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alt title(s): Logical Fallacy 
I live by syllogisms: God is love. Love is blind. Stevie Wonder is blind. Therefore, Stevie Wonder is God. I don't know what I'd believe in if it wasn't for that.
Logic, my dear Zoe, merely enables one to be wrong with authority.
Danger ahead: A lot of the examples on this page fail logic forever.
Logic. Every story needs it, unless you just want a series of unconnected images and no plot to speak of.
But the problem is, logic requires writers to think pretty hard about what they write, and not all writers have time (or intellect) for this. As such, they take shortcuts which at best can lead to Plot Holes, and at worst undermines the entire story. Most Straw Vulcans suffer from this, following the author's flawed view of what is logical. (For one thing, much of the time they say "logic" when they mean "rationality"; they aren't the same thing at all. But even when they get that much right, they still frequently fall into the errors listed below, or have their "logical" characters do so.)
Fallacies are common errors in logic. By strict standards, fallacies don't address the truth of the premises or syllogism; they only address to the validity of the logic, and as the final section of this page demonstrates, "truth" and "validity" are not the same thing when speaking of formal logic.
Other times, writers deliberately invoke this, to make their characters more human, or to explain why they didn't take the best choice.
For examples of writers intentionally or unintentionally failing logic forever, see Insane Troll Logic.
Not to be confused with Logic Bomb.
The fallacies and examples thereof.
Also Called:
As the alternate names indicate, this is presenting a problem as having only two solutions, for example, telling someone "either you stop eating ice cream or you will get fat" — This ignores that there are other actions one can take besides stopping eating ice cream to avoid weight gain. Commonly invoked to set up a Friend Or Idol Decision or The Sadistic Choice. Subverted whenever a character Takes A Third Option.
- A common version of this is to assume that only the extreme ends of a scale are possible, without considering intermediate positions. For example "You're either with us or against us" or "If you're not part of the solution, you're part of the problem".
- Classic examples of this include such gems as "Do you like Kirk or Picard?" "Do you like drama or comedy?" and the particularly tenacious "Do you believe in science or faith?" These things and more are magnificent examples of attempts to force a person into choosing between two things that are entirely compatible.
- Other examples include most modern politics.
Looks like this fallacy but is not:
- When there are, in fact, only two choices available.
Also called the Golden Mean Fallacy and "Regression to the Mythical Mean".
- In some sense the opposite of a false dichotomy, assuming that the extreme ends of the spectrum are necessarily wrong and the best option must lie somewhere in the middle:
Bob wants to kill all puppies in the world.
Alice doesn't want to kill any puppies.
Therefore, we should compromise and kill 50% of all puppies.
Belkar: See, now that's what being on a team is all about. You didn't want to kill any hobgoblins. I wanted to kill all the hobgoblins. So what did we do? We compromised, I killed one of the hobgoblins.
- South Park loves this one. In fact another name for this is the "South Park Fallacy".
- The Simpsons on the American political process: "Abortions for all! [booooooo] Very well, no abortions for anyone! [booooooo] Hmmm. Abortions for some, miniature American flags for others! [yaaaaaaaaaaaaaaay]"
- Begging the question
 : "Proving" that something is true by taking your conclusion as one of your premises, usually done implicitly rather than explicitly (few people are fooled by having your conclusion as your only premise, such as: "Joe is mad at Jill, therefore Joe is mad at Jill."). Such arguments are valid, and sound if the premises are true, but utterly vacuous. Be aware though, that "Begging the question" has come to mean "leading inevitably to the question" in popular use and for this reason, this fallacy is often referred to by its Latin name, petitio principii in more formal settings.
Alice says she is honest.
If an honest person says something, it must be true.
Thus, if Alice is an honest person, her statement that she is honest must be true.
Ergo, Alice is an honest person, because she says so.
- Circular Reasoning: Begging The Question used recursively. In many cases, the premises are all pushed into one sentence, or even, are simply implied. No matter how many steps there are in the argument it can be simplified to "It's true because it's true." It crops up a lot in political discussions.
I would support this bill if I thought it had enough support to pass
It doesn't currently have enough support to pass
Therefore, I will not support it, because it won't pass.
- Sharpshooter fallacy: A way of fiddling statistics where you change the conditions until you "prove" what you want. The prototypical example is of a person shooting a gun at a wall, then painting a target around the bullet-hole, and claiming to have scored a bullseye.
- Anyone who claims to have found codes in The Bible or Shakespeare has more likely than not committed this one, since finding the codes involves trying every combination of letters until a message that suits your particular type of eschatology/authorship appears, and ignoring all the times that it does not.
- This particular case was specifically shot down by a skeptic in a History Channel documentary about such Bible Codes - to prove that such a "spectacularly rare occurrence" actually was more likely than people were willing to admit, he applied the principles for finding codes to Moby-Dick, and found "predictions" of the assassination of JFK. As with the metaphor of monkeys with typewriters, any sufficiently long stream of data, if looked over using enough different formulas, will produce a vague enough piece of text to correlate to some kind of event that occurred after that book was written.
- Likewise, John Safran vs God put this exact argument against the Bible Code to the test by feeding the entirety of Vanilla Ice's back catalogue (song lyrics and liner notes) into the decoder; even "Ice Ice Baby" is able to turn up 9/11 "predictions."
- Likewise with all those claims of how various people's names are secret encodings of the Number of the Beast, 666. There are a lot of ways you can assign numbers to letters or words — try enough of them, and you can probably make "666" somehow. Here's a fun little program that will look for 666 in any string of letters.
- Fun Fact: It can't come up with anything for "Satan," or "The Beast," with "the number of" being optional.
- Mentioned on NUMB3RS, but the accusation proves to be invalid.
- Moving The Goalposts (also called Raising The Bar) is closely related to the Sharpshooter Fallacy, but instead of you setting your goal wherever you want, you insist that your opponent must make a new argument, meeting a more restrictive set of requirements, each time he succeeds in proving his case.
- Are you listening, Judge From Ace Attorney Games?
- The book "Blink" describes how, in order to test out some new technology, war games were set up where the side representing the home team had said technology and the other side had what the enemy was expected to have. The "enemy" then proceeds to win the war games, completely legitimately, through cunning use of outdated or unorthodox technology and strategies. Rather than think, "Well, shit. Maybe we need to work on this some more," the commanders reset the games, declared the previous winning strategies against the rules, and tried again. This keeps going around in circles until finally the new technology renders the home team victorious.
- Gambler's fallacy: believing that dice/coins have memory: if a coin has just landed on heads four times in a row, surely it's much more likely to get tails this time, to even things out... or alternatively, heads is on a roll and will appear next time too. See also Random Number God and You Fail Statistics Forever.
- In fact, if you toss a previously untested coin and (say) heads come up, there's a larger chance to get heads on a second roll, because the coin might be biased, although not very much larger, unless the coin is so warped that the imperfection is clearly visible.
- A Darths & Droids strip covered this one, with one player having a carefully prepared 20-sided die that had previously rolled two ones — the chances of rolling 3 ones in a row is only 1 in 8000, so surely another one is almost impossible, right?
Pete: (the one who prepared the die)? "Awesome! That die will be even luckier next time!"
- Any Warhammer gamer or tabletop roleplayer will tell you that this is absolutely true.
- Some tabletop players will believe this. Others believe in the existence of one or more "Dice Gods".
- Discussed at length in Rosencrantz & Guildenstern Are Dead, in which Rosencrantz flips a coin eighty-five times in a row and gets heads every time. Guildenstern suggests that it shouldn't be surprising since each coin has an equal chance of coming up heads as tails. Rosencrantz is not satisfied with this explanation, and neither is Guildenstern.
- And the reason Rosencrantz and Guildenstren are confused? If a coin does do something like that, then it is probable that there's a bias towards the result it's constantly getting (e.g. that die that rolls ones more often than pure change would indicate? Use it when you want to roll a one!)
