History Main / ConvictionByContradiction

** One of the cases involved the apparent suicide of an actor and Haledjian claiming that the note left behind was a fraud written by an English rival of the deceased because the note used "theatre" instead of "theater" and other British spellings. (Because apparently, Americans are only supposed to use American spellings. And no one ''ever'' uses "-re" to refer to stage productions and "-er" to refer to a local multiplex.)This one is particularly egregious: most actors, even American ones, probably ''would'' spell it "theatre", unless they were specifically referring to a movie house. In fact, [[Wiki/TVTropes This Very Wiki]] uses "Theatre" as the namespace for plays, not "Theater".

* [[http://en.wikipedia.org/wiki/Shibboleth Shibboleth]]: A word or custom specific to a particular group or subculture that most outsiders incorrectly identify or pronounce. Getting the name or tense of a local slang, street or landmark can identify someone as a foreigner at best (see the myriad differences in the ways Americans vs. Canadians pronounce words like ''about'') and a German spy at worst (see the Isaac Asimov short story with the Star Spangled Banner). Shibboleths were used in history during ethnic and cultural conflicts as tests to distinguish an outsider trying to conceal themselves and the penalty was typically execution on the spot, as in the [[TropeNamers Word Origin]], the biblical story in the Book of Judges of the execution of Ephraimite refugees who mispronounced "Shibboleth" as "Sibboleth". [[Wiki/{{Wikipedia}} That Other Wiki]] has a full breakdown of the [[http://en.wikipedia.org/wiki/Comparison_of_American_and_British_English subtle differences in American and British English]] that are possible Shibboleths in everyday conversation.

The classic whodunit challenges the viewer to solve the crime along with the detective. Since the viewer isn't a professional, the crime has to be set up so that the solution doesn't rely on skills only a professional criminologist would have. These mysteries often work by reducing the crime to a logic puzzle: you solve the mystery by finding the fact that doesn't fit.

** Haledjian knows someone is the culprit because he claims that a cook in the kitchen was yelling and waving a bright red lobster before he was found murdered. The lobster wasn't supposed to be cooked yet, and lobsters are only red when they're cooked. However, that detail wouldn't be impossible, just weird. The back cover of a regular mystery might well say something like, "Why was the cook waving an already-cooked lobster before he was killed?" Another question is, was the cook yelling ''because'' the lobster had already been cooked?

* Some examples from ''Literature/EncyclopediaBrown'' author Donald J. Sobol's less famous solve-it-yourself series for adults, ''Literature/TwoMinuteMysteries'', starring Detective (no first name given) Haledjian:

* Book 7, chapter 10 ("The Case of the Foot Warmer"): A young inventor named Melvin is accused of smuggling two BB riffles out of a toy shop, but the kid claims he was just wearing his new invention at the time. Encyclopedia realizes the inventor is lying when the toy shop owner remembers Melvin bent down to pick up a baby: Melvin's invention prevented him from bending down, so he couldn't be wearing the foot warmer at the time.

* Book 7 ("The Case of the Foot Warmer"): A young inventor named Melvin is accused of smuggling two BB riffles out of a toy shop, but the kid claims he was just wearing his new invention at the time. Encyclopedia realizes the inventor is lying when the toy shop owner remembers Melvin bent down to pick a baby: Melvin's invention prevented him from bending down!

* A man tries to claim insurance money on a painting he's reported stolen. His story goes that while shaving after a shower, he saw reflected in the mirror a man stalking away with the painting. Encyclopedia explains that the claim is a fraud because a mirror would be foggy after a shower and so the man wouldn't have been able to see anything. (Never mind that it only takes a second to wipe away condensation, something people often do when they ''need to shave''. Or cold showers, or how movement and shapes are still discernible through a foggy mirror. Or how some people use a fan or leave the bathroom door open specifically so that the mirror doesn't fog up in the first place. And finally, as ScienceMarchesOn, fog-free mirrors now exist.)
* One case was solved because the culprit claimed their wobbly table was knocked and various possessions spilled on the floor. EB points out that the table was three-legged, and that such tables can't tilt. Three-legged tables won't be wobbly even if the legs are different lengths. However, if the table was on a slant to begin with, jostling it might very well knock it over, or at least knock the items off.

