Problems with time travel in Harry Potter… and in everything

Time travel plots are the most infuriating thing any author can put into his or her fiction. For one, they’re almost impossible to get right and, for two, they will almost always end in closed loops.

A closed loop, or a predetermination paradox, is why you’re currently sitting in front of your computer and why you’re not the Magic King of Earth (first image that popped up). The convention wills that if your older self travels backwards in time whatever changes he or she makes will ultimately result in the creation of the present.

For instance, an elementary school a bully breaks your favourite toy. Fifty years later, you invent time travel and your first destination is that fateful day. You slink into the elementary school and just as you’re about to run in to snatch the toy, you get tackled by a security guard. That bully still breaks that toy and you still invent time travel as a result.

Imagine if you were able to get into the classroom. You bitch slap the bully and snatch the toy, but you blink out of existence and return to your present day without knowledge of time travel, but a faint memory of that lock down you had one time in elementary school. Then the universe explodes.

Time travel requires that bully, that catalyst in order to work. Without that event, time travel isn’t feasible in the real world or in fiction.

Harry Potter and the Prisoner of Azkaban is one of my favourite in the series, but I cringe every time I hear people say, “Why don’t they just use the Time-Turner to go back in time to kill You Know Who?”

Well, like everything else in Harry Potter there are rules to using magic and reasons why wizards aren’t obliterating the universe every other day.

Time Magic

In the Harry Potter universe there are two documented cases of the use of time travelling magic. During an experiment in 1899, Eloise Mintumble used time travel in an attempt to go back in time a few hours, but ended up going a little too far… almost 500 years too far.

When she was retrieved five days later, it was discovered that Eloise’s jaunt into the past resulted in the un-births of almost 25 of her relatives and a significant amount of damage to the universe itself. And in the process of coming back, her body aged almost 500 years. She ended up in St. Mungo’s where, presumably, she died of being half-a-millennia old.

The event was enough to make Time-Turners a heavily guarded asset at the Ministry of Magic. So why the hell does Minerva McGonnagall give Hermione Granger one for studying?!

Also had it so she could take boxing lessons.

So she could take Hagrid’s boxing lessons.

In Harry Potter and the Prisoner of Azkaban, Hermione is given a Time-Turner so she can attend several classes at once in her pursuit of outstanding academics. While it seems pretty mundane, her trips into the past and back again are fraught with danger.

The Time-Turner requires the witch or wizard to return back to the same moment when he or she originally used the device in order to create a closed loop. That way you are in the same place as when your past self disappears and you continue on living in the present. The caveat is you cannot allow your past self to see you.

As Hermione explains in the film, wizards and witches who meet themselves while time travelling often go mad. Whether that means you end up trying to kill your doppelganger or trying to bed them is entirely up to your preference, but the gist of it is: avoid disturbing the closed loop at all costs. But perhaps, the Time-Turner has found an easy way around the potentially disastrous effects of creating a paradox.

For example, here’s a step-by-step of how Hermione attends both Ancient Runes and Divination:

  • Hermione leaves the Gryffindor common room and goes to Ancient Runes
  • At the same time Harry Potter and Ron Weasley are taking the divination class
  • Class ends. Hermione returns to the common room, hides, and turns her Time-Turner 2 times
  • Back in the past, she sees herself leave and quietly follows Harry and Ron to Divination. She then takes the class with Harry and Ron, while in the past knowing that her past self is currently taking Ancient Runes. She then returns to the Gryffindor common room at the same time as her Doppleganger who then uses the Time-Turner and disappears into the past
  • The loops is closed and time resumes its regular schedule

Imagine having to do this for every class, you’d get frizzy hair just like Hermione too.

Hermione's hair in its natural, untamed state.

Hermione’s hair in its natural, untamed state.

There’s also the other scenario that she quietly attends Divination with Harry and Ron only to use the Time-Turner at the start of class, goes to Ancient Runes, and returns back to her seat as her past self is going back in time making Ron Weasley wet himself in the process.

