History Main / CannotTellALie

* The main character of ''LiarLiar'' was forced to never tell a lie for one day, to the point he couldn't speak one, write one, or even ask a question that would lead to a lie. Furthermore, he couldn't even conceal the truth by not speaking, which led to most of the film's humor. Also the fact that the "no lying" thing interfered with his occupation as a lawyer.

->[[ThisIsSPARTA "... I! Can't! LIE!"]]

->Truthful, adj: dumb and illiterate
-->-- '''Ambrose Bierce''', ''The Devil's Dictionary''

* In Plaidder's ''Women on Fire'' series, shriia are required to tell the truth at all times; a shriia who tells a lie permanently loses her ability to do her signature type of magic, making magical fire.

* In Plaidder's ''Women on Fire'' series, shriia are required to tell the truth at all times; a shriia who tells a lie permanently loses her ability to do magic.

* In ''[[JaysJourney Jay's Journey]]'', the character of Puff can't lie, but he can definitely omit information. When asked by a villain if he's seen Jay, he manages to twist the conversation into making it seem as though he has no idea who Jay is, [[ExactWords all without lying]]. Specifically, he points out that he's traveling with [[RalphWiggum a complete moron]], which is true, while failing to point out that he's traveling with about a dozen ''other'' humans.

* The guard who tells the truth in ''{{Labyrinth}}''.

* The protagonist of William Sleator's ''Others See Us'' cannot lie, at least until he gains telepathy and realizes everyone around him is lying [[strike:even]] ''especially'' to themselves.

Children are prone to it, being [[ChildrenAreInnocent too innocent]] to think of suppressing the truth -- many truths have been blurted out by unwitting children -- but this can not be relied on; most children outgrow it. (Even if they may warn of it by becoming a BadLiar.)

* In DanAbnett's ''{{Warhammer 40000}} GauntsGhosts'' novel ''Blood Pact'', the witch can not lie. About anything. And foresees the future. And ''babbles'' -- she can not even keep quiet.

** They're also pretty easy to trick.
*** However, most people online who claim to have Aspergers usually are lying as it is the most common self diagnosed condition to excuse {{Jerkass}}ery.

* Yorick (yes, that Yorick) in ''The Skull of Truth'' from Bruce Coville's ''Magic Shop'' series was "blessed" with the inability to lie. This led him to become a jester, the only position in which one could tell the king the truth and get away with it. It was implied this also led to his painful death, after which he became the title skull.

* Due to a cookie-stealing incident as a toddler, Rod Allbright of {{Bruce Coville}}'s ''Aliens Ate My Homework'' cannot lie when asked a direct question. This leads to a number of instances of CassandraTruth once Grakker et al show up, including the titular response to a teacher's asking where his math assignment is.

* Due to a cookie-stealing incident as a toddler, Rod Allbright of Bruce Coville's ''Aliens Ate My Homework'' cannot lie when asked a direct question. This leads to a number of instances of CassandraTruth once Grakker et al show up, including the titular response to a teacher's asking where his math assignment is.

* The [[TheFairFolk faeries]] in ''TheDresdenFiles'' are unable to tell a direct lie, but that doesn't stop them from being shifty, misleading SOB's.
** Throughout most of the series, Harry himself can't tell a lie -- or, he technically can, but he's so shitty at it that everyone can see right through it. He seems to have gained the ability in later books, possibly as a result of [[spoiler: Lasciel's influence]].

* The Aes Sedai from ''{{The Wheel of Time}}''. (Instead, they don't always tell the ''whole'' truth.) This was a magically-created prohibition to make people trust them. Unfortunately, because they refuse to go along with the spirit of the oath, they have such a reputation for bending the truth that people don't believe anything they say on the basis that they must be {{Literal Genie}}ing.
* Actually, Aes Sedai cleave to the Oath rather faithfully -- they literally ''cannot'' speak a lie, even when that lie would save millions of lives. Most Aes Sedai have found ways around the oath by not ''directly'' speaking a lie, but instead using careful phrasing to sneak around the Oath.

* In Tamora Pierce's second and third trilogies of the Tortallen books, one cannot lie around Griffins.

** ''Liar Liar'' is a partial remake of the 1941 Bob Hope comedy ''Nothing But the Truth'', which by contrast has a WillNotTellALie plot: Hope's character bets $10,000 that he can go 24 hours without fibbing.

* In the episode of KimPossible "Truth Hurts", Kim and her comrade Ron are accidentally blasted by a TruthRay, forcing both of them to speak nothing but the truth. HilarityEnsues with Kim being unable to keep her darkest secrets to herself (including what her father said about his bosses in confidence) while Ron surprisingly gains popularity for a brief time due to saying things he never had the guts to say.

* Many people with autism, AspergerSyndrome, or the like have a hard time lying to others. Aspergers can impair the capability to think in 'abstract' concepts, so the concept of deception (which requires the use of abstract thought to effectively construct a believable lie) is often difficult for someone with Asperger's syndrome to grasp. Of course, it varies on a case-by-case basis; people with mild autism/Aspergers can often lie easily, while those with a more sever version often have to enact significant mental preparations before being able to lie, for making things up on the spot is much harder for then.[[/folder]]

** They can't? Why are they used as spymasters? Why did Hawat try to infiltrate the Harkonons?

->Truthful, adj: Dumb and Illiterate

* The main character of ''LiarLiar'' was forced to never tell a lie for one day, to the point he couldn't speak one, write one, or even ask a question that would lead to a lie. Furthermore, he couldn't even conceal the truth by not speaking, which led to most of the film's humor.