how the "cursed child" cursed time.
SPOILERS for HARRY POTTER and the CURSED CHILD
Harry Potter and the Cursed Child, being JK Rowling's last foray into the life of the titular Harry Potter, has been met with reviews more mixed than Ron's various children. My official stance is: it's a great script, I'd like to see it performed, and Scorpius Malfoy is now my patronus.
However, one area in which the story irked me is when it came to time travel. For those of you that know me well, you know I'm extremely nitpicky when it comes to portrayal of time travel in movies and books. I understand that from a theoretical physics point of view, the specifics of scooting across the fourth dimension are still up for a lively debate, but I'm a Dhanani, dammit. And we're nothing if not stuck in our ways.
The Multiverse Theory
For starters, let's look at the two main types of time travel: universe and multiverse. Going back in time isn't the issue, it's coming back... to the future. Coincidentally, Back to the Future features multiverse time travel. When Marty McFlies to the past, he alters the heck out of it. When he gets back to the... present, he finds himself in a completely different life with his parents all rich and a new Jeep.
What Marty did back in 1955 was split the universe up into two pieces: one where he didn't do anything, and one where he jumpstarted the civil rights movement and invented rock and roll. When we get to the present, there's two universes: the one Marty left and the one Marty came back to.
The Universe Theory
In Prisoner of Azkaban, Hermione and Harry turn back time using a Time Turner.
But, unlike in the Multiverse Theory, their actions in the past don't change the outcome. For example, future Hermione what I can only describe as a crustacean drool cube at past Harry's head, only because past Harry already got hit in the head by said drool cube. Future Harry knew he had to cast a stag patronus because past Harry watched him cast a stag patronus. As a viewer/reader, we see people going back in time to cause events that have already happened, not changing anything along the way.
Personally, I prefer the Universe Theory, because it keeps things more succinct. But a lot of people don't like it because it relies on Determinism. Basically, if you travel back in time, but can't alter the past, you pretty much don't have free will. But what about when you're not time-travelling, do you even have free will then? It's a scary thought for some people, but not as scary as the ability to split the universe in twain seemingly at random.
The Cursed Child
Long ago, JK Rowling set up the rules for time travel in the Wizarding World with the introduction of the Time Turner in Prisoner of Azkaban. But Cursed Child pooped on all of those rules. Hermione's Time Turner could only take her back a couple hours, but Albus' can go back years. With Hermione's Time Turner, you just wait until you're back at the present and continue on, but Albus' drags you back after five minutes. After Hermione used her Time Turner for treason, they were all destroyed, except for the two we have stashed away somewhere.
Those aren't the rules I'm going to fixate on, because for crying out loud, they were just trying to tell a story. No, Rowling set up universal time travel, and I'll be damned if she doesn't stick to it.
When Albus and Scorpius go back to Goblet of Fire times, their actions should've had no effect on Cedric Diggory's outcomes. Mostly, because we've already seen the outcomes played out in the books and movies. Not to mention that it's wildly out of character for Hermione to see two Durmstrang students cheating and not report it.
But what's most important is that during Part II, after Scorpius breaks his Time-Turner and realises that he's super cool, he rallies the support of the Order of the Phoenix to help him restore the timelines. Realistically (he says unironically, speaking about time-travelling wizards), this wouldn't happen. None of the other characters would have any motivation to risk their lives making sure this one kid got back to his own timeline. They wouldn't be going with him. None of the Hermiones or Snapes or Harries that Scorpius talks to have any stake in his own timeline. And, once he goes back and "fixes" everything, they'd go on living their Voldemort-filled lives. The entire universe that they know would remain unchanged.
The most accurate time-traveling that happens in this whole play is when Harry is in Godric's Hollow and he understands there's nothing he can do. Although, the play would be a lot shorter if Albus and Scorpius realised that they couldn't change the past and just gave up on Cedric, like any normal person would.