1. Three clocks A, B and O are co-located in one spot.
2. Synchronize them.
3. Physically measure a distance L from O in the opposite directions
4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
5 Measure the one-way speed of light as follows:
-- One-way speed of light between O and A.
--One-way speed of light between O and B then
If Einstein's P2 is correct then
The one-way speed of light between OA = The one-way speed of light between OB.
If Einstein's P2 is wrong then
The one-way speed of light between OB =/ The one-way speed of light between OA..

On 10-Sept-23 5:27 am, Ken Seto wrote:
> 1. Three clocks A, B and O are co-located in one spot.
> 2. Synchronize them.
> 3. Physically measure a distance L from O in the opposite directions
> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> 5 Measure the one-way speed of light as follows:
> -- One-way speed of light between O and A.
> --One-way speed of light between O and B then
> If Einstein's P2 is correct then
> The one-way speed of light between OA = The one-way speed of light between OB.
> If Einstein's P2 is wrong then
> The one-way speed of light between OB =/ The one-way speed of light between OA..
>

Measuring the one way speed of light requires a model of space time, but
in your proposed experiment you can avoid that just be appealing to
symmetry instead.

I suggest you spend the required amount of money to test this. No one
else is going to do it for you.

Sylvia.

On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> 1. Three clocks A, B and O are co-located in one spot.
> 2. Synchronize them.
> 3. Physically measure a distance L from O in the opposite directions
> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> 5 Measure the one-way speed of light as follows:
> -- One-way speed of light between O and A.
> --One-way speed of light between O and B then
> If Einstein's P2 is correct then
> The one-way speed of light between OA = The one-way speed of light between OB.
> If Einstein's P2 is wrong then
> The one-way speed of light between OB =/ The one-way speed of light between OA..
The second postulate is not a claim the one-way speed is c. It claims the velocity is "independent of the source velocity." In your experiment, everyone agrees it would be c for both. It is only a claim the one-way speed is c regardless of source velocity. Your source and sinks are not moving. One-way speed of light is directly observed by the Doppler shift and, in Roemer's measure, by the moon of Jupiter.

On Saturday, September 9, 2023 at 8:40:10 PM UTC-7, Laurence Clark Crossen wrote:
> On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> > 1. Three clocks A, B and O are co-located in one spot.
> > 2. Synchronize them.
> > 3. Physically measure a distance L from O in the opposite directions
> > 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> > 5 Measure the one-way speed of light as follows:
> > -- One-way speed of light between O and A.
> > --One-way speed of light between O and B then
> > If Einstein's P2 is correct then
> > The one-way speed of light between OA = The one-way speed of light between OB.
> > If Einstein's P2 is wrong then
> > The one-way speed of light between OB =/ The one-way speed of light between OA..

> The second postulate is not a claim the one-way speed is c.

Really?

https://en.wikipedia.org/wiki/Postulates_of_special_relativity

"2. Second postulate (invariance of c)

As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference."

> ... One-way speed of light is directly observed by the Doppler shift...

Really?

You cannot measure the speed of light using the Doppler shift, that only tells you about the change in both frequency and wavelength as you observe light from a moving source. The speed of light remains c, a constant... as proclaimed in the second postulate.

This is high-school freshman stuff, first week in the course. Apparently you either have never taken a course in physics or you have forgotten everything that was taught to you. Read a dang textbook and quit embarrassing yourself with rank beginner mistakes!

On Sunday, 10 September 2023 at 06:25:15 UTC+2, Paul Alsing wrote:
> On Saturday, September 9, 2023 at 8:40:10 PM UTC-7, Laurence Clark Crossen wrote:
> > On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> > > 1. Three clocks A, B and O are co-located in one spot.
> > > 2. Synchronize them.
> > > 3. Physically measure a distance L from O in the opposite directions
> > > 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> > > 5 Measure the one-way speed of light as follows:
> > > -- One-way speed of light between O and A.
> > > --One-way speed of light between O and B then
> > > If Einstein's P2 is correct then
> > > The one-way speed of light between OA = The one-way speed of light between OB.
> > > If Einstein's P2 is wrong then
> > > The one-way speed of light between OB =/ The one-way speed of light between OA..
>
> > The second postulate is not a claim the one-way speed is c.
> Really?
>
> https://en.wikipedia.org/wiki/Postulates_of_special_relativity
>
> "2. Second postulate (invariance of c)
>
> As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference."

