Jack is the face of Boe and has lived for millions (or billions) of years; The Doctor has called him a fixed point in time and space. In the short of 'time crash' the paradox of meeting himself and the Tardis' colliding would destroy a portion of the universe the size of Belgium. The Doctor is a very important part of the universe, but Jack being a "fact" is also very important. What would happen if he time traveled and met himself long enough to create a paradox? Canon if possible


The best answer you will get is that whatever the writers want to happen will happen. There are a veritable crap-ton of paradoxes in Doctor Who (and I've only watched the reboot), and none of them are handled the same way.

In Father's Day:

Rose saves her father, creating a paradox, and then somehow creates a bigger one by touching the baby version of herself. In this case, Reapers came to "fix" the problem.

In A Good Man Goes To War:

We learn that Amy and Rory named their child after their best friend from childhood who was their child. Nothing happens.

In The Hungry Earth:

Amy and Rory wave to each other from a distance, even though that should not be possible since Rory is later erased from time.

And then there's the whole Clara thing. Basically, it is impossible to know, because Doctor Who is invariably inconsistent.

  • 1
    Amy and Rory isn't really a paradox... and in the last portion that happened because that time wasn't a fixed moment... The fix moment was created when the last episode with amy / rory happened... Wibbly Wobbly timey wimey Apr 15 '14 at 18:00
  • In Episode One and Two of The Three Doctor's, (Classic series) the Chancellor comments that the Doctor can't cross his own Time Stream, the First Law of Time forbids him to meet his other selves. The response? Its an Emergency and the first law will be obeyed later...making it alright. It is definitely up to the writers and I think the only "canon" answer you'll receive is as @DoctorWho22 put it, "Wibbly Wobbly timey wimey.."
    – sipp
    Apr 15 '14 at 18:11
  • Generally in the Doctor Who universe, maybe it is not a paradox. But by its base definition, it definitely is a paradox. They use the "fixed point" thing when it's convenient. The timeline has been rebooted a few times now, though, so even the "fixed points" are pointless (ha!). Apr 15 '14 at 18:15
  • Actually from a pretty good User on here named BSW or something he mentioned something called The Web of Time and some other stuff that helps repair paradoxes and stuff like that. Apr 15 '14 at 18:40
  • @DoctorWho22 If you're referring to the middle spoiler, yeah, it's called the bootstrap paradox. There's information that came from nowhere - how did the name come into existence?
    – Izkata
    Apr 15 '14 at 23:15

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