* Book 1, chapter 9 ("The Case of the Missing Roller Skates"): Combining with "INeverSaidItWasPoison", Encyclopedia is at the dentist's and has his roller skates stolen. The perp [[INeverSaidItWasPoison manages to identify himself]] because he never even heard of him (Dr. Vivian) until Brown mentioned him, and he wasn't at the dentist's because "I had a sprained wrist, not a toothache". Because he couldn't have found out that Vivian was a dentist through other means (such as being close enough to notice that this is a dentist's office), or simply assumed "Vivian" was male since Vivian is a gender-neutral name. (In fact, it's only been seen as a feminine name [[NewerThanTheyThink Since around the 40s or 50s]].)

Book 9, chapter 4 ("The Case of the Headless Runner"): The perp claimed to have been awoken by a thunderclap, then saw the crime during a lightning flash. E Brown knew that the perp was lying, since in real life, thunder follows lightning, not the other way around. Of course, it's inconceivable that there would be more than one lightning flash during the course of a thunderstorm.

* Book 1, chapter 5 ("The Case of the Bank Robber"): A blind man is the only witness to a crime; a perp fleeing the scene with a bag of cash crashed into him, and it is thought that the man might have felt his face well enough to identify him if he felt it again. Turns out the blind man is not blind, and was in on it the whole time: he swapped bags with the thief when they collided. How does Encyclopedia prove this? When he visited the man in his hotel room, the lights were on and there was a newspaper on the table despite the man claiming he hadn't had visitors in "a long time". Because no hotel in the world offers complementary newspapers that they put in your room. And they ''never'' have the lights on when you arrive. And a blind man would totally notice if they were on, and turn them off. This is a lesser example, however. Once Brown figures out what happened getting a doctor to confirm that the guy can see shouldn't be too hard. Overlaps with ConvictionByCounterfactualClue since most blind people aren't completely blind and it is entirely possible for one to leave the lights on and read a newspaper.

** Still another case hinged on the detective's belief that a real resident of San Francisco would never ever refer to the city as "Frisco." While it's true that residents of the city traditionally hate that nickname, it's not exactly an enforced law, at least not since [[http://en.wikipedia.org/wiki/Emperor_Norton Emperor Norton]] died.

* A boy blows his fake alibi by tracing a shirt pocket on the wrong side of his chest. This is perfectly understandable, since everyone is accustomed to seeing images of themselves in the mirror, where left and right are flipped.

* Still another case hinged on the detective's belief that a real resident of San Francisco would never ever refer to the city as "Frisco." While it's true that residents of the city traditionally hate that nickname, it's not exactly an enforced law, at least not since [[http://en.wikipedia.org/wiki/Emperor_Norton Emperor Norton]] died.
* In one story, a man claimed an item of his had been stolen during a thunderstorm. The house was dark because the power was out. He was awoken by a thunderclap, then saw the burglar ''in the lightning flash that followed''. E Brown knew that the man was lying (he had actually stolen his own property for the insurance money, then made up the story), since in real life, thunder follows lightning, not the other way around. Of course, it's inconceivable that there would be ''more than one lightning flash'' during the course of a thunderstorm.

* Parodied in ''WesternAnimation/MoralOrel'', in which Orel starts a detective agency. There are two suspects when the contents of Reverend Putty's collection basket is stolen: Joe the DevilInPlainSight, and a clearly-innocent Susie. Orel ignores the expensive ice cream Joe has bought, and the fact Susie wasn't even in church at the time, and bases his conclusions on which Commandments they broke (or didn't break): Joe honored the Commandment about keeping the Sabbath Holy by refusing to cut his grandfather's lawn, while Susie broke the Commandment of honoring her parents by volunteering at a retirement center instead of going to church like she was told. If she broke one Commandment, then [[JumpingOffTheSlipperySlope surely she would be the sort of person to break "Thou shalt not steal".]]

* Parodied in ''WesternAnimation/MoralOrel'', in which Orel starts a detective agency. There are two suspects when the contents of Reverend Putty's collection basket is stolen: Joe the DevilInPlainSight, and a clearly-innocent Susie. Orel ignores the expensive ice cream Joe has bought, and the fact Susie wasn't even in church at the time, and bases his conclusions on which Commandments they broke (or didn't break): Joe honored the Commandment about keeping the Sabbath Holy by refusing to cut his grandfather's lawn, while Susie broke the Commandment of honoring her parents by volunteering at a retirement center instead of going to church like she was told. If she broke one Commandment, then [[JumpingOffTheSlipperySlope surely she would be the sort of person to break "Thou shalt not steal".]]