Most of your fellow idiots are denying that. Well,
nobody should expect a bunch of fanatic clowns
to be able to detemine a common version of
anything.

On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> 1. Three clocks A, B and O are co-located in one spot.
> 2. Synchronize them.
> 3. Physically measure a distance L from O in the opposite directions
> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> 5 Measure the one-way speed of light as follows:
> -- One-way speed of light between O and A.
> --One-way speed of light between O and B then
> If Einstein's P2 is correct then
> The one-way speed of light between OA = The one-way speed of light between OB.
> If Einstein's P2 is wrong then
> The one-way speed of light between OB =/ The one-way speed of light between OA..

There is no way to measure light speed because the measuring device is never at
rest and we do not know its motion in the unmarked.

On 11-Sept-23 11:51 am, mitchr...@gmail.com wrote:
> On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
>> 1. Three clocks A, B and O are co-located in one spot.
>> 2. Synchronize them.
>> 3. Physically measure a distance L from O in the opposite directions
>> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
>> 5 Measure the one-way speed of light as follows:
>> -- One-way speed of light between O and A.
>> --One-way speed of light between O and B then
>> If Einstein's P2 is correct then
>> The one-way speed of light between OA = The one-way speed of light between OB.
>> If Einstein's P2 is wrong then
>> The one-way speed of light between OB =/ The one-way speed of light between OA..
>
> There is no way to measure light speed because the measuring device is never at
> rest and we do not know its motion in the unmarked.

We can measure the speed relative to the measuring device.

Sylvia

On Monday, 11 September 2023 at 08:29:04 UTC+2, Sylvia Else wrote:
> On 11-Sept-23 11:51 am, mitchr...@gmail.com wrote:
> > On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> >> 1. Three clocks A, B and O are co-located in one spot.
> >> 2. Synchronize them.
> >> 3. Physically measure a distance L from O in the opposite directions
> >> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> >> 5 Measure the one-way speed of light as follows:
> >> -- One-way speed of light between O and A.
> >> --One-way speed of light between O and B then
> >> If Einstein's P2 is correct then
> >> The one-way speed of light between OA = The one-way speed of light between OB.
> >> If Einstein's P2 is wrong then
> >> The one-way speed of light between OB =/ The one-way speed of light between OA..
> >
> > There is no way to measure light speed because the measuring device is never at
> > rest and we do not know its motion in the unmarked.
> We can measure the speed relative to the measuring device.

And You can't ever comprehend that Your precious
measurements are just repeaters of Your insane
postulates.

Sylvia Else <sylvia@email.invalid> wrote:

> On 11-Sept-23 11:51 am, mitchr...@gmail.com wrote:
> > On Saturday, September 9, 2023 at 12:27:06?PM UTC-7, Ken Seto wrote:
> >> 1. Three clocks A, B and O are co-located in one spot.
> >> 2. Synchronize them.
> >> 3. Physically measure a distance L from O in the opposite directions
> >> 4. Send A and B in the opposite directions at equal speed mechanically and
stop them at distance L away from O.
> >> 5 Measure the one-way speed of light as follows:
> >> -- One-way speed of light between O and A.
> >> --One-way speed of light between O and B then
> >> If Einstein's P2 is correct then
> >> The one-way speed of light between OA = The one-way speed of light
> >> between OB. If Einstein's P2 is wrong then The one-way speed of light
> >> between OB =/ The one-way speed of light between OA..
> >
> > There is no way to measure light speed because the measuring device is
> > never at rest and we do not know its motion in the unmarked.
>
> We can measure the speed relative to the measuring device.