- The chance of this series happening (with unbiased coins) is one in 38 septillion (that's million million million million), in case you are wondering. But the odds of getting any particular ordered set of 85 results is the same 38 septillion.
- Psychologically this fallacy tends to come from the fact that the odds to replicate a pattern do go up cumulatively. The odds of rolling 20 on a d20 twice is 1/400. The odds of rolling the first is 1/20, and the odds of rolling the second is also 1/20. The fallacy occurs when someone attempts apply the full cumulative odds to the next roll. Similarly the odds of rolling a 5 and a 17 on a D20 in that order are also 1/400, so that number's pretty irrelevant.
- Another factor is that many people confuse "a number of independent events" with "a series of independent events". If we flip a coin twice, we have a 50% chance of getting heads and tails in some order (heads-tails and tails-heads; the other two possibilities are heads-heads and tails-tails). But if we specify that we want the the series to be "heads-tails", the probability that that particular series will come up is only 25% — the outcome tails-heads no longer fits the criteria.
- City of Heroes utilises a system called the Streak Breaker. This mechanic in the attack calculations forces misses to instead hit, based on the current number of misses in a row versus your chance to hit.
- Post Hoc, Ergo Propter Hoc (After this, therefore because of this): One thing happens, then another thing happens. Therefore, the first thing caused the second thing.
- Pastafarianism claims that pirates prevent global warming, as the number of pirates is decreasing while temperatures increase as a parody of this type of thinking to demonstrate the flaw in logic.
- This xkcd strip using the rise of both Firefox and Wicca to imply that Firefox causes witchcraft. It's addressed directly in this strip.
- One episode of Justice League features a journalist claiming that since white-collar crime has risen since the League formed, the League clearly causes that crime. (In fact, given the League's style, it's entirely possible that the smarter criminals turn to white-collar rather than blue-collar crime to reduce the chances of Superman slapping them around Metropolis, but his logic still doesn't track.)
- In The Simpsons episode "Much Apu About Nothing", an isolated bear attack leads the Mayor to fund a massive Bear Patrol scheme. Homer claims the lack of bears proves the Bear Patrol works, at which point Lisa points out that you might as well say that a rock keeps tigers away, since she's holding the rock, and she can't see any tigers. Homer's response? "Lisa, I want to buy your rock."
- Sesame Street had a Bert & Ernie sketch where Ernie held a banana in his ear, claiming it kept away alligators.
Bert: "But there aren't any alligators on Sesame Street!"
Ernie: "I know, it's working!"
- In an episode of Numb3rs, Charlie tells Don about the ice cream-rape correlation. As the sales of ice cream goes up, so do the number of rapes. The key is both take place during summer.
- The West Wing had an episode named after the Latin name for this fallacy, Post Hoc, Ergo Propter Hoc. In the episode, some of the White House staffers think President Bartlett's electoral problems with Texas stem from him making fun of their 'big hats'. Bartlett mentions the above stated phrase, correcting them that his problem with Texas is his immigration policy.
- Another prominent example often used in statistics classes: The declining number of storks is responsible for the declining birth rate. It should be noted that the stork population and the birth rate of humans are usually both being affected by some third factor.
- A particularly absurd (joke) example: the pretty-much-undefinable Column 8 in the Sydney Morning Herald once featured a letter correlating the difficulty of the newspaper's Sudoku with the price of petrol.
- Cum Hoc, Ergo Propter Hoc: "With this, therefore because of this." A less well-known sibling fallacy to Post hoc, Cum hoc is saying that because A and B occur together, A causes B. The difference between Post hoc and Cum hoc is that Post Hoc has a clear temporal relationship — A happens first, then B, while Cum hoc does not have that temporal relationship; the two things may occur at the same time. Like Post Hoc, Cum Hoc ignores the possibility that there may be one or more additional factors that affect both A and B.
- This fallacy often comes up in discussions of videogame-related violence; the claim is that violent video games cause or encourage violent behavior in real life. The other possible sources of correlation include, but are not limited to: that violence-prone people tend to enjoy violent games; that some violent people prefer non-social activities that include games; that video games are simply becoming ubiquitous enough that almost every child plays them, so naturally the violent ones did too.
- This exact argument is used in an episode of Law And Order: Some kids attacked a woman and killed her. The kids played a video game with a similar attack, therefore, the video game caused them to attack the woman.
- In another episode of Law And Order, the defense lawyer for the serial killer of the week used a Media Watchdog witness to try to prove his clients violent actions were caused by violent TV. The prosecution destroys the argument by pointing out that if violent TV created violent people then everyone in the courtroom would be violent because everybody watches violent TV.
- This fallacy was used by Frederic Wertham to establish the comics code. He noted that juvenile delinquents tended to read comic books, so comic books must cause juvenile delinquency. Of course, during this time period comic books were more popular in America than they had ever been before or since. The typical child read about 5 comics a week, and adults, many of whom had picked up the habit during WWII when comics were sent overseas to servicemen, were not far behind.
- This has also been used to argue that listening to country music causes higher suicide rates, since places with a higher percentage of country music listening tend to also have a higher percentage of suicide.
- Since Type 2 diabetics are often overweight, it's commonly claimed by tabloid newspapers that "obesity causes [Type 2] diabetes" — which has not been established by research, and ignores other possibilities, such as that Type 2 diabetes causes obesity, or (perhaps most likely) that both are caused by a genetic defect they have in common. After all, Type 1 diabetics are usually underweight, but nobody has ever suggested that "anorexia causes Type 1 diabetes".
- Four terms fallacy: Using a standard 3-step proof-of-concept to prove your theory, but including one unconnected tenet which breaks the line of reasoning. Results from equivocation. It's best explained by this example from Land Of The Blind:
A dry crust of bread is better than nothing
Nothing is better than a big, juicy steak.
Therefore, a dry crust of bread is better than a big, juicy steak.
- This uses two different meanings of the word "nothing": the first line uses "nothing" to mean "a lack of food", while the second line uses "nothing" as "no such thing exists"
- The Stephen Colbert quote at the top of the page is an example of such a fallacy.
- An episode of Yes Minister called this fallacy "The Politician's Syllogism", specifically the form: "Something must be done. This is something. Therefore we must do this." The two different meanings of "something": "A solution to this problem" and "A thing" are mixed and said to be the same.
- The Stephen Sondheim musical Anyone Can Whistle explains in "simple" terms what's wrong with leftists:
The opposite of left is right,
The opposite of right is wrong,
So anyone who's Left is wrong — right?
- Real Life Example: In a museum, an employee sees a patron tapping on one of the replicas with his fist. Employee: "Sir, please don't touch that." Patron: "But it's a replica, isn't it?" Employee: "Yes, it is, but we still ask for you not to touch it." Patron: "Well, it's not under a glass case, which means it's not valuable. I have every right to touch it." Employer: "No, actually-" Patron: "Yes, If I see something that's not cased , it means I can touch it, AND I WILL TOUCH IT!" The four terms here are 1: "it is not in a glass case" 2: "I can (am physically able to) touch it", 3: "I can (am permitted to) touch it" and 4: "I will touch it". If 1 is true, then 2 is true; if 3 is true, then 4 is true. What's missing is the necessary step establishing either that 2 and 3 are the same (they aren't), or, that if 2 is true, 3 is true as well (it isn't).
- This fallacy, combined with Reification, is the reason that one of the classic "paradoxes" is not really a paradox at all, namely, "If God can do anything, can he make a stone so big he can't lift it?" The term used twice is the idea of "can do anything". In the first sense it is abstract, referring to a lack of limitations; in the second sense it is referring to the limitations of physical strength and the laws of physics.
- Dealt with in Runaways - 'Could God make a sandwich so big He couldn't eat it?' 'Yes, and then He would eat it anyway.'
