[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/everybodys_doing_it.jpg]]

->''"They voted for the impossible, and the disastrous possible happened instead."''
-->-- History lesson (talking about ''us''), Creator/RobertAHeinlein, ''Literature/StarshipTroopers''

!!'''[[http://en.wikipedia.org/wiki/Argumentum_ad_populum Appeal To Popularity]]''':
!!! Also called
* Argumentum ad populum ("appeal to the people")
* [[http://www.nizkor.org/features/fallacies/appeal-to-common-practice.html Appeal to Common Practice]]
* [[https://en.wikipedia.org/wiki/Illusory_truth_effect Illusory truth effect]] (when you yourself start succumbing to this)
* QualityByPopularVote
* Any relevant population figure (sixty million Frenchmen, a billion Chinese, etc.)
* CommonKnowledge
* Five Billion Flies (as in "Eat shit, five billion flies can't be wrong!")
* Democratic Fallacy
* [[JustForFun/EverybodyKnowsThat Everyone Knows]]...
* Argumentum ad numerum ("appeal to the numbers")

----

The appeal to popularity is built around the belief that something is true (or false) because a lot of people believe it is. This is fallacious because it confuses whether an idea is ''justified'' with whether it is ''accepted''. Demonstrating widespread support for something only proves it is popular, not that it is true or false.
-->'''Alice:''' Don't you know smoking's bad for you, Bob?\\
'''Bob:''' Bah, it's just propaganda. If it were really bad for you, why would millions of people do it, hm?

This is the standard version; the belief that a large group is incapable of being incorrect. The fallacy can also be inverted, however, with popularity being taken as a sign something is ''wrong'':
-->'''Bob:''' Alice, what's that terrible noise coming out of your speakers? I thought you liked The Band.\\
'''Alice:''' Geez, get with the times! The Band sucked since they [[SellOut sold out]] and went mainstream.

The latter logic is referred to as the "Appeal to Minority," and it underlies the phenomenon of ItsPopularNowItSucks, often used with regard to "edgy" and unconventional media. This also often plays a role in the so-called "Galileo Gambit" or "Galileo Fallacy", which refers to Galileo Galilei's famous persecution for his championing of heliocentrism which challenged the scientific consensus' acceptance of geocentricism, the then-held majority belief in Europe. At the center of this fallacy is the assumption that if the establishment or mainstream opinion find an unpopular belief or a theory ridiculous or even offensive, then that belief or theory must be unfairly persecuted and therefore correct. In short, it can be summed up as "everyone says I am wrong, ''therefore'' I am right." But the matter of fact is that there is no necessary link between being perceived as wrong and actually being correct; if people perceive something to be wrong, there is always a fair chance that it is wrong. As Creator/CarlSagan once put it:
-->''"The fact that some geniuses were laughed at does not imply that all who are laughed at are geniuses. They laughed at Columbus[[note]]Ironically, this itself is an example of the Appeal to Popularity. While the belief that Columbus was fighting against a flat Earth majority is popular even today, the reality was that the Earth's sphere shape was a well known fact in Europe at the time. Columbus' actual opposition was the (correct) belief that the distance he had to sail was so great that he would never make it to Asia. It's only luck that they found another continent and weren't killed by starvation.[[/note]], they laughed at Fulton, they laughed at the Wright brothers. But they also laughed at Bozo the Clown."''

The "silent majority" argument combines this with [[UsefulNotes/LogicalFallacies Begging the Question]], since the lack of existence of popular support is held to show something is so popular nobody bothers to openly declare support for it rather than so unpopular nobody supports it at all.

!!!Examples
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[[folder:Anime and Manga]]
* On ''Manga/SayonaraZetsubouSensei'', various people start talking about some comments they are tired of, [[NeverHeardThatOneBefore because they have heard them a million times]]. Kiri mentions that many people ask if she has an older brother, even though she is an only child, but Kafuka states that something said by a million people cannot be wrong, and "discovers" an older brother for Kiri, simply because it must be true.
[[/folder]]

