Plot synopsis
When Harry starts his third year at Hogwarts School of Witchcraft and Wizardry, he notices that his friend, Hermione, is acting strangely. He discovers she is using a time-turning hourglass necklace to take herself back in time, so she can attend two classes simultaneously.
Harry, Ron and Hermione go to save Buckbeak, the hypogrif (half eagle, half horse) from having his head chopped off. They are not able to do so and from a distance, they see the executioner’s axe coming down, but do not notice that he was chopping a pumpkin instead.
Professor Dumbledore suggests that Hermione and Harry go back in time to help his wrongly accused godfather, Sirius Black, escape from prison and save Buckbeak.
She places the chain around both of their necks and turns her device over three times. They arrive three hours into their past and can view themselves from a distance.
Without being noticed, they then save Buckbeak from his execution by helping him to escape. Harry and Hermione fly on him to the tower to rescue Sirius Black, who then escapes on Buckbeak.
They arrive back at the hospital wing where they observe themselves just about to start their time travel. Ron, lying in bed, sees them disappear in front of him and then re-appear on the other side of the room.
He asks them in amazement how they did that trick. Little did he realise that they had just left and returned on a time travelling trip.
My comments
This film has a few examples of the predestination paradox:
Harry was saved from the dementors by what he thought was his dead father’s ghost. During his time travel, he watches the attack from afar, but when the ghost does not appear, he casts a spell. It creates the apparition that saves the earlier version of himself. This causal loop could not have happened if he had not gone back in time.
Another example was when a stone hits Harry on the head that Hermione threw when she went back in time. Had she not gone back in time, she would never have thrown the stone. This would have created an inconsistency in the storyline.
Also, if they had not thought that Buckbeak has died, they would not have gone back to save him, and he would have died.
Summary of time travel
They go back in time and can see themselves. But when they change events, they realise that they are not changing anything, as they remember that these events already happened.
These causal loops indicate that a fixed timeline was being used. The past and future only appeared to be changing.
Category of time travel
Fantasy: magic
Model of time
Closed past, closed future with a fixed timeline and causal loops.
