before, we can't answer WHO is younger... but we KNOW that one of them is younger... I think there's an important difference, because again, we can't save our practical problem, but yes the theoretic one. Now, why the science community choose the first interpretation of SR, which is so cruel with our logic if the second interpretation take us the SAME equations and preserves our logic? Is there some problem with this second interpretation? Please, again, I'm not trying to break up the SR or something similar, I'm just trying to solve this logic paradox... Thanks for read! (and thanks a lot if you reply...) enrique.