- Reification (no, not at all related to that Rei): Sometimes related to the four terms fallacy, this is treating a abstract idea as a physical object. For example: "eating ice cream makes you happy. Therefore, eating more ice cream makes you more happy". This assumes that happiness is a thing that can be measured and which is a physical property of ice cream — in fact happiness is an unmeasurable emotional response to ice cream, and would probably tail off at around the point that you started to get really sick and/or fat.
- Ad hominem fallacy: Refuting an argument by attacking the person presenting it, rather than addressing the content of the argument itself. Ad hominem is very often mistakenly claimed in cases where an argument's opponent attacks its proponent in addition to presenting a valid counterargument. "You're stupid, therefore your argument is invalid" is an ad hominem; "your argument is invalid, therefore you're stupid" is not. Similarly, some people seem to think that Ad Hominem is necessarily abusive, which it isn't. "You've used the 'Four Terms' fallacy, you stupid retard, therefore you're using faulty logic" is not Ad Hominem. "Mike has clearly put a lot of thought into whether we should buy a pool, but he is a convicted felon" is. For example:
Bob thinks we shouldn't buy a pool, because it would be too expensive to maintain.
Why should we listen to someone who kicks puppies?
Therefore, we should buy a pool.
- This even applies when the ad hominem attack itself is related to the argument. Even if the supposition comes from a source that is known for fallibility, that does not logically make it untrue.
Bob thinks we shouldn't buy a pool, because it would be too expensive to maintain.
Bob once went bankrupt.
Why should we listen to economic advice from someone who went bankrupt?
Therefore, we should buy a pool.
- In fact, in some cases that fallibility may be a good reason to take advice from that person. We might well want to listen to economic advice from someone who went bankrupt. Maybe he went bankrupt because of the expense of maintaining a pool. Similarly, an admonition not to smoke would have more resonance coming from a smoker than from someone who never tried it themselves.
- Most people can recognize such a simplistic ad hominem attack as humorous, but that didn't stop DirecTv from flipping out at a spot by Time Warner asserting that "DirecTv hates puppies"
- If you want to email Jack Thompson and argue against his beliefs about video games, mention that you're a gamer and that'll be all he needs to fire an ad hominem sniper rifle at you
r counterpoints.
- Poisoning the Well is a variant of Ad Hominem where a person uses an Ad Hominem attack before the other person even speaks, in an attempt to get the audience to preemptively discredit what they are about to say.
- The movie Enemy of the State has the evil NSA officer order his minions to destroy Robert Clayton Dean's (Will Smith) reputation before Dean can go public with his proof of the officer's misconduct.
- Tu Quoque: (literally "you, too!"), another variant of Ad Hominem, refers to the attempt to deny an argument by asserting that the person presenting the argument also suffers from the same flaw or has held an opposing view in the past.
Bob: "Smoking is a highly addictive habit and causes health problems. You should not smoke."
Alice: "But you yourself smoke! Therefore your argument is invalid."
(The fact that Bob smokes does not mean he is wrong.)
Bob: "This bill will be expensive and will not work, therefore you should vote against it."
Alice: "You supported the bill last month, so obviously you're wrong."
(Bob changed his mind in the meantime.)
- In some cases, Tu Quoque is a valid argument, but only when it is being used to question the speaker's reliability. It does not inherently invalidate the statement.
- Reductio ad Hitlerum (also known as "Reductio Ad Nazium"): Hitler did it, therefore it's bad. Can be extended to other evil or unpopular people, such as Osama bin Laden. While persuasive, it's not always true, since while Hitler did a lot of evil things, he also was a massive advocate of animal rights (more so than Jewish, gay or Gypsy rights...), built motorways, painted pictures, hosted the Olympics, ate sugar and breathed oxygen. Arguably the most extreme possible form of guilt by association, since everybody but Those Wacky Nazis hates Hitler. Related to Godwins Law and Hitler Ate Sugar.
- Classic example: "Y'know, Hitler was a vegetarian." And therefore vegetarians are as morally suspicious as a dude with a German accent in an Indiana Jones film.
- "Vegetarianism then: not all it's cracked up to be. In some extreme cases may cause genocide." — Bill Bailey
- "Hitler was an absitent vegitarian, do your part for world peace- have sex and eat meat" —demotivational
- Therefore, following all of the above: being an omnivore or being a vegan is fine, but anything in-between is evil.
- An anti-abortion Chick Tract claims abortion is wrong because Hitler killed Jewish babies, and therefore doctors who carry out abortions are as bad as Hitler.
- Of course, Chick seems to have forgotten (or never knew) that Hitler himself was strongly anti-abortion. At least, when the babies weren't Jewish. So, according to Chick's anti-logic, pro-lifers are as bad as Hitler. So, whatever stance you take on abortion, a raving Fundamentalist looney still thinks you're a Nazi.
- There's an interesting Inversion of this making the rounds on the internet. Whenever some distressing news is revealed to the world, someone will inevitably use the clip from Downfall where Hitler has a Villainous Breakdown upon learning that Berlin will be overrun. The person making the video will often put their words into Hitler's mouth. Rather than declaring "Hitler would agree with you," they are implying "Hitler would agree with me."
- Association Fallacy: Claiming a quality of one thing must be inherently a quality of another because they have something in common, e.g. "Water is a liquid. Water will put out most fires. Therefore, any liquid will put out most fires." (Lucky idiot disproves this one.)
- One popular form is "guilt by association," linking a negative quality of one thing to another. If used to discredit a person's arguments, guilt by association also becomes an ad hominem fallacy.
- The debate over a recent ballot measure in Oregon that paid for children's health care by increasing the cigarette tax is an illustration of the guilt by association. The argument of many of the measure's supporters was essentially, "Big Tobacco opposes this measure. Big Tobacco is evil. Therefore, if you oppose this measure you are as evil as Big Tobacco."
- Recent conversation:
Speaker 1: "Judaism is weird. There are so many holidays on its calendar."
Speaker 2: "Well it depends on culture. The Mayans had a calendar so complicated only priests could understand it."
Speaker 1: "Didn't the Mayans SACRIFICE PEOPLE!!?"
- (Equating complex calendars with human sacrifice)
- Stalin is sometimes used by religious conservatives to prove that atheism is bad.
- Likewise, things like (literal) witch hunts and radical Islamic terrorism are sometimes used by atheists to prove that religion is bad.
- The flip side of this is "honor by association," linking a one thing to another by a positive quality both share.
- One Usenet poster who claims "we should all become vegetarian" claims in his sig that "Jesus was a vegetarian". His reasoning: Jesus was good; Jesus was vegetarian; therefore vegetarianism is good. Since Jesus celebrated the Passover (which includes lamb) and was explicitly said to eat fish after his resurrection, he not only uses the association fallacy, he builds it on an incorrect premise.
- No True Scotsman: Similar to Moving The Goalposts, in that the opponents argument is disregarded because you redefined the terms in your argument to match the conclusion you want. The classic example works by redefining the word "Scotsman" from "person from Scotland" to "person from Scotland who doesn't eat sugar with their porridge":
Alice: No Scotsman puts sugar on their porridge.
Bob: That's not true — my Scottish uncle Scotty McScotscot from Glasgow puts sugar on his porridge all the time!
Alice: But no true Scotsman puts sugar on their porridge!
- It's worth noting that simply saying that something isn't really a member of a set isn't automatically this fallacy; No True Scotsman requires that the terms be redefined more narrowly after the counter-argument is presented. Also, if the group being referred to has clearly-defined or generally-accepted membership standards, pointing out that someone or something does not meet them is not No True Scotsman. For instance if a statement is made about Eagle Scouts, and a rebuttal is offered concerning "Boy Scouts in general", pointing out that not all Boy Scouts are Eagle Scouts is not No True Scotsman.
- The game Metal Wolf Chaos features propaganda news reports that define a true American as "anyone who supports the idea of having the families and friends of terrorist sympathisers murdered in the streets" rather than "anyone who is a citizen or long-standing resident of America".
