22 featured an episode in which the resident Big Bad, a Bedouin who is secretly a terrorist, goes back in time to try and drive the Jews away from Palestine and prevent the establishment of the State of Israel in several different points in time: he tries to kill Moses with a bazooka, King David (before his coronation, during his fight with Goliath) with a rifle, and King Solomon with a thrown axe, and to convince Theodor Herzl not to found a Jewish state.
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This trope is not to be confused with "Groundhog Day" Loop. Since many examples of this trope aren't revealed until late in the story, and the existence of a loop can itself be a Spoiler, consider yourself spoiler-warned. For the Recursive Fiction variant of this, see Mutually Fictional. See Retroactive Preparation for one way this can be exploited. If this occurs in a universe where you can Set Right What Once Went Wrong, you most likely have a Timey-Wimey Ball on your hands.
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Compare You Already Changed the Past, which often results in this. Time Loop Trap is when you use a time loop as a way to imprison someone or something. Tricked Out Time is when you "change" the past on purpose to resemble this Close-Enough Timeline is when you partially succeed but decide the end result will suffice. The paradox can be resolved as regards physical objects by noting that such a process would imply the spontaneous creation and subsequent elimination of mass-energy, which violates the 1st Law of Thermodynamics (a principle established 150 years ago to which no exceptions have ever been found).Ī Time Travel-specific subtrope of the Chicken-and-Egg Paradox. The simplest version is the one where the time machine itself is the product of the stable time loop the character sees a version of himself pop into existence with a time machine, hand it to him, and press the button, only to be whisked into the past where he hands it to his past self and presses the button note This exact example is also an Object Paradox, wherein the time machine has no past and no future outside the loop, no origin, and somehow never decays or suffers wear and tear. Eventually, they become so ubiquitous or so common that you, ten, twenty years younger (and thus from a time period where you aren't aware that you would go on to patent and mass-market them after returning to your present), show up and steal one. The classic hypothetical bootstrap paradox is to jump into the future, steal some wondrous gadget, come back to the original time, grab the patent on that gadget and start mass-producing them immediately. Heinlein short story, " By His Bootstraps" (also called the ontological paradox), in which the time loop allows for the existence of information or objects that have no origin. And John Connor.) and the even more mind-squirming "bootstrap paradox" note from the classic Robert A.
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There are two basic types of time loop: a Predestination Paradox, in which knowledge of events in the future, even attempts to evade them, ultimately causes those events to happen (Sorry Oedipus. This trope is actually Older Than Feudalism, since, while time travel is a relatively new concept, prophecy (which is basically information time travel) is not, and Self-Fulfilling Prophecy is the earliest form of stable time loop.