Time travel is dangerous! (part 1)

[nkafkafi]

No: HPFGUIDX 88636

This may be the first part of several posts I wanted to write about 
the possibilities and problems of time travel in the HP books (hoping 
I'll ever get to writing the others parts). It was inspired by the 
DD=Ron theory, which was suggested by several people, and is only a 
part of the Knight2King theory, which is extensively discussed by its 
originators in 
http://homepage.mac.com/ixchelmala/Knight2King/Personal51.html. 
Even if this theory is not true (read on for my personal problems 
with it), JKR have already made use of time travel in PoA, and it is 
a fair gamble she will somehow use it again in the future books. In 
the first five books JKR have demonstrated that, although she plays 
the universe building game in a very creative way, she tends to 
compromise internal consistency here and there for dramatic effect. 
Until now, these inconsistencies (for example, the Number OF Students 
issue and the problem of pensive objectivity/subjectivity) were not 
very serious, and personally I much prefer a captivating-but-slightly-
inconsistent story over a boring-but-perfectly-consistent one. If, 
however, JKR is going to use time travel again, and especially if she 
does it Big Time, such as in a DD=Ron twist, I really hope she did 
her homework *very* carefully, because time travel is dangerous, not 
only for the traveler, but for the Author. There is no subject like 
time travel to get you into a novel-shattering paradox or three.

Time travel was extensively discussed in science fiction and, in 
fact, in theoretical physics. There are several optional theories of 
time travel, each with its own set of premises, problems and 
paradoxes. The simplest (well, the less complicated) theory that 
allows traveling to the past manages to avoid the paradoxes by 
assuming that What's Done Is Done (WDID) and you can't change it. 
Harry and Hermione's 3 hours excursion into the past in PoA suggests 
that this is the theory that JKR prefers. If you read it again you 
will notice that JKR carefully arranges the plot so Harry and 
Hermione don't change anything that had already happened the first 
time around. In fact, Harry enables something that had already 
happened to take place, when he casts the patronus and saves the past 
HRH lives from the dementors. This is allowed in the WDID theory 
because we know that in the past, HRH were really saved from the 
dementors. So "helping the past along its way" is OK in this theory, 
but changing it is Not Possible (for an excellent and detailed 
explanation of this point, see http://www.hogwarts-
library.net/reference/potterverse_faq.html#time_travel ). DD also 
seems to act upon this theory, because he does not send Harry and 
Hermione to change something that happened in the past, but something 
that, at that point in time, did not happen yet (that is, Sirius' 
execution). Note also that when DD sends Harry and Hermione to the 
past, he had already witnessed that Buckbeak was stolen, and so he 
knows that if he sends them back in time, it is possible for them 
to "help the past along" by doing the stealing. No paradox.

The price that the WDID theory pays for avoiding paradoxes is that it 
tends to lead to depressingly deterministic scenarios. Contemplate 
Harry and Hermione from 3 hrs in the future sitting outside Hagrid's 
cabin and listening to the voices of the past Hermione and Harry (as 
well as Ron and Hagrid) inside. Harry wants to go inside and grab 
Scabbers-Wormtail, preventing him from escaping. Hermione stops him 
from doing so. But according to the WDID theory, even if Hermione 
would have agreed with Harry, they could not have entered the cabin. 
Something would have prevented them from doing so, because What's 
Done Is Done and we know that they did not get inside and Wormtail 
did escape.

