[HPforGrownups] Re: Time turner theory

[James Sharman]

No: HPFGUIDX 161887

Sarah:
It's been well established in interviews that one thing magic can't do
is bring back the dead. (Except as Inferi, which isn't quite the
same. :) ) The Time-Turner is magic, therefore it can't bring back
the dead. This is why the belief in a "first reality" scenario where
Buckbeak actually died breaks our understanding of the Potterverse,
and opens up possibilities like this where every dead person ever
isn't beyond hope of being brought back.

If Harry is ever going to do something like this, his future self
would have already done it in his past. He would have grown up with
parents. Since he didn't, an attempt to do so would either fail (most
likely) or I don't know, explode the universe or something (less
likely).

James:

I think a lot of discussion of what might/can happen during time travel is
redundant with regard to the books.  There is no single agreed theory on how
potential paradox is handled by the universe but we simply don't need to
worry about that. Unlike the laws of physics, in the HP world there is an
absolute and her name is JKR. 

Sarah makes an excellent case on the Buckbeak issue. To understand this you
just need to realize that it's not necessary for the death to have ever been
real, just for the people involved to believe it was real. When we see the
"execution" the second time round we see things to explain everything the
trio experienced that gave them that impression but we now understand it
better. JKR may have been assuming an unchanged time line, or she may have
been writing a changed time line in which the reader's perception is
unchanged. 

We are told that terrible things happen to anyone who tries to change the
past. I conclude from this that it's either impossible in JKR's world or in
some way paradoxical catastrophic, so I see no scope for harry going back in
time to mess with the past. I could easily see (but I'm not expecting) some
time travel to gain a new understanding of events. I could even see someone
else trying to time travel with the resultant terrible things happening to
them (maybe Voldemort or Wormtail making a last ditch attempt at changing
the past).