History Main / ClapYourHandsIfYouBelieve

* In ''Crimson'', it's apparently the vampire's religious background that counts, as one man learns when the vampire he's trying to ward off takes his cross away and beats him with it, remarking "My name is Steinman, [[GratuitousYiddish schmuck]]! Why would this work on me?"

* Laurel K. Hamilton's ''Anita Blake'' novels also has this; if the person does not believe in the religious symbol, it will not work. To do with the beliefs of the person against the vampire.

* Wiki/SCPFoundation: this is how [[RealityWarper SCP-239's]] power works. If she believes something to be true, then reality instantly reshapes itself so that her beliefs ''are'' true. The fact that she's an 8-year-old who's aware of her power, but not how it works, makes things... [[MikeNelsonDestroyerOfWorlds problematic for the rest of humanity]]. [[DangerouslyGenreSavvy The Foundation]] tried to convince her that she can only cast spells out of "spellbooks", and although this failed to limit her power, it made her much easier to enroll in [[SecretGovernmentWarehouse "magic school"]].

*** It's clearly stated that "machine spirit" is an artificial intelligence[[hottip:*:it still qualifies as Clap Your Hands, though, because the AI is decidedly NOT powerful enough to pilot the vehicle under ''normal'' circumstances without human crewmembers]], and it is in there, because Tech-priests build their vehicles according to the designs of the {{Precursors}}, without really understanding them. And the civilization of said precursors was destroyed in a civil war with TurnedAgainstTheirMasters AI, that's why creation of an artificial mind is absolutely forbidden for humans of 41 millenia. [[{{Dune}} Does this sound familiar?]]

* In the ''Series/BuffyTheVampireSlayer'' episode "Out of Sight, Out of Mind," a girl is actually rendered invisible because no one ever noticed her (an effect heightened by the school she attends being built over a {{hellmouth}}).

*** It's clearly stated that "machine spirit" is an artifical intelligence, and it is in there, because Tech-priests build their vehicles according to the designs of the {{Precursors}}, without really understanding them. And the civilization of said precursors was destroyed in a civil war with TurnedAgainstTheirMasters AI, that's why creation of an artificial mind is absolutely forbidden for humans of 41 millenia. [[{{Dune}} Does this sound familiar?]]

* The most recent chapter of ''{{Berserk}}'': [[spoiler:People's desire... Fantasia]].

* [[http://notalwaysright.com/ah-managers/1229 An argument]] in NotAlwaysRight involves this trope when a customer seeks a blue camera and no such item exists in stock, so the manager plays along in order to get the customer to buy a red one.

* In the Iron Druid Chronicles, all gods and supernatural entities are created by human belief and thought, including Jesus, the Celtic gods, the Norse gods, Elvis Presley and the comic book version of Thor.

This creates a vicious cycle for non-believers, as magical events are "[[PuffOfLogic disproved]]" in their presence because they don't believe in the first place, thus cementing their disbelief. Particular savvy characters may [[JustIgnoreIt take advantage of this]] by getting others to yell "ImNotAfraidOfYou!"

* In ''BarbieAndTheDiamondCastle'', while a song is the key to the castle, the lyrics indicate that it's belief in the song that actually makes the castle appear. "Believe/Your song will hold the key"

** While only gods need faith, ''belief'' is hugely important to the setting. Youkai (most of the cast) are created from humans ascribing the mysterious to unknown forces, and will fade away if people stop existing in them. Since this has mostly happened, the setting is behind a barrier that causes it to be sort of the opposite of the rest of the world, pulling in things that people don't believe in.

* In ''VideoGame/WorldOfWarcraft'', the ability to use the [[WhiteMagic Light]] comes from the belief of the individual--for this reason, non-sentients who lack free will are unable to use it the conventional way, crises of faith such as disasters can often have the side effect of cutting off individual contact, and people who commit atrocities can still access the Light if they believe they are acting for the greater good.

* The {{Defictionalization}} of ''Webcomic/DresdenCodak''[='=]s ''[[DungeonsAndDragons Dungeons and Discourse]]'' takes place InAWorld like this filled with philosophers. The upshot is that they can do things like use their belief in Cartesian duality to do two moves in one round.

* A rare inversion with a short story ("Obstinate Uncle Otis") about an obstinate Vermonter (and as such, the most obstinate man in the world) whose power of disbelief was legendary, to the point where he could almost convince others that their eyes were tricking them. And then he got struck by lightning, and got a dose of [[YourMindMakesItReal Your Mind Makes It Reality]]. The statue in the town square to the man he hated? Gone after he commented about how "No one would build a statue to a nincompoop like that!" The barn that was obstructing a nice view? Also gone when he commented how "No barn there, boy! Nothing but th' view - finest view in Vermont." His nephew realizes the danger this poses (e.g. his hatred of FranklinRoosevelt, his recent disbelief in stars, etc.). It comes back to bite the elderly man on the ass, though, as he got a bit of EasyAmnesia and believed himself to be a traveling salesman with a different name. "Humph - ain't no such person as Otis Morks."