- This is a common reaction to a mention of any unjust event involving or perpetrated by Christians in a discussion of the value of Christian morality (though this tactic itself is an association fallacy).
- Excessive use of this in the 2008 Presidential campaign led to The Daily Show (fake news for fake Americans) producing a handy test: 'Are You A Real American?'
- See also instances of Fan Dumb redefining "a true fan" from "someone who likes this work" to "someone who agrees with me."
- In a line from the webcomic RPG World, the "player" of the RPG in the comic takes time out from playing to bash the game horribly on the Internet. After which he turns to face the viewer and explains "You can tell I'm it's biggest fan, because I hate it the most." Ultimately, it's paradoxically true that only a rabidly, irrationally devoted fan of a work or genre will get that worked up about any perceived They Changed It Now It Sucks.
- Many questions fallacy: Phrasing your question in such a way that only one question is being asked directly, but other questions are implied, then refusing to accept answers that include any qualifiers. The classic example is "have you stopped beating your wife? Answer Yes or No!" — If you answer "Yes" you are admitting that you used to beat her, but if you answer "No" you are admitting that you still beat her. A qualified answer such as "I haven't stopped because I never did." is not accepted.
- One episode of The Simpsons has the family being accused of being unpatriotic but, when given the chance to clarify, are asked loaded questions such as, "Which part of America do you hate the most?" There is no "correct answer", since naming any part allows the assumption that you hate the other parts too, just not as much.
- Another episode showed the Springfield Police Department official website, whose front page says "If you committed a crime and you wish to confess, click 'Yes'. Otherwise click 'No'". If you click 'No', the site assumes you committed a crime but don't wish to confess and dispatches a police car to your house.
- This is an easy way to brand someone a traitor in Paranoia- simply ask "Are you a happy communist?" If they say no, they're saying they're not happy, which is treason. But if they say yes, then they're saying they're a communist, which is also treason.
- It's a common cross-examination trick to do this, because the attorney conditions the witness to respond "Yes" or "No" to everything and then *Bam!* traps them with this and forces them to give a detailed answer. The delay as the person scrambles to shift back and think of the correct answer is what makes them look "shifty." It's the reason for the objection "Assumes a fact not in evidence."
- Strawman: Beloved of Author Tracts the world over, this fallacy involves misrepresenting your opponent's views, or only attacking their weakest arguments, and then claiming that because you beat this "straw man", you beat their entire argument. See The War On Straw.
- One variant is sometimes known as a "Red Herring" argument. Whereas the Straw Man will extrapolate details into a second argument in order to apparently defeat the first, a Red Herring will establish a second, different, argument to try to make everybody else involved forget all about the first one. It's named for an old method of training hound puppies to follow a scent trail, by using a a "red herring" (a type of smoked, dried fish with a distinct scent) to lay down a trail for them to practice on. Because this was the scent they were originally trained to follow, dragging a bundle containing red herring across a real scent trail could draw an adult pack off on a false trail.
Alice: "Health Insurance is too expensive. Something must be done to bring down the costs."
Bob: "It wouldn't be so expensive if doctors didn't order so many unnecessary, expensive tests."
Alice: "Most of those tests are not unnecessary! They save lives!"
- Bob has successfully sidetracked Alice from the cost of health insurance to the necessity of many medical tests.
- Affirming the consequent: Claiming that because the result of something is true, the original statement must also be true. For example:
If a car is a Ferrari, it is fast.
My car is fast.
Therefore it is a Ferrari.
- Denying the antecedent: The flip side of the above, where you say that because the initial conditions did not happen, the result is impossible. Example:
If a person is wearing a hat, they have a head.
I am not wearing a hat.
Therefore I do not have a head.
- Sunk cost fallacy: When somebody's sacrificed or invested a great deal in a cause or project, they tend to become irrationally dedicated to it. This applies even when the costs invested can't be recovered. More of a cognitive bias than anything. Example:
If I spend fifteen dollars on this contest, I can win the prize.
I can buy the prize elsewhere for five dollars.
I have already spent eight dollars on the contest. Since I don't want the money to be wasted, I will continue.
- A particularly tragic example of this — with much higher stakes — can be found in The Order Of The Stick: Start of Darkness.
- And in fact, following his My God What Have I Done moment in the main comic, Redcloak does it again. He seems to like it.
- Tends to afflict professional sports teams as well. Team A signs Johnny Studmuffin to a 10-year, $200 million guaranteed contract. Turns out, Johnny's a bit of a malingerer and spends the first three years playing poorly for Team A. Many, many teams in this situation will continue to play Johnny, even after it's clear that he's a bad player, simply because they invested assloads of money in him. The reality is, Johnny's getting that $200 million no matter what, so the best move is to cut him and play the best players.
- Professional sports are a curious example, because it takes a high degree of confidence to coach at that level, and so many, many coaches will keep playing Johnny in the belief that they can coax back the talent that made him rich. Similarly, in such a public-relations driven business, cutting ties with such an expensive failure reflects terribly on the team that signed him, while watching said player stink it up in the field draws the attention to him.
- Not to mention fake sports companies. Far too often a "talent" is given a generous amount of screen time not because they're skilled, but because they've been signed to fixed-term, guaranteed-money contracts and the company feels that they have to get some use out of them, even if they pull down the show with them.
- In psychology this is generally related to cognitive dissonance theory, which is basically the idea that when people think of themselves one way, but act in another way they will try to rationalize it. Specifically people think they make good decisions, but when the decisions aren't paying off, they throw more effort after it to make the decisions good rather than admit they made a bad decision.
- It's also known on social psychology as a great way to inspire obedience or adherence to a group. Cults are known for using this: How about you read a flyer? Sure, that cost nothing. Hey, why don't you answer this quiz on how happy you are with your life? Well... You've already read the flyer, that's not much more effort. How about going to a session? This technique is called Foot In The Door, or The Camel's Nose.
- In business, this is known as "throwing good money after bad."
- In poker, the term is "pot committed". The best poker players can overcome the fact that they've put half of their money into the pot to get away from a hand that has little chance of winning (rather than throwing the other half in and busting out). This assumes, however, the the player still has a healthy amount of money in relation to the pot. If the pot has become very large in relation to the player's remaining money, putting the remainder of their money in with a hand that will lose most of the time can still, on average, be a profitable move, because one large win will compensate for many small losses.
- In movie production, it's a "Pay or Play" contract. An actor, in forethought, has a contract made that says either they play a certain role in a future film, and are paid accordingly, or they are paid anyway to not take the role. Best example would be Billy Dee Williams, as Harvey Dent in Tim Burton's first Batman film. He knew the character, as opposed to the producers (Burton has gone on record as bragging that he has never read a comic book), and knew what could come in sequels. Then comes the third movie and Williams gets paid-off so they can have Tommy Lee Jones take the role.
- More serious in life or death matters. Dead troops are a sunk cost, but many nations across history have continued on losing military campaigns because their leadership could not face up to having wasted troops. As in gambling or business, the usual result is even more waste. To counter this, a crucial military principle, going back as far as Sun Tzu, is "reinforce victory, do not reinforce defeat."
- Used by proponents of continuing USA's presence in Iraq, usually with touching stories of dead soldiers' mothers saying "please, don't let my son's death be in vain". Not that it's only been used regarding Iraq; in 1971, John Kerry referred to others' use of it regarding Vietnam when speaking to the Senate Foreign Relations Committee: "How do you ask a man to be the last one to die for a mistake?"
- This is often the reason people will spend lots of time on internet arguments, even after they're losing. Or as Scott Adams put it, "Nothing makes [someone] argue harder than being proven wrong."
- This is one of the main reasons why people continue to play MM Os even when they aren't enjoying them. It's arguable that MMO designers deliberately use this fallacy to encourage people to continue playing the game.
- Retrospective determinism: Assuming that because something happened it was therefore bound to happen. Often brought up as justification for Hitlers Time Travel Exemption Act by saying that World War II was inevitable.
