Re: SR's velocity addition -- ANY Experimental Evidence?

From: Darrin Edwards (edwards_at_nouce.trurl.bsd.uchicago.edu)
Date: 07/21/04 

Date: Wed, 21 Jul 2004 23:37:01 GMT

In article <bTsLc.4695$PY3.46950542@news-text.cableinet.net>, Androcles wrote:
> "Darrin Edwards" <edwards@nouce.trurl.bsd.uchicago.edu> wrote in message
> news:slrncfrf5f.hie.edwards@trurl.bsd.uchicago.edu...
>| In article <ctaLc.3976$Sn2.39699610@news-text.cableinet.net>, Androcles
>| wrote:
>| > Time is not a vector,
>|
>| Sure it is, it's modeled as a one-dimensional vector.
>|
>| > it has no inverse.
>|
>| Cf. the English word "ago".
>|
>| > You can return from where you were by travelling a distance 1 mile
>| > and returning a distance of -1 mile. When you are able to return to
>| > when you were by waiting one second and then unwaiting -1 second
>| > then you can call time a vector, and not before.
>|
>| That's because of physics.
>
> Yes, and physics is the topic of discussion.

And in physics, time is modelled as a (one-dimensional) vector. (At
least in classical mechanics, special relativity, quantum
mechanics... I had always assumed the same was true of GR, but would
welcome correction on this point.)

>| Mathematically, time is modelled as a
>| one-dimensional vector in both Newtonian mechanics and SR.
>
> Mathematics is Art.
> Scientists and Engineers use math as a useful tool, but that doesn't entitle
> anyone to pretend they can convert time into distance, mass into time or
> distance into mass, even if it possible to do so mathematically. GIGO
> applies.

I don't need to "pretend" I can convert time into distance; every day
I convert a half hour of my time into the roughly two miles between my
home + workplace by the simple expedient of walking at roughly four
miles an hour. But none of what you said has anything to do with time
being modeled as a (one-dimensional) vector.

Are you familiar with the definition of "vector"? If so, what
specific property of a (one-dimensional) vector space are you claiming
is _not_ possessed by time?

Some hints: you can add two times together to get another time, and
you can multiply a time by a number to get another time. As for the
"unwaiting -1 second" red herring above, if someone says their plane
leaves in five hours, and that they have to leave home for the airport
three hours _before_ that, is anyone really mystified by the conclusion
that they have 5-3=2 hours left to pack? 

-- 
Cheers,
Darrin

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