The point of Time-Turning (was Paradox of Time Travel in PoA)

[jlv230]

No: HPFGUIDX 132176

Sorry Davenclaw, I can't help but butt in
 again


> > Del:
> > The problem is not the TT!people seeing their past selves. It's 
the
> > other way around: the past selves seeing the TT!people. As 
Hermione
> > explains to Harry, if past!Harry saw TT!Harry, he would most 
probably
> > assume that some dark magic was at work, and he might attack TT!
Harry
> > before any explanation could be given.
> 
> Davenclaw:
> If there is no way to "change" the past, but only to "participate" 
in 
> it, then wouldn't the TT-Harry already know if he had encountered 
his 
> TT-self?  Then we would see this conversation:
> 
> Harry: "Let's use the time-turner!"
> Hermione: "Okay, but you can't let your past self see your time-
> traveling self!"
> Harry: "Well, if I had seen my TT-self, I would know now, wouldn't 
I? 
> But in the past three hours, I never saw another me.  So there's 
> nothing to worry about!"
> Hermione: "Oh... well... but maybe that's only because you're going 
to 
> be careful!"
> Harry: "Well, if we already know I'm going to be careful, then you 
> don't need to tell me to be careful, do you?"
> Hermione: "I suppose not... but be careful, just the same!"

JLV:
Exactly. Harry didn't run out because Hermione warned him not to, so 
he didn't run out, so he never saw himself run out. You have it 
exactly right. Where is the problem? Is it the `backwards' 
or `circular' causation /still/?

> Davenclaw:
> Now, just so we understand, since you are saying that the past 
can't 
> be changed, but only fulfilled, then the only reason you would use 
the 
> TT would be to witness or participate in a different set of events 
> than your non-TT self.  So Hermione can be in two classes at once.  
> You would NEVER say "well, what just happened was really awful, 
let's 
> go change it!" Because then you would say, "Well, it just happened, 
> period, so if I choose to go back, it means that either going back 
> will cause it, or at least not prevent it, so I can't change 
things, 
> or else they would be changed."  So if something bad happened, you 
> wouldn't bother going back.

JLV:
Exactly right – now I think we're getting somewhere! Except 
the `going back would cause it' thing. Going back wouldn't have 
caused it if you never did go back


> Davenclaw:
> And if something good happened, you might 
> say "Well, I'm so glad things turned out that way... but what if 
the 
> only reason things worked out is because I used the time-turner to 
> change them? 

JLV:
Oh no! There is no `change' about it! Rid your mind of the word. 
There /is/ no change. Harry and Hermione just provide an extra set of 
hands to do the rescuing – hands with a really fabulous alibi! That 
is the point of the time-turner in this situation. They do *not* 
change anything. There really is nothing more complex happening here.

> Davenclaw:
> Well, I just won't bother, since things turned out as 
> they did, so whatever decision I make now won't change things." 

JLV:
Just because a decision can't `change' things, doesn't mean a 
decision can't affect things. Really, you use the word change very 
lightly. Carefully consider what change means – can you change 
things? Or were you caused to do something that had a certain effect? 

I may think I have no `free' will (as I said before) – my 
interactions with everything are governed by logic and laws of nature 
etc – but I haven't give up because I don't think I can `change' 
anything. I do have effects – this post for one – but I think I write 
this, say, because some complex interaction in my brain occurred. To 
some extent the future is determined by past events. Choices and 
change are a bit like names we give to some events but there isn't 
anything special about things which we call `choices' or `decisions' 
really – they are just events like anything else.

> Davenclaw:
> So no one would actually ever use the time-turner, since they would 
> never know that it was necessary in order to bring about events as 
> they occured, unless they saw something when they weren't time-
> traveling that tipped them off to the presence of their time-
traveling 
> selves.  Or in this case, something tipped off Dumbledore.

JLV:
I don't think the conclusion is that no-one would ever use the time-
turner. How else could Hermione get to all her lessons? How else 
could someone be in two places `at once'? How else would Harry and 
Hermione have an alibi for the Sirius rescue?

And note that Harry *was* tipped off by his counterpart to cast the 
Patronus.

You seem to be upset by the conspiracy of circumstance
 well remember 
that in fiction, conspiracy of circumstance is often the bread and 
butter of a good plot. I see no need for what I consider to be worse 
conspiracies (Dumbledore casting the patronus first) and logical 
inconsistencies involving the overwriting of the past.

> Davenclaw:
> I think this is my last post on the topic...

JLV:
So I have the last word


Seriously, I'm very disappointed that myself and my fellow posters 
couldn't make you think about this differently. But I'm also glad you 
raised the point so I could have so much fun thinking about it!

Anyone interested about reading more about the philosophy and real-
life physics of time-travel would do well to consult:

http://plato.stanford.edu/entries/time-travel-phys/

But be warned some bits are a bit (i.e very) technical. But some 
parts can be read by those with a non-physics background.

And Davenclaw, I here quote from the conclusion of this article which 
is relevant to this debate:

"If time travel entailed contradictions then the issue would be 
settled. And indeed, most of the stories employing time travel in 
popular culture are logically incoherent: one cannot "change" the 
past to be different from what it was, since the past (like the 
present and the future) only occurs once. But if the only requirement 
demanded is logical coherence, then it seems all too easy. A clever 
author can devise a coherent time-travel scenario in which everything 
happens just once and in a consistent way."

I think this `too easy' point is part of your concern, but I have no 
reason to think that this is a problem or, ideed, a clue in the books 
that something else happened first. After all, it /is/ fiction. What 
I am saying is that the time travel scenario is just fine the way it 
is. There is *no* `hidden' sequence of events necessary to make sense 
of the plot, and the plot *wouldn't* make sense if in fact we had the 
scenario you described.

JLV xx