Problem with time travel in PoA

[Stacy Stroud]

No: HPFGUIDX 31583

At 02:43 PM 12/14/01 +0000, slurm3001 wrote:

>Thanks for taking the time to elaborate on an explanation, Stacy. I
>agree with most of what you wrote. However, I'm still not convinced
>regarding the problem I meant.

Hmm.  You're right.  I wound up explaining a totally different thing, and 
in the process implicitly accused you of ignorance on a subject you knew 
very well.  Sorry 'bout that.



>I perfectly understand that two Harrys and Hermiones are present at
>the same time, that the effects of their time travel already creates
>the situation we read about at first (misunderstood by Harry1 and
>Hermione1). I like this treatment of time travel, too - compared to
>other time travel situations. The only problem I see, which I think
>is a vital mistake, is the causality surrounding their survival (see
>quote from my original post above).

Hmm.  I still think this is soluble, but it may be a matter of the two of 
us just having different ways of visualizing the problem.

Your reading is "Harry can't survive unless he survives, because he is 
saved by a Harry who has already survived."  The question is (and I'm no 
longer sure myself, so let me analyze it in writing here), is this 
situation significantly different from other self-reinforcing loops?  We do 
have a very strong causal connection between the two events -- a 
character's own existence directly depends on his actions in the past -- 
which is absent in cases like the Terminator and Babylon 5 loops.  One 
could argue that the time-traveling characters in both those universes 
*would* have died had not their past offspring/selves done the deeds 
they're known for, and certainly the history each remembers would have been 
radically different, but there is no case of a character personally saving 
his own life.  That *could* be enough to put Harry's loop in the paradox 
category -- the very ability of the loop to occur depends on the loop 
having occurred, while no self-dependence of that kind occurs in the other 
well-known loops.  (The old sci-fi shocker plot in which a character 
becomes his or her own parent is probably most similar to the Harry 
situation, since the character has to be born in order to be born.)

I still think the Harry loop is salvageable, but that might depend on my 
particular way of thinking about time travel situations.  I tend to 
visualize "world lines" showing the complete map of a person's life in 
spacetime, rather than a "flow" from past to future.  We know the "Harry" 
line extends well past the end of PoA, so looking at things this way, the 
existence of both Harry1 and Harry2 as points on the line is a simple 
fact.  It's not "Harry1 *did* survive the dementor attack, so Harry2 *will 
be* able to go back and save him" (which hurts the brain) but "Harry1 
*does* survive, and Harry2 *is* the one who saves him."  No matter how 
wonky the causality is, the world-line perspective only cares if things are 
*consistent*, and the Harry loop is.  Yes, in order for the situation to 
make sense, Harry1 must survive to become Harry2, and Harry2 must travel 
back in time to save Harry1.  And what does happen?  Exactly that.  The two 
events reinforce each other.

I'm still somewhat troubled by your revelation that some loops are more 
self-dependent than others -- the "he survives because he survives" thing 
does bug me -- but I think that the world line/consistency perspective 
still manages to reduce that to a counterintuitive-but-true situation 
rather than an actual contradiction.  Admittedly, it's at the cost of 
assuming that, from at least one theoretical perspective, the future is 
just as certain as the past -- but for a fictional character like Harry, at 
least, that's literally true.  JKR, and those of us who have read PoA and 
are now debating it, know that Harry1 does survive to become Harry2 -- his 
line extends beyond the crisis with the dementors, and the seeming danger 
of his death in that situation is actually just as much a problem of 
limited perception as the kids' misinterpretation of Buckbeak's fate.  That 
the line has an odd little loop at that point is unusual, but it's just 
part of the line -- part of the total life of Harry.  The line is not 
damaged or rewritten, and so things are consistent all 'round.


Stacy Stroud (deadstop at gte.net)
Hex Entertainment, Inc. (http://www.hexgames.com)


Stacy Stroud (deadstop at gte.net)
Hex Entertainment, Inc.  (http://www.hexgames.com)