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

From: Darrin Edwards (edwards_at_nouce.trurl.bsd.uchicago.edu)
Date: 07/23/04 

Date: Fri, 23 Jul 2004 00:52:09 GMT

In article <GvDLc.5284$FD1.51990683@news-text.cableinet.net>, Androcles wrote:
>
> "Darrin Edwards" <edwards@nouce.trurl.bsd.uchicago.edu> wrote in message
> news:slrncftvgt.tfi.edwards@trurl.bsd.uchicago.edu...
>| In article <bTsLc.4695$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.
>
> No sensible physicist would seriously make such a gross error
> as travelling backwards in time. If you know of one, he's actually a kook.

Another red herring. One doesn't need to be a "time traveler" to be
able to understand the concepts embodied by the English words "ago" and
"before".

>| >| 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.
>
> When you can reduce the time it takes you to get there to zero by walking at
> 186,000 miles per second, arriving instantly, let me know.

Eh? What on earth are you trying to say here? x=vt is only valid if
v=c? "GIGO" indeed.

> When you can go
> home again, arriving where you were when you were, you can call time a
> vector. Until then, it isn't.

That argument is exactly equivalent to, and no more valid than,
claiming that positions can't be modelled by (three-dimensional)
vectors, since you can't travel a certain distance and return to your
starting point in zero time.

>| 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"?
> Yes. You can find references to it all over the internet. Look it up,
> vectors have inverses.

If A will happen an hour from now, and B will happen an hour before A,
then B is happening... now! That's all that's meant by "inverse"
here, no need to pull in "time traveler" red herrings.

>| If so, what
>| specific property of a (one-dimensional) vector space are you claiming
>| is _not_ possessed by time?
>
> No inverse. I've told you that already.

Yes, inverses. Anything else?

>| Some hints:
> I don't need any fucking hints, or stupidity about time being a vector.

>| 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?
>
> It's 6:00 pm, the plane leaves at 5:00 pm. Go and board the plane, you
> have -1 hour to do so.

That's correct, 5-6 = -1. My plane did indeed leave an hour _ago_.
Sucks to be me, but then, how on earth could we have reached that
conclusion without making use of the additive inverse of 6 hours?

> Since time is a vector, -1 hour should be no trouble to you.

It's certainly no trouble to understand the _physics_ of the
situation, i.e. that my plane left an hour _ago_. Since you got the
right answer as well here, it's obviously "no trouble to you" either.

> If there are any red herrings around here, it is 5-3 = 2 when the 5
> exists in the future.
> Do so when it is in the past and time will be a vector.

Um, sure, now the person is sitting happily on the plane just as it
takes off. They fondly look back on the time five hours _ago_ when
they started packing, and on the time three hours _ago_ when they left
home. Hmm, -3 - -5 = 2 hours spent packing. Again, "is anyone really
mystified by this conclusion"? 

-- 
Cheers,
Darrin