With the recent release of the third Harry Potter book, my sister-in-law went back and reread the third book, Harry Potter and the Prisoner of Azkaban. This lead to a discussion which lead to what I’m about to nitpickety obsess over below. This has bothered me since I first read the novel. All passages cited will reflect my edition, the American Scholastic edition in trade paperback format. Where things run a bit confusing, I’ll use the notation of Harry1 to describe Harry Potter the first time he lives through an event, and Harry2 for when his time travelling self comes back and acts within the same time frame as Harry1. This will apply to Hermione as well.
For those of you who’ve neither read the book nor seen the movie, there are major spoilers below so I’d quit reading at this point and come back next week when I write a scathing criticism of how Bill Murray essentially has negated all the good work he’s done in his life, as well as earned himself a special place in the Pit of the Damned for doing the voice of Garfield in the film of the same name.
The difficulty comes from the time travel deus ex machina invoked at the book’s conclusion. Let me recap: Harry and Hermione Granger go back in time three hours, using the magical hourglass Hermione’s been employing throughout the book to fulfill her overloaded class schedule. They do this so they can rescue the hippogriff Buckbeak who has been sentenced to die, then plan to use Buckbeak to rescue Sirius Black, Harry’s godfather, who is locked in a tower, also awaiting execution.
This three hour trip to the past allows Harry and Hermione to sneak to the back of Hagrid the Gamekeeper’s hut and release Buckbeak from where he’s tied, awaiting the final moment. As described in Chapter Twenty-One, “Hermione’s Secret,” page 397:
They made their way silently through the trees, keeping to the very edge of the forest. Then, as they glimpsed the front of Hagrid’s house, they heard a knock upon his door. They moved quickly behind a wide oak trunk and peered out from either side. Hagrid had appeared in his doorway, shaking and white, looking around to see who had knocked. And Harry heard his own voice.
From here on out, Harry2 and Hermione2 go about their rescue plans, watching the events they just lived through transpire, seeing them from different perspectives. The figure Harry1 saw by the edge of the woods the first time around? That was just Harry2 in the future, watching on and rescuing himself by the expression of his Patronus.
Here’s what bugs me though. We have to flash back to Chapter Seventeen, “Cat, Rat, and Dog,” page 347 where Professor Lupin explains to Harry1 how he managed to find out where Harry1 and Hermione1 were going and what they were up to. If you recall, Harry had loaned Lupin The Marauder’s Map, a magical plan of the grounds of Hogwarts School of Witchcraft that shows in tiny real-time illustrations all the people on the grounds and where they’re located replete with little name tags indicating who’s who.
(The sheer jumble that this would produce when all the students were in the Dining Hall or their dormitories is not something I will go into and it is not something that is ever addressed. Apparently, only the characters that matter to the forwarding of the plot actually show up on this device.)
Lupin tells Harry:
“I was watching it [The Marauder’s Map] carefully this evening, because I had an idea that you, Ron, and Hermione might try to sneak out of the castle and visit Hagrid before his hippogriff was executed. And I was right…I watched you cross the grounds and enter Hagrid’s hut.”
He then relates how he managed to catch up to Harry1, Ron, and Hermione1. Now the issue I have with this, is looking at the map, watching specifically the area around Hagrid’s hut to see if Harry1 and Hermione1 go there, why doesn’t Lupin see Harry2 and Hermione2 around the back of the hut? Surely they would show up on the map as well. And surely that would concern him to some degree. Yet he never mentions it.
I suspect that the thought didn’t occur to Ms. Rowling, as time travel is a tricky subject to tackle when writing, as there are implications within implications. And as her books are concerned first and foremost with the magical world, the scientific concept of time travel doesn’t come to mind. What is also problematic is that Hermione is able to go an entire year taking two classes at the same time, just turning the magic hourglass, but if you create a second set of you, then what happens to that first set?
If Hermione is taking Divination from 8 to 10, then at 10 she’s traveling back to 8 to take Potions then at 9 o’clock there will be two Hermiones, one in each class. What would happen if something was provoked by Hermione2 in Potions, say, an explosion that disrupted the original flow of class for Hermione1? Are Hermione1 and Hermione2 always existing simultaneously? When Hermione1 takes that class, before she gets to class’ end and goes back in time, is Hermione2 already in that class? And if so, would Hermione2 be tired, having lived through this life already?
What happens at the end of the book would suggest it.
Time travel first and foremost is a scientific and philosophical problem. Scientific because outside of such fantastical devices as magical hourglasses, we understand the element of time differently since Einstein posited that space and time together made up the fabric of the universe, that time was the fourth dimension in which space existed. Philosophically, we approach the problem because all of the scientific possibilities for time travel devices are impossible creations, like a spinning tube almost as long as infinity. Good luck getting the underwriting on that.
And so time travel is the ultimate philosophical device in fiction. Do we dare risk changing the past and what implications will that have on the future? There is a pithy saying that if you move a single grain of sand in the past, the entire future will change. Imagine if you went back in time and accidentally killed your own primitive ancestor. Would you, the time traveling murderer, wink out of existence in that moment because you had prevented yourself from ultimately being born? Or would you stay on existing, ultimately becoming your own ancestor?
The simplest argument against the type of time travel fiction incorporates is the free lunch argument. Essentially, time travel, as demonstrated, is a matter creation machine, and the first law of thermodynamics makes it quite clear that matter can not be created in this fashion. This can be stated as such that you can’t fund the research into time travel by having your terribly successful fifty year old time travel inventor self send your penniless twenty year old inventor self the money to fund the project. You also can’t put bag of ten thousand dollars in the time machine and send it five minutes into the past and have twenty thousand dollars (you’d also have two time machines then). There is no free lunch here.
So what’s the point? The point is that you have to be decidedly careful when you write about time travel because it is perhaps the trickiest subject to get exactly right. Many things can be completely overlooked, and once you’ve committed it to the publishers, no amount of magic or science can let you go back and fix it.