Talk:Predestination paradox

Contents

1 Time-machine schematics paradox 2 Voyager reference 3 Wrath of Khan scenario 4 Back to the Future 5 Predestination Paradox vs. Self-fulfilling Prophecy

Time-machine schematics paradox

I've heard the following paradox somewhere, but I don't know the name of it or who invented it.

A man designs a time machine from some schematics that were given to him. After testing the machine, the man travels back in time to give the schematics to himself on his 30th birthday. The man appears in front of his self and explains to him that he shouldn't worry about designing the time machine, as he has done it in the future and will give the schematics to his own self. The man's self receives the schematics and start building the time machine. Time passes until he finally completes it, test it, and remembers that he has to travel back in time on his 30th birthday to give the schematics to himself. He does and a time loop is created. The paradox is: who, where and when did the schematics were created?

So, in which category should this paradox be included?

--Maio 07:06, Jan 19, 2004 (UTC)

It's a staple of science fiction as well - see By His Bootstraps by Robert Heinlein for an example. Other examples include a time traveller going back in time and giving William Shakespeare a set of his complete works. It's a variation on the predestination paradox, but more properly should be termed an ontological paradox, since it deals with the origins of things. I've added it to the main entry with that clarification. --khaosworks 07:38, 30 Jun 2004 (UTC)

There's another story by Asimov, completely around this theme. It involves going through a time loop to ensure time travel remains in action, and ends by a man who chooses to not follow the loop, and at that very moment the time-travelling structure dissapears. Someone who has an idea about what novel it is?

Found it: 'The end of eternity'

Voyager reference

Unless I'm very much mistaken the 30 years Braxton referenced was about the "Future's End" double episode and had already happened before the events of the episode "Relativity". As such I removed the last sentence of that paragraph. -- 203.79.112.66 13:18, 22 Jul 2004 (UTC)

Wrath of Khan scenario

I wonder if the Star Trek II: The Wrath of Khan scenario ("...the antique eyeglasses Captain Kirk receives from Doctor McCoy in Star Trek II: The Wrath of Khan, which Kirk leaves in the 20th Century in Star Trek IV: The Voyage Home so it can be eventually bought by McCoy") might be complicated by the fact that the glasses are intact when McCoy gives them to Kirk in the 23rd century, but one of the lenses is cracked when Kirk later pawns them in the 20th century. Assuming they're the same glasses, then they must be repaired sometime before McCoy buys them for Kirk, and with each repetition of this loop they age by another 300 years. Most of the other examples given involve the origins of information or genetic code (i.e. people), both of which can be reproduced easily. --Arteitle 05:45, Nov 6, 2004 (UTC)

To be frank, there is no reason to believe that the glasses will be the ones that McCoy buys in future aside from Kirk's remark. It's one of those things that should not be examined too closely lest it falls apart. -khaosworks 07:59, 6 Nov 2004 (UTC)

Back to the Future

I fail to see how Back to the Future falls in this category, since the 1985 Marty returns to is definately not the 1985 he left. -- ckape (talk) 07:22, 2005 Jan 19 (UTC)

I agree that it's not a "pure" presdestination paradox, insofar as Marty's time trip is not predestined to happen, but that he creates a grandfather paradox which he then has to correct by substituting a predestination paradox for it, thereby altering his own history, but the end result is almost the same. I've rewritten the paragraph slightly to account for this. -khaosworks 15:23, 19 Jan 2005 (UTC)

Predestination Paradox vs. Self-fulfilling Prophecy

In some respects, predestination paradox and self-fulfilling prophecy can just be a case of to-MAY-to and to-MAH-to. From the perspective of a paradox, receiving information about an event from the future that causes a series of events that culminate in the said event if and only if the information was sent back in time in the first place is a predestination paradox. DonQuixote 17:51, 1 Jun 2005 (UTC)