discussion at 1 hour 14 minutes
https://www.youtube.com/watch?v=yWPi5WC_IV0
Well you know we teach it to ourselves at least, when we teach it to ourselves at least, we make it as clear as possible, what assumptions we're making. And we're making a lot of assumptions. I'm just taking about ordinary special relativity...that three dimensional space is local and Euclidean. And that the light is traveling IN it, but that the light satisfies Einstein's postulates. Then you get to use the Pythagorean Theorem if you want to. And you get to use those things, and you make the conclusions that you do, given Einstein's postulates. And it's logical and it's also very unintuitive in the end,
....Then you have to ask yourself am I really going to stay there or am I going to go into a deeper set of assumptions? ...in Einstein's time, tried to investigate lots of other assumptions about the background space and this goes on. And so this goes on and so there's this continual investigation about the modeling about the background space. Or perhaps the saying that there should be no background space.
Instead of assuming and you can't anymore assume, that there is just some unknown liquid luminiferous aether. You can't do that. You can't just say there's something rather that behaves like a fluid, that's elastic...You've got to make the model more explicit in these times. And so people try and they're still trying to make background space models of different kinds. An example of a nice extreme one is Roger Penrose's attempt by Spin Networks, to create a background process model, for spacetime itself. And this kind of thing continues, so this is an ongoing investigation.
And Einstein's original words are not written in stone.
End of Rant....
As a student it seems really strange, and you have to understand the background, which is that the speed of light is calculated out of electromagnetic theory, and therefore independent of the inertial frame. And Einstein is setting up a theory which shows what the consequences of that are... Of course you're assuming all your classical ideas except one, and seeing what happens when you do that derivation.
I mean, I wouldn't know what convinces you. Some geometric thought experiment is one that convinced me ,... where you have the moving training And you look at the photon and on the train it's going back and forth between two mirrors in a vertical tube. But from the observer's point of view it's going up the hypotenuse of a right triangle. And then you compare using the Pythagorean Theorem and out come the relativistic transformations. So the derivation at the mathematical level is crystal clear. But, then, of course when you first learning it you resist this thing. It doesn't seem right.
And you're probably right that it doesn't seem right. That you'd like to understand it in a deeper way than that.
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But this is like finding...but you see the problem is how do you understand, shows it to you. But you could ask, how do I understand it? In mathematics there's situations where we do an understanding...They found non-Euclidean Geometries but they didn't have Models. Then we found models, curved surfaces, Gauss and so on. And we began to understand what we understand with non-Euclidean geometry. Something might be possible with relativity but I haven't seen it yet.
The question is when will your intuition rest. But that is not a mistake of the person who made the discovery...
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yeah there's a problem in the background here, I want to articulate; and that goes all the way back to Maxwell. You remember Maxwell wanted to make a mechanical model for electromagnetism and he gave it a good try and it didn't work. And nobody since could do it either: that's the old hidden variables problem if you think in modern terms. He wanted to do it, he wanted to get that theory of electromagnetic waves to be palpable as the way waves work in water and he could not do it. And so the theory became abstract. And the ether disappeared at that point. THAT's when the ether disappeared. It disappeared at the failure of that model.
Ah yeah [that model was quaternionic] haha.
Yeah but the difference is between how you understand how waves in water because you have a substrate and you think of the molecules moving in their patterns and the waves coming out. You have a substrate in which you understand where the waves come from and what they do. And you don't have that and the aether was supposed to do that. That's what the aether was supposed to do.
I'm not talking about words! I'm talking about the non-existence of a hidden variables model for the electromagnetism. It doesn't exist. The aether doesn't exist in that sense. You could want one but it doesn't exist. So we moderns make the mistake: Well the aether is just the manifold, it's just the background model of what we produce. But that isn't what people had in mind for the aether.
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