- Extremely common in the form "If I (we) don't do/make/use it, someone else will". Often used by fans of fantasy fiction to claim that gunpowder is an inevitable invention when the idea of mixing up sulfur, charcoal, and saltpeter (made from urine) in the proper proportions is anything but inevitable.
- Saying that intelligent life must have evolved in other places in the universe because it evolved here is an somewhat common evolutionary fallacy. The evolution of DNA (or its Star Trekkian equivalent), for instance, is not by any means a foregone conclusion.
- Error of Composition — claiming that because a statement is true of the parts, it must be true of the whole. Example:
Everything is made of atoms.
Atoms are invisible to the naked eye.
Therefore everything is invisible to the naked eye.
- Wild Wild West. Will Smith and Barry Sonnenfield were a great team with Men In Black, so any movie made by this pair will be a hit.
- Cirque Du Soleil and Criss Angel are both popular, so it was believed that a collaboration between the company and the magician on a Las Vegas magic show was money in the bank; instead, Criss Angel — Believe is shaping up to be an embarrassing flop.
- Comedian Dave Attell uses this in his stand-up act.
Two smells together just reek. Even your most favorite smells. Like cotton candy, I love it! And scotch whiskey, yum-a-dumb-dumb. But cotton candy and scotch, that's a weird funk, it's like: "Oh MAN! Did someone just fuck a clown in here?"
Fruit, good. Cake, great. Fruitcake, nasty crap.
- Occassionally, musicians from a number of different bands may come together and form a "supergroup" with the overall hype being that the sum of the supergroup's parts are better than the original bands they came from (i.e. Velvet Revolver, Audioslave), only for it all to end up being complete shit.
- Error of Division: Generalizing from a whole to the parts. Example:
This ensemble show is extremely popular
Therefore, any show starring any member of the ensemble should be popular.
- The supposed Seinfeld curse is a classic example disproving this fallacy.
- Trail of the Pink Panther, Curse of the Pink Panther, Son of the Pink Panther: everyone likes a Pink Panther movie regardless of whether Inspector Clouseau (as played by Peter Sellers) is actually in it, right?
- Star Wars: The Clone Wars: a Clone Wars movie? The Warsies will love it, even though it is not directed by Genndy Tartakovsky or George Lucas and it's CGI.
- As of early 2009, Marvel seems to think Iron Man 2 will be just as good without Terrence Howard. Or Samuel L Jackson. Or potentially Jon Favreau.
- As of mid 2009, Terrence Howard's not in it, but Jackson and Favreau are.
- And Howard was replaced with Don Cheadle, which as far as critically acclaimed modern actors go, a fairly even switch.
- "Hey, Myth Busters is popular, and it has explosions in just about every episode! Let's make a show centered around Stuff Blowing Up!"
- Joey: A spin-off of Friends that flopped horribly. Apparently the developers fell afoul of this fallacy.
- Subverted in the M*A*S*H episode "Rumor at the Top" in which the gang thought the Army was planning to send one of them to a new MASH being set up because the 4077th was so efficient. However, it turned out that the Army was planning no such thing as they realized that the 4077th only worked so well because of the combination of people.
- Applied full-force to the television franchise itself, which had two unsuccessful spinoffs - After MASH and W*A*L*T*E*R - that, for the most part, banked on the popularity of the second-tier cast and connections to the parent show itself. A third, Trapper John, M.D., was somewhat more successful than the other two, but did not include any of the original actors and was legally recognized as a spinoff of the movie.
- Many side-projects and solo works made by musicians who are/were part of bands that have already established a popular reputation can fall into this when they don't live up to the glory of their other/former, more popular band. i.e. Sid Vicious' solo project and Billy Corgan's band Zwan.
- The Cab Driver's Fallacy: Similar to the sunk-costs fallacy; having a particular goal in mind and refusing to give up on it, however impossible it seems, while also ignoring the possibility of doing even better. Named for the tendency of taxi drivers to have a specific amount they'll try and earn each day. On slow days they will keep going to reach the target, while on good days they will quit early as soon as the target is reached. They would do much better when they go home early on slow days and keep going past their target if it's busy.
- Perfect Solution Fallacy: Arguing that a course of action is no good because it isn't perfect. It either infers or asserts the False Dichotomy that implementing an imperfect solution will preclude a "perfect" solution. (Rejecting a solution which actually does preclude a better one from being implemented, or based on an unacceptable cost:benefit ratio, is not an example of this fallacy.) For example,
Using reusable bags instead of paper or plastic will help the environment.
However, using them won't solve the problem completely.
Therefore, since it isn't the best possible single solution, it isn't worth doing at all.
- This is popular when answering a technical question on the internet: "There is no solution to your problem which I can guarantee to work in 100% of all cases. So I'm not going to bother telling you what will work in 99% of all cases."
- Used often by anti-vaccinationists. Their reasoning: a particular measles vaccine only protects 95% of the time, so they'd rather take their chances with a potentially fatal disease. This reasoning ignores that, due to herd immunity, 95% of the time is more than enough.
- The U.S. Army. In a series of tests to find a replacement for the M-16 assault rifle, all of the competitors were disqualified for not producing a guaranteed first-round hit. The cost:benefit ratio associated with replacing hundreds of thousands of rifles may have been an underlying reason, but no gun can guarantee a hit.
- People who oppose condom distribution with the argument that since condoms don't prevent pregnancy and STDs 100% of the time, we shouldn't make a solution available that "only" works over 98% of the time.
- The responses to a single case of HIV being reported in the American porn industry. Dozens of activists screaming that the industry's voluntary testing system was worthless, because it had not prevented someone from contracting HIV in the first place. They ignored the fact that this system was what gave the porn industry an infection rate vastly, vastly lower than that of the general population.
- Among people opposed to welfare, it's used thus: "In spite of welfare, there are still poor people, therefore welfare doesn't work."
- This is often used by those who oppose animal testing. They cite the fact that animal testing isn't 100% perfect as a reason to do away with it altogether, even though we're still much better off with it than we'd be without it. (For the concerned, the law requires that researchers use non-animal analogs whenever they're available. Animal testing is only used when there is no other option.)
- Undistributed Middle: This fallacy occurs when the middle term of a standard three-step syllogism is not distributed in either premise. The picture at the top of this page is a case of undistributed middle. Using that image, "black and white" is the middle term: the term that appears in both premises; it is undistributed because neither premise refers to all things that are "black and white". Newspapers are black and white as well, and they are neither penguins nor old TV shows. "Things that are black and white" is the superset, and it contains many subsets that do not overlap at all. In casual use, undistributed middle can be hard to spot:
Conservatives always want to raise taxes.
Alice says that she's a Liberal, but she also says that the sales tax needs to be raised.
She's lying about being a Liberal; she's really a Conservative.
- The point is not how "Liberal" and "Conservative" are defined, it's that at no point is it established that "only Conservatives want to raise taxes".
- '''Two Negative Premises: If A is not B, and B is not C, then A is C. This is always wrong, it is not possible to make a valid conclusion from two negative premises, logic is not arithmetic.
No Jews are Muslims.
No Muslims are Christians.
Therefore Jews are Christians.
- See the one below for a clear example.
No dogs are reptiles.
No reptiles are magenta.
Dogs are magenta.
- Proof By Example(s) or Inappropriate Generalization: Taking one or more non-exhaustive examples from a group that have a property, and making a generalization that everything in that group has that property.
3 is a prime number, and it is odd.
13 is a prime number, and it is odd.
97 is a prime number, and it is odd.
Therefore, all prime numbers are odd.
- Note that it would be logical to prove that "at least three prime numbers are odd" by these three examples; it simply cannot be generalized to all prime numbers, since 2 is also a prime number, but is even.
- Also note that the generalization can be made if the list of examples is exhaustive, in which case it is known as "proof by exhaustion" or "proof by cases", and is not a fallacy anymore:
The sum of the angles of any acute triangle on a plane add up to 180°.
