[Niamh.]

Originally Posted by Toy Soldier

Exactly. What is stopping them using it, if it exists and is simple enough that it can be handed out to a school kid? They essentially STOP using it because Dumbledore realises that it's a bad idea to **** about with time, don't they? But what's stopping a Dark Wizard with no moral code? The fact that it's established as existing IS the entire problem... just look at any sci fi or fantasy that involves time travel: they always end up needing a "filter" to stop it being a narrative disaster. That's why for example DC has things like "Flashpoint" (to teach The Flash not to mess with time even though he can), and things like the Legends (whose entire remit is keeping time roughly on track when villains try to mess with it)... Terminator basically establishes that trying to change the future is futile... Back To The Future has Doc Brown realise that it's a can of worms and gets Marty to destroy the time machine (then inexplicably throws caution to the eind and builds another)...

The list goes on but essentially "if time travel is possible you have to close the loop". It could be done relatively easily in the HP universe I suppose. Just make it that it's only permitted for "frivolous" things and have there be a Ministry department mysterious, benevolent, all-powerful group of future-wizards!! that exists purely to put things back on track if anyone ****s around, so no one bothers.

But in this case, we know that wizards CAN time travel, but just... don't... with no explanation .

I might write to JK and demand answers. She can just make something up and stick it on that Potter website, then it's canon and I can relax .