From: ingles@engin.umich.edu (Ray Ingles)
Subject: Re: Feedback, Boundary Conditions, and Time Travel (long....)
Date: Sun, 27 Sep 92 12:49:38 EDT
Organization: University of Michigan Engineering, Ann Arbor

In article <1992Sep27.024729.13482@unlinfo.unl.edu> aberigan@nde.unl.edu (A. Berigan) writes:
>ingles@engin.umich.edu (Ray Ingles) writes:
>>tbmg9061@uxa.cso.uiuc.edu (Thomas B MacIukenas) writes:
>>>ingles@engin.umich.edu (Ray Ingles) writes:
>
>>>> Knowing something about the future or the past is like setting a
>>>>boundary condition. It constrains the possible timeline into a set of
>>>>timelines that contain that element.
>
>Sorry, I'm firmly in the belief that knowledge has little to do with
>time travel and jelly doughnuts.  And if it does, then everyone has a
>passive knowledge about the wholeness of time.  Displace a little air in
>the past, and the tornado that hit your house as a child never happened.

 Purely out of curiosity, did you jump into this thread or have you been
reading it for a while? My money's on #1....

>>>There
>>>are no quantum uncertainties about the past (except for quantum systems
>>>which have not resolved yet, in which case changing their internal state
>>>won't alter anything else).
>>>
>>>You can't even travel into the past
>>>at all under this theory because simply by appearing you'll be changing
>>>information about the past (changing the positions of air molecules,
>>>blocking and reflecting photons that previously had passed right through
>>>your position, etc.).  All this stuff was previously "known" by the
>>>universe, so there's no way you can suddenly appear there.
>
>Apparently I'm in agreement with you.
>
>> NO, NO, NO! I understand why you think this way, but it's NOT what I've
>>been talking about!
>> In the worldview under discussion, I *already* appeared back then. In
>>fact, part of the reason history turned out the way it did is because I
>>was there to "change the positions of air molecules, block and reflect
>>photons, etc."
>
>Your putting your effects before your causes in a single Universe.  No

 Isn't "putting effects before causes" the *definition* of time travel?

>changes have been made until you do them.  Sure you can travel back to
                        ^^^^^

 Define "until" in the context of time travel. How do you measure "when"
something occurred?

>the "present" and see the effects of your changes, but they weren't
>there in the first place.  Indeed, that is not your Universe.  In your

 As has been pointed out in previous articles, this requires at least five
dimensions, three of space, one of normal time, and one perpendicualar to
normal time. Mind you, this doens't make it impossible, but it's not the
multiverse I was talking about.

>Universe, you ceased to exist the moment you left, never to return.
>(The last part I'm still uncertain about that last bit however, and of
>course that is unprovable, even with time travel available.)
>
>> History in this view is a static sculpture in four dimensions. Past,
>>present, and future all 'already' exist, just in directions we can't
>>normally perceive or gain access to. Whether this view conflicts with
>>free will is another topic.
>
>In such a universe, time travel is an impossibility.  If it is possible,
                     ^^^^ ^^^^^^ ^^ ^^ ^^^^^^^^^^^^^
 Not if the travellings are 'already' built into the structure of that
universe.

>you throw quantum theory out the window.  Indeed, quantum theory is
>already out the window.

 Explain this in detail, please. (BTW, have you ever seen "The Terminator?")

>-- 
>aberigan@nde.unl.edu (Greg Berigan)


Sincerely,

Ray Ingles                  || The above opinions are probably
                            || not those of the University of
ingles@engin.umich.edu      || Michigan. Yet.