Actually the speed of light isn't measured that way anymore.
And it wasn't, before it was fixed by definition.
Precision measurements of the speed of light were done,
when they could still be done, on standing waves,
that is, in a cavity, or between mirrors.

If you analyse what those measurements were actually doing
you'll see that what was actually done in those measurements
was to establish a ratio of units. [1]
(the second from an atomic clock, the meter from a Krypton line)

When it was found that this ratio could be measured more accurately
than the length unit could be realised in practice
the ratio c was defined, and the length unit was abolished.
(as a fundamental unit of the SI)

You should realise that all this pottering about with flashlights,
clocks and trains and rulers is for didactic purposes only.
No one ever mounted a light speed measuring apparatus
on a railway carriage.

It is make believe physics, for didactic purposes,
good only for those who feel a philosophical need
to believe that relativity can be derived from experiments. [2]
(or at least could have been derived, in principle)
It can't, a postulate of some kind is needed.
And yes, it took someone of Einstein's genius to see it,

Jan

[1] The same kind of experiments are still being done,
and they still do the same kind of thing.
(with ever increasing precision)
Only the name of those experiments has changed.
Nowadays we call it a calibration of a (secondary) meter standard,
or the determination of the (absolute) frequency of a light source.

[2] Mostly naive empirists, positivists, or worse, neo-positivists.
Maybe you should try your hand at naive Popperianism for a while.

On Monday, 11 September 2023 at 11:47:51 UTC+2, J. J. Lodder wrote:

> When it was found that this ratio could be measured more accurately
> than the length unit could be realised in practice
> the ratio c was defined, and the length unit was abolished.
> (as a fundamental unit of the SI)

Noone cares about your moronic SI, unfortunately,
anyone can check GPS - their ideological madness
is useless and ignored when it comes to serious
measurements.

On Sunday, September 10, 2023 at 12:25:15 AM UTC-4, Paul Alsing wrote:
> On Saturday, September 9, 2023 at 8:40:10 PM UTC-7, Laurence Clark Crossen wrote:
> > On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> > > 1. Three clocks A, B and O are co-located in one spot.
> > > 2. Synchronize them.
> > > 3. Physically measure a distance L from O in the opposite directions
> > > 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> > > 5 Measure the one-way speed of light as follows:
> > > -- One-way speed of light between O and A.
> > > --One-way speed of light between O and B then
> > > If Einstein's P2 is correct then
> > > The one-way speed of light between OA = The one-way speed of light between OB.
> > > If Einstein's P2 is wrong then
> > > The one-way speed of light between OB =/ The one-way speed of light between OA..
>
> > The second postulate is not a claim the one-way speed is c.
Really? Does it claims that the one-way speed of of light is isotropic in all frames???
> Really?
>
> https://en.wikipedia.org/wiki/Postulates_of_special_relativity
>
> "2. Second postulate (invariance of c)
>
> As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference."
>
> > ... One-way speed of light is directly observed by the Doppler shift...
>
> Really?
>
> You cannot measure the speed of light using the Doppler shift, that only tells you about the change in both frequency and wavelength as you observe light from a moving source. The speed of light remains c, a constant... as proclaimed in the second postulate.
>
> This is high-school freshman stuff, first week in the course. Apparently you either have never taken a course in physics or you have forgotten everything that was taught to you. Read a dang textbook and quit embarrassing yourself with rank beginner mistakes!

On Saturday, September 9, 2023 at 8:51:00 PM UTC-4, Sylvia Else wrote:
> On 10-Sept-23 5:27 am, Ken Seto wrote:
> > 1. Three clocks A, B and O are co-located in one spot.
> > 2. Synchronize them.
> > 3. Physically measure a distance L from O in the opposite directions
> > 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> > 5 Measure the one-way speed of light as follows:
> > -- One-way speed of light between O and A.
> > --One-way speed of light between O and B then
> > If Einstein's P2 is correct then
> > The one-way speed of light between OA = The one-way speed of light between OB.
> > If Einstein's P2 is wrong then
> > The one-way speed of light between OB =/ The one-way speed of light between OA..
> >
> Measuring the one way speed of light requires a model of space time, but
> in your proposed experiment you can avoid that just be appealing to
> symmetry instead.
My experiment only testing the isotropy of the one-way speed of light.
>
> I suggest you spend the required amount of money to test this. No one
> else is going to do it for you.
>
> Sylvia.