* An episode of ''WesternAnimation/TheRaccoons'' titled "Simon Says" involves an aardvark claiming to be Cyril Sneer's long lost brother, Simon, who wants his share of the Sneer fortune. Simon claims to have been trapped on a desert island for a long time and eventually built a boat to get himself off the island. Bert however is suspicious and spends the episode trying to expose Simon as a fraud. [[spoiler: Bert succeeds and when asked what made him wary, it's explained that during their initial handshake, Bert noticed Simon's hands were very smooth. If he had worked on building his own boat, his hands should have been rough and callused.]]
* Zigzagged in "False Alarm," an episode of ''WesternAnimation/HeyArnold''. [[ButtMonkey Eugene]] is accused of pulling a fire alarm, and a jury of students--consisting of Arnold, Gerald, Phoebe, Helga, Harold, and Curly--is called to find him guilty. Arnold is the lone holdout (much of the episode parodies ''Film/TwelveAngryMen''), and eventually uses this trope to prove his point: one of the pieces of evidence is a pencil from Wankyland, an amusement park, found near the broom closet where Eugene was discovered hiding. Arnold argues that Eugene ''couldn't'' own a Wankyland pencil, as he was banned from the park for [[NoodleIncident somehow ruining a Thanksgiving Day parade]] the previous year. It's never suggested that Eugene might have had the pencil from ''before'' being banned (Arnold himself simply says that it's "not ''likely'' that he'd have one"), but it turns out to be a moot point, as the real culprit--Curly--reveals himself once Arnold makes this argument.

* One riddle involves having to figure out why a suspect was let go. It turns out he was deaf, and thus couldn't understand his {{Miranda rights}} when read to him. Aside from the fact that many deaf individuals know how to lip read, the whole idea hinges on {{Hollywood law}}, as no mention of him confessing is made. Obviously if he confessed the police would quickly have learned of his deafness and made sure his rights were understood, giving them in writing or through a sign language translator if necessary. A deaf person will most likely tell the police immediately they're deaf to facilitate this, if they didn't notice already.

** In "Mr. Monk and the Birds and the Bees", sports agent Rob Sherman has made it look like he shot and killed a burglar who apparently broke into his house and killed his wife (the trick is that he shot the "burglar" with a semi-automatic and the wife with a revolver, then planted the revolver on the "burglar", making great use of a DeceasedFallGuyGambit). Monk suspects Sherman is lying because he gave the alleged invader one single shot, instead of unloading his gun on him in a fit of rage and fear like someone would do in a situation like that. Further evidence is that the "burglar" owned a .22 caliber (which he left at home), the revolver found on the body was a .38 caliber, and there is no .38 caliber ammunition in his apartment.

** In ''Literature/AfterTheFuneral'', Poirot deduces that [[spoiler: the "murder victim" who showed up at the titular funeral was actually the murderer ''disguised'' as her. The two clues he notices? One: when the murderer later comes to the house where the repast was held supposedly for the first time, she comments on a vase of flowers that she could have only seen if she'd been there before. Two: the murder victim had a habit of twisting her head to one side when she asked probing questions, but the imposter had practiced her mimicry in a mirror and thus [[ImposterForgotOneDetail turned her head in the opposite direction]]]]. That's enough to start him on a path toward the real motive behind the murder.

** The suspect claims it is his first time in the victim's house, but when a doorbell rings, he knows to answer the back door. (Because nobody can ''hear'' where a given sound is coming from, and it's certainly not that front doors often always have a double ring (ding-dong) and back doors a single ring (ding). And because there's no way at all the suspect could be from, live in, or have lived in a town where it's customary to do everything at the back door except on special occasions.)

* [[PlayingWithATrope Played with]] in ''Manga/CaseClosed'' - the detectives will sometimes find an inconsistency and then ask the culprit to explain. Not using this as specific evidence that they are guilty, but to force them to come clean.
** A notable example of forcing the culprit to come clean after being caught in a misstep is in one case in which a person is murdered in a cabin during a blizzard. The culprit's alibi is that they were buying snacks, but did not buy ice cream because they were "sold out". And why would anyone be sold out of ice cream in a blizzard? The culprit could have just as easily lied and said she didn't get ice cream because it would melt due to it being a blizzard (Thus requiring the car to have the heat on, and the trip up being slowed.)