[[folder:Films -- Animated ]]
* "The Mob Song" from ''WesternAnimation/BeautyAndTheBeast'' includes the line "Here we come, we're fifty strong and fifty Frenchmen can't be wrong".
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[[folder:Films -- Live-Action]]
* ''Film/TheCaseForChrist'': A priest in the film whom Lee interviews states there are many more copies of Gospels than other ancient works and thus implies that the Resurrection happened. This however does not mean they were ''accurate'' (he compares it for instance with ''Literature/TheTrojanCycle'', a work of fiction, having less). At most, it proves that this was really popular (which is obviously true).
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[[folder:Live-Action TV ]]

* On ''Series/HaveIGotNewsForYou'', Louise Bagshaw argued against the Alternative Vote method based on the fact that very few countries use it. This prompted Ian Hislop to point out that much of the world is starving, which is a pretty strong argument against eating.
* The BBC PanelGame ''Series/{{QI}}'' uses this extensively. Points are awarded for "quite interesting" answers, and are taken away for boring ones. If the answer given to a question is one that "everybody knows" and is '''wrong''', a klaxon sounds and ten points are taken away. Both the examples of lemmings and piranhas have been used. Sometimes, however, the obvious answer ''is'' the real answer, which sometimes leads to the panel members phrasing their answers very carefully in case the question is a double bluff.

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[[folder: Radio ]]

* On Radio/TheDebaters, Rebecca Kohler's argument against the Canadian flag: there are more Google results for "why are some farts hot?" than for "why the Canada flag is cool."

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[[folder: Theatre ]]

* For a meta example, the {{Vaudeville}} act of The Cherry Sisters attracted a very large audience. However, this was solely due to BileFascination; they were at the time unanimously considered absolutely dreadful. They, however, were completely oblivious to this fact, and figured that because they were getting such large audiences, they must be absolutely fantastic and dismissed the savage reviews they got as CriticalDissonance.[[note]]Ordinarily, it would be dangerous to list audience opinions of a work as an example of a non-YMMV trope, but in this particular case, [[MissingEpisode those opinions are all that remains of it]]; no recordings of any of their shows survive, and this was so long ago that the only people who could possibly subjectively discuss them are time travelers and ghosts -- none of which, to our knowledge, are TV Tropes users.[[/note]]

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[[folder: Real Life ]]

* Lots of "common knowledge" surrounding various animals survives because of the appeal to popularity.
** Lemmings are a prime example, as well as an ''Appeal to Authority''. If everyone, including random authorities, say that lemmings commit mass suicide.... The truth: [[http://www.abc.net.au/science/news/stories/s979473.htm stoats]]. Not to mention that a famous lemmings-jumping-off-a-cliff video, as filmed by Disney, had people off-camera herding the lemmings over said cliff. This isn't as horrific as it sounds, because [[SquareCubeLaw lemmings fall slowly enough to be unharmed by the fall]], but still dodgy.
** The idea that the adult sizes of fish and reptiles are determined by tank size falls into this.
** As does the idea that birds won't take back hatchlings that smell like humans (fun fact: very few birds actually have a sense of smell acute enough to ''notice'' if their baby smells strange). Similarly, mother rabbits don't kill their babies if a human has touched them. However, they do kill them at times for other reasons.
** This is also why people think piranhas are solely carnivorous. In fact, they're omnivores, and eat primarily insects, seeds, and other fish.

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!!!Looks like this fallacy but is not:
* If the criteria being measured ''is'' popularity, or something that ''can be determined by'' popular vote. For instance, in a list of "best-selling books", the ranking is determined solely by how many copies of each book were sold, and whether it's a good book or not doesn't enter into it. However, claiming that a bestseller is necessarily good is this fallacy.
* If the investigated subject isn't an objectively measurable thing, but a social concept, that is indeed determined by popularity. For example:
** "Gold is valuable because many people pay for it."
** "'Trope' is a word meaning 'storytelling device', because that's how most people use it."
** "Most people would agree that it is improper to talk in the cinema during a movie, so don't do it."
::These concepts, like economical value, linguistic meaning, or etiquette, are things that only exist because a large number of us believe that they exist. While it is ''objectively'' the case that gold has certain physical properties that give it useful applications in, say, electronics, if everyone collectively decided that it was worthless ''anyway'', [[WorthlessYellowRocks its value would indeed disappear]] (this happens at the beginning of the novel ''Galapagos''). It's also happened somewhat already in the world, as gold is no longer used for currency much.