A fallacy is the use of poor, invalid or flawed reasoning. Logical fallacies may be deceptive tricks or illusions of thought committed either intentionally to manipulate or persuade people, or committed unintentionally through carelessness or ignorance. They're often used by politicians and the media. Try spotting them yourselves once you've familiarised yourselves with the common fallacies below. The fallacies listed below are taken from the excellent sites: logicallyfallacious.com and Nizkor.org, who have kindly allowed us to use their content here.

  • 1. Ad Hominem
      AKA:
    • argumentum ad hominem
    • personal attacks
    • name calling
      logical form:
    • Person 1 is claiming Y.
    • Person 1 is a moron.
    • Therefore, Y is not true.
    definition:

    Attacking the person making the argument, rather than the argument itself, when the attack on the person is completely irrelevant to the argument the person is making.

    example:

    "My opponent suggests that lowering taxes will be a good idea -- this is coming from a woman who eats a pint of Ben and Jerry’s each night!"

    The fact that the woman loves her ice cream, has nothing to do with the lowering of taxes, and therefore, is irrelevant to the argument. Ad hominem attacks are usually made out of desperation when one cannot find a decent counter argument.

  • 2. Ad Hominem Tu Quoque
      AKA:
    • you too fallacy
      logical form:
    • Person A makes claim X.
    • Person B asserts that A's actions or past claims are inconsistent with the truth of claim X.
    • Therefore X is false.
    definition:

    This fallacy is committed when it is concluded that a person's claim is false because 1) it is inconsistent with something else a person has said or 2) what a person says is inconsistent with her actions.

    The fact that a person makes inconsistent claims does not make any particular claim he makes false (although of any pair of inconsistent claims only one can be true - but both can be false). Also, the fact that a person's claims are not consistent with his actions might indicate that the person is a hypocrite but this does not prove his claims are false.

    example:

    Peter:"Based on the arguments I have presented, it is evident that it is morally wrong to use animals for food or clothing."

    Bill:"But you are wearing a leather jacket and you have a roast beef sandwich in your hand! How can you say that using animals for food and clothing is wrong!"

  • 3. Appeal to Authority
      AKA:
    • argumentum ad verecundiam
    • argument from authority
    • appeal to false authority
      logical form:
    • According to person 1, Y is true.
    • Therefore, Y is true.
    definition:

    Using an authority as evidence in your argument when the authority is not really an authority on the facts relevant to the argument. As the audience, allowing an irrelevant authority to add credibility to the claim being made.

    example:

    "The Pope told me that priests can turn bread and wine into Jesus’ body and blood. The Pope is not a liar. Therefore, priests really can do this."

    The Pope may believe what he says, and perhaps the Pope is not a liar, but the Pope is not an authority on the fact that the bread and wine are actually transformed into Jesus’ body and blood. After all, how much flesh and blood does this guy Jesus actually have to give?

  • 4. Appeal to Common Belief
      AKA:
    • groupthink
    • appeal to the masses
    • consensus fallacy
      logical form:
    • A lot of people believe X.
    • Therefore, X must be true.
    definition:

    When the claim that most or many people in general or of a particular group accept a belief as true is presented as evidence for the claim. Accepting another person’s belief, or many people’s beliefs, without demanding evidence as to why that person accepts the belief, is lazy thinking and a dangerous way to accept information.

    example:

    "How could you not believe in virgin births? Roughly two billion people believe in them, don’t you think you should reconsider your position?"

    Anyone who believes in virgin births does not have empirical evidence for his or her belief. This is a claim accepted on faith, which is an individual and subjective form of accepting information, that should not have any effect on your beliefs. Don’t forget that there was a time that the common beliefs included a flat earth, earth-centered universe, and demon-possession as the cause of most illness.

  • 5. Appeal to Faith
      AKA:
    • -
      logical form:
    • X is true.
    • If you have faith, you will see that.
    definition:

    This is an abandonment of reason in an argument and a call to faith, usually when reason clearly leads to disproving the conclusion of an argument. It is the assertion that one must have (the right kind of) faith in order to understand the argument.

    example:

    Jimmie:"Joseph Smith, the all American prophet, was the blond-haired, blue-eyed voice of God."

