I think that's an acceptable way of putting it.So Lorentz invariance, as you understand it, means that the two views should be ok, but in fact only one is and the other is not.
Which would not refute what I said; I said "Lorentz invariance says this scenario is not possible". Obviously if Lorentz invariance is wrong then one can no longer use it to say the scenario is not possible. I have already said that several times. But Lorentz invariance has been verified by countless experiments, so it is certainly not just wrong. It is possible that Lorentz invariance is violated in ways we can't (yet) measure; we won't know for sure until we can make more accurate measurements, over a wider domain.That is a non sequitur. At leat there is another possibility: Lorentz invariance, as you understand it, is wrong.
This only works if you exclude "Lorentz invariance" from "relativity". But how do you justify that, when Lorentz invariance is a fundamental feature of the theory? Both SR and GR include Lorentz invariance (local Lorentz invariance, in the case of GR, but that's enough for what we're discussing here). You can't "reinterpret" SR or GR to change that; the Lorentz invariance of SR and GR makes definite physical predictions, which for the scenario we've been discussing are the ones I've described. There's no way to alter those predictions without altering the theory.You are assuming that relativity, when stressed under the tension of FTL, brings about two contradictory situations; hence you kill the messenger, you rule out FTL travel. Instead I assume that relativity, in face of FTL travel, only seems to offer contradictory explanations; hence I infer that those explanations are not really contradictory, so I reinterpret them.
So if you are admitting the possibility that Lorentz invariance is wrong, you are basically saying we can't use SR or GR to analyze this situation. If that's the case, all bets are off: we can't say anything about it at all unless you can offer some alternative theory that matches all the experimental predictions of SR and GR in the domains where they've been verified, but also allows violation of Lorentz invariance and consequent FTL travel in a situation like we've been discussing.
I don't think I disagree with this as a general statement, in so far as I can parse a meaning from it at all. But for any specific case, how you actually make the connections between concepts and empirical measurements is theory-dependent. If you fix the theory, you fix the connection; conversely, if you want to change the connection, to change, for example, how an observer would "interpret" the light signals he receives that seem to indicate physically unreasonable consequences under standard SR, you have to change the theory.For this purpose, my epistemological approach is quite a down-to-earth one, apparently not clashing with scientific method. I am saying that the meaning of our concepts (in our discussions, the spacetime coordinates associated to events) is determined by why and how they are in practice set up, that is to say, for which practical purpose and on the basis of which empirical measurement activities.
Of course not. The reason is that it is required by the logical structure of the theory; you can't change it without changing that logical structure, and hence changing the theory. The domain of applicability is at least as large as the domain of all the experiments that have been done that have confirmed the theory's predictions. It may be larger than that; we won't know for sure, as I said, until we've done more experiments over a wider domain. Obviously nobody has yet done direct experiments with rockets traveling at relativistic velocities, nor has anyone actually observed spacelike separated events that are causally connected. So the domain we're discussing here is definitely not part of the domain in which SR and GR have been experimentally confirmed. I've never suggested otherwise.Why period? You mean, “for no reason and hence without any domain of applicability”?
I didn't say you did. I said only that what you did specify in that thought experiment, combined with the logical structure of SR, leads to physically unreasonable consequences. If you want to reject the conclusion, you have only two alternatives:In my thought experiment, I did not include any unreasonable result, did I?
(1) Change the specifications of the thought experiment so that, combined with the logical structure of SR, they do not lead to physically unreasonable consequences. The only way to do that is to eliminate the FTL travel--i.e., to ensure that no pair of spacelike separated events are ever causally connected.
(2) Change the theory: stop using standard SR and start using some other theory, with a different logical structure, that leads to different consequences, physically reasonable ones, when combined with the specifications you gave. I have no objection to taking this option in principle, but it doesn't mean much unless you have such an alternative theory. It doesn't seem like you do; and without it, we can't have a useful discussion because we don't have a set of common premises to start from.
You appear to think that there is a third option: keep the specs as they are, keep SR as it is, but somehow "reinterpret" things so the physically unreasonable consequences don't happen. That's not a possible option: the predictions of physically unreasonable consequences, which I have spent quite a bit of time now elucidating, don't depend on "interpretation". They are straightforward logical consequences of SR plus the assumption that any pair of spacelike separated events can be causally connected. Here "SR" does include the physical meaning we assign to coordinates in particular inertial frames in which particular observers are at rest. But as I said above, that's part of the theory; you can't change it without changing the theory's predictions, which means changing the theory.