Re: Teaching logic is urgent

[pvalev <pvalev@BAS.BG>]

--- Bob LaMontagne <rlamont@POSTOFFICE.PROVIDENCE.EDU> wrote:
> Pentcho Valev wrote:
>
> > Some time ago I showed that special relativity is based on
inconsistent premises.
> > Now I am giving another example. In
thermodynamics, .............. (Snip)
> I've been away for a while and am catching up on postings to the
list. I was curious
> about one of your previous postings related to the statement above.
I assumed there
> would be some responses, but for some reason I can't find a thread
that continues your
> subject heading "a Relativity Problem". I'm a little hesitant to
reply, because I find
> all the treads related to your postings end after one response. I
hope I'm not about
> to post something that no one else on the list is interested in.
>
> Anyway - your previous post stated (I'll put it in quotes and
separate it by a  dashed
> line since it runs a few paragraphs)
>
> --------------------------------------------------------------------
> "The following problem could be given to students. For the
derivation
> of Lorentz transformations, Einstein introduced
>
> (A)  x' = 0  <->  x = vt
>
> He should have introduced, or WE now introduce, in accordance with
> the special relativity principle, a premise symmetrical to (A):
>
> (B) x = 0  <->  x' = -vt'
>
> Einstein also introduced, for a beam moving along the x-axis,
>
> (C) x = ct  <->  x' = ct'
>
> Now the problem is that (A), (B) and (C) are incompatible. (A) and
> (C) are compatible and lead to Lorentz transformations but it is
easy
> to see that one cannot deduce (B) from Lorentz transformations. (A)
> and (B) are also compatible and lead to transformations different
> from Lorentz transformations. (B) and (C) are also compatible and
> lead to transformations insignificantly different from Lorentz
> transformations. So, in order to be able to proceed, we must declare
> either (A) or (B) or (C) as false. Which one is false?"
> --------------------------------------------------------------------
-----
> You say (A) and (C) are compatible and lead to the Lorentz
transformations. If I take
> one of those transformations, namely
>
> x = (x' + vt')/sqrt(1-v^2/c^2)
>
> and substitute x' = -vt', I get x=0, which is your statement (B).


You have chosen a version of Lorentz transformations that agrees with
(B) but does not agree with (A). Substitute x=vt and you will not
obtain x'=0.


> In like manner, Starting with (B) and (C) and applying the Lorentz
transformations,
> (A) appears as a result. Also, (C) itself is just a trivial result
of applying the
> same transformations. What's always surprising is how easily the
standard Lorentz
> transformations tie (A), (B), and (C) together so well.


They don't.


> > From past discussions on this list, I know there are differences
of opinion as to
> whether (A), (B) and (C) all by themselves are sufficient to
produce the Lorentz
> transformations, but the transformations (once proposed) certainly
make (A), (B) and
> (C) consistent.
>
> Also, while I'm catching up, I don't quite follow why non-
conservative bulk dielectric
> effects in the capacitor problem require a revision of the
fundamentals of electricity
> and magnetism. Non-conservative tidal effects between gravitating
objects don't demand
> a revision of the conservative gravitational force - or a rejection
of the Second Law
> of thermodynamics.


I agree about the second law (the presence of non-conservative forces
does not necessarily refute it) and I am incompetent about
gravitational theory. However, if the latter, like electostatics, is
built on the assumption that only conservative forces are acting, the
presence of non-conservative (gas pressure-like!) forces is fatal for
the theory.

Pentcho