On Sunday, September 10, 2023 at 11:29:04 PM UTC-7, Sylvia Else wrote:
> On 11-Sept-23 11:51 am, mitchr...@gmail.com wrote:
> > On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> >> 1. Three clocks A, B and O are co-located in one spot.
> >> 2. Synchronize them.
> >> 3. Physically measure a distance L from O in the opposite directions
> >> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> >> 5 Measure the one-way speed of light as follows:
> >> -- One-way speed of light between O and A.
> >> --One-way speed of light between O and B then
> >> If Einstein's P2 is correct then
> >> The one-way speed of light between OA = The one-way speed of light between OB.
> >> If Einstein's P2 is wrong then
> >> The one-way speed of light between OB =/ The one-way speed of light between OA..
> >
> > There is no way to measure light speed because the measuring device is never at
> > rest and we do not know its motion in the unmarked.
> We can measure the speed relative to the measuring device.
>
> Sylvia

How do you measure the relative that shows it is not an absolute
order instead sylvia?

Mitchell Raemsch

On Saturday, September 9, 2023 at 11:18:15 PM UTC-7, Maciej Wozniak wrote:
> On Sunday, 10 September 2023 at 06:25:15 UTC+2, Paul Alsing wrote:
> > On Saturday, September 9, 2023 at 8:40:10 PM UTC-7, Laurence Clark Crossen wrote:
> > > On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
> > > > 1. Three clocks A, B and O are co-located in one spot.
> > > > 2. Synchronize them.
> > > > 3. Physically measure a distance L from O in the opposite directions
> > > > 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
> > > > 5 Measure the one-way speed of light as follows:
> > > > -- One-way speed of light between O and A.
> > > > --One-way speed of light between O and B then
> > > > If Einstein's P2 is correct then
> > > > The one-way speed of light between OA = The one-way speed of light between OB.
> > > > If Einstein's P2 is wrong then
> > > > The one-way speed of light between OB =/ The one-way speed of light between OA..
> >
> > > The second postulate is not a claim the one-way speed is c.
> > Really?
> >
> > https://en.wikipedia.org/wiki/Postulates_of_special_relativity
> >
> > "2. Second postulate (invariance of c)
> >
> > As measured in any inertial frame of reference, light is always propagated in empty space with a definite velocity c that is independent of the state of motion of the emitting body. Or: the speed of light in free space has the same value c in all inertial frames of reference."
> Most of your fellow idiots are denying that. Well,
> nobody should expect a bunch of fanatic clowns
> to be able to detemine a common version of
> anything.
Relativity is like a hydra with many heads because it is totally inconsistent nonsense.

On Monday, September 11, 2023 at 2:47:51 AM UTC-7, J. J. Lodder wrote:
> It is make believe physics...
> to believe that relativity can be derived from experiments.
> (or at least could have been derived, in principle)
> It can't, a postulate of some kind is needed.

Not at all. The principles of physics, including the principle of relativity, are all derived from experience. Of course, the induction is always incomplete, e.g., in every closed system we've ever observed, momentum is conserved, but we can never observe every closed system for all time, so when constructing a physical theory we assume the principle of momentum conservation, but this is not an arbitrary or conventional assumption, it is the most firmly of all empirically-founded propositions. Similarly for the principle of relativity, which leaves only a single degree of freedom in the relationship between the standard inertial coordinate systems (operationally established), and that degree of freedom is fixed by any one of many empirial facts, which unambiguously establish special relativity.

