Einstein's Clock Synchronization Convention

[reilly]

There's always the simple minded observation that, as far as I know, the conventional approach to SR has served us well for about a century. So, why change, unless there are strong empirical reasons to do so?

As pervect suggests, anything but the standard synchronization of clocks, is a matter of General Relativity. Any consistent set of conventions for synchronization must map into the standard one, and vica versa, and the transformations will be nonlinear. That is, off beat conventions will lead to non-inertial frames, basically by definition.

Again, the canonical approach will be modified or thrown out only when it fails to pass an empirical test.
Regards,
Reilly Atkinson

 

[Jimmy Snyder]

OK, but why are you showing me an article on the word 'axiom' to convince me of something about the word 'postulate'?

For two reasons.
1. Because as the article says: "The term (axiom) is often used interchangeably with postulate". The difference is in the field, not in the meaning.
2. Because the postulates as stated in Einstein's original paper on SR (On the Electrodynamics of Moving Bodies) are to be understood in this way.

Examples of this sort, together with the unsuccessful attempts to discover any motion of the Earth relatively to the "light medium,'' suggest that the phenomena of electrodynamics as well as of mechanics possesses no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good. We will raise this conjecture (the purport of which will hereafter be called the "Principle of Relativity'') to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body. These two postulates suffice for the attainment of a simple and consistent theory of the electrodynamics of moving bodies based on Maxwell's theory for stationary bodies.

 

[Aether]

For two reasons.
1. Because as the article says: "The term (axiom) is often used interchangeably with postulate". The difference is in the field, not in the meaning.

You would have to show me a definition of 'postulate' rather than 'axiom' before I would consider it relevant.

2. Because the postulates as stated in Einstein's original paper on SR (On the Electrodynamics of Moving Bodies) are to be understood in this way.

That quote contains the word 'postulate', but it doesn't say that the postulates are unprovable. You would have to show me a quote from a source like that which actually says something explicit to that effect, like this: "It is standard practice in the field of physics to label any unprovable assumption as a 'postulate', and of course what we mean by that is that counterexamples can't exist".

I looked up 'postulate' in several dictionaries, and all I saw was "a proposition taken for granted to be true". That doesn't necessarily mean that I couldn't also prove the proposition to be true also. Your definition of "axiom" on the other hand actually says that it is "unprovable". Show me a definition of 'postulate' that says that.

It's a method of argumentation first practiced by Socrates, and described by Plato. It tends to fall to pieces when challenged in this way.

Go back and see if either Socrates or Plato indicated which end of the argument was supposed to "fall to pieces when challenged in this way".

 

[Aether]

There's always the simple minded observation that, as far as I know, the conventional approach to SR has served us well for about a century. So, why change, unless there are strong empirical reasons to do so?

No reason to change unless there are strong empirical reasons to do so. However, the proliferation of crackpots may be a strong empirical reason for teachers to take care to keep SR clearly within the context of inertial reference systems. Some percentage of students is going find the relativity of simultaneity hard to accept, and quite rightly so, outside of this context; and for every genuine crackpot there may be a thousand others who just gave up trying to understand. Be prepared to give the right answer on this question. The constancy of the speed of light and the relativity of simultaneity are not what experiments prove, they are mathematical, as opposed to physical, properties of coordinate systems called "inertial reference frames".

Again, the canonical approach will be modified or thrown out only when it fails to pass an empirical test.

That is as it should be, except that alternate approaches will always need to be explored by those who would design and carry out new empirical tests.

Thank you for your help DrGreg, Hans, pervect, Hurkyl, JesseM, and to everyone else who participated. If I had a typist, I would thank them to, but I did all the typing on this end myself.