    Hollie:"What is your evidence for that?"

    Jimmie:"I don't need evidence — I only need faith."

    There are some things, some believe, that are beyond reason and logic. Fair enough, but the moment we accept this, absent of any objective method of telling what is beyond reason and why, anything goes.

  • 6. Appeal to Fear
      AKA:
    • scare tactics
    • appeal to force
    • ad baculum
      logical form:
    • Y is presented (a claim that is intended to produce fear).
    • Therefore claim X is true (a claim that is generally, but need not be, related to Y in some manner).
    definition:

    This line of "reasoning" is fallacious because creating fear in people does not constitute evidence for a claim. It is important to distinguish between a rational reason to believe (RRB) (evidence) and a prudential reason to believe (PRB) (motivation). A RRB is evidence that objectively and logically supports the claim. A PRB is a reason to accept the belief because of some external factor (such as fear, a threat, or a benefit or harm that may stem from the belief) that is relevant to what a person values but is not relevant to the truth or falsity of the claim. For example, it might be prudent to not fail the son of your department chairperson because you fear he will make life tough for you. However, this does not provide evidence for the claim that the son deserves to pass the class.

    example:

    "You know, Professor Smith, I really need to get an A in this class. I'd like to stop by during your office hours later to discuss my grade. I'll be in your building anyways, visiting my father. He's your dean, by the way. I'll see you later."

  • 7. Ambiguity Fallacy
      AKA:
    • amphiboly
    • type-token ambiguity
      logical form:
    • Claim X is made.
    • Y is concluded based on an ambiguous understanding of X.
    definition:

    When an unclear phrase with multiple definitions is used within the argument; therefore, does not support the conclusion. Some will say single words count for the ambiguity fallacy, which is really a specific form of a fallacy known as equivocation.

    example:

    "It is said that we have a good understanding of our universe. Therefore, we know exactly how it began and exactly when."

    The ambiguity here is what exactly “good understanding” means. The conclusion assumes a much better understanding than is suggested in the premise; therefore, we have the ambiguity fallacy.

  • 8. Anonymous Authority
      AKA:
    • appeal to anonymous authority
      logical form:
    • Person 1 once heard that X was true.
    • Therefore, X is true.
    definition:

    When an unspecified source is used as evidence for the claim. This is commonly indicated by phrases such as “They say that...”, “It has been said...”, “I heard that...”, “Studies show...”, or generalized groups such as, “scientists say...” When we fail to specify a source of the authority, we can’t verify the source, thus the credibility of the argument. Appeals to anonymous sources are more often than not, either a way to fabricate, exaggerate, or misrepresent “facts” in order to deceive others into accepting your claim. At times, this deception is done subconsciously -- it might not always be deliberate.

    example:

    "You know, they say that if you swallow chewing gum it takes 7 years to digest. So whatever you do, don’t swallow the chewing gum!"

    “They” are wrong as “they” usually are. Gum passes through the system relatively unchanged, but does not hang around for 7 years like a college student terrified to get a job. “They” is a common form of appeal to anonymous authority.

  • 9. Argument from Ignorance
      AKA:
    • appeal to ignorance
    • absence of evidence
    • argument from incredulity
      logical form:
    • X is true because you cannot prove that X is false.
    • X is false because you cannot prove that X is true.
    • Therefore, X is true.
    definition:

    The assumption of a conclusion or fact based primarily on lack of evidence to the contrary. Usually best described by, “absence of evidence is not evidence of absence.”

    example:

    "Although we have proven that the moon is not made of honey, we have not proven that its core cannot be filled with it; therefore, the moon’s core is filled with honey."

    There is an infinity of things we cannot prove - the moon being filled with honey is one of them. Now you might expect that any “reasonable” person would know that the moon can’t be filled with honey, but you would be expecting too much. People make wild claims, and get away with them, simply on the fact that the converse cannot otherwise be proven.

  • 10. Begging the Question
      AKA:
    • petitio principii
    • assuming the answer
    • circular reasoning
      logical form:
    • Claim X assumes X is true.
    • Therefore, claim X is true.
    definition:

    Any form of argument where the conclusion is assumed in one of the premises. Many people use the phrase “begging the question” incorrectly when they use it to mean, “prompts one to ask the question”. That is NOT the correct usage. Begging the question is a form of circular reasoning.