The sum of the angles of any right triangle on a plane add up to 180°.
The sum of the angles of any obtuse triangle on a plane add up to 180°.
All triangles on a plane are either acute, right, or obtuse, therefore the sum of the angles of any triangle on a plane add up to 180°.
- (While triangles on the surface of a sphere, for example, do weird things, the surface of a sphere is not a plane; therefore, that case is not relevant to the proof.)
- It's also proper to disprove by example:
2 is a prime number, and it is even.
Therefore, not all prime numbers are odd.
- Usually, in mathematics, no matter how many examples you might have, proof by example is not a good idea.
- Proof by example works where there is 'there exists' and not 'for all'.
- Proof By Obfuscation: Making your argument as confusing as possible in hopes that people can't find the flaws in your logic, then claiming you're right since nobody refutes you.
- Taken to its (il)logical extreme with South Park's Chewbacca Defense
- The converse of that is to ignore or discredit an opinion just because it is confusing or poorly communicated. Just because the poster committed Aggravated Assault on their spellchecker is not proof that their points are incorrect.
- Argumentum ad nauseam, also known as proof by assertion: Repeating a statement until nobody cares to respond anymore, then claiming you're right since nobody contradicts you.
- The Slippery Slope Fallacy: Based on the idea that an object placed at the top of a slippery slope will slide all the way to the bottom if given even a small nudge, the Slippery Slope fallacy is arguing that even a small step taken in one direction will lead to some drastic consequence. This "argument" usually ignores the individual connections between events in favour of simply linking one event inevitably to another. However, it is not a fallacy if one does establish the chain of logical implications (or quantifying the relevant probabilities).
- Used frequently by politicians, naturally. Especially shows up around election time where voting for an opponent will usually be portrayed as resulting in a dystopia of some sort, usually authoritarian in nature, but is also used to argue against such changes as universal health care in favour of Status Quo Is God.
- Tropers Law is a reaction to a slippery slope argument commonly found on this very wiki. "If we do anything in a way similar to the way that Wikipedia does it, we will become as restrictive and bureaucratic as Wikipedia is."
- Bill Maher rebutted this type of fallacious reasoning in a routine: "Gay marriage will not lead to dog marriage! When we gave women the vote we did not also have to give it to parakeets. When we freed the slaves we were not obligated to free the gerbils."
- The slippery slope fallacy is often combined with the strawman or red herring: Poster A explains why we should legalize Marijuana. Poster B claims that legalizing Marijuana will require us to legalize Heroin, and then post reasons why legalizing Heroin is a bad idea. If Poster B can show a proper logical chain, then this is an acceptable refutation, but rarely is that possible.
- If you give a mouse a cookie...
- One iaijutsu (a Japanese sword style) master wrote that students should never practice cutting objects with their swords. The reasoning was that tatami mats aren't realistic enough, so they should cut chickens. But chickens aren't realistic enough, either, so they should cut human cadavers. But cadavers aren't realistic enough, either, so they will end up kidnapping people and chopping off their limbs to perfect their sword stroke.
- Practice murders were actually a significant problem in feudal Japan.
- Interestingly, this can be a valid argument in the case of a legal decision that will be establishing a legal precedent because of the nature of legal precedent.
- Eugene Volokh has written a paper about the slippery slope that analyzes examples where it can be valid.
- One particular counter-argument that shows the absurdity of the slippery is a method this troper found on the web: reverse the slippery slope e.g. "If we ban gay marriage, then we'll ban straight marriage as well!"
A special subset of fallacies are appeals: claims that a position is right made by making a purely emotional argument.
- Appeal To Nature: Claiming that something is good, or better than another thing, because it is natural, regardless of whether or not this is actually an advantage — after all, snake venom is natural, but that doesn't make it good. For examples, see All Natural Snake Oil.
- "Drink up, Socrates, it's all natural."
- In Troll 2, an evil witch is able to convince someone to drink a steaming green broth that has just turned someone else into green goo because "it is made from vegetable extracts".
- The Sarah Jane Adventures, where aliens convince millions of people to drink a new energy soda that contains alien parasites called "Bane" simply by claiming that Bane is "organic" (and by extension "healthy").
- In the Discworld novel Carpe Jugulum, King Verence is talked into drinking a potion after being told "It's got herbs in", on the assumption it must be healthy. He spends most of the remainder of the book foaming at the mouth and randomly attacking inanimate objects. This, however, turns out to be useful. It should be noted that said potion is what the Feegles, six-inch pictsies who can drink their weight in lamp oil with no ill effects, drink to get their spirits up before marching into battle.
- Also, scumble is made from apples. Well, mostly apples.
- A famous example from mathematics is Giovanni Saccheri's attempt to prove the parallel postulate. In his book, Euclid Freed of Every Flaw, Saccheri assumed the postulate was false and tried to derive a contradiction. Instead, he derived results that got stranger and stranger, finally concluding that they were "repugnant to the nature of straight lines". Saccheri didn't know it, but he was developing what we now call hyperbolic geometry — a fruitful field of study that just doesn't work the same way Euclidean geometry does.
- Eureka had an episode where everyone was becoming dumber, and the supposedly-a-genius farmer didn't think the additives she were using were bad, since they were "organic"...In a town of super-geniuses, granted lacking in common sense sometimes, this seemed rather glaring in its stupidity
- Parodied in a Fry and Laurie sketch where a doctor is offering his patient cigarettes as a cure. "They're herbal are they?" asks the patient. "Yes, a naturally-occurring herb called tobacco, I believe."
- Another Fry and Laurie sketch had a bedtime drink containing "nature's own barbiturates and heroin".
- Rep. Michelle Bachman of Minnesota has made several speeches that are notable for their sheer illogical vacuousness. In one example, she said that Global Warming can't be real because scientists claim that it is caused by carbon dioxide. Carbon Dioxide occurs in nature, and therefore, it is impossible for it to do harm, therefore, Global Warming either can't be real, or if it is real, will only help us.
- Eric Schlosser mentions this in Fast Food Nation: sometimes artificial things are better for you than natural ones. The example he uses is almond flavoring; extracted naturally, it contains trace amounts of cyanide.
- Appeal To Inherent Nature: If something is naturally predisposed to a certain act or state, it must be accepted. Snakes bite, bears maul, poisons kill, babies scream and shit themselves, sociopaths torture and Nazis commit genocide; but those are their natures so we should not hold it against them.
- This one is Older Than Dirt. In the form of The Tale of the Scorpion and the Turtle, it dates back to an ancient Sanskrit collection of folklore that was first translated into English in 1570.
A scorpion, being a very poor swimmer, asked a turtle to carry him on his back across a river. "Are you mad?" exclaimed the turtle. "You'll sting me while I'm swimming and I'll drown."
"My dear turtle," laughed the scorpion, "if I were to sting you, you would drown and I would go down with you. Now where is the sense in that?"
"You're right!" cried the turtle. "Hop on!" The scorpion climbed aboard and halfway across the river gave the turtle a mighty sting. As they both sank to the bottom, the turtle resignedly said, "Do you mind if I ask you something? You said there'd be no sense in your stinging me. Why did you do it?"
"It has nothing to do with sense," the drowning scorpion sadly replied. "It's just my nature."
- Real Life: Often used by people who want to excuse their own bad behavior rather than admit that maybe they crossed a line somewhere. "It's just the way I am." Not a 100% fallacious argument in that it's got some basis in fact when taken on the level of a single person, but fallacious enough that it usually comes off as lame and immature when people use it.
- In a crossover between media and real life, this fallacy often shows up on reality shows, with at least one contestant each season declaring proudly "That's just who I am." when called out for acting like a bigot, an asshat or a bitch.
- When John Crichton, in Farscape, comes off to Aeryn as being unnaturally sex-obsessed, he says, "I'm a guy!"
- This is also a trope in certain religious/spiritual teachings, where it is assumed that value is subjective and not inherent to the thing in question.