Hermione just needs to ensure that her past self does not see her. It’s why, for example, Hermione cannot use the Time-Turner in order to redo a test because then she’d have to be in the same space as her past self, which would then drive her mad… blah, blah, blah.

But as we see in the film, predetermination plays a huge role in how Sirius Black is able to escape Hogwarts, but there’s another force at play here during their time travelling escapades.

According to a Princeton University (which sounds a lot more reputable even though it’s pretty much a Wikipedia article) write up on Novikov’s consistency principle, keeping the time stream clear of debris might a little easier than you’d think:

Stated simply, the Novikov consistency principle asserts that if an event exists that would give rise to a paradox, or to any “change” to the past whatsoever, then the probability of that event is zero. In short, it says that it’s impossible to create time paradoxes.

An example is the Titanic sinking; even if there were time travelers on the Titanic, they obviously failed to stop the ship from sinking. The Novikov Principle does not allow a time traveler to change the past in any way at all, but it does allow them to affect past events in a way that produces no inconsistencies—for example, a time traveler could rescue people from a disaster, and replace them with realistic corpses if history recorded that bodies of victims had been found. Provided that the rescuees were not known to have survived prior to the date that the time traveler stepped into the time machine (perhaps because they were taken forward in time to a later date, or because their identities were hidden), the time traveler’s motivation to travel back in time and save them will be preserved. In this example, it must always have been true that the people were rescued by a time traveler and replaced with realistic corpses, and there would be no “original” history where they were actually killed, since the notion of changing the past is deemed impossible by the self-consistency principle.

In other words, if time travel in Harry Potter acts in the same way as described above there’s very little to no chance of creating a universe-destroying paradox as the changes that occur have already been made by the time you go back into the past. A time traveling person will essentially create the same set of events that created the present that wills them to go back into the past.

Sirius Black will always escape his prison atop Hogwarts because by the time Harry and Hermione are in the hospital wing as another set of them is racing to free Sirius and racing to return to their original spot near Ron. There’s nothing that says other people can’t see your doubles, but only your past self cannot see you hence why Ron being surprised to see them “there” and then “over there” is ok.

In essence, there’s no way that Harry and Hermione would not try to use the Time-Turner to go back in time and help save Sirius Black. It has to happen as it already has happened

Ten years into the future when the Ministry of Magic creates more Time-Turners (they were all destroyed in the 5th book, how convenient) no one could ever go back in time and stop Harry and Hermione from freeing Sirius Black from his prison atop Hogwarts. They would either end up dead or meet their past self and go mad.

It is written history, solid and unchanging.

Using a Time-Turner to your advantage

Ooo, I bet you could sell one of these in Knockturn Alley for a mint.

Ooo, I bet you could sell one of these in Knockturn Alley for a mint.

Now that we’ve gotten all of the nitty gritty temporal details out of the way, the question remains: how can I use a Time-Turner to benefit my every day life?

Well, unless you plan on killing people or un-birthing your relatives you better keep the tasks simple. Whatever you choose to do it is essential to prepare some things ahead of time:

“A Meeting Point”

You need to create a point of origin for the beginning and end of your closed loop. Wherever you first spin the Time-Turner is where you need to be when time catches up with you.

“Ninja Equipment”

Whether it’s a vanishing cloak, a vial of Polyjuice potion, or a broomstick, you need to have some equipment that can help you disappear if you are confronted with yourself.

“Cameras or a notebook”

I know, I know electronics don’t work in the Wizarding World, so perhaps this applies more to being in the Muggle World instead. Remember what Albus Dumbledore said, the best way for them to save Sirius is to retrace their steps. The best way to prevent yourself from stepping on your own toes is to have those steps recorded either in photos or a notebook, and knowing where to not go at what times. Even the best of us can forget where we were at 1:14 p.m. on a Tuesday.

