"Bill Hobba" wrote in message ...
"Bill Hobba" wrote in message
...

The argument I am making is simple. SR is based on the POR - aether
theories are not. But the POR is also the basis of classical mechanics
and
in fact is the reason it has its conservation laws (via Noethers
theorem).
Now when formulating a new theory, SR, what you rather base it on - a
new
assumption (the existence of an aether we have no experimental support
for)
or a principle we already know to be true from another area of physics?
Why
introduce new principles? I guess it is an 'Ockham's razor argument'.

Thanks
Bill

Mark Szlazak wrote:
OK, please correct me if I'm wrong but I take it that you have a
couple of related complaints with Lorentz-Poincare type views. 1)
Extra space-time structure that you claim there isn't any experimental
support for, and 2) because of this extra structure a status change
occurs, POR and conservation laws get a secondary status unlike the
primary status they enjoyed in Galilean and Einstein-Minkowski
space-time. [Well, that's what you get when you move to a better
neighborhood ... just kidding.]

Bill, did I get it right?

No. Look here is an example. I plug in a shaver and switch it on - from
experience I formulate the explanation that it is the electric power that
makes it work.
I go somewhere else and plug it in - do I need to make another assumption
about why it works - that the outlet supplied electric power still explains
it; there is no reason to give a different explanation. The same with SR
and the POR. I know the POR and the PLA explain classical mechanics. I
then look at SR - do I assume a different explanation if the old one - the
POR - still works. Without additional evidence I doubt that most people
would.

Thanks
Bill

OK, but in SR don't you have to presuppose that the entity "spacetime"
exists instead of "space" and "time"?

Mark Szlazak wrote:
OK, but in SR don't you have to presuppose that the entity "spacetime"
exists instead of "space" and "time"?

No - not at all. All you assume is exactly the same thing you assume in
classical mechanics, that something occurs at a point in space and at a
particular time. Such a point is called a space-time event. The assumption
that changes it from classical to SR is the existence of a maximum speed.
In classical mechanics there is none - in SR we assume that maximum is the
speed of light. That is the only difference. However that implies that
distances and time intervals no longer are invariant like they are in
classical mechanics. What is invariant is ct2 - x2 - y2 -z2. This defines
a geometry called Minkowski space. It is the logic of that geometry, a
geometry not found in classical physics, that forces the concept of
space-time into us. In fact, in SR, space-time is Minkowski space.

Thanks
Bill

"Bill Hobba" wrote in message ...
Mark Szlazak wrote:
OK, but in SR don't you have to presuppose that the entity "spacetime"
exists instead of "space" and "time"?

No - not at all. All you assume is exactly the same thing you assume in
classical mechanics, that something occurs at a point in space and at a
particular time. Such a point is called a space-time event. The assumption
that changes it from classical to SR is the existence of a maximum speed.
In classical mechanics there is none - in SR we assume that maximum is the
speed of light. That is the only difference. However that implies that
distances and time intervals no longer are invariant like they are in
classical mechanics. What is invariant is ct2 - x2 - y2 -z2. This defines
a geometry called Minkowski space. It is the logic of that geometry, a
geometry not found in classical physics, that forces the concept of
space-time into us. In fact, in SR, space-time is Minkowski space.

Thanks
Bill

I'm sorry Bill, what I meant to say is that in your previous posts,
one complaint was that the Minkowski interpretation "preserves
traditional values" (i.e., POR, Galilean or Lorentz symmetries, etc.)
but Lorentz-Poincare interpretations don't. This is a bit confusing
because in the Minkowski interpretation the cost of this was to get
rid of a lot of other "traditional values" like replacing "space" and
"time" with "spacetime." This conservative stance, in more the
political sense, is a mixed bag.

I'm left with the impression that the real crux of the complaint is a
claim about there being no evidence for breaking Lorentz symmetries,
or no evidence for absolute simultaneity, or no evidence from
compatibility with other theories and domains favoring one view over
the other, or some other "no evidence" concern that needs to
specified. This also needs clarification.

Bill, this is a bit off our current course and we may want to take it
up in another thread, but I would appreciate a response. My initial
readings indicated that there is no necessity to the Minkowski
ontology for STR, there was at least one other ontological
interpretation and it was Einstein's original view before he heard of
Minkowski. However, looking back at your remarks indicates that there
is no other possible way to construct a space-time structure besides
Minkowski if one sticks *just* to the basic postulates of STR. Bill,
you *are* claiming a necessity for *only* the Minkowski ontology from
*just* these postulates?

