qsa
That does not address my point. Which was how do we know light is the fastest?
Though your response "the critical speed in space time" does indicate where the flaw is. The issue is not about the precise speed, it is about the conflation of physical existence and a physically existent representation thereof (eg light). Which if modelled renders light, which is just a physical entity that enables sight, as having all sorts of influences and properties it does not possess physically, ultimately through to the assertion that E=mc2. In other words, the problem is with the model of physical existence.
The simplest way I have of explaining that is to copy over a few paragraphs from a paper. This is not my essay, so I am not trying to make a point just in order to market my essay. The references are to Why does E=mc2 By Brian Cox and Jeff Forshaw.
The circular argument for spacetime
47 The next step is seen as calculating 'distance' between existent and non existent (ie previously existent) physical states, ie their supposed spatial relationship given that there is a time difference in their occurrence. That is, their distance in spacetime. But physical distance over time is a contradiction, by definition. Something cannot be a distance from something else when they do not exist at the same time. So really the question is: can physically existent states which existed at different times be compared in terms of some conceptual relative spatial position?
48 A key error is revealed on page 74: "...because they are not of the same type of quantity. We can, however, convert distances into times and vice versa if we use the equation...v = xt...distance and time can be interchanged using something that has the currency of a speed. Let us therefore introduce a calibrating speed; call it c". This is only correct if, as explained in para 3, it is understood that it is not actually duration, just a conceptual alternative way of expressing distance. And whilst it is explicitly stated that this velocity could represent anything, in fact it represents light speed, by virtue of the conflation of reality and light reality in the ensuing analysis. Indeed, the next sentence gives an example of light years. The issue was seen as best resolved by assuming an equivalence in the units of time and space.
49 So the 'distance' in terms of a combination of space and time, known as s, was therefore deemed to be the hypotenuse of an imaginary triangle relating the two entities, with physical distance and elapsed time representing the other sides. Hence the two possibilities were: s2 = (ct) 2 x2 or s2 = (ct) 2 - x2. The decision on which option is correct is based on causality, which is correct as such, in that effect must exist after cause. The 'negative' option was therefore chosen. This issue is with the presumptions and the analysis.
50 & 51
52 The argument is circular, because (page 89) it is asserted in relation to an examination of causality that: "Nothing can travel faster than c because if it did it could be used to transmit information that could violate the principle of cause and effect". And hence "we have finally managed to interpret the speed c: It is the cosmic speed limit". Then: "No matter how two different observers are moving, they must always measure c to be the same." and "The speed c is beginning to look a lot like another special speed we have encountered in this book: the speed of light, but we haven't proved the connection yet". And: "Certainly the existence of a universal speed limit offers promise, especially if we can interpret it as the speed of light".
53 But the assertion that 'nothing can travel faster' is incorrect. Because if there is something which can travel faster than light, it is irrelevant, as it is not the information transmitter. In respect of sight, it is light, a physical effect in photons, which is utilised as the information transmitter. And this presumption is only true in respect of the physically existent light based representation of physical existence, it is not necessarily true for the physical existence being represented, and would be a coincidence if it was. In other words, what occurred is not defined by light, and its physical properties, what is observable of that is. So the conflation of reality and light reality results in c, as in light speed, being seen as proven to be the constant, whereas this was a presumption from the outset, and it was not observational light anyway, as presumed.
54 & 55
56 So, the argument is both circular, and incorrect. The final part of this being a reference back to the apparent effect on time with moving clocks. Proof of this is seen in the fact that (page 91): "the [derived] enhancement factor is equal to:
c/√(c2 - v2) or 1/√(1 - v2/c2), which is exactly what we got in the last chapter but only if we interpret c as speed of light...We have deduced the same formula...". With the added statement that: "We didn't even need to give light a special role". The only two presumptions are seen as: an invariant distance between events, and cause and effect are not to be violated. Then it is argued that the speed, and hence distance, through spacetime must be universal and that the variance is in observation, in that time varies with movement. Page 95: "...but there is something special about the motorcyclist's watch, because the motorcyclist does not move relative to himself". And then: "...a moving clock doesn't move so fast through time as a stationary one, which is just another way of saying it ticks more slowly". None of which is correct.
[to make this understandable I have to insert an earlier paragraph:
7 Yet another way of putting this is that establishing the timing relationship of A and B must involve another reference, so that the two can be compared and any difference identified. But this is what timing does, because the time shown on any device only has meaning if it is corresponds with the single reference to which all such devices are related, ie a conceptual constant rate of change. That is why they must be synchronised, otherwise the system is useless, allowing for the practicalities of so doing. That reference is not another time, but the time (in Einstein's terminology "common time"). Timing devices just 'tell' the time.]
57 Finally, on (page 103): "We haven't proved that c has anything to do with the speed of light yet...in the spacetime way of looking at things, light is not so special...everything hurtles through spacetime at the same speed, c...Light just happens to use up all its spacetime speed quota on motion through space and in doing so travels at the cosmic speed limit: The apparent specialness of light is an artifact of our human tendency to think of time and space as different things" . This is incorrect. Light speed is the speed limit, but not necessarily in physical reality. Light just enables sight.
Paul