From: Thomas Smid on
Dirk Van de moortel wrote:

> Combining the equations like he did (algebraicly "solving a system
> of two equations with two unknowns") is the analytic geometry
> equivalent of finding the interesection between the light paths:
> { x - c t = 0
> { x + c t = 0
> ==>
> { 2 c t = 0
> { x - c t = 0
> ==>
> { t = 0
> { x = 0
> So the intersection of the signals happens at time t = 0 at
> distance x = 0.

Dirk, I am sorry to say you have a flawed understanding of maths. These
two equations are *only* valid at x=0 and t=0, so they can not possibly
describe light paths. According to your 'method' you might as well
conclude from the two equations
(1) x=1
(2) x=0
and by inserting (1) into (2) that
(3) 1=0

Thomas

From: Thomas Smid on
Daryl McCullough wrote:

> You can't subtract (1) from (3), since x in (1) refers
> to a *different* event than the x in (3). It's not the
> same value of x, and it's not the same value of t.
> Think about it in terms of a *car* driving down a
> road that runs East-West at 10 meters/second.

Don't blame me for it. I am merely reproducing Einstein's derivation at
http://www.bartleby.com/173/a1.html here.

Thomas

From: russell on
Thomas Smid wrote:
> Daryl McCullough wrote:
>
> > You can't subtract (1) from (3), since x in (1) refers
> > to a *different* event than the x in (3). It's not the
> > same value of x, and it's not the same value of t.
> > Think about it in terms of a *car* driving down a
> > road that runs East-West at 10 meters/second.
>
> Don't blame me for it. I am merely reproducing Einstein's derivation at
> http://www.bartleby.com/173/a1.html here.

Huh? You told us that equation 3 was not "explicitly"
in Einstein's paper. (I wonder why that was?) So, you
are not telling the truth here, are you?

>
> Thomas

From: Thomas Smid on
russ...(a)mdli.com wrote:
> Thomas Smid wrote:
> > Daryl McCullough wrote:
> >
> > > You can't subtract (1) from (3), since x in (1) refers
> > > to a *different* event than the x in (3). It's not the
> > > same value of x, and it's not the same value of t.
> > > Think about it in terms of a *car* driving down a
> > > road that runs East-West at 10 meters/second.
> >
> > Don't blame me for it. I am merely reproducing Einstein's derivation at
> > http://www.bartleby.com/173/a1.html here.
>
> Huh? You told us that equation 3 was not "explicitly"
> in Einstein's paper. (I wonder why that was?) So, you
> are not telling the truth here, are you?

You should wonder why Einstein was not explicitly writing down my
equations (3) and (4) but merely stated 'If we apply quite similar
considerations to light rays which are being transmitted along the
negative x-axis...' and then went on straight to the combined equation.
Maybe it was because he did not want the mathematical inconsistency to
be that obvious?

Thomas

From: russell on
Thomas Smid wrote:
> russ...(a)mdli.com wrote:
> > Thomas Smid wrote:
> > > Daryl McCullough wrote:
> > >
> > > > You can't subtract (1) from (3), since x in (1) refers
> > > > to a *different* event than the x in (3). It's not the
> > > > same value of x, and it's not the same value of t.
> > > > Think about it in terms of a *car* driving down a
> > > > road that runs East-West at 10 meters/second.
> > >
> > > Don't blame me for it. I am merely reproducing Einstein's derivation at
> > > http://www.bartleby.com/173/a1.html here.
> >
> > Huh? You told us that equation 3 was not "explicitly"
> > in Einstein's paper. (I wonder why that was?) So, you
> > are not telling the truth here, are you?
>
> You should wonder why Einstein was not explicitly writing down my
> equations (3) and (4) but merely stated 'If we apply quite similar
> considerations to light rays which are being transmitted along the
> negative x-axis...' and then went on straight to the combined equation.
> Maybe it was because he did not want the mathematical inconsistency to
> be that obvious?

The reason is that he would have had to use different
notation (to distinguish the different x's and t's)
making the presentation unnecessarily awkward. Though
actually it is something of an abuse of notation to
use "x" at all to mean a specific value of x. (Daryl's
use of "L", for example, is better.) It's quite a
customary abuse, but unfortunately it seems to confuse
the hell out of cranks who read Einstein's paper. You
are not the first.