Re: philosophy and the vacuum

[Joel Rauber <Joel_Rauber@SDSTATE.EDU>]

Thanks for the reply, a few questions (quibbles)
> > the meter is defined to be the distance light travels in a
> vacuum in a
> > certain number seconds
>
> OK
>
> > Philosophically, (logically and perhaps operationally) is this a good
> > definition?
>
> Logically and operationally, yes.
>
> Philosophically, it depends on one's philosophy, Horatio.
>
> > This requires a definition of the vacuum.
>
> OK
>
> >   Is there only one vacuum?
>
> Logically and operationally, the requirement is that you and
> I need to be
> able to set up the speed-of-light experiment (i.e. the
> meter-stick-calibration experiment) and agree on the
> results.  Operationally, it is not particularly hard to do this.

More is required, or implied in your comment.  We have to operationally use
the same vacuum as you imply later.  Logically, see comment below.

> >  Is the speed of light in the vacuum between two infinite parallel
> > conducting sheets (casimir, effect) different than for
> other vacuums?

This means that the standard for the meter will be different depending on
which vacuum you use as a reference.  Which implies a logical problem in
the
definition.  Unless we agree on which vacuum to use, and then are we using
the same one that the SI guru's intend?



Joel Rauber
Joel_Rauber@sdstate.edu