Now we’re getting somewhere and you’ve given me something to work with other than just “no, you’re wrong”.
So what if Larmor (Kudos to you for knowing who he is. His publicist wasn’t as good as some of the other rock star physicists working at the time) predicted time dilation before Einstein? It’s no secret that he built on the work of a lot of people who were coming up with hints and bits of pieces of what was to become SR. The point is, Einstein is the one who made all the pieces of the puzzle fit together. That is what was so extraordinary.
You said
Relativity is not needed for Time Dilation
You’ve got the whole argument backwards. You seem to think that Einstein came up with Relativity and then used time dilation to support the theory. That’s not what happened. By taking those bits and pieces of time dilation, length contraction, integration of space and time, which were all ideas other people had already explored and putting them together with the equivalence principle ultimately led him to the logical conclusion that spacetime is warped and that is what causes gravity. The Theory of Relativity may not be needed for time dilation, but time dilation is evidence of relativity and spacetime warp. If spacetime is moving at different speeds at different places, by definition it is warped.
I can understand rejecting that if you don’t accept that spacetime is an actual physical entity, but relativity demands that it is. And claiming that relativity doesn’t lead to the conclusion that spacetime is warped is a different debate than relativity is wrong because spacetime is only an abstract concept, without material existence.
You’ve made the point that effects of relativity could also exist in Newtonian space, and on one level I agree with that. If the only space you know is Newtonian, and effects of relativity are observed, then the obvious conclusion is that they can exist in Newtonian space, even if you don’ t understand exactly how.
But on a more fundamental level, it is not true. Newton conceived space and time as absolute, unchanging. Time “flows equably without relation to anything external” and space “in its own nature, without relation to anything external, remains always similar and immovable”. This is obviously in direct contradiction to SR, which make space and time relative. Time doesn’t flow equably without relation to anything external. If flows relative to motion. And space is not always similar and immovable. Its dynamic, it moves and changes, it acts upon things and can be acted upon.
You can’t argue that space is absolute when it supports your position and then also argue that it is relative when it supports your position. Either time dilation and length contraction exist (no matter who first had the idea) and spacetime is relative or they don’t exist and spacetime is absolute. Both views are supportable to different degrees, people have been debating it for millennia. But pick a lane and stay in it.
As for Levy, he makes the same stale argument that you must measure the one way speed of light in order to know if its constant. It’s hardly a novel argument. Remember when I posted the animation of the light clocks and told you to count the clicks as a round trip...this is why. To measure the speed of light in one direction, you’d need a synchronized stopwatch at each end, but relative motion affects the rate of your clocks relative to the speed of light. You can’t synchronize them without knowing the speed of light, which you can’t know without measuring. What you can do is use a single stopwatch to measure the round trip and divide by two. That’s what Einstein did. He
assumed it was the same speed both ways.
But here’s the thing...it doesn’t matter. All experiments agree with that assumption, but they also agree with the idea that the speed of light coming towards us is ten times faster than its speed going away from us. Light doesn’t have to have a constant speed in all directions, it just has to have a constant “average” round-trip speed. Relativity still holds if the speed of light is anisotropic. There’s actually a train of thought that the speed of light isn’t constant, but that time and space contract and expand in such a way that we will always perceive and measure it to be c. If you think about it, it makes sense. If speed is always measured the same, but time and space are not, then its not a big leap to conclude that spacetime adjusts itself in such a way that speed will always be measured the same.