On Tuesday, 12 September 2023 at 08:27:34 UTC+2, Bill wrote:
> On Monday, September 11, 2023 at 2:47:51 AM UTC-7, J. J. Lodder wrote:
> > It is make believe physics...
> > to believe that relativity can be derived from experiments.
> > (or at least could have been derived, in principle)
> > It can't, a postulate of some kind is needed.
> Not at all. The principles of physics, including the principle of relativity, are all derived from experience.

It's just a mad lie, and even some of your fellow idiots
are admitting it is.

On 12-Sept-23 4:02 am, mitchr...@gmail.com wrote:
> On Sunday, September 10, 2023 at 11:29:04 PM UTC-7, Sylvia Else wrote:
>> On 11-Sept-23 11:51 am, mitchr...@gmail.com wrote:
>>> On Saturday, September 9, 2023 at 12:27:06 PM UTC-7, Ken Seto wrote:
>>>> 1. Three clocks A, B and O are co-located in one spot.
>>>> 2. Synchronize them.
>>>> 3. Physically measure a distance L from O in the opposite directions
>>>> 4. Send A and B in the opposite directions at equal speed mechanically and stop them at distance L away from O.
>>>> 5 Measure the one-way speed of light as follows:
>>>> -- One-way speed of light between O and A.
>>>> --One-way speed of light between O and B then
>>>> If Einstein's P2 is correct then
>>>> The one-way speed of light between OA = The one-way speed of light between OB.
>>>> If Einstein's P2 is wrong then
>>>> The one-way speed of light between OB =/ The one-way speed of light between OA..
>>>
>>> There is no way to measure light speed because the measuring device is never at
>>> rest and we do not know its motion in the unmarked.
>> We can measure the speed relative to the measuring device.
>>
>> Sylvia
>
> How do you measure the relative that shows it is not an absolute
> order instead sylvia?
>
> Mitchell Raemsch

That's just gibberish.

Sylvia.

On Monday, September 11, 2023 at 12:23:08 PM UTC-6, Laurence Clark Crossen wrote:
>
> Relativity is like a hydra with many heads because it is totally inconsistent nonsense.

Larry-boy's version of relativity is inconsistent nonsense because he doesn't understand
the most basic things about it. Larry-boy's version of the Doppler effect is also
inconsistent nonsense because he doesn't understand it either.

On Tuesday, September 12, 2023 at 2:27:34 AM UTC-4, Bill wrote:
> On Monday, September 11, 2023 at 2:47:51 AM UTC-7, J. J. Lodder wrote:
> > It is make believe physics...
> > to believe that relativity can be derived from experiments.
> > (or at least could have been derived, in principle)
> > It can't, a postulate of some kind is needed.
> Not at all. The principles of physics, including the principle of relativity, are all derived from experience

Not at all, The principles of physics are derived from postulates and postulates are assumed statements.
For example: P2 is an assumed statement, No one-way speed of light ever been measured.
..
..>https://acrobat.adobe.com/link/track?uri=urn:aaid:scds:US:25556228-4404-3c67-b0cb-3d04d2636aaeOf course, the induction is always incomplete, e.g., in every closed system we've ever observed, momentum is conserved, but we can never observe every closed system for all time, so when constructing a physical theory we assume the principle of momentum conservation, but this is not an arbitrary or conventional assumption, it is the most firmly of all empirically-founded propositions. Similarly for the principle of relativity, which leaves only a single degree of freedom in the relationship between the standard inertial coordinate systems (operationally established), and that degree of freedom is fixed by any one of many empirial facts, which unambiguously establish special relativity.

On 9/12/23 10:48 AM, Ken Seto wrote:
> The principles of physics are derived from postulates and postulates
> are assumed statements.

Those postulates are used for mathematical derivations of useful
equations. The postulates are based on experience in observations and
experiments. So the PHYSICS is based on experience, the MATH is based on
idealizations of experience codified as postulates.