- Appeal To Novelty: Arguing that one thing is automatically better than another because it is newer. See New And Improved.
- British Television Quiz QI is extremely guilty of this trope. The entire premise of the show is turning "popular" knowledge on its head or proving old preconceptions wrong. As a result, lots of people believe the alternative, not for the inherent value of the statement, but because it's different.
- Appeal To Tradition: The opposite of appeal to novelty, where the older position is right. See They Changed It Now It Sucks.
- The short story "The Lottery" uses this.
- Illustrated in The Simpsons episode "Wacking Day", where snakes are herded to the town square and beaten to death with clubs. Lisa and Barry White are the only characters who are initially disgusted with the idea.
- In a similar vein, Weird Al's song Weasel Stomping Day is about a fictional holiday where people spread mayonnaise on their lawns, put on viking helmets and hiking boots in order to crush weasels to death. Complete with tongue-in-cheek lyrics such as "It's tradition that makes it okay" in order to mock the idea that an abhorrent act is acceptable if it is 'traditional'.
- Often used in political debates, especially about social issues.
- Appeal To Authority: This fallacy name is applied to two similar but distinctly different fallacies.
- The first is "I'm right because this expert says the same thing." It is essentially a positive version of the ad hominem fallacy
- Instead of discarding the argument as bad because of who states it, it is accepted as good because of who states it. Seeking an expert to provide his arguments generally is a good idea. An expert simply has the expertise in the area of question and can be expected to give a more reasonable, thought-through argument than an average person, or even an expert in another field. The fallacy consists in the following statement: "something must be true because an/the/all experts say so". For example, arguing that "Black Holes must exist because Albert Einstein said so" is fallacious - even when Black Holes really do exist and Albert Einstein is right, it's still fallacious reasoning because that's not why they exist.
- The second form is more accurately called Irrelevant Authority, Inappropriate Authority, or Questionable Authority, and is citing someone as an expert even though they are not really an expert on the question under discussion.
- In Left Behind, the entire world believes a Technobabble nuclear physics explanation of the Rapture because a botanist and the president of Romania (note: not a nuclear scientist) say it's so. Later on in the book, the pseudo-religious explanation of the Rapture is accepted because it's espoused by an airline pilot.
- In The Simpsons episode "The Monkey Suit", creationists seeking to ban the teaching of evolution succeed by getting a scientist to testify in court that evolution is a myth — a scientist with a degree in "Truthology" from "Christian Tech".
- Likewise, in one episode of Dinosaurs, in a trial for the heretical view that the earth is round, the "expert" who testifies that the world is flat's stated qualifications are that he is wearing a white lab coat and his "proof" that the world is flat is the existence of a flat-earth "globe". If a man in a white lab coat has a flat-earth globe, he can't possibly be wrong.
- A combination of this and Appeal To Popularity (below) is used whenever people talk about however many scientists oppose or support the theory of evolution or climate change. Anthropogenic climate change may be true and so may be the evolutionary origin of species. However, arguments based on the authority or number of experts are not valid logical arguments.
- In Real Life, organizations such as the Discovery Institute provide lists of people who have doubts about evolution as evidence for their position - but they're loaded primarily with people who have prestigious-looking science degrees in a different field, such as physics or engineering. Parodying the use of this fallacy, the National Center for Science Education started Project Steve, a much longer list of scientists (mostly in biology) who support evolution... named Steve.
- Which is much less than 1% of scientists worldwide, but the joke is that if having M.S. or Ph.D. in one's name confers authority in every branch of science, having "Steve" in one's name must confer authority in evolutionary biology (as a tribute to the late Stephen Jay Gould).
- Or, conversely,
If global warming is occurring and is caused by humans, then we are obligated to do something to stop or slow it.
The most effective way to do so is for businesses to cut down on carbon emissions.
The long-term economic benefits of stopping global warming will be enormous.
Q.E.D.: Global warming is both occurring ''and' caused by humans.
- Ain't it fun when you can use the same fallacy and essentially the same argument and "prove" diametrically opposite conclusions?
- A related attempt to prove the existence of God is Anselm's Argument. To wit: Man can think some thoughts and imagine some ideas which are greater than others. An idea which is conceived of and which exists is better than one which is only imagined. There must exist some idea which is greater than all others. Such a thing would be God. Therefore God exists. This can be said to be an appeal to consequences because it assumes the most desirable possibility to be the real one, a bit like the preceding example about global warming. It also uses "greatness" in a rather shady way, leaves out the possibility that a fictional idea can be so much greater than all others that it doesn't need the added bonus of being real, and assumes that existence is proven by the idea of a thing and not the experience of it, But that's beside the point.
- Creationists like this one. In fact, even if Hitler's policies had been informed by a book that was banned under his rule, and the systematic slaughter of 14 million people could in any way be considered to be natural selection, this would have no bearing in the slightest on the scientific validity of evolutionary theory.
- Appeal To Obscurity: Something is wrong because nobody's ever heard of the person who did the thing. The person used in the example may not even exist.
Alice: I don't think I want to drill a hole in my head.
Bob: Yeah, Chuck Smithenson didn't drill a hole in his head either.
Alice: Who?
Bob: Exactly.
- If you break this one down and examine it, it's actually two fallacies wrapped up in one. Bob starts with a single example — Chuck Smithenson did not drill a hole in his head and did not become famous. First he commits an error of composition, extrapolating that into the general rule that anyone who does not drill a hole in their head will not become famous. Then he Denies the Antecedent — Anyone who does not drill a hole in their head will not become famous. Alice will drill a hole in her head, therefore Alice will become famous. Bad logic all around there, Bob.
- It is worth noting that Darryl Revok did drill a hole in his head and is moderately famous, but most of his fame derives from exploding someone else's head. Although his fame and his drill-scar are not coincident (they both derive from his being a mad psychic), correlation is not causation.
- Notably used in a milk advert, alongside an Appeal To Authority, in Britain in the '80's. Two kids had just finished playing football (soccer) and gone inside for refreshments. Kid 1 got himself a glass of milk:
Kid 2: Urgh... Milk? Kid 1: Ian Rush says that if I don't drink milk, when I grow up I'll only be good enough to play for Accrington Stanley. Kid 2: Accrington Stanley? Who're they? Kid 1: Exactly. (They then proceed to fight over the milk)
- Parodied in this ad for orange juice:
Kid: I'm not drinking [orange juice.]
Father: Oh no, it's sweet, you'll like it.
Kid: I don't believe you.
Father: Then who would you believe?
Kid: I don't know, Robert Loggia?
(Robert Loggia enters)
Kid: Whoa, Robert Loggia!
- "Bill Finger is an obscure comic book writer, so he couldn't possibly have created Batman."
- Appeal To Force, also termed "argumentum ad baculum", or "appeal to the stick": Perhaps the crudest form of appeal, this is, quite simply, saying that "I am right, because I will hit anyone who disagrees with me with this large stick." Ad Baculum is always a logical fallacy, but can be quite effective, nevertheless.
- Most commonly known by the phrase "Might Makes Right"; also sometimes expressed as "Changing a man's mind by altering the shape of his face."
- Jayne from Firefly referred to this as the Chain of Command. ("It's the chain I go get and beat you with 'til you understand who's in ruttin' command here!")
- This is the Krogan hat.
- This fallacy is often shown as one person saying to another "One good reason? I'll give you five good reasons" as they very obviously curl their fingers one by one into a fist, held under the other's nose. Charles Schultz used this image several times in various Peanuts strips, as well as A Charlie Brown Christmas, usually with Lucy using it against either Charlie Brown or Linus.
- A slight variation of this appears often in political foreign-policy debates: "The time for diplomacy is past — we must bomb Tropeistan now!"
- In the movie No Man's Land, the Bosnian and Serbian soldiers are arguing over whose country started the war, with the Bosnian eventually threatening the other with his gun to get him to agree. Later, the Serbian gains control of the gun and uses the opportunity to force the Bosnian to say that it was Bosnia who started it.