This becomes more depressing if you think about the DD=Ron theory. 
According to this theory, Ron is somehow transported, at some point 
in time (probably during book 7, but before the outcome of the final 
battle between Harry and LV) about 130 years into the past and 
becomes DD and a teacher in Hogwarts. He knows that Tom Riddle is 
going to be born, turn into LV, start a terrible war and kill a lot 
of people, and he has to sit and watch it all happens as it already 
had happened, and he can't do a thing to change it. He knows that 
Riddle will kill Myrtle and frame Hagrid. He knows that Wormtail is 
going to betray James and Lily to their death. He knows that he (DD 
himself) will neglect telling Harry about the prophecy, that LV will 
take advantage of this to trick Harry into the DoM and Sirius will 
die there. But even if he does try to do something to prevent it, he 
will fail. Even if he tries to shout while passing Harry in the 
corridor: "Don't go to the DoM by the end of the year! If you do 
Sirius will die!" something will happen that will prevent him from 
shouting, or will prevent Harry from hearing him. Because Ron-DD 
knows that DD did not warn Harry, and What's Done Is Done. This 
sounds weird, but then again, all time traveling (and many other 
kinds of magic) are weird. Yet WDID is fully consistent in its 
weirdness. No paradoxes. It is just that, IMHO, this scenario is very 
depressing. Not to mention that it makes the whole "Sirius death was 
my fault" speech of DD at the end of OotP a lie. 

If you also don't like this scenario, then you may allow (or, more to 
the point, JKR may allow) that it is possible to change the past. In 
PoA this is suggested by one piece of canon: Hermione's fear about 
interfering with the past. She claims that one of the most important 
wizarding laws is "Nobody's supposed to change time", and that Prof. 
McGonagall told her that wizards that tried to do it "ended up 
killing their past or future selves by mistake". According to the 
WDID theory it is possible to kill your future self (although it is, 
again, depressingly deterministic because you then knows that in your 
future you are doomed to travel to the past and die by the hand of 
your past self, and there's no way you can avoid it) but it is *not* 
possible to kill your past self. So unless McGonagall mislead 
Hermione, JKR employs a different time travel theory than WDID, and 
it *is* possible (although dangerous and forbidden by law) to change 
the past in the Potterverse. But when you allow for changing the 
past, this is when the paradoxes start to raise their ugly heads and 
bite their own tails with vengeance.

Consider again Ron transported more than a hundred years into the 
past and becoming DD. He may not know who was Tom Riddle's mother, 
but surely he can locate the Riddle family. Riddle is not a common 
name, after all, and we are talking here about the great DD, with 70 
years time for preparations. He can prevent Tom's father and mother 
from ever meeting each other, and Tom Riddle from ever being born. 
Failing that, he still could ensure that Tom would be adopted by a 
loving wizarding family, instead of growing up in a muggle orphanage 
and becoming a lonely person full of hate. Failing that, he could 
have personally instruct Tom in Hogwarts and prevent him from ever 
going to the dark side (again, we are talking about the great 90-yrs-
old DD and an 11 yrs old boy). Failing even that, he could have stop 
Tom before Myrtle's death and defeat him when he is still very young 
(well, maybe he couldn't do that. Here we get to the disturbing 
question, is the prophecy valid 40 years before it was ever made?). 
So why didn't he do any of these? If, for this or that reason, he 
avoids meddling with the past, then this again becomes similar to the 
depressing WDID scenario. But if he does do any of these, it all 
becomes even more disturbing: If he manages to prevent the first and 
second war from happening, then the incident in which Ron was sent to 
the past also would not have happened, and then, there should not be 
a DD at all. And in the meantime, what happens to Harry, LV, and all 
the rest of the people at the present that is now very different? Do 
James and Lily suddenly spring to life? What happens to the present 
DD??? Most ways I know for tackling such paradoxes involve multitude 
parallel universes, and I'm not going to even try getting into this. 
This is JKR we are talking about, after all, not Asimov or Heinlein.

So you can see why I am apprehensive about the DD=Ron theory, 
although I concede that it has some surprising support in canon and 
also sounds just like something JKR might pull out of her hat. In 
fact, I am apprehensive about any use of the time travel in a big 
way, unless JKR manages to get it all both internally consistent, 
plot-wise satisfying, and intelligible. This is not impossible, 
merely very tricky. In fact, I think I can see more than one optional 
way to bring off a DD=Ron twist. Wait for part 2.

Neri