Time-Travel Again? (Of course we can change the past)

[Richard Jones]

No: HPFGUIDX 116665



It is clear from the POA that under JKR's theory we can change 
history.  True, time-traveling Harry and Hermione didn't change 
history in the POA — they just participated in events twice and so 
the events came out differently than if they had not time-traveled 
and participated in them only once.  But we are not limited to just 
that — Hermione tells Harry that McGonagall told her that "loads of 
[time-traveling wizards and witches] ended up killing their past or 
future selves by mistake" (p. 399).  That is definitely changing 
history: the "earlier" wizards have been eliminated from history by 
time-travel events.  How can you go back in time and kill your 
former self without changing the past?

Some people will argue that we can't change history through time-
travel because of the basic paradox that you could accidentally kill 
yourself.  In fact, the cardinal rule of time-travel in sci fi is 
that time-travelers cannot change events that would affect their 
ability to time-travel.  But JKR is the only physicist in the 
Potterverse, and what she says goes.  If she says that time-
travelers can change history — e.g., by killing their former selves —
 then time-travelers can change history, and that's that.  JKR sets 
the rules, and that has to be our starting point for thinking about 
time-travel.

Also notice that in the POA time-traveling Harry wanted to run out 
of the forest when he and time-traveling Hermione were hiding there 
to get the Invisibility Cloak (p. 405) and to get Wormtail (p. 
408).  Hermione had to grab and stop him.  She only expressed 
concern about being seen, but the fact remains that Harry would have 
changed the history that got them to that point if he had done what 
he wanted to do.  If Harry had stopped Wormtail or had just gotten 
the Invisibility Cloak, all the events of that evening from that 
point on would have changed.  No "laws of nature" or "magical 
forces" or "laws against time paradoxes" kept Harry from changing 
history — only Hermione's quick action did.

Also consider Dumbledore's comment about being careful because time-
travel's consequences are complicated and unpredictable (p. 426).  
Why say that if the past is "fixed" and unchangeable?  We wouldn't 
have to be careful since we couldn't change history even if we 
wanted to!  If history is fixed, it is not as if we could make a 
mistake and change things -— what happened happened, and there is 
nothing we can do accidentally or intentionally about it.  So why 
would he say to be careful?  In sum, if our actions during time-
travel are somehow fixed and predetermined, his comment doesn't make 
sense; and if our actions aren't fixed, then we can intentionally or 
accidentally change the course of events and thus we must be 
careful.