(HenriWilson) wrote in message . ..
What you don't understand is that OWLS has never been measured.
There is no evidence at all that it is universally constant.
TWLS has been measured many times and found to be apparently constant only to
within about 1 part in about 10^9 which tells us nothing since the term (v/c)^2
is the expected order of the difference between OWLS and TWLS.

Relativity describes the geometry of space as it would have to appear if OWLS
was truly constant and equal to TWLS.

What you say about OWLS doesn't matter that much anyway.

The status of simultaneity to an inertial frame (i.e, convention of
simultaneity which is different from the relativity of simultaneity)
didn't seem to matter much to Einstein in his 1905 paper.

I got the following from Adolf Grunbaum's online paper, "David
Malament and the Convention of Simultaneity: A Reply"

Section 1, entitled "Definition Of Simultaneity", he uses the German
word "Festsetzung" which can be translated as "stipulation," when he
tells us of the need for a "Festsetzung" to make temporal comparisons
at spatially separated points. This "Festsetzung" comes into play, he
says, when we endeavor to define a "time" that is "common" to space
points A and B. The latter time, he explains, can now be "defined,"
"indem man durch Definition festsetzt" i.e., "by stipulation be means
of a definition," that the one-way transit times of a reflected light
ray in opposite directions of the path are equal. This is his optical
specification of the familiar standard synchrony of clocks. Thus,
events at A and B that are assigned equal time coordinates by this
stipulation are metrically simultaneous on the strength of it.

In 1954 (originally 1916), Einstein made it even more explicit that he
contrasts a "stipulation" with a "supposition" or a "hypothesis" such
that there is no fact to the matter whether two events are
simultaneous relative to a particular inertial observer. There he
considers two points A and B at a railway embankment, and the line
segment between them whose mid-point is M. An observer at M can
observe the joint arrival at M of light flashes originating at A and
B, respectively. As to whether the two flashes originate
simultaneously on the embankment, Einstein writes: " ... That light
requires the same time to traverse the path A-M as for path B-M is
in reality neither a supposition nor a hypothesis about the physical
nature of light, but a stipulation which I can make of my own freewill
in order to arrive at a definition of simultaneity."

Graunbaum defends the conventionalist view of simultaneity within a
frame against Malament's famous 1977 paper "Causal Theories of Time
and the Conventionality of Simultaneity" (Nous 11: 293-300) which
argues that choosing the one-way trip time as half the round-trip time
is not trivially conventional. Reichenbach also takes the
conventioanlist view and instead of using the standard half, he uses
the variable epsilon in which is 0 epsilon 1. John Winnie (1977)
derives the "epsilon-Lorentz transformations" which leave epsilon as
an unspecified variable, his work is based on such earlier
axiomatizations due to Alfred Robb (1914, 1921).

The Stanford University Encyclopedia Of Philosophy has this entry on
the Conventinality of Simultaneity.
http://plato.stanford.edu/entries/sp...e-convensimul/

It's also discussed in Chapter 5 "Philosophy Of Space And Time" by
John Norton in the book "Intoduction To The Philosophy Of Science" by
Salmon, et. al.

A few more links:

http://www.bun.kyoto-u.ac.jp/~suchii/janis.html
http://users.ox.ac.uk/~jrlucas/time/transten.html

I'm more convinced by non-conventionalists like Malament and Lucas
than by the conventionalists like Grunbaum and Reichenbach.
Conventionalist arguments all seem to be catagory mistakes,
misdirections or specious.

In either case, Henri, there is no problem here. Except maybe thinking
there was one? Hmm?