    This sort of "reasoning" is fallacious because simply assuming that the conclusion is true in the premises does not constitute evidence for that conclusion. Obviously, simply assuming a claim is true does not serve as evidence for that claim. This is especially clear in particularly blatant cases: "X is true. The evidence for this claim is that X is true."

    Some cases of question begging are fairly blatant, while others can be extremely subtle.

    example:

    "Paranormal activity is real because I have experienced what can only be described as paranormal activity."

    The claim, “paranormal activity is real” is supported by the premise, “I have experienced what can only be described as paranormal activity.” The premise presupposes, or assumes, that the claim, “paranormal activity is real” is already true.

  • 11. Biased sample fallacy
      AKA:
    • biased statistics
    • loaded sample
    • unrepresentative generalisation
      logical form:
    • Sample S, which is biased, is taken from population P.
    • Conclusion C is drawn about population P based on S.
    definition:

    Drawing a conclusion about a population based on a sample that is biased, or chosen in order to make it appear the population on average is different than it actually is.

    example:

    "Based on a survey of 1000 UK homeowners, 99% of those surveyed have two or more automobiles worth on average £100,000 each. Therefore, Britains are very wealthy."

    Where did these homeowners live? Mayfair, London? If the same exact survey was taken in another suburb or another city, the results would be quite different. It is fallacious to accept the conclusion about the UK population in general based on not just the geographical sample, but also the fact that homeowners were only surveyed.

  • 12. Emotive Language
      AKA:
    • argument by emotive language
    • loaded words
    • loaded language
      logical form:
    • Person A claims that X is true.
    • Person A uses very powerful and emotive language in the claim.
    • Therefore, X is true.
    definition:

    Substituting facts and evidence with words that stir up emotion, with the attempt to manipulate others into accepting the truth of the argument.

    example:

    "By rejecting God, you are rejecting goodness, kindness, and love itself."

    Instead of just “not believing” in God, we are “rejecting” God, which is a much stronger term — especially when God is associated with “goodness”.

  • 13. Equivocation
      AKA:
    • doublespeak
    definition:

    Using an ambiguous term in more than one sense, thus making an argument misleading.

    example:

    "I want to have myself a merry little Christmas, but I refuse to do as the song suggests and make this celebration gay. I don't think sexual preference should have anything to do with enjoying the holiday."

    The word, “gay” is meant to be in light spirits, joyful, and merry, not in the homosexual sense.

  • 14. Failure to Elucidate
      AKA:
    • Obscurum per Obscurius
      logical form:
    • Person 1 makes a claim.
    • Person 2 asks for clarification of the claim, or a term being used.
    • Person 1 restates the claim or term in a more confusing way.
    definition:

    When the definition is made more difficult to understand than the word or concept being defined.

    example:

    Tracy:"I don’t like him because of his aura."

    TJ:"What do you mean by that?"

    Tracy:"I mean that he is projecting a field of subtle, luminous radiation that is negative."

    This is such a common fallacy, yet rarely detected as one. Usually, out of fear of embarrassment, we accept confusing definitions as legitimate elucidations, that is, we pretend the term that was defined is now clear to us. What exactly is the field? How is it detected? Are there negative and positive ones? How do we know?

  • 15. Fallacy of Composition
      AKA:
    • composition fallacy
      logical form:
    • Individual F things have characteristics A, B, C, etc.
    • Therefore, the whole class of F things has characteristics A, B, C, etc.
    definition:

    Inferring that something is true of the whole from the fact that it is true of some part of the whole.

    example:

    "A tiger eats more food than a human being. Therefore, tigers, as a group, eat more food than do all the humans on the earth."

  • 16. Fallacy of Division
      AKA:
    • diviaino fallacy
      logical form:
    • The whole, X, has properties A, B, C, etc.
    • Therefore the parts of X have properties A, B, C, etc.
    definition:

    The fallacy of Division is committed when a person infers that what is true of a whole must also be true of its constituents and justification for that inference is not provided.

    example:

    "Bill lives in a large building, so his apartment must be large."

