Motor Daddy:
Why should I believe any test results of your experiments when it is shown over and over again that mistakes are made, equipment malfunctions etc. You keep testing till you get a result that you desire and then claim it as a fact?
No experiment ever establishes any fact beyond all doubt. What happens in science is that a prevailing consensus develops over time. Usually such a consensus cannot develop until many separate experiments have been done independently by different people or groups, all of which point towards the same conclusion.
All scientists know that all science is provisional. Science is our best current explanation of the way the world works. Nobody ever said it is infallible.
The main fact to consider with distance and time is the definition of the meter. A plain and simple fact that can't be proven wrong, by definition. No experiment can prove that definition wrong, by definition!
Right. You can't prove a definition wrong. A metre, like any unit of length, is completely arbitrary. The universe doesn't know about metres. The metre is just a unit defined by human beings for convenience. The inch is no different. The second is no different. The kilogram is no different.
The preisthood somehow believes that Einstein's second postulate is a law of physics. That is ridiculous.
In all your time here, you have never established in all your efforts why this is ridiculous. You'd like it to be ridiculous, but your fantasy world is not going to establish anything. You need actual experiments and evidence. This is an idea you don't seem to have got the hang of yet. The universe doesn't care about Motor Daddy's fantasies.
If Einstein believes that to be true and bases his entire theory on that concept, and later that postulate is shown to be false, his theory is garbage!
Right. But relativity is tested in labs around the world every single day. And in over 100 years it has never failed any experimental test. So, what do you conclude?
BTW, Using SR to try and prove that postulate correct is absurd circular logic. In order to defend that postulate you can not use SR.
Right. To take another example, you cannot use Motor Daddy thought experiments to prove that Motor Daddy's postulates about light are correct, because that's circular logic.
Is the light starting to come in on you yet?
What grounds does the priesthood have to stand on in order to defend that second postulate?
Experimental, real-world evidence - something you don't have and apparently don't even know about.
You mention the word theories. Why don't you refer to them as facts?
You can refer to them as facts if you like.
Has there ever been a theory that physics once held to be true, and then later that theory was shown to be incorrect? Has the wonderful world of physics ever believed a fact to be true, only to find out later that that fact wasn't really a fact after all?
Usually it doesn't work like that, because scientists know that things are seldom black or white in science. As I explained about, scientists know that science is provisional.
There are many examples of theories that have been refined over time and improved. Most scientific theories have a particular domain of applicability, beyond which a more detailed or different theory is more appropriate or 'correct'.
For example, to a good approximation, the Earth is flat. However, we find that on large enough scales the spherical-Earth theory is a better description of the Earth's surface than the flat-Earth theory.
Another example: to a good approximation, Newton's laws of motion are correct. However, we find that at high speeds and at very small or very large distances, Einstein's relativity is a better description of motion.
ughaibu:
There has been no observation of the speed of light being the same in different frames, has there?
Yes there has. In fact, that observation is made every day in student labs around the world. Compare the results of a speed-of-light experiment in England to one in Australia, say. Two different frames - same result.
