In the movie Predestination:

Jane is born as a result of John and Jane having sex. John and Jane are the same people from different timeline.

Is Jane's birth because of a predestination paradox or bootstrap paradox?

which one is it?

  • I'm confused. In your previous question you asserted that "the movie deals entirely with Predestination Paradox." Now you suddenly don't know what sort of paradox it was? – phantom42 Mar 5 '15 at 6:19
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    You'll first have to give us exact definitions of what you mean by "predestination paradox" and "bootstrap paradox". And in fact, as you work through the process of defining your terms, you'll probably then be able to answer your own question. – Mike Scott Mar 5 '15 at 6:21
  • @phantom42, Yes I've edited the previous question too. In the discussion a point came up about a particular event - the birth. While the movie might deal with the predestination paradox... im more interested in knowing about the birth event - predestination or bootstrap. – Gomes Mar 5 '15 at 6:34
  • @MikeScott, predestination paradox deals with a closed time loop. An event of the future that triggers an event of the past which in turn triggers the event of the future. Bootstrap is an object which is created in such a closed loop which has no origin. In the movie - Jane is an object and her birth is an event. So is Jane the result of a predestination or bootstrap paradox, clear now? If yes, then I can edit my question. – Gomes Mar 5 '15 at 6:36
  • "Bootstrap is an object which is created in such a closed loop which has no origin. In the movie - Jane " Is this a typo/incomplete thought? Because it reads like you're saying Jane is the result of a bootstrap paradox - answering your own question. – phantom42 Mar 5 '15 at 6:40


As noted by Michael Edenfield in his answer to a related question, the bootstrap and predestination paradoxes are very closely related. It's not unusual for a work of time travel fiction to involve both simultaneously, and this one does.

The case for a Bootstrap Paradox

The bootstrap paradox is when an object or piece of information has no "source"; a perfect example is provided on the Wikipedia page:

An old woman gives a young man a watch; the young man then goes back in time and hands the watch to a young woman; she later grows into the older woman who hands the watch to him. The watch therefore has no point of origin1.

The watch never "begins" anywhere; there's no point in its timeline where it can be manufactured or assembled. And if it's never assembled, how can it exist? This is the core of the paradox.

In Predestination, Jane's genetic code is the subject of the Bootstrap Paradox. Looking at Jane's timeline, this becomes clear:

In humans (normal humans, anyway), our genetic material comes from our parents, which comes from their parents, and so on, all the way back to Y-chromosonal Adam and Mitochondrial Eve. This is not true with Jane: because she is her own father and mother, she is also her own grandmother and grandfather, and so on. Her DNA never makes it back to Adam and Eve.

Jane's genetic code is fundamentally the same as the watch in the example above; it just goes around and around it's own timeline, with no "start".

This is exactly a Bootstrap Paradox.

The case for a Predestination Paradox

The difference between a Bootstrap and Predestination paradox is sometimes hard to wrap your head around, but Michael Edenfield does a good job in the above-linked answer, so I'm just going to quote him:

[A]n event in the past creates a chain of events that leads to some second event in the future, but that second event is ultimately the cause of the first event.

How this works is hard to explain in words, so I created a diagram. The diagram shows only a few of the events of the film, but it summarizes the closed loop I wanted to illustrate:

Predestination's Predestination paradox

As you can see from the above (spoiler-hidden) diagram, the events of Jane's life form an inevitably closed loop: her existence is dependent on choices she makes after she is born, and because of the unique circumstances of her birth2, she inevitably ends up making those choices. Paradox.

It's technically possible to get around this problem by introducing multiple timelines, but this is not the case in Predestination.

The Temporal Agent renders the Predestination paradox absolute, because he remembers all of the events he's causing - the loop I described above must have happened, because otherwise the existence of the Temporal Agent (and his memories) is impossible.

1 I'm ignoring the complication that the watch would get progressively older and older each time it passed through the loop, until it eventually broke. This issue is sidestepped when you're dealing with information, but tangible objects make better examples

2 I left those out of the diagram for brevity. The full interconnectedness of Jane's timeline is way too complicated to summarize

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  • +1. Of course, there is a slight possibility that Jane's first birth was accidental and may have had a different birth parents. However, all subsequent births were controlled and directed. – TenaliRaman Mar 7 '15 at 3:03
  • @TenaliRaman I'd thought about that, but I couldn't think of a way to make that consistent with the existence of the Temporal Agent. If the Agent remembers all of the events of the film (I'm trying to keep this comment spoiler-light), then I can't imagine any other possible origin for Jane. But then I also haven't actually seen the movie, so it may be possible – Jason Baker Mar 7 '15 at 3:09
  • The movie doesn't give much of a clue on the first birth, so it is all up to speculation. Of course, your assumption that the natural origin of Jane's birth was herself is also the most acceptable because that's what makes her uniquely special. – TenaliRaman Mar 7 '15 at 3:19
  • @JasonBaker, thank you for that... – Gomes Mar 9 '15 at 7:25
  • @TenaliRaman - When you say "first birth" and "subsequent births" it sounds like you are assuming some multiple timeline model (or a timeline which 'changes' in some kind of meta-time dimension), but I think the movie makes more sense in terms of the single fixed timeline theory (where time travel is bound by the Novikov self-consistency principle), in which case there would only have ever been a single birth of John/Jane in the timeline. – Hypnosifl Mar 18 '15 at 3:24

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