  • 17. Fallacy of the Middle Way
      AKA:
    • golden mean fallacy
    • fallacy of moderation
      logical form:
    • Position A and B are two extreme positions.
    • C is a position that rests in the middle between A and B.
    • Therefore C is the correct position.
    definition:

    This fallacy is committed when it is assumed that the middle position between two extremes must be correct simply because it is the middle position. This line of "reasoning" is fallacious because it does not follow that a position is correct just because it lies in the middle of two extremes.

    example:

    "Some people claim that God is all powerful, all knowing, and all good. Other people claim that God does not exist at all. Now, it seems reasonable to accept a position somewhere in the middle. So, it is likely that God exists, but that he is only very powerful, very knowing, and very good. That seems right to me."

  • 18. False Dichotomy
      AKA:
    • false dilemma
    • either-or reasoning
    • fallacy of false choice
    • excluded middle
    • polarisation
    • black and white thinking
      logical form:
    • Either X or Y is true.
    • Either X, Y, or Z is true.
    definition:

    When only two choices are presented yet more exist, or a spectrum of possible choices exists between two extremes. False dilemmas are usually characterized by “either this or that” language, but can also be characterized by omissions of choices. Another variety is the false trilemma, which is when three choices are presented when more exist.

    example:

    "You are either with God, or against him."

    As Obi Wan Kenobi so eloquently puts it in Star Wars episode III, “Only a Sith deals in absolutes!” There are also those who simply don’t believe there is a God to be either with or against.

  • 19. Hasty Generalisation
      AKA:
    • argument from small numbers
    • insufficient sample
    • over generalization
      logical form:
    • Sample S is taken from population P.
    • Sample S is a very small part of population P.
    • Conclusion C is drawn from sample S.
    definition:

    Drawing a conclusion based on a small sample size, rather than looking at statistics that are much more in line with the typical or average situation.

    example:

    "My father smoked four packs of cigarettes a day since age fourteen and lived until age sixty-nine. Therefore, smoking really can’t be that bad for you."

    It is extremely unreasonable (and dangerous) to draw a universal conclusion about the health risks of smoking by the case study of one man.

  • 20. Loaded Question
      AKA:
    • plurium interrogationum
    • complex question fallacy
    • trick question
    • fallacy of presupposition
    definition:

    A question that has a presupposition built in, which implies something but protects the one asking the question from accusations of false claims. It is a form of misleading discourse, and it is a fallacy when the audience does not detect the assumed information implicit in the question, and accepts it as a fact.

    example:

    "How many times per day do you beat your wife?"

    Even if the response is an emphatic, “none!”, the damage has been done. If you are hearing this question, you are more likely to accept the possibility that the person who was asked this question is a wife-beater, which is fallacious reasoning on your part.

  • 21. Magical Thinking
      AKA:
    • post hoc fallacy
    • superstitious thinking
    definition:

    Making causal connections or correlations between two events not based on logic or evidence, but primarily based on superstition. Magical thinking often causes one to experience irrational fear of performing certain acts or having certain thoughts because they assume a correlation with their acts and threatening calamities.

    example:

    "Mr. Governor issues a proclamation for the people of his state to pray for rain. Several months later, it rains. Praise the gods!"

    Suggesting that appealing to the gods for rain via prayer or dance is just the kind of thing crazy enough to get you elected President of the United States, but there is absolutely no logical reason or evidence to support the claim that appealing to the gods will make it rain.

  • 22. Misleading Vividness
      AKA:
    • -
      logical form:
    • Dramatic or vivid event X occurs (and is not in accord with the majority of the statistical evidence).
    • Therefore events of type X are likely to occur.
    definition:

    Misleading Vividness is a fallacy in which a very small number of particularly dramatic events are taken to outweigh a significant amount of statistical evidence. This sort of "reasoning" is fallacious because the mere fact that an event is particularly vivid or dramatic does not make the event more likely to occur, especially in the face of significant statistical evidence.

    example:

    Joe and Drew are talking about flying.

    Joe:"When I was flying back to school, the pilot came on the intercom and told us that the plane was having engine trouble. I looked out the window and I saw smoke billowing out of the engine nearest me. We had to make an emergency landing and there were fire trucks everywhere. I had to spend the next six hours sitting in the airport waiting for a flight. I was lucky I didn't die! I'm never flying again."

