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Re: starship-design: Re: Paradox

Ken Wharton wrote:
>Lee writes:

>>Does anyone know of any arguments that would tend to prove or disprove
>>the case for paradoxes? I don't mean FTL in particular, just time travel

>Ooh-- the philosophy of time travel.  I've run across three possibilities:

>A) All future time travel is ALREADY taken into account in our present,
>and is therefore self-consistent.

This possibility is more problematic than it first appears, but
according to current theory, it is possible due to the dual nature
of wave-particles.  It's a lot more like the "many worlds" scenario
than you'd think.

>B)  The second possibility is the alternate reality, where by going back in
>time the universe branches off into a "new" version of what's happening.
>This isn't quite as philisophically unweidly as A), but it does have some

This possibility is rather easy to grasp, but the problem with it is
that by symmetry, every time you travel FTL, you are travelling into
a "new" universe.  What happenned to the old universe?  Does it
continue, with you winked out of existence?  Or does it cease to be
and you've murdered everyone you ever cared about?

>...  But at least in this case, you CAN kill your grandfather;
>you don't need to invent some physical mechanism to keep you from doing 
>whatever you want.

No you can't.  You can't kill _your_ grandfather.  You can only kill
someone a lot like your grandfather who's an inhabitant of this new (?)

>C) The third, and most philisophically pleasing possibility has been hitting
>the bookstands in the last few years, in SF like "Pastwatch" by Orson Scott
>Card and "Einstein's Bridge" by John Cramer.  In this, by travelling backwards
>in time you destroy the entire universe that exists between the time you
>leave and the time you arrive, and start creating a new one.

This isn't time travel at all, any more than perfectly reconstructing
a destroyed building.  It's the same principle, but applied on a much
larger and intricate scale.

This is actually identical to the previous possibility, except that it
specifies precisely what happenned to the old universe.
    _____     Isaac Kuo kuo@bit.csc.lsu.edu http://www.csc.lsu.edu/~kuo
/___________\ "Mari-san...  Yokatta...
\=\)-----(/=/  ...Yokatta go-buji de..." - Karigari Hiroshi