Re: A. Einstein and science-fairs

[Cliff Parker <cparker@EMPOWERING.COM>]

Bob Sciamanda wrote:

> ----- Original Message -----
> From: Cliff Parker <cparker@EMPOWERING.COM>
> To: <PHYS-L@lists.nau.edu>
> Sent: Wednesday, October 06, 1999 6:02 PM
> Subject: Re: A. Einstein and science-fairs
> > . . .I have a
> > problem with the idea expressed previously that the speed of light is
> something that
> > is defined and therefore can not be measured.  God does not check our
> definitions or
> > declarations to see how fast light should travel today. . . .
> > Cliff Parker
>
> There is nothing (outside of logical consistency and usefulness -
> certainly not "correctness") to be checked about a definition, even by
> God!

I am always willing to be corrected, but as far as I know there is no such
thing as a definition for the speed of light.  There are accepted values based
on old definitions of length.  We have defined the meter based on the speed of
light, but to my way of thinking that does not mean that the speed of light
has therefore been defined.  Such reasoning would seem to be very circular.
Using our current definition of the meter we can certainly say that c will
undoubtedly be 299,792,458 m/s, but what does that mean?  As Maurice Barnhill
indicated in another post the meter is a consistent and reliable measure of
length only as long as c is constant based upon comparisons using physical
things such as atoms.

> If God were to  "alter the value of the speed of light in m/sec" he
> will not thereby have altered our definition of the speed of light (unless
> he has indeed interfered with our "free will decision") , he will rather
> have altered the definition of the meter and/or the second.

Please note that I specifically said in my previous post that an accepted
distance unit other than the meter would have to be used if any meaningful
MEASUREMENT of the speed of light was to be made.

Cliff Parker