History Main / ConverseError

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* In ''WesternAnimation/AmericanDad'', Stan sinks his entire savings to build a rocket for Steve to win a contest.

--> Stan: You gotta spend money to make money.\\
Francine: But you didn't make any money!\\
Stan: So logically, I didn't spend any money! [[NoFourthWall *waves at the camera*]] Goodnight everybody!

* In ''Series/YesPrimeMinister'', Sir Humphrey Appleby explains the fallacy and how foolishly people can fall for it. He demonstrates the illogic of the fallacy by saying:

--> All cats have four legs.\\
My dog has four legs.\\
Therefore my dog is a cat!

* On the soundtrack album of ''Film/MontyPythonAndTheHolyGrail,'' a logician sorting out the movie's witch burning scene goes off on a tangent, stating that "given the premise 'all fish live underwater' and 'all mackerel are fish,' my wife concludes not that all mackerel live underwater but that [[InsaneTrollLogic if she buys kippers it will not rain, or that trout live in trees, or even that I do not love her anymore."]]

--> Ducks float.
--> This woman shares a notable quality (weight) with a duck.
--> Therefore, this woman must float.
--> Wood floats.
--> Therefore, this floating woman must be made of wood.
--> Things made from wood burn.
--> Witches burn.
--> Therefore, this woman made of wood must be a witch!

!!! Looks like this fallacy but is not:

I must provisionally reject A or modify it to account for D, then continue to seek new information and propose new possible explanations.\\

[[quoteright:347:http://static.tvtropes.org/pmwiki/pub/images/converse_error350_9795.jpg]]
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* In ''YesPrimeMinister'', Sir Humphrey Appleby explains the fallacy and how foolishly people can fall for it. He demonstrates the illogic of the fallacy by saying:

Has nothing to do with shoes (despite what TheAdvertisementServer thinks).

* On the soundtrack album of ''MontyPythonAndTheHolyGrail,'' a logician sorting out the movie's witch burning scene goes off on a tangent, stating that "given the premise 'all fish live underwater' and 'all mackerel are fish,' my wife concludes not that all mackerel live underwater but that [[InsaneTrollLogic if she buys kippers it will not rain, or that trout live in trees, or even that I do not love her anymore."]]

*** A example to compare with the Ferrari one above would be: I clocked my car at 121 mph, therefore it is likely to be a high-performance car (i.e. Ferrari, Bugatti, Lamborghini, etc...) rather than an average family car.

I clocked my car at 101 miles per hour.\\

* On the soundtrack album of ''MontyPythonAndTheHolyGrail,'' a logician sorting out the movie's witch burning scene goes off on a tangent, stating that "given the premise 'all fish live underwater' and 'all mackerel are fish,' my wife conclude not that all mackerel live underwater but that [[InsaneTrollLogic if she buys kippers it will not rain, or that trout live in trees, or even that I do not love her anymore."]]

*** A example to compare with the Ferrari one above would be: I clocked my car at 101 mph, therefore it is likely to be a high range car (i.e. Ferrari, Bugatti, Lamborghini, etc...) rather than an average model.

I must provisionally reject A or modify it to account for D, then continue to seek new information and propose new possible explanations.\\

On the soundtrack album of ''MontyPythonAndTheHolyGrail,'' a locigian sorting out the movie's witch burning scene goes off on a tangent, stating that "given the premise 'all fish live underwater' and 'all mackerel are fish,' my wife conclude not that all mackerel live underwater but that [[InsaneTrollLogic if she buys kippers it will not rain, or that trout live in trees, or even that I do not love her anymore."]]

* In ''YesPrimeMinister''', Sir Humphrey Appleby explains the fallacy and how foolishly people can fall for it. He demonstrates the illogic of the fallacy by saying:

* A current argument made by Obama supporters against conservatives.
-->Racists who don't like black people oppose Obama's presidency
-->Bob opposes Obama's presidency
-->Therefore Bob is a racist.
** This is not to say that you can't make an argument that someone that opposes Obama is a racist, but it [[FallacyFallacy does not follow automatically]] from being opposed to his presidency and/or policies.
** A similar argument from Obama detractors is that anyone who voted for Obama did so only for affirmative action's sake, rather than because they believed Obama was a strong candidate on his own merit.

** This is not to say that you can't make an argument that someone that opposes Obama is a racist, but it does not follow automatically from being opposed to his presidency and/or policies.

All cats have four legs.
My dog has four legs.
Therefore my dog is a cat!

** I opposed Obama because I was for Hillary, [[HypocriticalHumor you sexist!]]

:: This is popular in conspiracy theories. Here the fallacy is fairly obvious; given the evidence, the car ''might'' be a Ferrari, but it might also be a Bugatti, Lamborghini, or any other model of performance car, since the ability to travel that fast is not unique to Ferraris. Note that while this may appear to call all hypothesis / evidence experiments fallacious, they are based on additional evaluations of the likelihood of ''other'' theories, thus establishing that A ''is'' a likely cause of B.

--> A is the best explanation for B, so I will claim "A is the most likely explanation."\\
--> If A, then C.\\
--> Therefore, if not C, not A (valid contrapositive).\\
--> Is C true? Yes? I will increase my confidence that A is the correct explanation.\\
--> If A, then D.\\
--> Not D!\\
--> I must provisionally reject A or modify it to account for D, then continue to seek new information and propose new possible explanations.\\

** I opposed Obama because I'm for Hillary, [[HypocriticalHumor you sexist!]]

* In ''AmericanDad'', Stan sinks his entire savings to build a rocket for Steve to win a contest.

:: Note that, by the [[http://en.wikipedia.org/wiki/Contrapositive contrapositive]] rule, these two fallacies are equivalent. For example, you could replace "If a person is wearing a hat, they have a head" by the logically identical statement "If a person has no head, they aren't wearing a hat" to turn the first example of denying the antecedent into an example of affirming the consequent.

Therefore, A.

* Sherlock Holmes, of all people, used this a lot.

:: Note that, by the [[http://en.wikipedia.org/wiki/Contrapositive contrapositive]] rule, these two fallacies are equivalent. For example, you could replace "If a person is wearing a hat, they have a head" by the logically identical statement "If a person has no head, they aren't wearing a hat" to turn the first example of denying the antecedent into an example of affirming the consequent.

Has nothing to do with shoes (despite what the AdvertisementServer thinks).