In the case of SR, we have a rich and useful theory that has been tested
explicitly hundreds of times, and implicitly billions of times; it has
never been found wanting.

> No one-way speed of light ever been measured.

NONSENSE! The one-way speed of light has been measured zillions of
times, subject of course to the condition of how the clocks were
synchronized, or assuming isotropy in cables. It is frequently performed
in undergraduate physics labs.

[This is no different in principle from measuring the
one-way speed of runners in a track meet. But the
errorbars are quite different.]

I could walk down to our optics lab today, and within an hour or two
perform a measurement of the 1-way speed of light in air or in optical
fiber or in coaxial cable. As I am a physicist, I first estimate the
accuracy I could expect, and that is at best ~ 0.1%, making it not
useful for much of anything, so not worth the bother.

[To be useful, such a measurement must be at the few
parts per billion level, and in vacuum -- that is
very challenging.]

Tom Roberts

On Tuesday, 12 September 2023 at 18:48:24 UTC+2, Tom Roberts wrote:
> On 9/12/23 10:48 AM, Ken Seto wrote:
> > The principles of physics are derived from postulates and postulates
> > are assumed statements.
> Those postulates are used for mathematical derivations of useful
> equations.

It's you saying they're useful. Well, anyone can check
GPS: you're mistaken.

Ken Seto wrote:

> On Tuesday, September 12, 2023 at 2:27:34 AM UTC-4, Bill wrote:
>> On Monday, September 11, 2023 at 2:47:51 AM UTC-7, J. J. Lodder wrote:
>> > It is make believe physics...
>> > to believe that relativity can be derived from experiments.
>> > (or at least could have been derived, in principle)
>> > It can't, a postulate of some kind is needed.
>> Not at all. The principles of physics, including the principle of
>> relativity, are all derived from experience
>
> Not at all, The principles of physics are derived from postulates and
> postulates are assumed statements.
> For example: P2 is an assumed statement, No one-way speed of light ever
> been measured.

this thief stealing theories doesn't know what a postulate is, nor the
obvious difference between a postulate and a statement. Piss yourself in
the mouth, you disgusting charlatan. You are stealing theories which are
not yours.

Gary Harnagel wrote:

> On Monday, September 11, 2023 at 12:23:08 PM UTC-6, Laurence Clark
> Crossen wrote:
>> Relativity is like a hydra with many heads because it is totally
>> inconsistent nonsense.
>
> Larry-boy's version of relativity is inconsistent nonsense because he
> doesn't understand the most basic things about it. Larry-boy's version
> of the Doppler effect is also inconsistent nonsense because he doesn't
> understand it either.

Doppler has nothing to do with relativity. And it's not american. Nor the
𝗳𝗮𝘀𝘁𝗲𝗿_𝘁𝗵𝗮𝗻_𝘀𝗽𝗲𝗲𝗱_𝗼𝗳_𝗹𝗶𝗴𝗵𝘁 has anything to do with relativity. You guys are
confusing 𝗮𝗿𝗱𝘂𝗶𝗻𝗼 with 𝗿𝗲𝗹𝗮𝘁𝗶𝘃𝗶𝘁𝘆,

𝗥𝗲𝘀𝗶𝗱𝗲𝗻𝘁𝘀_𝗼𝗳_𝗖𝗿𝗶𝗺𝗲𝗮_𝘀𝗽𝗲𝗮𝗸_𝗼𝘂𝘁_𝗼𝗻_𝘁𝗵𝗿𝗲𝗮𝘁𝘀_𝗼𝗳_𝗶𝗻𝘃𝗮𝘀𝗶𝗼𝗻_𝗳𝗿𝗼𝗺_𝗣𝗲𝗻𝘁𝗮𝗴𝗼𝗻_𝘁𝗲𝗿𝗿𝗼𝗿𝗶𝘀𝘁𝘀_𝗶𝗻_𝗨𝗸𝗿𝗮𝗶𝗻𝗲
https://bi%74%63%68ute.com/video/qgGYBTeweAJn

