Eckard
1 Actual vrs logical
On many occasions precisely what happens is irrelevant to a correct logical/generic depiction. I could ask questions about precisely how does light work, but not knowing the answers does not detract from certain key logically correct statements. Similarly the point about local time is about designating a time to each 'point' in an elapsed sequence, which is correct, as opposed to using local time in a different way.
2 Fundamental vrs technical
As per the above, in respect of my question about the expectation from the M&M experiments, which you did not answer, I was asking whether your assertion meant: a) they should have not have been expecting that outcome because it does not occur, or b) they should not have been expecting it because the experiment would never identify it/the maths was wrong/etc.
3 Earth movement
I am not sceptical, it is a fact, and the point is not about absolute space. We can never know what is absolute and what is not. The simple fact is that, irrespective of what reference is used to calibrate motion (both in the sense of speed and direction), the earth is a moving entity, so too is light. Therefore, there must be differences with respect to one another, depending on relative direction and speed. A 'preferred' reference is just some entity which is best fit for purpose, it has no mystical properties and is not an absolute. And then, having chosen it, it must be maintained for all calibrations so that they are comparable. Irrespective of their precise concerns about ether, etc, their original point was correct, the speed of light going one way as opposed to the other wrt earth will be different.
4 Fundamental point
Just to amplify the underlying logic of the above and demonstrate that it is omnipresent: How do we know any given thing exists? Answer: because it is different from something else. Everything is relative. Every judgement has the logical form of comparison to reference in order to identify difference. This applies whether it be a manifest attribute (eg motion) or the very substance that is manifesting this. But we can progress in what is effectively a state of anarchy, because what we can know is a closed system. So all the logical possibilities which we cannot know are irrelevant, otherwise it would be impossible to make any objective judgement. In other words, what is relative within a closed system, has, within that closed system, an absolute quality, presuming that we did the sums correctly, etc.
5 Time
The point about local time revolves around its application to sequence, which is a series of events over time. This is the correct use of the concept known as local time. And as I said, Lorentz was using it correctly. Poincaré was the problem. Read his nonsense about time which starts in 1898 with The Measure of Time. Based of that, he incorretly applied the concept of local time. It must be understood that the reference in the measuring system known as timing is a constant rate of change. Timing devices just 'tell' the time, they are a practical manifestation of that. That is, they all individually function with the most constant and highest frequency of change possible, and are then synchronised, within the realms of practicality, to one common constant rate of change. If they do not work properly, or are not synchronised, then they are useless. Achieving this is a practical problem.
6 Synchronisation
The point was not whether we need Einstein's/ Poincaré's view, we need a proper view, which their's is not anyway. And we need to apply that in the context of a time delay between existence and receipt of representation of existence. Einstein relentlessly used time to express distance, he keeps on asserting that this is how we measure movement, ie change in spatial position. Obviously time is dervived from the deployment of some velocity, and he uses light. Now, this is where the error lies, so he has to, although he probably just did rather than make any conscious decision, maintain that flawed perspective for it to work. All that happens is he shifts the variable from one cause to another (or at least Poincaré did really). The point here being, distance can be expressed, conceptually, in terms of duration incurred. The concept being that instead of expressing distance as the fixed spatial quantity which it is, it can alternatively be quantified as the duration which would have been incurred had any given entity been able to travel along it, either way. But it must be understood that there is no duration as such, this is just an alternative to, and the equivalent of, a spatial measure, ie a singular quantity. Try this: put two things on the table. There is now a distance, or space, between them. This does not physically exist, it is a difference, the result of comparison between two things that are existent. Now take one of them away. There is no distance. There can only be a distance between physically existent entities which exist at the same time. And there is no duration in physical existence for something to travel over this distance, because any given physical existence only occurs in that particular physical state for a 'point in time'. In the subsequent state, that distance may be the same, but it may not be. There are different physical states which are determining that distance. The idea of measuring distance as a function of time and velocity is correct, so long as it is not presumed that the duration thereby derived is real. The difference (ie distance) is not actually there for anything to actually travel along it. What we are saying is: had it been possible then z would have taken t at v to travel x.
7 Einstein
And finally(!), note that Einstein used c whenever he did this. It always struck me from the outset that a) relativity 'works' so if there is a problem then it involves compensatory errors, or the incorrect attribution of a real variable, b) that approximating light speed to constant cannot be a logical problem (see para 1). It obviously is more or less so, therefore that simplification cannot be a fundamental issue. What must be happening has something else to do with the conceptualisation of light. All these arguments over the actual speed of light are 'red herrings', they will never resolve the issue, because they are not the issue.
Paul