Peter
"Make up your mind!!"
I said:
1 "The speed of the bullet wrt to the video camera, or anything else on the platform, is not v+c The bullet is travelling at c, you said so. It is not part of the train. Unless the train is hermetically sealed, in the sense that it is solid. In which case the speed would be the composite speed wrt all that which was on the platform.
2 "For somebody or something on the train, indeed including he train itself, the speed of the bullet is c-v wrt these things, assuming the bullet was fired in the same direction as the motion of the train, because they are travelling at v, you said so".
"why should one observer off the train have any preferential treatment over any other, i.e. those ON the train!"
It is not preferential, it is a function of wrt. Any judgement involves a reference, and, by definition, the outcome of the judgement reflects the reference used. Any reference can be selected, but to ensure comparability, consistency of reference must then be maintained. In other words, to establish a comparable set of speeds in this scenario, one could select any of the entities involved and assess the speed of the others wrt that. This is proper referencing.
The other point is that you keep assuming that calibration of speed is a function of observation, which it is not. What people or cameras see is irrelevant. Observation, physically, is a function of light, which are (because there is more than one) just additional physically existent phenomena, along with trains, cameras, observers, etc, in this mix of variables.
"The whole point your comprehension has not yet reached is that there is NO preferred observer outside the frame in which the bullet travels!"
See above. Apart from which, this 'frame' you refer to must be different at every point in time, so how does one have comparability of results, and how does one reference everything else to that? Time, as I said in the post, has nothing whatsoever to do with it. This outcome is a function of physical existence. There are things (including light) in relative spatial positions, which are changing in relative spatial position. That's it. Timing is external to this, it is a method for differentiating what is occurring at any given point in time (if we could ever have a timing device that good) across the whole spectrum. So at point in time A, the train is spatial position X, light which is going to reach platform observer spatial position Y, bullet in spatial position Z, etc. Then at point in time B...Etc, etc, etc.
"we are now also considering a train on Mars, why not"
Indeed, you can put the train anywhere, and reference the calibration of its speed to anything, just maintain the referencing rules. It makes no difference, just gets more difficult, taking trains to Mars that is!
"The passenger will see and be hit by a bullet travelling at c. This is because the whole train, air, passengers and gun IS an inertial frame K, in which, as Galileo and Einstein correctly assumed, the speed limit c and laws of physics are identical to ALL other inertial frames".
The passenger will be hit by the bullet travelling at c wrt to him (or her), (assuming they are in front of it!) because they are on a train and are travelling at the speed of that train, in the direction it is going. So is the gun and whoever fired it. The air is not of the train, unless the train was hermetically sealed. This is the physics of the circumstance. It is not about frames. Which as I have said many times before, are about referencing, not observation.
Lorentz expressed misgivings about the highjacking of 'local time' to account for dimension alteration. But he appears to have been swept away by the tide. Which all starts with the incorrect definition of what constitutes simultaneity. Here is a quite from my post on my blog (11/7 19.33):
3 The A & B example (copied from Poincaré) in Einstein section 1 1905, is not correct. The timing of existence is not the same if entities are in the "immediate proximity", and then different if they are not. All entities are at a different spatial location at any given point in time, some are just further apart than others. Different entities cannot be at the same spatial point at the same time. And timing is just a measuring system. So, select a particular point in time, and whatever existed then, did so, even if it is 10 trillion light years away. Each entity, except when it is in the "immediate" proximity" does not have its 'own time', and then there is a "common time".
4 Einstein: "We have not defined a common "time" for A and B, for the latter cannot be defined at all unless we establish by definition that the "time" required by light to travel from A to B equals the "time" it requires to travel from B to A. Let a ray of light start at the "A time" t(a) from A towards B, let it at the "B time" t(b) be reflected at B in the direction of A, and arrive again at A at the "A time"t'(a). In accordance with definition the two clocks synchronize if t(b) - t(a) = t'(a) - t(b)".
5 The distance between A & B is the same, by definition, whether it is expressed as A-B or B-A, because it is a difference. It is incorrect to express this in terms of how long light (or anything else) takes to travel one way and THEN the other. The important word being "then". If light speed is constant, it is just the same as using a ruler, or any other measuring tool. The particular use of light speed is pointless. But the problem is that this single distance (a difference) is being expressed as a difference between two different timings (what is used, so long as it is constant, is irrelevant). The equation should be: t(b) - t(a) = t(a) - t(b), which is the same as, and as meaningless as, A-B=B-A. A constant (because there is only one), ie the distance, is being expressed in terms of variance between two different measurements. Timing has been reified into physical reality.
6 This mistake then becomes embodied in the expression of light speed in terms of timing and distance. Hence c = 2AB/(t'(a) -t(a)). The real question here being: what has light got to do with it? The answer being: nothing. The fact that it enables sight is irrelevant to what constitutes physical reality.
Paul
