From: rick@tessi.uucp (Rick Lindsley)
Subject: Re: timetravel backwards? - perhaps
Organization: Test Systems Strategies, Beaverton, Oregon
Date: Thu, 8 Oct 1992 07:38:26 GMT

Ok, time to propose my time travel theory :)

Each moment in time is both followed and preceded by an infinite number
of possibilities.  There is a moment (a time stream, if you will) where
you got up and got a drink of water before finishing this paragraph.
There is another where you didn't - you simply took a breath. There is
another where one more molecule of fat deposited on your artery and you
had a heart attack.  And another where the phone rang. And so on.

These coexist, but our actions at this moment determine which moment of
time we slip into next.  There are an infinite number of ways in and an
infinite way of ways out, but that's not to say all of them are
infinitely interconnected. If I die from a heart attack right now, this
time stream will not lead to that moment when I become President. There
is one where I do, however. (I might have already missed the turn for
that one though :)

Ok. So let's assume we have this means to travel in time. Forward or
backward. It's entirely possible to get lost in either direction. There
was the moment before this one, where I got a drink. And one where I
breathed. And one where the phone rang. How do I know which way to go?
Well fortunately, all of these will lead back to the time almost four
years ago when George Bush was elected President. If my goal is
election day, I can largely ignore these insignificant choices. To move
backward in time, I can chart my course by major events, to make sure
I'm on the right path.

Unfortunately this also renders time travel pretty useless. You can't
"prove" something in history happened, because nobody has yet mapped
the time streams. With your hypothetical travel, you can prove
something *could* have happened, but not that it did.

To put it another way, you can go to Chicago from San Francisco via
Denver, Dallas, Omaha, Lincoln, Fargo ... any number of cities and even
multiple connections, but if somebody is simply standing there in
Chicago, in the absence of other information it's hard to *prove*
exactly how they got there.

And it gets worse. You can see the future, but you really don't know
which way it's going to go. So many people making choices .. and
NONE of that has been charted yet! You might
find a future where you are president, but unless you trace all the
bizillion of moments and make all the right decisions at the critical
points, it won't happen. How do you know what are the key points?

Don't forget others may affect your future too. Be sure to avoid the
time streams where the terrorists killed you on your trip in 1997.

So where are the travelers from the future? Shoot, there are so many
moments to go back to, they've not even begun to crowd us yet! I'd be
surprised if any of them even run into each other! There's one now,
waiting to see Lincoln assasinated. His colleague is back there too,
but he's watching Lincoln get assasinated in the time stream where
Booth skinned his knee once when he was 10. It really had no effect on
the assasination, but it did manage to produce a different set of
memories for Booth and thus a slightly different time stream.

Under this scenario, one of the biggest obstacles to time travel is
insuring you get back. Make sure you follow the same moments to return
as you followed to go back! (or make sure your hardware does :)

Moving objects from one time stream to another does not violate the law
of conservation of energy. The universe still has as much matter or
energy before as after. The universe, when considered in greater than
three dimensions, simply has much more matter and energy than we
thought. When you move something from the fridge to the freezer, the
fridge apparently violated that law of conservation. But wait, whew,
the unit as a *whole* has managed to maintain it. There's as much mass
in the freezer/fridge unit now as before.

In a weird way, this would indicate that yes, all things are
predetermined ... but the freedom of choice provides us with enough
variety we really don't care or even notice. Ooops, starting to tread
on religious ground a bit there :)

Anyway, those are my fanciful thoughts on it.

Rick