- Appeal To Technological Paranoia: Playing on people's fears or misunderstanding about technology in order to convince them of your argument. A big favorite with conspiracy-theorists, and often used in association with the Slippery Slope fallacy, as in "Cell phones may be handy, but since they can be located by triangulating the signal from several towers, the government can use that to keep track of where you are, whenever you have your cell phone on!"
- Appeal To Technology: The opposite of the previous fallacy: if it's more technologically advanced, it must be better. This fallacy most often shows up in combination with Appeal to Novelty, and is a favorite of consumer goods manufacturers.
- One ad for a home pregnancy test uses this fallacy when it says "ClearBlue Easy is the most advanced piece of technology you'll ever ... pee on." The whole ad makes it rather clear that it's being done at least somewhat tongue-in-cheek, though.
- Multi-blade razors also rely on this fallacy. If two blades are good, three blades must be better, and five plus a moisturizing strip better yet. See also Shaving Is Science.
- A car ad that mentioned that the vehicle in question gathered a lot of data about the road surface. And then said absolutely nothing about what it uses the data for.
- Appeal to Ignorance: Claiming to have proven that a statement is true (or false) when all that has actually been proven is that the statement's truth value is not known (specifically, that it is not known to be false). Famously refuted by Carl Sagan with the statement, "Absence of evidence is not evidence of absence." Based on shifting the burden of proof onto whichever side of the argument you want to lose: if something can not be proven either way, just act like the opinion opposite of yours is inherently sillier, and you can assert that your position must be assumed correct until someone from the other side can prove you wrong. Usually involves an appeal to one's own authority: If you can't prove me wrong, I'm right, because my opinion is truth-by-default.
- To write out arguments from opposite sides using this to show the problem: "You can't prove that my argument is wrong, so I'm right." versus "You can't prove that your argument is right, so you're wrong and I'm right."
- Irrelevant Thesis (Ignoratio Elenchi): The formal name literally means "ignorance of refutation" — this is not refuting the opposing position at all, but acting as though you did. It's really a superfallacy, in the same way that "Rule Of Cool" is a supertrope; there are a number of fallacies which are all types of "Ignoratio Elenchi", among them all Appeals To Consequences, all Appeals To Emotion, all Strawmen and Red Herrings, Ad Baculum, Ad Nauseum, and all Ad Hominems.
- This one probably occurs in a supermajority of all arguments on the Internet.
- Appeal To Brevity: one that seems to have been born on the internet (usually expressed with "tl;dr" ("too long; didn't read")), this is assuming that somebody is wrong because they have spent a good deal of time and text explaining their position. (Or more often, simply assuming that their argument is not worth listening to and that one is justified in ignoring it.) Misuse of Occam's Razor, if you will.
- Appeal To Worse Problems (the Children Are Starving In Africa Argument): Accusing someone with a minor complaint of being a horrible person who doesn't care about the real problems in the world. This assumes three things:
- That it is not possible to care about big and small problems simultaneously.
- That venting a minor complaint is sufficient proof that the major problem is considered unimportant.
- That if the person irritated over the minor problem did help solve the big problems, he would then not mind at all that his car broke down or whatever the frustration was.
- Incidentally, I've never seen anyone who actually has charity work under their belt use disadvantaged people as leverage in arguments.
- This (specifically the starving African children) has become a fairly popular T-Shirt. It personifies Africa as saying "And you think you have problems..."
- Appeal to pity: (ad misericordiam): Attempting to make someone feel sorry for either the arguer or the subject of the argument, in order to convince them to accept the argument regardless of its validity.
- A Gentleman will always apologize to a Lady if it turns out that he was right and she was wrong.
Of course, before you get too carried away with these fallacies, there's one more you should remember:
- The Fallacy Fallacy (or Appeal to Fallacy): Claiming that a position must be false because the argument used to get to that position used a fallacy. It may sound logical, but just see an example:
- Albert Einstein says General Relativity dictates the existence of black holes
- Albert Einstein is a genius and expert on General Relativity
- Hence, Black holes do exist
- You just committed the Appeal to Authority!
- Hence, Black holes do not exist.
(Black Holes probably do exist)
To read TV Tropes, you must be on the Internet.
You are on the Internet, therefore you must be reading TV Tropes.
But wait, I just used the "Affirming the consequent" fallacy!
Therefore my argument was wrong, and therefore you're not reading TV Tropes at all!
- Lore has a nice video on the subject.
- One common cause of the Fallacy Fallacy is Completely Missing The Point. The speaker might primarily have in mind a different premise.
- For instance, in the Firefly episode where Simon and Mal are trying to save River from the townsfolk who are going to burn her as a witch, the arguments
River Tam is just a troubled girl.
Therefore River is not a witch.
- is Appeal to Pity (a witch can also be a troubled girl) and
Jayne is lookin' to kill some folk.
Therefore River is not a witch.
- is Appeal to Force (the fact that Jayne desires to kill people doesn't prove River is not a witch).
- But those two arguments assume that the real premise Simon and Mal are concerned about is "River is not a witch". The real premise is "Mal and Simon do not want River burnt", and therefore the argument is
Mal and Simon do not wish River burnt (true)
Incentives can potentially cause people to modify their actions (true)
Pity and force are potential incentives (true)
Therefore Simon's use of pity and Mal's use of the threat of force as incentives might potentially prevent the burning of River (indeterminable).
- And don't forget the opposite of that, the "garbage in, garbage out" principle. If one of your premises is wrong, then the argument can be logically valid and still have a false conclusion.
The moon is made of cheese.
Cheese is edible.
Therefore, the moon is edible.
- You can also guess the conclusion, but use a faulty premise, and then if the conclusion is right, pretend your guess was perfectly logical. The argument is still faulty.
—>"What else floats in water?"
"A duck."
"If she weighs the same as a duck...then she's made of wood..."
"And therefore...?"
That system wins, but everybody agrees it is because of games Y and Z, and circumstance W.
"I knew it would win!"
- And, to muddy the waters even more, your premises may be wrong, and your argument may be illogical, but you might reach a true conclusion anyway.
All humans are reptiles.
I have seen three reptiles that live on Earth.
Therefore, all humans live on Earth.
The moon is made out of green cheese.
Green cheese is delicious.
Hitler was the political leader of Germany from 1933 to 1945.
Therefore, the more massive something is, the stronger its gravity.
Your Head A Splode now.
And all of that is why logicians do not use the words "sound", "valid" and "true" interchangeably. The chain of reasoning itself can be sound or unsound, valid or invalid, but the argument as a whole is not "true" or "false". The premises and conclusion can be true or false, but they are not called "sound" or "valid".
- "True" refers to the factual accuracy of each individual premise and the conclusion. It's exactly what it sounds like but it does not address the validity of the argument. (A fallacious argument can give a true conclusion.)
All animals are dogs. (false premise)
Formal logic isn't as complicated as it seems. (true premise)
Therefore, all dogs are animals. (true conclusion; no logical argument at all)
- "Valid" refers to the chain of reasoning, the logic part of the argument. It does not address the truth of either the premises or the conclusion. The logic must be correct, though.
All animals are dogs. (false premise)
All dogs are terriers. (false premise)
Therefore, all animals are terriers. (false conclusion; valid logic)
- "Sound" refers to the argument as a whole. The premises must be "true", the conclusion must be "true", and the logic must be "valid". (Using a fallacy results in an unsound argument, as does using false premises or coming to a false conclusion.)
All terriers are dogs.
All dogs are animals.
Therefore, all terriers are animals.
The perfect argument, then, is true and valid, and therefore sound. In other words, the argument must be based on accurate information, produce a true conclusion, and not contain any errors in logic.
If you have read this entire page, you may find this webcomic page to be useful revision material. How many logical fallacies do you think Bob is making here?
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