Re: [Phys-l] relativity +- electromagnetism +- pedagogy

[John Denker <jsd@av8n.com>]

On 11/29/2006 07:43 PM, carmelo@pacific.net.sg wrote:

> > Doing it that way is IMHO vastly easier than doing it terms of Lorentz transformations, time
> > dilated clocks, Lorentz contracted rulers, velocity-dependent mass, et cetera.
>
>
> I suspect physicists have fully understood Lorentz transformations. That is why John find
> spacetime diagrams, 4-vectors, invariant length, proper time, invariant mass, et cetera to be
> *vastly easier*.

That diametrically misunderstands what I was saying about Lorentz
transformations.  I was suggesting avoiding them.  I was arguing for
ideas that are less-commonly-used (in introductory classes), not
more-commonly-used.

  Of course in advanced classes, and in the research literature,
  the shoe is on the other foot;  the spacetime approach is used
  to the near-exclusion of contraction and dilatation.

> Just ask some whether Lorentz transformation is real or apparent; 

Please note:  This is the physics list.

If you want to argue about what is "real or apparent", you would be
better off bringing it up on the metaphysics list.

> Then you may ask what do they understand by *real*. Physicists should be honest that they still
> do not fully understand relativity. What most understand well is the mathematics behind.

Galileo is called the father of modern science partly because he
emphasized that scientists do not need to answer metaphysical questions;
all we need to do is make correct predictions.  Newton restated the
idea in the immortal words "hypotheses non fingo".

I have not the slightest interest in getting into a debate about
what is "real".  It is better to ask which notions are /useful/
under this-or-that conditions.  For more on this, see
  http://www.av8n.com/physics/odometer.pdf
especially section IV on page 8.

The points I was making this morning are neither pro mathematics nor
con mathematics.  Understanding spacetime diagrams does not exclude
understanding mathematical models or vice versa.

Impugning my honesty will not make me more interested in metaphysics.