“Bright Clothing”

In your original attempt at the present, be sure to wear really bright clothing. It’ll help your past self spot you in a crowd, but when you travel back in time wear demure clothing to help you blend into the background. It’s a good thing Hermione was wearing bright pink, so her future self could see her, but not so great when she tries to go back in time unseen to help Sirius. I wonder if that means Luna Lovegood is a time traveler…

So what can you do?!

Have you ever wished that there could be two of you? One to do all of the work and one of you who can just chill out and relax? I wish I could do that all of the time, but I don’t have a self-sacrificing twin.

I can't remember which one died...

I can’t remember which one died…

There’s a whole bunch of crap you can do with a Time-Turner, but most of it has to do with leisure rather than action or danger, so I’d use it for…


Glorious, glorious sleep. You’ve been sitting through classes all day long and all you want to do is head back to the dormitory and catch up on some Z’s. However, you don’t want to waste away the evening. So what are you going to do? Well, four spins of the Time-Turner and you’re back in time almost four hours. All you need to do is find a good place to hide while you sleep and remember to set your alarm, but that’s where the danger starts to seep in.

What if you over sleep? What if you take a sleeping draught to give you a deeper sleep? The ramifications of you not being in the same place when you go back in time could be disastrous, so maybe take little naps instead of big slumbers.


There are not enough hours in the day to find time for exercise. In and around Hogwarts, students are given a huge vista to run through and lakes to swim in. Why not take the time to get a little fit? You’d be out of the way of everyone else and you’d get to spend the rest of the evening studying or doing whatever you want to.

While all of the other students are sitting at their desks, you’re riding brooms, swimming with Merpeople, and palling around with Thestrals (sorry for whoever died in your past…). The key here is to make sure you’re far enough away that people don’t start to get suspicious over your activities. No one wants to be brought in to see the Head Master while your actual self is still in the class. Might cause a bit of confusion.

Win a few Galleons

It’s the end of today’s Quidditch match between Ravenclaw and Hufflepuff. The Weasley Twins are raking in the dough and dolling out a little of it in return to those who bet with care. After the match, you sneak out to behind the pitch and spin the dial two times. In the past, you go up to the twins before the match and place a bet.

After the match is over, again, you run back to your hiding spot and close the loop. An hour later, you meet up with the twins in the Great Hall and tell them you weren’t around to pick up your winnings. Lo and behold they dish you out a few Galleons for your trouble and they say you’re still their luckiest customer.

Make lunch for tomorrow

I think this one works for Hogwarts and the real world too. If I had to use a Time-Turner for a completely mundane purpose, I’d use it to make myself an awesome lunch for tomorrow. Set time back two hours after you get home from work and then spend a little time going out to the grocery store and getting home in time to make a lunch.

You’d have to avoid the suspicion of checking your corners though as your present self. Knowing the laws of space and time in play here, it would be very likely that as you’re going home from work another you is already trying to make your lunch. Be very cautious when it comes to your hiding spot and never check it! You might just see yourself and your toned abs from all that exercise you’ve been doing in your spare time.

Read books… running out of ideas here…

Spend time in the library…

Well maybe that’s about all you could do with the limited style of time travel that the Time-Turner offers and that’s really its charm and its secret.


The reason why Professor McGonagall gives the Time-Turner to Hermione relates to the above: they’re used for pretty mundane stuff.

Hermione is given the little pendant with the understanding that she’s going to be using it for the sole purpose of improving her academics. McGonagall knows she’s a smart student and most likely won’t be destroying the universe any time soon.

The way Hermione and Harry use the Time-Turner to save Sirius Black is an extreme exception to the rule as I don’t think the Ministry of Magic would normally dole out the devices to people with nefarious schemes in mind. There are just too many pitfalls to warrant the use of the pendant in anything but the simplest of tasks.

