On Sep 9, 11:43*am, Pentcho Valev wrote:
http://philsci-archive.pitt.edu/arch.../Minkowski.pdf
Harvey R. Brown and Oliver Pooley: "What has been shown is that rods
and clocks must behave in quite particular ways in order for the two
postulates to be true together. But this hardly amounts to an
explanation of such behaviour. Rather things go the other way around.
It is because rods and clocks behave as they do, in a way that is
consistent with the relativity principle, that light is measured to
have the same speed in each inertial frame."
This seems to be a rant against the circularity of using
relativity to analyze experiments, rather than trying to establish the
validity of relativity first. I am not sure exactly what you are
saying, but I have thought of that point.
Relativity is a "symmetry property, and as describes a subset of
physical causes. Being an spectroscopic experimentalist who has worked
with his hands, I have often used the established symmetries of a
system to determine other properties. A priori rejecting a symmetry as
being part of the system would have eliminated just about every useful
physical study.
In most fields of physics, the symmetries of a system are
considered part of the cause for the systems behavior. Yes, the
symmetries are part of the description of the forces. Yet, a lot of
physics is greatly simplified by concentrating on the symmetries of a
system.
If you want to generalize your attacks, there are many physical
scientists that you can blame for "not considering causes."
Crystallographers often analyze the chemistry, optics and mechanics of
a system in terms of the crystal symmetry. Chemists and
spectroscopists frequently analyze the symmetry of a molecule. When
analyzing a Raman spectrum, the symmetry of the molecule and its bonds
are the first things discovered. When the symmetry of the molecule is
discovered, the scientific study of that substance doesn't end.
However, one must know the symmetry of the molecule first. The
symmetry of a crystal or molecule is sometimes just as important as
the elements it is made from.
I note that you never rant against the use of group theory in
chemistry. Group theory is important in analyzing IR absorption
spectra, Raman spectra, and X-ray diffraction spectra. The symmetry of
a molecule or crystal is the first thing that has to be known when
studying the nonlinear optical properties (or even the linear optical
properties) of a substance.
When Einstein postulated special relativity, he was really saying
that the universe was invariant to the Poincare group. This means all
forces and interactions are invariant to the Poincare group. This is a
perfectly good "physical description" of the universe. Whether or not
you like the words "space and time" are immaterial, so to speak.
General relativity adds a few more group operations to the description
of the universe. However, this is all part of the symmetry of dynamic
interactions.
Complaining that "Einstein did not give a cause" is rather stupid
since Einstein did give a cause. All interactions are invariant to a
certain group of interactions described by tensor theory. Certain
interactions can't exist because of this invariance. The nonexistence
of these interactions is a cause for the odd effects on space and
time. If you read the papers of Einstein carefully, you will see where
he made these assumptions.
Lorentz did a more complete job in that he mentioned more causes
than symmetry. He didn't actually assume a symmetry, he used the well
known equations for electromagnetic force and derived the invariance.
However, he ended up guessing at the forces that held together an
electron. The electron flattens according to the formula necessary to
make the invariance exact. He was wrong for two reasons. First,
electrons don't have a spherical form that flattens with velocity
because electrons are better described by quantum mechanics. Second,
he never explained "the cause" of electrons being so special.
From Lorentz's writings, one can see even from his writings how
this conjecture of "special relativity" was so "useful" (his word).
The difference between Einstein's and Lorentz's results was that
Einstein assigned a "symmetry" as a cause. This made Lorentz's results
both simpler to calculate and more accurate. However, there was
something more important. Einstein's work on relativity broadened the
concept of "cause." A symmetry can be a "cause." The invariances
(i.e., symmetries) of a system contain most of the important features
of that system. There is a lot to study after the symmetries are
established. However, if you don't understand the symmetry of a system
you can't find out anything else about it. Try analyzing a Raman
spectrum without any consideration of symmetry, and you will know what
I mean.