The Untestable Einstein

[Shubee]

The physicist Tom Roberts once wrote in a trash-filled newsgroup that Einstein discussed the hidden postulates of special relativity in his "Jahrbuch" article of 1909. Today I checked a Wikipedia article (another unreliable source) on special relativity, in the section titled “Postulates”, and found that it mentions “several tacit assumptions,” one of which is “the independence of measuring rods and clocks from their past history.” The reference cited there is Einstein, "Fundamental Ideas and Methods of the Theory of Relativity", 1920.

 

I’ve never heard of an experiment to test “the independence of measuring rods and clocks from their past history.” If this principle is referring to reality, then why can’t it be tested? If the principle could cease to be true at this instant, then how would the world change? If changing the principle wouldn’t change the world, then exactly what did Einstein mean by this so-called tacit assumption?

 

It seems to me that Einstein didn’t understand special relativity well enough to write about it with clarity.

 

Shubee

The Axiomatization of Physics - Step 1

[swansont]

Why, specifically, is this a problem?

[pioneer]

The independence of measuring rods and clocks from their past history sorts of sounds like time travel backwards is not possible. Maybe the idea was, to prevent the argument of future humans playing jokes on us. If they could time travel backwards, we can't rely on any measurement, since jokes could occur due to children playing with their new time machine toy. This argument could challenge anything since we can't depend on accuracy.

 

The thing that comes to mind is the long jump in the 1968 Olympics by Bob Beamon where it broke the world record by 21 inches. I could picture future kids with a time machine playing a prank on those silly primitive humans and getting a lot of laughs. They just tweaked the calibration.

[nm-8]

"independence of clocks and rods from their past" is the fact that it doens't matter how the clocks and rods came to their place.

 

imagine a rectangular field of clocks covering a big area in space. so we know how fast time is running at the place of each clock (and relatively faster/slower in respect to other clocks).

Independence means, it doesn't matter how the clocks came there. So we may synchronize the clocks on one place, and slowly move them to their points. slowly enough, to ignore relativistic effects of their movement.

the same for the rods...

[Obelix]

In his famous gedankenexperiment, regarding the lightnings striking thw front and the rear of a rushing train (relativity of simultaneity) Einstein ponders momentarily over the question whether light has the same speed in two different directions. This was clearly the issue of the Michelson - mOrley experiment.

 

Nevertheless, einstein dismisses the question, declaring that "the independence from direction of the speed of light is a POSTULATE we can make in adopting this method (seeing the lightnings simultaneously in a mirror) in order to DEFINE simultaneous events".

 

In other words, when one DEFINES what is to be meant by "simultaneity" or by "time - " or "length - interval", details like uniformity of light speed, or the history of clocks and/or measuring rods may be irrelevant. E.g. the time interval for a certain event is DEFINED as the ticks of that specific standard clock (or clocks, if more than one are employed) which is (are) synchronized with the event under consideration".

 

Such "tacit assumptions" are necessary in all theories, all branches of science. Consider for example a very major tacit assumption made for centuries in Newtonian mechanics:

 

"The gravitational pull between two masses is independent of their history".

 

Indeed one can ask the question:

 

"We measure masses A and B, e.g. by the Cavendish device, and find them to satisfy the inverse square law. HOW DO WE KNOW, nevertheless, that, if we had measured the same masses A and B after they had been through an entirely different history, they would yield the same result?"

 

Or, even worse:

 

"If we measure any other pair of masses, would the result be the same (inverse square law)?"

 

Or even:

 

"If we measure the same pair of masses one more time (however many times we have already done so) how do we know the result would not differ, this one time?"

[pioneer]

In his famous gedankenexperiment, regarding the lightnings striking thw front and the rear of a rushing train (relativity of simultaneity) Einstein ponders momentarily over the question whether light has the same speed in two different directions. This was clearly the issue of the Michelson - mOrley experiment.

 

Nevertheless, einstein dismisses the question, declaring that "the independence from direction of the speed of light is a POSTULATE we can make in adopting this method (seeing the lightnings simultaneously in a mirror) in order to DEFINE simultaneous events".

 

In other words, when one DEFINES what is to be meant by "simultaneity" or by "time - " or "length - interval", details like uniformity of light speed, or the history of clocks and/or measuring rods may be irrelevant. E.g. the time interval for a certain event is DEFINED as the ticks of that specific standard clock (or clocks, if more than one are employed) which is (are) synchronized with the event under consideration".

 

Such "tacit assumptions" are necessary in all theories, all branches of science. Consider for example a very major tacit assumption made for centuries in Newtonian mechanics:

 

"The gravitational pull between two masses is independent of their history".

 

What this sort of sounds like is they were trying to play down random by defining very definite things. The speed of light is constant, simultaneous, and not some probability function. Again it comes down to assumptions. We could have assume in a way to support probability by simply invalidating simultaneous references. Einstein wasn't too big into using assumptions that played dice with the universe. But the fact remains, that two references like the lab and electron don't mesh, exactly, (uncertainty) suggesting that maybe these two references are not simultaneous. We can't get our clock to line with the electron's space-time clock no matter how hard we try. Something about the past of the electron's clock or meter stick got messed up and it does make a difference.

[Pete]

The physicist Tom Roberts once wrote in a trash-filled newsgroup that Einstein discussed the hidden postulates of special relativity in his "Jahrbuch" article of 1909.

The Jahrbuch article was published in 1907, not 1909.

 

Pete