* Book 17, chapter 1 ("The Case of the Masked Robber"): Encyclopedia's dad described a case to him after the fact that involved a professional tennis instructor who reported that a set of ivory screens had been stolen that morning. He saw the thief's face; it could be either of two identical twins -- one who worked as a cashier and one who played tennis. Encyclopedia figures out that the victim was just lying so he could get insurance money for the screens, because the crook was wearing a T-shirt, and if the tennis player had been the culprit, one arm would be more developed, while equal arms would incriminate the cashier. This assumes that the cashier had the presence of mind to make such an astute observation, and also assumes the [[ConvictionByCounterfactualClue untrue "fact"]] that all tennis players have asymmetrical arms.

* Book 16, chapter 10 ("The Case of the Mysterious Handprints"): Two precious ivory bookends belonging to a former circus owner are stolen when two of the man's friends are visiting. Encyclopedia and his father find strange handprints in the beach near the circus owner's house, and so suspicion falls on one of the visitors, a crippled acrobat, because the only way he could have walked was on his hands. Encyclopedia, however, insists that the thief is in fact the other visitor, a former bareback rider, because she said her leather gloves were missing, and "no one brings leather gloves to a seaside town in the summer." (Again, an assumption of concrete fact out of a generalization, but even so she could have brought the gloves for a legitimate reason like playing golf, as driving gloves, or even riding a horse. Or maybe she packed them by accident.)

* Book 12, chapter 6 ("The Case of the Old Calendars"): A note about who was supposed to receive some calendars couldn't have been written by a math teacher because it says "divide the calendars by 1/2", which would actually be multiplying by 2, because math teachers never make mistakes in grammar or use common English-language phrasing fallacies outside of the context of the classroom.

* Deconstructed in an episode of ''Series/StarTrekTheNextGeneration'' where hearings were being held of Starfleet officers out of fear that there was a Romulan spy on board the Enterprise. One officer questioned was revealed to have falsified some personal information claiming he had a Vulcan grandfather, when the grandfather was actually Romulan. The witch-hunter who started the hearings took that alone as just-about-proof that he was the spy they were searching for, but Picard and a few other ''Enterprise'' officers recognized that while the lie is cause for disciplinary action in and of itself [[note]]not for the ''content'' of the lie, but for lying on his official record at all[[/note]], it didn't prove that he was involved with any kind of deeper conspiracy.

* Deconstructed in an episode of ''Series/StarTrekTheNextGeneration'' where hearings were being held of Starfleet officers out of fear that there was a Romulan spy on board the Enterprise. One officer questioned was revealed to have falsified some personal information claiming he had a Vulcan grandfather, when the grandfather was actually Romulan. The witch-hunter who started the hearings took that alone as just-about-proof that he was the spy they were searching for, but Picard and a few other ''Enterprise'' officers recognized that while the lie is cause for disciplinary action in and of itself, it didn't prove that he was involved with any kind of deeper conspiracy.

* ''Series/TwentyFour'': in the first season, Jack is [[JackBauerInterrogationTechnique interrogating]] a businessman in his limo, trying to prove he isn't who he says he is while connecting him with the conspirators in the day's events. His initial "contradictions" are fairly shaky, such as why is an honest businessman is meeting someone in a garage unless the person was a criminal. The real clincher that he's a phony is when he tries to attack Jack with a knife he keeps in a secret compartment of the limo; why would an ordinary businessman who can presumably afford security carry a blade in his car unless the guy he was meeting with was a criminal? Perhaps the guy's just CrazyPrepared? In this case, it may have been as much about the knife itself as the fact that it was a specialized blade: a Microtech HALO that's something only a KnifeNut would procure.

** Cole asks the husband of a murder victim what size shoes he wears. The husband responds by saying, "size nines, I think". The player needs to press "lie", to prompt Cole to accuse the husband of purposefully lying to him, then present the work shoes Cole found in his bedroom, which are size eights. While not on the level of InsaneTrollLogic it's still a ridiculous assumption to make for a while multitude of reasons, particularly since it's only a single shoe size in difference.