Thanks. Mark.

Bill Hobba wrote:
No - not at all. All you assume is exactly the same thing you assume in
classical mechanics, that something occurs at a point in space and at a
particular time. Such a point is called a space-time event. The
assumption
that changes it from classical to SR is the existence of a maximum
speed.
In classical mechanics there is none - in SR we assume that maximum is
the
speed of light. That is the only difference. However that implies that
distances and time intervals no longer are invariant like they are in
classical mechanics. What is invariant is ct2 - x2 - y2 -z2. This
defines
a geometry called Minkowski space. It is the logic of that geometry, a
geometry not found in classical physics, that forces the concept of
space-time into us. In fact, in SR, space-time is Minkowski space.

Mark Szlazak wrote:
I'm sorry Bill, what I meant to say is that in your previous posts,
one complaint was that the Minkowski interpretation "preserves
traditional values" (i.e., POR, Galilean or Lorentz symmetries, etc.)
but Lorentz-Poincare interpretations don't.

It doesn't - the POR and the ocnstancy of the velocity of light imples
Minkowki space but not the other way around. Minkowski space say nothing
aobut all the law sof physic slike the POR does - it only talks about
space-time events.

Mark Szlazak wrote:

'This is a bit confusing because in the Minkowski interpretation the cost of
this was to get rid of a lot of other "traditional values" like replacing
"space" and "time" with "spacetime." This conservative stance, in more the
political sense, is a mixed bag.'

No - the pupose of Minkowsi space is to make explicit the geomentical
implications of the Lorentz transformations. Minkowki space applies equally
to LET or any theory that has th eLorentz transformations because the
Lorents transformations imply ct2 - x2 - y2 -z2 which is the deifning metric
of a Minkowski space. LET, SR and many othet theoreis all imply Minkowski
space. For an example of this see the following on modern LET theory or
GLET as it is called http://ilja-schmelzer.de/GET/.

Mark Szlazak wrote:
I'm left with the impression that the real crux of the complaint is a
claim about there being no evidence for breaking Lorentz symmetries,
or no evidence for absolute simultaneity, or no evidence from
compatibility with other theories and domains favoring one view over
the other, or some other "no evidence" concern that needs to
specified. This also needs clarification.

If you read the link I gave you might understand the issues a little better.
Ilja is from the other side so to speak. I have stated my view - I believe
in SR because it is a simple extension of classical mechanics which is based
on three postulates 1. The POR 2. The PLA 3. only the infinite velocity is
content between inertial reference frames. To get SR all you change is 3 -
the speed of light is the same in all inertial frames.

Thanks
Bill

Mark Szlazak wrote:
Bill, this is a bit off our current course and we may want to take it
up in another thread, but I would appreciate a response. My initial
readings indicated that there is no necessity to the Minkowski
ontology for STR, there was at least one other ontological
interpretation and it was Einstein's original view before he heard of
Minkowski. However, looking back at your remarks indicates that there
is no other possible way to construct a space-time structure besides
Minkowski if one sticks *just* to the basic postulates of STR. Bill,
you *are* claiming a necessity for *only* the Minkowski ontology from
*just* these postulates?

True one does not need to introduce Minkowski sapce. But that such a space
exits is guranteed by ct2 - x2 -y2 -z2 being invariant. Exploring the
consequence of theories is a natural thing to do.

Thanks
Bill

Thanks again Bill. I'll give a recap after the weekend which I think
fits what's been said and may include stuff on COI and remarks of the
other posts.

For an example of this see the following on modern LET theory or
GLET as it is called http://ilja-schmelzer.de/GET/.

I've also recently found this link to Mayeul Arminjon's
(http://geo.hmg.inpg.fr/arminjon/) article, "Ether theory of
gravitation: why and how?" (http://arxiv.org/abs/gr-qc/0401021). He
talks about his own Lorentz-Poincare type theory but does a review of
others working in this same approach and mentions Schmelzer's work in
footnote 7. Both articles use a lot of mathematical-physicist language
that I'm not familiar with so I'll leave it to others to evaluate
those parts.

Mark.