You Already Changed the Past: Difference between revisions

This does not necessarily mean that [[You Can't Fight Fate]]. For example, if Bob wanted to go back in time to stop Alice's death, he could simply convince his past self that Alice still died in the future. Following this logic, Alice never dies at all -- andall—and Bob suddenly remembers how several months ago, some "other" Bob came up to him insisting that Alice was going to die of ''something'' and the two of them had to go save her, which they did, so she's still very much alive and well all along. ([[Mind Screw|Do you have a headache yet?]]) Or to avoid the headache and ensuing paradox, Future Bob could go back and save Alice in such a way that Past Bob still thinks that she died.

Note that [['''You Already Changed the Past]]''' implies [[Only One Possible Future]], which is the version of [[You Can't Fight Fate|fatalism]] found in many [[Older Than Feudalism|older]] works, such as Greek Drama, that don't involve time travel.

This trope ''arguably'' makes the most sense when considering time travel from a scientific point of view, see the [[wikipedia:Novikov self-consistency principle|Novikov self-consistency principle]].<ref>Novikov's self-consistency principle was named "the Law of Conservation of History" by [[Larry Niven]] in his short piece "The Theory and Practice of Time Travel," published at least ten years prior to Novikov's work. Of course, [[Larry Niven]] is a [[Science Fiction]] writer, which may explain why [[Sci Fi Ghetto|nobody cares]]. Alternatively, this is an illustration of something called [[wikipedia:Stigler%27s's law of eponymy|Stigler's Law of Eponymy]]: nothing ever gets named after the first person to discover it.</ref> However, the number of time-travel plots that it allows for are extremely limited and the logic gets complicated ''very'' quickly. This, however, also has the side-effect of creating a '[[Functional Magic|self-correcting universe]]' usually by a slew of [[Contrived Coincidence|Contrived Coincidences]]s (ie. if you try to shoot your grandfather the gun will jam; if you try poisoning him he will recover; if you try strangling him you will be overcome; if you wear [[Power Armor]] from the future you will have second thoughts; if you try [[Beyond the Impossible|sending a bomb back through time and detonating it directly inside his chest]] the time machine will break down). This can also lead to a scenario where the ''only'' reason why the past is not changed is because someone else says 'you cannot' and you take his advice. Meaning ''the advice itself'' is a part of the universe's self-correcting nature.

* ''There Will Be Time'' by [[Poul Anderson]]. A substantial number of humans have had the innate ability to [[Time Travel]] since before recorded history (possibly because it was inserted into the genome by future travelers). So little of human history is known exactly, and the book's scope is so great (from Jesus' crucifixion to a far-future [[After the End|postapocalyptic]] revival of civilization--atcivilization—at ''least'') that the inability to change the past comes up only rarely--butrarely—but the protagonist is nearly broken {{spoiler|when his Byzantine wife dies of an illness because other travellers have abducted him to the future}}.

* Douglas Adams' ''[[The Hitchhiker's Guide to the Galaxy]]'' universe works this way. in the second book, ''[[The Hitchhiker's Guide to the Galaxy/The Restaurant At The End of The Universe|The Hitchhikers Guide to The Galaxy]]]]'', while stranded on prehistoric Earth with an exodus' worth of incompetent aliens who are plainly going to begin colonizing, Ford Prefect tells Arthur Dent "This doesn't change the past, this is the past."

* ''The Skull'' by [[Philip K. Dick]]. An assassin is sent back in time to kill the founder of a subversive religion before he gives a famous speech, only to realize that the Founder is himself -- thehimself—the 'miracle' that inspired the religion's creation was him appearing after he'd been killed (he'd arrived at the wrong point in time) thus 'coming back from the dead'. The [[Rousing Speech]] supposedly given by the Founder never actually happened, but was a result of history being embellished after his death.

* The first [[Time Travel]] episode of ''[[Stargate SG-1]]'' ("1969") can be perceived as following this logic, but none of the subsequent [[Time Travel]] episodes in the [[Stargate Verse]] can -- theycan—they all involve alternate timelines instead.

* In the time-traveller role-playing game [[Continuum]], it's an ironclad article of Spanner faith that there is only one universe -- includinguniverse—including one past and one future. A player will meet fellow spanners who've been affected by changes that are in the player's Yet, and you'd better do them or risk Frag.

* In ''[[Ōkami|Okami]]'', the evil Orochi was defeated by a legendary hero named Nagi and a miraculous white wolf, who died in the attempt. The wolf was actually Amaterasu in physical guise, and was resurrected a century later as you, the player character. But then you travel back in time and discover -- youdiscover—you were the one who defeated Orochi then too, and the wolf who died was a different version of you.

* In ''[[Homestuck]]'', only [[Time Master|Dave, the Knight of Time and Aradia, the Maid of Time]] get to go back in time and create [[Alternate Universe|Alternate Universes]]s. Everyone else, no matter how much they've screwed around with the timeline, can only make [[Stable Time Loop|Stable Time Loops]]s, and the Trolls regularly insist that they've already lost the game and that [[You Can't Fight Fate]]. It probably helps that all in-universe timechanging items have built-in failsafes against causing paradoxes.