
Originally Posted by
Ouch!
There's a difference between putting your world inside a box and setting down some ground rules. Rowling's only rule was that magic can't bring people back to life. Otherwise, there were very few specifications to its limitations. That aside, the rules for a given system of magic never have to be made clear to the reader. In the end, I just think that explaining away the ending with a vague, "Nobody could have known!" is one of the worst cop-outs ever.
That aside, there are other (and arguably better) ways to be unpredictable without resorting to such an unsatisfying technique as a deus ex machina.
But really, nobody in Rowling's world
could have known. Harry's relation to Voldemort is unique; no one has ever experienced the same situation before. To propose that some character could have predicted how such events would unfold is bizarre! Even the range of what simple spells and can be "invented" is unknown, it's really no surprise that the effects of such arcane magic is unknown.
Either way, I suggest we call it a matter of differing opinions before this turns into a discussion of literary technique. :)