Re: LET is on shaky ground - continued

From: Martin Hogbin (goatNOSPAM1_at_hogbin.org)
Date: 06/20/04 

Date: Sun, 20 Jun 2004 08:35:34 +0000 (UTC)

"Trevor Morris" <tedd90@freeuk.com> wrote in message news:a98f5d4d.0406180406.427c3a16@posting.google.com...
> "Martin Hogbin" <goatNOSPAM1@hogbin.org> wrote in message news:<c8lq18$kdq$1@hercules.btinternet.com>...
> > "Trevor Morris" <tedd90@freeuk.com> wrote in message news:a98f5d4d.0405200710.1a818287@posting.google.com...
> > > [Sorry for the delay - picking it up via Google]
>
> > >
> > > "Martin Hogbin" <goatNOSPAM1@hogbin.org> wrote in message news:<c72eq9$ivk$1@hercules.btinternet.com>...
> >
> > This reply shows very clearly what your problem is. When you
> > talk about what *is*, you are actually referring to a model in your
> > own mind of how the world must be. This is not reality. The only
> > reality is the results of experiment.
>
> And if they are in accord with the predictions of a particular model,
> the model is not invalidated.

Yes but I have never claimed that LET is invalid. You are claiming
that LET and Galilean represent how the world actually 'is'.

LET and SR are both valid models (within their common realm of
applicability). You cannot use the validity of LET to disprove SR.

> [...]
>
> > > For example, can
> > > you tell us why you prefer a measurement recipe to a definite,
> > > unambiguous model of light propagation?
> >
> > What model?
> >
> > > > -------
> > > > 1) There exists a special reference frame in which no information,
> > > > matter, or energy can travel faster than light.
> > > > -------

That is no more a model and no less a recipe than SR.

> > > > This postulate is essentially of a conceptual nature
> > >
> > > Hardly: it is a strong statement about what is possible in physics and
> > > what is not possible: there is nothing I can see as "conceptual" about
> > > an unbreakable speed limit.
> >
> > You give no reason for this speed limit or any mechanism in terms
> > of pre-existing physics for it.
>
> That is why it is a postulate.

Agreed, but no less conceptual than Einstein's postulates.

> >
> > If it is not about that which can be measured it is even more
> > conceptual than the light speed postulate.
>
> It is certainly about measurements. It offers an explanation of why
> the measurements turn out the way they do, which imho is better than
> merely stating how they will turn out without offering any
> explanation.

We may as well give this one up and agree to differ. I can see
no reason to say that your postulates offer any more in the way
of an 'explanation' than Einstein's postulates do.

We agree that from either set of postulates the others can be
derived (more or less) so which you take as your starting point
is a matter of personal choice. I, and all the world's physicists,
prefer Einstein's postulates, you prefer yours.

> > > ... something may be going on which is not necessarily
> > > revealed by a naive interpretation of "measurements" and appearances.
> >
> > You have just stated the same thing in different words. In
> > what sense is this something 'going on'?
>
> In the sense that they relate to a particular model of field
> propagation which explains why certain measurements (e.g. of c) turn
> out as they do, which otherwise are unexpected and have no
> explanation.

But the workings of this model are entirely hidden from us. You
might as well put it all down to pink fairies or green goblins, you
cannot disprove either.

> > This is nonsense. You are back to your old trick of trying
> > to get Maxwell's equations to prove themselves valid in any
> > inertial frame.
>
> No trick. Maxwell's equations are merely those which apply to the
> kinds of fields under discussion. Their relevant property is a
> characteristic propagation speed for those fields, as if in a fixed
> medium. If that speed turns out to be an upper limit for all speeds
> (as a separate hypothesis), then the equations are indeed valid in any
> inertial frame and we have LET / SR.

You said, 'retarded potentials illuminates the physics underlying
Einstein's postulates, for those who want to see'. You now
agree that this is only true if you introduce a completely new
hypothesis.

> ... following Einstein
> it has become conventional to deny that his postulates could lead to
> those of Lorentz - iow the reciprocity you stated is denied,
> incorrectly.

Not by me. It is essentially a matter of choice as to what
are your starting postulates and what are considered to be
derived results.

>Now, accepting that reciprocity as you seem to do, do
> you really think it is better to start as Einstein did with empirical
> assertions about how the laws of physics should look to inertial
> observers and how measurements of c would turn out if done in a
> specific way (as if Nature gave a damn),

Yes.

> or is it better to have a
> specific model of field propagation - w.r.t. a single frame of
> reference in which there is an upper speed limit (c)

You have no model, just a statement.

I think we have pushed this as far as we can. I prefer one model
and you prefer another.

If you are really serious about what you say then you should
start writing a physics book (your version of Spacetime Physics)
which uses the LET model. In it you can derive all the standard
SR/LET results. When you have completed this you will probably
come to realise just how pointless it was. We already have a
theory that works.

Next will you need to start on your own theory to replace GR.
Good luck.

Martin Hogbin

Relevant Pages

  • Re: A little challenge for relativists.
    ... Speeds are measurements, and the outcome of any measurement *may* depend on the perspective from which it's made. ... do you agree that nature knows nothing of frames of reference? ... the physics of how we are composed. ...
    (sci.physics.relativity)
  • Re: A little challenge for relativists.
    ... Speeds are measurements, and the outcome of any measurement *may* depend on the perspective from which it's made. ... decide what Nature must do. ... the physics of how we are composed. ...
    (sci.physics.relativity)
  • Re: LET is on shaky ground - continued
    ... > You give no reason for this speed limit or any mechanism in terms ... It is certainly about measurements. ... but arguably the two postulates should be ... If that speed turns out to be an upper limit for all speeds ...
    (sci.physics.relativity)
  • Re: LET is on shaky ground - continued
    ... I claim that LET offers a model which explains why the SR postulates are ... of physics shall appear to inertial observers, ... It offers an explanation of why ... If that speed turns out to be an upper limit for all speeds ...
    (sci.physics.relativity)
  • Re: Some Beginner SR Questions
    ... >with any physical content in physics (that is, ... measurements of c are the same, ... >speeds very close to c. ... >conclusion is that the ether simply does not exist. ...
    (sci.physics.relativity)