Relativity and Lorentz Symmetry: What is the Relationship to Reality?

[JesseM]

Actually, I too rather prefer to suppose that "matter is spherically spatially extended, and thus to reject the concept of the particle" in a classical sense at least. Nevertheless, "the Logic of Relativity is founded on, and completely consistent with, an Absolute Space. (Contrary to current opinions)". I am so glad to see that I do not have to justify this position at all, as it has been Einstein's own position all along.

The parts you are quoting are just the opinions of the author of that website, not quotes from Einstein himself. And all this is irrelevant to what we've debating on this thread--let's not take a thread that was split for being off-topic and make it off-topic again, OK? The only section of that page that was relevant to our debate was the one I quoted, where Einstein gave a definition of Lorentz covariance.

 

[Aether]

The parts you are quoting are just the opinions of the author of that website, not quotes from Einstein himself.

There are three quotes from Einstein himself there.

And all this is irrelevant to what we've debating on this thread--let's not take a thread that was split for being off-topic and make it off-topic again, OK? The only section of that page that was relevant to our debate was the one I quoted, where Einstein gave a definition of Lorentz covariance.

Ok.

Here are a set of articles that seem to address the subject of this thread "Relativity, LET, and Reality" more or less directly. For example, from page 84 of Ref. 2: "An examination of these effects will help to clarify the status of the physical "reality" of length-contraction and time-dilation in the Special Theory."

It would be helpful if you would try to reference your argument directly to something within these papers, or else to something in some other published reference of your choosing; and I will try to do the same.

1. C.B. Giannoni, Special Relativity in Accelerated Systems, Philosophy of Science, Vol. 40, No. 3. (Sep., 1973), pp. 382-392.

2. J.A. Winnie, Special Relativity without One-Way Velocity Assumptions: Part I, Philosophy of Science, Vol. 37, No. 1. (Mar., 1970), pp. 81-99.

3. J.A. Winnie, Special Relativity without One-Way Velocity Assumptions: Part II, Philosophy of Science, Vol. 37, No. 2. (Jun., 1970), pp. 223-238.

4. A. Grunbaum, Simultaneity by Slow Clock Transport in the Special Theory of Relativity, Philosophy of Science, Vol. 36, No. 1. (Mar., 1969), pp. 5-43.

5. W. Salmon, The Conventionality of Simultaneity, Philosophy of Science, Vol. 36, No. 1. (Mar., 1969), pp. 44-63.

6. B.C. van Fraassen, Conventionality in the Axiomatic Foundations of the Special theory of Relativity, Philosophy of Science, Vol. 36, No. 1. (Mar., 1969), pp. 64-73.

7. B. Ellis and P. Bowman, Conventionality in Distant Simultaneity, Philosophy of Science, Vol. 34, No. 2. (Jun., 1967), pp. 116-136.

 

[JesseM]

There are three quotes from Einstein himself there.

None are supporting the notion that "the logic of relativity is founded on absolute space" though.

Here are a set of articles that seem to address the subject of this thread "Relativity, LET, and Reality" more or less directly. For example, from page 84 of Ref. 2: "An examination of these effects will help to clarify the status of the physical "reality" of length-contraction and time-dilation in the Special Theory."

I'm not talking about the physical reality of length contraction or time dilation, but only of the physical reality of the statement that "the laws of physics will work the same way in each inertial ruler/clock statement constructed according to Einstein's procedure" (which does not constrain you to use a coordinate system based on these ruler/clock systems, and thus does not mean you will see length contraction or time dilation work the same way that it does in those coordinate systems). Unless your references address this specifically, I'm not interested, I'd rather you responded in your own words to my arguments, like the ones in post #45.

I also wonder--if you don't think the symmetry of the laws of physics as measured by different inertial ruler/clock systems qualifies as a "physical truth" about the laws of nature, then would you also say that rotation invariance and translation invariance (the fact that the laws of physics don't change in an inertial system if you rotate the spatial coordinate axes or move the origin) aren't physical truths either? Note that by theorem[/url], conservation of linear and angular momentum is a direct consequence of these symmetries, and likewise energy conservation is a direct consequence of time-translation invariance (the idea that the laws of physics don't change in an inertial system if you change the moment defined as t=0).

 

[Aether]

I'm not talking about the physical reality of length contraction or time dilation, but only of the physical reality of the statement that "the laws of physics will work the same way in each inertial ruler/clock statement constructed according to Einstein's procedure" (which does not constrain you to use a coordinate system based on these ruler/clock systems, and thus does not mean you will see length contraction or time dilation work the same way that it does in those coordinate systems). Unless your references address this specifically, I'm not interested, I'd rather you responded in your own words to my arguments, like the ones in post #45.

Ok. 1. Conservation of linear momentum is one of the laws of physics implicitly referred to in your statement; 2. this law of physics does "work the same way in each inertial ruler/clock statement (sic?) constructed according to Einstein's procedure"; 3. but linear momentum is not an objective physical quantity, so this law of physics is not an objective physical law; 4. therefore your statement does not seem to be about objective physical reality.

