In the end of MIB 3, J's father got killed by Boris when he saved K.

J was watching all of this and had a time machine in his hand. Why didn't he go back a few minutes in time and kill Boris which would have saved his father?

  • 2
    ... Which would have likely created a huge temporal paradox.
    – phantom42
    Jan 27, 2015 at 14:36
  • Because bad writing.
    – Valorum
    Jan 27, 2015 at 14:37
  • Long answer short: even if he did, he didn't. The long one: suppose he did. That creates a diversion in timeline, resulting in a temporal paradox inside that diverted timeline. The paradox causes that diverted line to collapse, so it would never happen. This btw. complies with Novikov's self-consistency principle. Jan 27, 2015 at 15:02
  • @AndrásHummer Of course, the premise of the film is a paradox. Boris is upset that K put him in prison, so he goes back in time to kill K before he captures Boris. So then Boris was never imprisoned, and has no reason to go back in time...
    – KSmarts
    Jan 27, 2015 at 15:16
  • @KSmarts Every time travel movie is a paradox.
    – Elmo
    Jan 27, 2015 at 15:23

1 Answer 1


If he tried, he would have had to un-write everything he'd accomplished up until that point.

The time-travel watch works in a very specific way. You can only "go back" as far as you can fall. And the only high enough place from which it could safely be activated was the rocket tower, which he'd already used.

Using it again would risk going back and undoing his defeat of Boris - and without knowing ahead of time what he'd do during their fight, him beating him, or being able to redo it again, would be much less assured.

On top of that, he was emotionally compromised at the moment, and didn't have the clarity of thought to use time travel appropriately.

Alternately, he may have purposely allowed the event to play out as it was, because saving his father would have irrevocably and dangerously changed himself.

Without losing his father, he wouldn't have been inspired to join a dangerous but highly important job of the NYPD, and he wouldn't have been noticed by the MIB, and he wouldn't have saved the world from the Bugs, and he wouldn't have travelled back in time to stop Boris.

It's possible he could've been recruited anyway, but there's no way he'd know, and no reason to take that chance.

In the words of Spock, the needs of the many outweigh the needs of the few...or the one.

  • 3
    Out of universe you also need to take account of the fact that they were literally re-writing the end of the film as they were filming the start. So.Many.Plotholes.
    – Valorum
    Jan 27, 2015 at 16:17

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