Jean-Marc Levy-Leblond disturbs Einsteiniana's serenity:

http://ebook30.com/science/mathemati...elativity.html
"My first remark is that I cannot understand the reason why textbooks
in English (as this one) insist in deriving the Lorentz transformation
using Einstein's second postulate on the speed of light: as already
pointed out by Jean-Marc Levy-Leblond (Am. J. Phys., Vol. 44, pp.
271-277, 1976), this second postulate is not only superfluous but also
epistemological misleading..."

Pentcho Valev wrote:

The solution to the fundamental problem of theoretical science offered
by Einsteiniana's highest priests:

http://o.castera.free.fr/pdf/onemorederivation.pdf
Jean-Marc Levy-Leblond: "The evidence of the nonzero mass of the
photon would not, as such, shake in any way the validity of the
special relalivity. It would, however, nullify all its derivations
which are based on the invariance of the photon velocity."

Are the concepts of time dilation and length contraction,
Einsteiniana's most famous miracles, results of "derivations which are
based on the invariance of the photon velocity"? Or, perhaps, "the
evidence of the nonzero mass of the photon would not, as such, shake
in any way" their validity? For more than 30 years no one has asked
any such question and, accordingly, Jean-Marc Levy-Leblond sees no
reason why he should answer. At present the most serious discussion of
Einstein's relativity in France is this one:

http://www.youtube.com/watch?v=eN4DthXDu68

Pentcho Valev