𝗧𝗵𝗲_𝗪𝗛𝗢_𝗗𝗲𝗰𝗹𝗮𝗿𝗲𝗱_𝗧𝗲𝗿𝗿𝗼𝗿𝗶𝘀𝘁_𝗢𝗿𝗴𝗮𝗻𝗶𝘇𝗮𝘁𝗶𝗼𝗻
https://bi%74%63%68ute.com/video/pbjWP9nxoyF1

Bill <davos2329@gmail.com> wrote:

> On Monday, September 11, 2023 at 2:47:51?AM UTC-7, J. J. Lodder wrote:
> > It is make believe physics...
> > to believe that relativity can be derived from experiments.
> > (or at least could have been derived, in principle)
> > It can't, a postulate of some kind is needed.
>
> Not at all. The principles of physics, including the principle of
> relativity, are all derived from experience.

Yes, and so what? (if you replace 'derived' by based on')

> Of course, the induction is
> always incomplete, e.g., in every closed system we've ever observed,
> momentum is conserved, but we can never observe every closed system for
> all time, so when constructing a physical theory we assume the principle
> of momentum conservation, but this is not an arbitrary or conventional
> assumption, it is the most firmly of all empirically-founded propositions.

So you need to postulate it. (or derive it from a deeper postulate)

> Similarly for the principle of relativity, which leaves only a single
> degree of freedom in the relationship between the standard inertial
> coordinate systems (operationally established), and that degree of freedom

And a postulate is needed there too.
There just is no way in which you can -derive-
the geometry of spacetime from experience.
(or any other geometry, for that matter)

Nothing new of course, Euclid and Plato already knew that,

Jan

On Tuesday, September 12, 2023 at 1:54:02 PM UTC-7, J. J. Lodder wrote:
> > > It is make believe physics...
> > > to believe that relativity can be derived from experiments.
> > > (or at least could have been derived, in principle)
> > > It can't, a postulate of some kind is needed.
> >
> > Not at all. The principles of physics, including the principle of
> > relativity, are all derived from experience.

> Yes, and so what?

You said relativity couldn't be derived from experiments, and I pointed out that you were mistaken, and explained why. You're welcome.

> > Of course, the induction is always incomplete, e.g., in every closed system
> > we've ever observed, momentum is conserved, but we can never observe
> > every closed system for all time, so when constructing a physical theory we
> > assume the principle of momentum conservation, but this is not an arbitrary
> > or conventional assumption, it is the most firmly of all empirically-founded
> > propositions.
>
> So you need to postulate it.

If by "postulate" you are referring to the fundamental process of incomplete induction on which all empiricism and indeed all rational thought is based, then your assertion is self-contradictory, because you are saying principles of physics can't be derived from experiment, whereas the very meaning of "derived from experiment" is the process of incomplete induction. We always observe that momentum is conserved, and from this we infer the principle of conservation of momentum, which we have thereby derived from experience. If, on the other hand, you are just saying solipsism can't be disproven, well, grow up.

> > Similarly for the principle of relativity, which leaves only a single
> > degree of freedom in the relationship between the standard inertial
> > coordinate systems (operationally established), and that degree of freedom
>
> And a postulate is needed there too.

Nope, not in any grown-up meaningful sense. You just don't understand special relativity.

> There just is no way in which you can -derive-
> the geometry of spacetime from experience.
> (or any other geometry, for that matter)

I've not asserted anything about "geometry". I've pointed out that we can operationally construct a grid of standard rulers and clocks mutually at rest and inertially synchronized, and then by direct observation we can determine that the readings on two such grids are related by a Lorentz transformation. This is an operational procedure with specific operational results.

Of course, we can't do this infinitely many times in infinitely many places, etc., but we can do it enough times in enough places to become as convinced as it is possible to be of anything that this is a general result, which is what grown-ups call deriving Lorentz invariance from experience. If you do not call this deriving from experience, then you are denying that deriving from experience has any meaning, and you just are a juvenile solipsist..