I'm reading "Relativity: The Special and the General Theory" and I'm at the end of Chapter 9 & confused. If I understand correctly, this is what he has said so far (in my own words): Say that lightning strikes 2 points (A and B) on a railway embankment. To determine whether the two strokes of lightning struck at the same time, you could place a person half way between A and B, and provide him with mirrors so that he could see points A and B at the same time. If that person saw the two lightning strokes hit at the same time, then they actually did hit at the same time. But now say there's a train traveling along the embankment going from A and towards B. If a person on the moving train tried use the same method to determine whether the two strokes of lightning hit at the same time (i.e. he looked into his mirrors when he was at the half-way point between A & B), he'd see that they did NOT hit at the same time... because he's traveling towards B and so the light from the lightning at B would hit his eyes sooner than the light from the lightning at A (which he's moving away from). I understand all of that, but then Einstein concludes (his words): "Thus we arrive at the important result: Events which are simultaneous with reference to the embankment are not simultaneous with respect to the train, and vice versa..." That's what I don't understand. Wouldn't it be more accurate to say that events which are simultaneous relative to the embankment ARE ALSO simultaneous relative to the train... BUT a person on the train just can't detect that they're simultaneous because of his motion.... in the same way that if the person on the train were trying to determine the simultaneity of two gunshots (at A and B) with his ears (not his eyes), he'd think that they were not simultaneous because he's moving towards the soundwaves from gunshot B and therefore hears them sooner? So to summarize, the guy in the train perceives a distorted view of reality because of his motion - he thinks two events were not simultaneous when they actually were. So who is right - me or Einstein? No doubt it's Einstein who is right, so if anyone can help me see what's wrong with my own explanation that would be great... thanks.