I also wonder--if you don't think the symmetry of the laws of physics as measured by different inertial ruler/clock systems qualifies as a "physical truth" about the laws of nature, then would you also say that rotation invariance and translation invariance (the fact that the laws of physics don't change in an inertial system if you rotate the spatial coordinate axes or move the origin) aren't physical truths either?

I think "that a conservation law can be derived from any continuous symmetry", and that these are physical truths within the limits of experimental error iff they are based on the observation of objective physical quantities to begin with. My complaint (whether or not it stems from my own confusion remains to be seen) about the standard formulation of SR is not that Lorentz-symmetry doesn't contain some grain of truth, it is that it also contains at least one non-physical limitation. Poincare symmetry is in fact the full symmetry of special relativity, and not Lorentz symmetry.

Note that by theorem[/url], conservation of linear and angular momentum is a direct consequence of these symmetries, and likewise energy conservation is a direct consequence of time-translation invariance (the idea that the laws of physics don't change in an inertial system if you change the moment defined as t=0).

Linear momentum is not an objective physical quantity (e.g., it is coordinate-system dependent); so, the conservation of linear momentum is apparently associated with a coordinate-system dependent symmetry; namely, Lorentz symmetry.

 

[Aether]

Irrelevant to my argument. The quantity being measured is coordinate-system-dependent, but all coordinate systems will agree on what a particular physical measuring system will get as a result for that measurement. Do you not see the distinction here?

No. Consider one particular measuring system that comprises an ideal atomic clock, and wherein the quantity being measured is the time on the clock when some well defined signal event occurs at the same location as the clock. For a first arbitrary synchronization of this clock, all coordinate systems will agree on the time indicated by this clock when the signal event occurs. The same would also be true for a second arbitrary synchronization of the clock and the time indicated by this clock when the same signal event occurs. In fact, the only difference between what all coordinate systems agree on as to the particular readings on this clock between the first and second abitrary synchronizations of the clock is in fact only the difference between these two synchronizations of the clock. Every coordinate system will agree on how we arbitrarily syncrhonized this clock, so what? The empirical content of special relativity has nothing whatsoever to do with this trivial agreement of all coordinate systems on how we arbitrarily synchronized this clock, but rather on anything but this that happens to the indicated time on the clock.

Fine, use the word "indicates" rather than "measures", although I'm pretty sure it is standard terminology to talk about all the inertial coordinate systems "measuring" the same laws of physics. But anyway, we can say that each physical measuring-system designed according to Einstein's procedure will "indicate" that the laws of physics obey the same equations. And this is a property of the laws of physics themselves--it wouldn't be true if the laws were Newtonian, for example. Do you disagree?

Yes I disagree. Einstein's procedure did nothing more for us in the above example than to synchronize our clock in an arbitrary way, and therefore it is shown to be completely irrelevant to the empirical content of special relativity.

Now you're talking about a generalized notion of "physical measuring-systems" which goes beyond the ones constructed according to Einstein's procedure--that's what I've been referring to just as "coordinate systems". You don't even need to physically construct a measuring system whose measurements will correspond to a coordinate system, you could just take some other measuring-system (like the ones described by Einstein), then pick some arbitrary mathematical transformation on that system's coordinates, then call the result "your" coordinate system (in this sense, even the two-way speed of light could be disagreed on, although it would be the same in all coordinate systems if you restrict your allowable coordinate systems to ones where differences in position coordinates would match measurements of physical rulers at rest in that coordinate system and differences in time coordinates between events with the same position-coordinates would match measurements of a physical clocks at rest at that position-coordinate). Anyway, no matter what coordinate system you choose to work in, local physical facts like "when this event occurred, it was right next to this physical clock, which read 30 seconds at the moment it occurred" will be agreed upon by all coordinate systems. And the fact that all the physical ruler-clock systems constructed according to Einstein's procedure will indicate the same "laws of physics" is itself a statement that can be broken down into a bunch of such local physical facts, so it's a fact that's agreed upon by all coordinate systems as well (including ones whose coordinates don't match any of Einstein's ruler-clock systems).

Einstein's procedure is completely irrelevant to any measurement that you can possibly make because the only thing it does is to arbitrarily synchronize clocks which is fully equivalent to uniquely determining the one-way speed of light. In J.A. Winnie, Special Relativity without One-Way Velocity Assumptions: Part I, Philosophy of Science, Vol. 37, No. 1. (Mar., 1970), p. 81 he states: "According to the CS thesis [conventionality of simultaneity], this situation reveals a structural feature of the Special Theory, and thereby of the universe it purports to characterize, which not only makes the one-way speed of light indeterminate, but reveals that its unique determination could only be at the expense of contradicting the nonconventional content of the Special Theory".

What I am after is the nonconventional content of the Special Theory, and Einstein's procedure is completely irrelevant to that. It is useful, but not for making empirical measurements.

Now I will ask you once again, please cite a published reference to support your argument.

 

[JustinLevy]

Are you quoting yourself?
Are you aware that all attempts in detecting Absolute Space have failed?

clj4, it is probably best that you stop trying to evade your ban. Your bizarre method of debating by insinuating insults and refusing to answer direct questions always points you out.

Moderators, if you check the IP addresses nakurusil has used, they should match some used by clj4. Thank you.