History Main / TemporalMutability

* FengShui revolves around the battle for [[PlaceOfPower Places of Power]] that generate powerful chi. Whoever controls enough Feng Shui sites can change the course of history. The only major catch is that there are only four major "junctures" of time available in the Netherworld, and whatever happens in one juncture, you cannot go back and try to stop what already happened from occurring because [[SanDimasTime time flows normally in each of the junctures]].

[{AC:TabletopGames]]

* This is how Time Travel works in HarryPotter -the trick is to [[NeverTheSelvesShallMeet make sure not to let the not-yet-time-traveled-you see the time-traveled-you]] so that you don't know that you were in the past until the moment you make the decision to time travel. It's said that terrible things happen to those who try to mess with time, but this is never shown on-screen.

* This is how Time Travel works in HarryPotter -the trick is to [[NeverTheSelvesShallMeet make sure not to let the not-yet-time-traveled-you see the time-traveled-you]] [[MindScrew so that the not-yet-time-traveled-you doesn't know it was the time-traveled-you making those changes (or the fact that there ''were'' changes at all) until the not-yet-time-traveled-you decides to time travel]]. It's said that terrible things happen to those who try to mess with time, but this is never shown on-screen.

* This is how Time Travel works in HarryPotter -the trick is to [[NeverTheSelvesShallMeet make sure not to let the not-yet-time-traveled-you see the time-traveled-you]] [[MindScrew so that the not-yet-time-traveled-you doesn't know it was the time-traveled-you making those changes until the not-yet-time-traveled-you decides to time travel]]. It's said that terrible things happen to those who try to mess with time, but this is never shown on-screen.

[[AC:{{Literature}}]]
* Orson Scott Card's ''Pastwatch: The Redemption of Christopher Columbus'' uses the Overwriting the Timeline version of this in order to sabotage Columbus's discovery of the New World and prevent the massacre of Native Americans and the African slave trade.

!!!Type 5: {{For Want Of A Nail}}/{{Butterfly Of Doom}}

As an aside, it's interesting that no one ever seems to be nearly as concerned about time travelers altering the present or the future.

Could you go back and [[SetRightWhatOnceWentWrong save your brother from that fatal car crash]]? Could you [[{{Primer}} punch your boss in the face, then go back and stop yourself]]? [[GodwinsLawOfTimeTravel Could you prevent]] WorldWarII [[GodwinsLawOfTimeTravel by going back to 1930 and killing]] AdolfHitler? [[spoiler:[[HitlersTimeTravelExemptionAct No.]]]]

Could you go back and [[SetRightWhatOnceWentWrong save your brother from that fatal car crash]]? Could you [[{{Primer}} punch your boss in the face, then go back and stop yourself]]? [[GodwinsLawOfTimeTravel Could you prevent]] WorldWarII [[GodwinsLawOfTimeTravel by going back to 1930 and killing]] AdolfHitler? [[supersecretspoiler:[[HitlersTimeTravelExemptionAct No.]]]]

Could you go back and [[SetRightWhatOnceWentWrong save your brother from that fatal car crash]]? Could you [[{{Primer}} punch your boss in the face, then go back and stop yourself]]? Could you prevent WorldWarII by going back to 1930 and killing AdolfHitler? [[supersecretspoiler:[[HitlersTimeTravelExemptionAct No.]]]]

* In ''Dragonriders of Pern'', turns out their crisis (Thread's back, and they only have one Weyr, with nowhere near enough dragons to protect the whole continent) was caused by Lessa's trip back in time to bring the other five Weyrs forward to solve that crisis.

* In his preface for ''The Great Divorce'', [=~C. S. Lewis~=] cited as an inspiration a short story (whose author he could no longer remember) from an American SF magazine about a man who traveled into the past "and there, very properly, found raindrops that would pierce him like bullets and sandwiches that no strength could bite--because, of course, nothing in the past can be altered."

* This is how time travel works in ''[[DragonBall Dragon Ball Z]]'', and the reason killing larval Cell in the main timeline didn't do anything to stop the fully-grown one from an another timeline. Trunks isn't able to prevent his BadFuture from happening, but he can use the power he gained in the past to stop it getting any worse.

* This is how time travel works in ''DragonBallZ'', and the reason killing larval Cell in the main timeline didn't do anything.

* ''StarTrek'': [[spoiler: Time works this way when the Enterprise encounters the Guardian Of Forever.]]

[[AC:TVTropes]]
* See article.

[[AC:TVTropes]]
* See article.

!!!Type 5: Temporal Chaos Theory

[[AC:TVTropes]]
* See ForWantOfANail and ButterflyOfDoom

[[AC:TVTropes]]
* See article.

<<|TimeTravelTropes|>>
<<|SortingAlgorithmOfTropes|>>

->''"When you're dealing with TimeTravel, it's important to establish whose rules are in play: Is this ''TwelveMonkeys'' rules where [[YouCantFightFate you can't change shit]], or ''BackToTheFuture'' rules where you [[SetRightWhatOnceWentWrong can ]] change shit but [[TimeyWimeyBall the timeline is kind of easygoing about it]], or ''{{Terminator}}'' rules where you [[ScrewDestiny can]] change shit, but maybe you [[YouCantFightFate can't]] change shit and then you make a god-awful TV series and Christian Bale yells at someone?"''
-->--'''Ben [[ZeroPunctuation "Yahtzee"]] Croshaw'''

* The time travel of {{Narbonic}} was revealed to be this variant in the "Director's Cut" version currently running. Dave Davenport be3comes unstuck in time, changes his own past, and as a result... becomes someone who never smoked and never had a nicotine addiction.

AKA '''The Sliding Scale Of How Easy It Is For Time Travelers To Change The Past, And Why'''.

->'''Professor Hubert Farnsworth''': You mustn't interfere with the past. Don't do anything that affects anything. Unless it turns out that you were supposed to do it; in which case, for the love of God, don't not do it!
->'''Fry''': Got it.
->'''Professor Hubert Farnsworth''': If, for example, you were to kill your grandfather, you would cease to exist.
->'''Fry''': ''[gasp]'' But existing is basically all I do!
-->-- ''{{Futurama}}'', "Roswell That Ends Well"

->"When you're dealing with TimeTravel, it's important to establish whose rules are in play: Is this ''TwelveMonkeys'' rules where [[YouCantFightFate you can't change shit]], or ''BackToTheFuture'' rules where you '''[[SetRightWhatOnceWentWrong can ]]''' change shit but [[TimeyWimeyBall the timeline is kind of easygoing about it]], or ''{{Terminator}}'' rules where you '''[[ScrewDestiny can]]''' change shit, but maybe you '''[[YouCantFightFate can't]]''' change shit and then you make a god-awful TV series and Christian Bale yells at someone?"
-->--'''Ben ''[[ZeroPunctuation 'Yahtzee']]'' Croshaw'', on [[http://www.escapistmagazine.com/videos/view/zero-punctuation/957-Darkest-of-Days time travel rules]].

* Rip Hunter in ''BoosterGold'' states that the future is in flux but major events in the past are immutable. This strange time scheme hinging on the present is particularly odd when you consider Booster is ''from the future himself'' making the present ''his past'', and Rip spent most of his time in the future ([[spoiler:and is also Booster's future son]]).