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Re: c

Hi all-
David Bowman's Parthian shot argues:
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Jack U. wrote:
But how would we know that "c" represents a limiting speed?
By hypothesis. The existence of a speed limit is intimately tied to the
requirement that there can be no instantaneous-action-at-a-distance (IAAAD).
If such a limiting speed didn't exist then there would be no bound on how fast
a cause "here" can influence an effect "there", and this would get us back to
an arbitrarily fast propagation of causal influences which would then
contradict the requirement of no IAAAD. The label "c" just is the name given
to this limiting speed.
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But the original question was, what leads the physicist to that
hypothesis? If there were a mass term in Maxwell's equations then
Einstein's clock and meter-stick arguments would fail.

Also, it has not escaped this skillful lawyer that the following
question, which was posed in the conjuctive ("and") is answered in
the disjunctive ("or"). So the question still stands.
**************************************************************
To
say that a photon mass "is not sufficient to invalidate special relativity"
does not respond to the deeper question, "Is special relativity a
consequence of the facts that (1)there is a limiting speed at which signals
can be transmitted [I carefully stipulated that the photon mass is the
smallest of all - no massless neutrinos] and (2) signals actually can be
transmitted at that speed?"
The answer is "yes" for #1, and "it is not absolutely necessary, but it sure
helps, and makes things a lot easier" for #2.
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Regards,
Jack

"These several facts prove nothing, for one cannot deduce a principle from so
few examples, but they do at least indicate that the ability to learn to spell
correctly is a gift; that it is born in a person, and that it is a sign of
intellectual inferiority. By parity of reasoning, its absence is a sign of
great mental power."
Mark Twain, "Extract from Eve's Diary'.