    Drew:"So how are you going to get home over Christmas break?"

    Joe:"I'm going to drive. That will be a lot safer than flying."

    Drew:"I don't think so. You are much more likely to get injured or killed driving than flying."

    Joe:"I don't buy that! You should have seen the smoke pouring out of that engine! I'm never getting on one of those death traps again!"

  • 23. Moving the Goalposts
      AKA:
    • gravity game
    • raising the bar
    • demanding impossible perfection
      logical form:
    • Issue A has been raised, and adequately answered.
    • Issue B is then raised, and adequately answered.
    • .....
    • Issue Z is then raised, and adequately answered.
    • (despite all issues adequately answered, the opponent refuses to conceded or accept the argument.)
    definition:

    Demanding from an opponent that he or she address more and more points after the initial counter-argument has been satisfied refusing to concede or accept the opponent’s argument.

    example:

    Ken:"There has to be an objective morality because otherwise terms like “right” and “wrong” would be meaningless, since they have no foundation for comparison. "

    Rob:"The terms “right” and “wrong” are based on cultural norms, which do have a subjective foundation -- one that changes as the moral sphere of the culture changes. The term “heavy” does not have an objective standard, yet we have no problem using that term in a meaningful way. In fact, very few relational terms have any kind of objective foundation."

    Ken:"But without an objective morality, we would all be lost morally as a race."

    Rob:"Many would say that we are."

    Ken:"But how can you say that torturing children for fun is morally acceptable in any situation?"

    Rob:"Personally, I wouldn’t, but you are implying that anything that is not objective must necessarily be seen in all possible ways. A feather may not be seen as “heavy” to anyone, but that doesn’t mean its “lightness” is still not relative to other objects."

    Ken:"But God is the standard of objective morality. Prove that wrong!"

    Rob:"That I cannot do."

    Ken starts with a statement explaining why he thinks there has to be an objective morality -- a statement based on a reasonable argument that can be pursued with reason and logic. Rob adequately answers that objection, as indicated by Ken’s move away from that objection to a new objection. This pattern continues until we arrive at an impossible request. Despite all the objections being adequately answered, at no time does Ken concede any points or abandon the argument.

  • 24. No True Scotsman
      AKA:
    • no true Christian
      logical form:
    • All X are Y.
    • (it is clearly refuted that all X are not Y)
    • Then all true X are Y.
    definition:

    When a universal (“all”, “every”, etc.) claim is refuted, rather than conceding the point or meaningfully revising the claim, the claim is altered by going from universal to specific, and failing to give any objective criteria for the specificity.

    example:

    John:"Members of the UbaTuba White Men's Club are upstanding citizens of the community."

    Marvin:"Then why are there so many of these members in jail?"

    John:"They were never true UbaTuba White Men's Club members."

    Marvin:"What’s a true UbaTuba White Men's Club member?"

    John:"Those who don't go to jail."

    This is a very common form of this fallacy that has many variations. Every time one group member denounces another group member for doing or saying something that they don’t approve of, usually by the phrase, “he is not really a true [insert membership here]”, this fallacy is committed.

  • 25. Poisoning the Well
      AKA:
    • discrediting
    • smear tactics
      logical form:
    • Adverse information (be it true or false) about person 1 is presented.
    • Therefore, the claim(s) of person 1 will be false.
    definition:

    To commit a preemptive ad hominem attack against an opponent. That is, to prime the audience with adverse information about the opponent from the start, in an attempt to make your claim more acceptable, or discount the credibility of your opponent’s claim.

    example:

    Tim:"Boss, you heard my side of the story why I think Bill should be fired and not me. Now, I am sure Bill is going to come to you with some pathetic attempt to weasel out of this lie that he has created."

    Tim is poisoning the well by priming his boss by attacking Bill’s character, and setting up any defense Bill might present as “pathetic”. Tim is committing the fallacy here, but if the boss were to accept Tim’s advice about Bill, she, too, would be committing the fallacy.

  • 26. Prejudicial Language
      AKA:
    • variant imagization
      logical form:
    • Claim A is made using loaded or emotive terms.
    • