History Main / ConvictionbyCounterfactualClue

->I wouldn't believe him if he ''swore he was lying.''
->- EncyclopediaBrown's best line

-> In short, EncyclopediaBrown needs to...check his encyclopedia. ('''''[[MemeticMutation YEEEEEAAAAHHHH]]''''')
->- This very page.

This is a specific kind of DidNotDoTheResearch, where a pivotal clue in solving a mystery or puzzle is actually erroneous. This is related to ConvictionByContradiction, where a single thing wrong with an alibi is sufficient to prove guilt, but goes further: the key that makes the claim or alibi wrong is ''itself'' factually incorrect. In short, EncyclopediaBrown needs to check his encyclopedia.

** Lampshaded in another episode. Captain Brass decides to reopen an "accidental death" case on the basis that, when he interviewed the bereaved husband, the man said that he [[SuspiciouslySpecificeTense "love''d''"]] his wife, and Brass' experience was that innocent people never referred to their loved ones in the past tense so soon after their death. While this is obviously never used as any kind of evidence (and the accused's lawyer pointed it out,) it did give him the impetus to start a formal criminal investigation.

** Lampshaded in another episode. Captain Brass decides to reopen an "accidental death" case on the basis that, when he interviewed the bereaved husband, the man said that he "love''d''" his wife, and Brass' experience was that innocent people never referred to their loved ones in the past tense so soon after their death. While this is obviously never used as any kind of evidence (and the accused's lawyer pointed it out,) it did give him the impetus to start a formal criminal investigation.

** Another case featured a perp who pretended his pig was kidnapped and said the kidnapper gave him a number where he could contact him to get the pig back. Encyclopedia immediately spots a hole in the perp's story because telephones don't have the letter "Z" on their dials. Originally, this was just ConvictionByContradiction, but now that some modern phones '''do''' have the letter Z on their keypads, it becomes ConvictionByCounterfactualClue. (Though in this case, the keyword "modern" makes this one more {{Technology Marches On}}.)
*** Even before technology marched on, I had an ancient rotary phone in my house, and it had a Z on the 0. Just because Encyclopedia Brown has never seen one doesn't mean they don't exist.

** One involving a sword from The War Between the States (or The American Civil War, to anybody not raised in the South). The guy hawking it claimed it was authentic due to the engraving showing that it was given to another general by Robert E. Lee after the First Battle of Bull Run. The 'correct' answer was that the sword was fake, because nobody would have called it FIRST Bull Run until there had been a Second Bull Run. Given how long it can take to commission, make, retrieve, and engrave a sword, it's entirely possible that the second battle a year later either already happened or was soon coming, necessitating the need for specificity. The sword was still fake, of course but a much sounder reason for doubting the authenticity is that any Southerner, including Robert E. Lee, would have called it the ''Battle of '''Manassas'''''. Throughout the war, the South always called battles by the nearest city while the North named battles after the nearest landmark, Bull Run in this case.) And the best reason of all, is that Robert E. Lee ''wasn't even present'' at First Bull Run/First Manassas, nor was he in a position to present a sword to anybody: he was in command of a force in western Virginia and wouldn't come to command the Army of Northern Virginia until after Johnston was wounded at Seven Pines. The commanding generals of the Confederate forces at First Bull Run were Beauregard and Johnston.
*** I may be mistaken, but I remember reading one where Bugs Meany claimed to have an authentic sword, same as the above, and the evidence that it wasn't authentic was that it was engraved Bull Run instead of Manassas. This troper was unaware that the same mystery was used twice in the series.

** However, it is entirely possible for fraternal twins to look nearly identical, except for slight variations. MaryKateAndAshleyOlson , for instance, are fraternal twins, though they are nearly indistinguishable.

** One solution in Encyclopedia Brown Takes the Cake relied on the fact that the culprit had used glycerin tears that fell from the outside corners of her eyes instead of the inside, thus revealing them to be fake. The problem is people shed outer corner tears all the time.

*** Wrong. It was specifically stated that cheese was lethal to the mice because that mice was of a BREED that could not digest cheese.

**** Kipling's reference is in turn influenced by the Hindus who do believe that snakes drink milk, and do in fact hold such ceremony, particularly if a snake has somehow managed to slither into the house. SoYeah.

NotSoFastBucko: female mules ''can'' be fertile; it's rare, but it happens.

NotSoFastBucko: female mules ''can'' be fertile; it's rare, but it happens; a mule's foal is precisely what the picture to the left depicts.

http://static.tvtropes.org/pmwiki/pub/images/20070725__20070726_A1_CD26MULE~p1.jpg
[[caption-width:350:Go away, Donald Sobol says you're impossible.]]

** An unintentional example: A professional photographer is brought in with mysterious symptoms, and the team immediately eliminates exposure to photo-chemicals because she's an obsessive blogger and would have been using a digital camera. Except, there are thousands of blogs devoted to vinyl records, ham radio, and yes, roll film photography.
*** The woman in question was a slice-of-life diarist; her blog wasn't devoted to any particular hobby.
** In another episode, Dr. House concludes that a woman's husband is a closet crossdresser because that is the only logical conclusion when the woman has a stain on the lapel of her coat.
*** That more accurately falls under SherlockScan.
*** [[SarcasmMode Because women]] ''[[CompletelyMissingThePoint never]]'' [[CompletelyMissingThePoint get stains on their clothing.]]

->I wouldn't believe him if he ''swore he was lying.''
->- EncyclopediaBrown's best line

->"''EncyclopediaBrown? What a hack! To this day, I occasionally reach into my left pocket for my keys with my right hand, just to prove that little brat wrong.''"
-->--ericbop, [[http://www.metafilter.com/73823/What-Book-Got-You-Hooked#2208064 MetaFilter]]

** In one, Haledjian asks for bicarbonate of soda for an upset stomach while in a bakery that produces only fruit pies. The baker says she doesn't have any in stock; this leads the detective to deduce that the bakery must be a front for smuggling, since bicarbonate of soda is baking soda and no real bakery would be without it. But fruit pies don't require baking soda! While there are recipes for fruit fillings and for pie crusts that use baking soda, most don't. [[ConvictionByContradiction There is also the possibility that the baker was unfamiliar with the scientific term for baking soda.]]

[[caption-width:350:Go away, little foal, you're screwing up the clue.]]

* A rather amusing in-story example in ''StarTrek: DeepSpaceNine''. When O'Brien is marked for death by some crazy aliens because he's one of the last people alive who knows how a forbidden superweapon works, they send a bogus video back to the Federation that shows him dying in an accident. His wife realizes something's fishy because he's drinking coffee in the video and she knows he never drinks coffee in the afternoon, when the video was supposedly taken. But then after the plot is foiled and Miles comes back home, she tells him how she knew he was still alive...to which he replies, "I ''always'' drink coffee in the afternoon."