Going back more than just a few hours puts you in serious risk of meeting yourself and destroying your sanity. Then there are the changes you can make to the present if the pendant is used improperly. However, there is one unsaid and serious drawback to using the device.

Like getting attacked by ravenous professors who haven't taken their medicine.

Aside from getting attacked by ravenous professor who hasn’t taken his medicine.

The time you spend using the Time-Turner will bite you in the butt. Say you spend the entire week going back in time for four hours each day. That’s 28 extra hours in a week you spend doing whatever you want to be doing. Now if you do that every week for an entire year… you end up adding on 1, 456 extra hours or 60 extra days onto your life.

It’s no wonder Hermione seems a lot smarter than her classmates, not to mention a bit more mature than most, but there are also issues with overloading yourself with too much as we see in the book with Hermione (her stress levels aren’t really see in the film). She spends every single night in the Griffindor common room – books strewn all about – trying to keep up with all of her studies.

And the scary part is we don’t get to see all the times she used the Time-Turner to go back in time to spend more time studying. We all know how obsessed her character is over perfect grades, so it seems perfectly reasonable that she might be obsessed enough to go back in time several times during the day just to read a little bit more.

A user could start becoming dependent on using the Time-Turner and with each slip backwards in time they risk destroying themselves. It’s this reason why time travel is so restricted in the Harry Potter universe.

As responsible as Hermione Granger might be, no one is infallible and I don’t doubt wizards and witches who end up using the devices end up either addicts or somehow exploded all over the room.

Also *breathes in* Hermione-Granger-gives-back-her-Time-Turner-to-Professor-McGonigall-at-the-end-of-the-year-and-they’re-all-destroyed-which-is-why-people-can’t-go-back-in-time-to-kill-You-Know-Who *breathes* ok, that’s off my chest.

So J.K. Rowling pretty much kills time travel in one little moment during the Battle at the Ministry of Magic. It’s a pretty convenient misfired hex that destroys them and destroys all hope of time travel returning to the series.

However, there’s a whole other set of magic that has to do with bending space and time, which I’ll be getting to in a future article.

For now, I’ll say that time traveling magic in Harry Potter is intriguing, but fraught with danger. While there are benefits to using a Time-Turner for mundane stuff like studying or exercising, using it for anything more complicated puts your very existence nay the existence of the universe at risk.

Sure, Novikov’s principle says there’s no way for us to actually end up destroying the universe through a time paradox, but he didn’t say anything about destroying ourselves like Eloise Mintumble did.


Like this article? Then you should read some of my equally magical short stories :3, click here to check them out:


8 thoughts on “Problems with time travel in Harry Potter… and in everything

  1. I couldn’t agree with you more! Time travel is hands down one of the hardest concept to execute flawlessly. I think the only team that got it right were the writers of LOST. Real life quantum physicists were analyzing their concepts. I myself have been studying time travel for about 5 years now along with alternate realities and the trick for me is to keep a map of every event and timeline. With proper research and the right amount of psychotropics, you might just nail it lol…

  2. The people who ask why don’t they just use the Time-Turner to go back in time to kill You Know Who are the same people who would wish for bottomless wishes if given a wish. 😀 It’s totally cringe worthy! 😀

  3. Pingback: WOULD YOU RATHER… have a Time-Turner or an invisibility cloak? Let us know with #MNWYR - MuggleNet

  4. Pingback: Not My Timeline – Nerd in the City

  5. But how did Harry survive the initial dementor attack? In the original timeline, he would not yet have gone back to save himself, meaning he would have died. I have struggled with to make sense of it.

  6. I agree that time travel only makes sense if it doesn’t result in paradoxes.

    The births of Mintumble’s relatives presumably occurred in the past. For them to be “unborn” would either be the established impossibility of altering past events (assuming it means that their births never happened), or that they suddenly stopped being alive and present.

    You’ve established that history can’t be changed by time spells so it must be the latter. In that case it’s still a potent weapon in certain circumstances.

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