In Harry Potter and the Prisoner of Azkaban, Harry is attacked by a swarm of Dementors and as his soul is being sucked out he is saved by what he thinks is his Father. He later learns that it is he himself performing the Patronus charm.

If he died in the first timeline, how can he be alive in order to 'go back' in time to save himself from that event?

  • Harry's soul and is not sucked out. Sirius's soul is sucked. Harry just fell unconscious.
    – Nog Shine
    Commented Aug 23, 2017 at 5:40
  • Indeed. Nothing in the movie indicates that Harry's soul is sucked out or that he's even close to being dead (see here). The dementors are only sucking out his happiness at that point, like they do to every person, because they feed off it.
    – Walt
    Commented Aug 23, 2017 at 7:39
  • The dementors are not sucking out peoples happiness they are actually sucking out your soul and they are controlled by the ministry of magic. The point of dementors is so then they can remove memory of that person and they forget what they saw, and it can also lead to death.
    – natural
    Commented Aug 23, 2017 at 8:18
  • 3
    Sorry, I don't know where you're getting this information from. Dementors do feed on positive energy, that's basically their food. The Dementor's Kiss that sucks out your soul is different from that and only performed when someone is basically sentenced to death. And AFAIK they don't make people forget what they saw (though de-souled people are basically catatonic, if that's what you meant).
    – Walt
    Commented Aug 23, 2017 at 8:42
  • Neither Harry nor Sirius is permanently affected by the Dementors; Harry interrupts the Dementors while they are still busy with Sirius, and time-traveling Harry intervenes before they can finish with either Sirius or "base timeline" Harry. In both cases, whatever is started by the Dementors is more-or-less reverted by the intervention, leaving them both merely unconscious.
    – Anthony X
    Commented Jun 20, 2020 at 17:00

3 Answers 3


There is no "first timeline"; there's only one timeline, in which Harry has always saved himself from the Dementors.

"I knew I could do it this time," said Harry, "because I'd already done it. . . . Does that make sense?"

Harry Potter and the Prisoner of Azkaban, chapter 21: "Hermione's Secret"

Different writers have different ideas of how time-travel works and how it influences the past or the future. Some of these ideas are of changing timelines and alternate futures, shifting from one into another. The most notable example of these is probably Back to the Future, where changes in the past ripple slowly into the future. People can go back in time to change the past, then witness how these changes affect the future.

In the case of Harry Potter and the Prisoner of Azkaban however, there is a stable timeline that happens to be folded back on itself. The timeline "just is".
There is a loop, but the loop has always been and will always be there. Harry couldn't have decided to do anything differently the second time. The grandfather paradox does not exist in a universe such as this; because no-one has murdered your grandfather before your father was conceived, no-one ever will. This is known as the Novikov self-consistency principle.

Another example of this principle is found in The Terminator, where Kyle Reese has always gone and will always go back in time to impregnate Sarah Connor with John. Note that the sequels in the Terminator franchise muddy the waters and introduce changing timelines and paradoxes, but the first film is consistent.
For a more complicated example, try the stories by Robert A. Heinlein "By His Bootstraps" and "'—All You Zombies—'", the latter of which was adapted into the movie Predestination.

  • True, it's a closed loop, but it seems this entire question is just based on the misconception that the dementors killed Harry, where he was in fact very much alive and still ensouled (he just passed out, like he did on the train).
    – Walt
    Commented Aug 23, 2017 at 9:01
  • @Walt well, what I read in the question is that there supposedly was a timeline in which Harry was killed by the Dementors and that that timeline was altered by his future self. Also, as can be read in the book, the Dementors were on the verge of killing Harry as well.
    – SQB
    Commented Aug 23, 2017 at 9:50
  • 2
    This is a Causal loop or "predestination paradox".
    – Anthony X
    Commented Jun 20, 2020 at 17:02
  • 3
    Another good book example is The Man Who Folded Himself. en.wikipedia.org/wiki/The_Man_Who_Folded_Himself
    – Dean F.
    Commented Jun 21, 2020 at 3:06

I don't think I'll be able to explain the theory of time travel in my answer but it all comes down to Temporal Paradox

Time travel creates a timeline which doesn't have a starting or an ending point (closed loop) which means that had the time turner not been present, Harry would have died.

The cause and effect are both dependent on each other. So, Harry never dies. It's the Harry present in the parallel timeline who produces the Patronus to save himself.


The future Hermione drew Lupin away from the present Harry and Hermione. It is unlikely that Harry would have made it to Sirius in time after dealing with Lupin. Thus Harry is only near Sirus because Harry and Hermione had time traveled.

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