"How Does Light 'Know' How Fast to Travel?"

On 4 Sept, 18:38, John Kennaugh
wrote in sci.physics.relativity:
Tom Roberts wrote:
John Kennaugh wrote:
Tom Roberts wrote:
John Kennaugh wrote:
SR is now a 'principle theory' and as such is only a mathematical
model. It has nothing to say on the subject as to what physical
processes the maths is describing [...]
no alternative physical explanation of what SR is describing has
been put forward

What "physical explanation" would you "put forward" for the fact
that light travels along a straight line? Note you must first "put
forward" a "physical explanation" for what a straight line is.
Interesting how much you have snipped. Not because you agree with it
but
because you cannot fault it.

No, I snipped because your verbiage was IRRELEVANT to the central
issue, which I chose to address.

It isn't irrelevant. It is what a great deal of modern physics has been
built upon.



Is there any more meaningful definition of 'straight' than it is the
path light takes. Light travels in straight lines - by definition.

I see. So you don't require "physical processes" either. So you cannot
logically require SR to provide them.

SR is not a physical theory - I made that perfectly clear. Physical
processes must be involved in the transfer of light from A to B which
the mathematical model you call SR is describing. Einstein put forward
no specific hypothesis of what those physical processes might be and 100
years on that situation remains. Lorentz did but his explanation is
contrary to present dogma.



I'll remark that there are MANY other meanings and
definitions of "straight" than those related to light.

I am straight in both my dealings and my sexual orientation. I was
assuming you meant 'straight' in the physical sense. I know no way of
checking whether something is straight which does not either consist of
comparing it with another object assumed to be straight or assuming that
light travels in straight lines.



In SR, the fact that light travels at c is GEOMETRICAL, not
"physical", as is the fact it travels along straight lines.
No. Geometry is a purely mathematical description.

Of real aspects of our world. Or alternative worlds.
You cannot transport energy from A to B by means of geometry.

I never said or implied that one could. But one CAN infer what
"straight" means from geometry. And one can infer what "c" is from the
geometry of SR.

History: It was believed light is a wave travelling in the aether
(Maxwell). The experiment to show the observers speed relative to the
aether showed it to be zero - the second postulate describes exactly
what an observer stationary w.r.t the aether would experience but no
specific hypothesis was put forward as to how an observer can always be
stationary w.r.t the aether or what else might be going on.

The geometry of SR was constructed by Minkowski assuming the light
principle is correct with no specific hypothesis put forward as to
physical process involved. You cannot turn around and say that the
light principle is correct because the geometry constructed assuming it
to be correct shows it to be so. That is circular.

Circular but works. In Einstein zombie world. A few years ago Roberts
and his brothers taught something much more idiotic and it worked as
well (in Einstein zombie world):

http://groups.google.ca/group/sci.ph...4b543c9ed073e?

Pentcho Valev