Not My Canon!

WTF: Time

When I first realized that time travel was turning out to be a plot device in Cursed Child, I was genuinely confused. Jo had been very vocal about the fact that she'd made a mistake in creating Time-Turners because they were too powerful. That's why she chose to destroy all of them in Order of the Phoenix. Well done. I can respect that. But, if they were such a thorn in her side (hahahaaa Thorne in her side), why would she approve the plot of the 8th story when it's based entirely on the use of Time-Turners? Are we wrong here? Isn't this peculiar?

Oh, it's stranger than you would expect.

Time Travel according to J.K. Rowling (pre-Cursed Child)

Harry and Hermione are sent into the past during the conclusion of Prisoner of Azkaban in order to rescue both Sirius Black and Buckbeak. Harry is especially interested in going back. He's certain that his deceased father had saved him from the Dementor attack because the Patronus was a stag. He soon discovered that it was actually him who had successfully cast the Patronus Charm.

This is the most significant factor in our understanding of how time travel works in the wizarding world.

The fact that the present/future version of Harry saved the past version of Harry from the Dementors proves that both of them existed in the same timeline and that, while their actions affected one another, they were incapable of changing anything. It's confusing, I know. The best way to explain it is that, in the fictitious wizarding world, time travel is self-fulfilling. Self-consistent. Circular.

Buckbeak never actually died because Harry and Hermione were ALWAYS in the past saving the Hippogriff from Macnair, the executioner.

According to the original source books (OS-Canon), your actions while time traveling lead to a causality that simultaneously fulfills both the present and the future. In other words, everything you do while time traveling to the past brings about the events of YOUR present. It is unchangeable. The history of the past ALWAYS included present you and what you did while you were back there... even with the full knowledge of the past influencing your actions. Mind-blowing, right?

I've spent years on theorizing this causality for a different book of mine (that I should be publishing on Wattpad soon - yes, it's a (wait for it) romance), so it doesn't take a lot for me to see this form of time travel and accept it straight away. But I can understand how the concept can be a struggle to wrap your head around. This is made significantly more difficult when you read Cursed Child because JKR and Co. promptly abandoned the established rules of magical time travel altogether.

Time Travel according to J.K. Rowling (post-Cursed Child)

Time-Turners now work differently. Where events of the books used to follow a single timeline, and visiting the past would not alter the future, the events of Cursed Child do the complete opposite. Their actions are no longer fulfilling the existing future. They now have the power to change whatever they'd like. This means entirely different events take place in the life of Harry Potter and the rest of the gang the very instant Albus and Scorpius travel into the past - OVERWRITING BOOKS 4-7.

This is absolutely bananas. Why in the world would an author help to create something new that completely tramples over storylines that everyone already loves? It's as if she secretly hates her books!

On the first go, the effects of Albus and Scorpius going back in time are minor and laugh-out-loud-able. On the second go, everything is completely changed, and to epic levels of eye-rolling ridiculousness.

What else? Time travel can not only change the future but now you can go back years. Well, only five minutes at a time. And be careful! Apparently, it also uhm... hurts... you...? That's correct, class. Time-Turners now cause pain and have duration limitations. Why? Because why not?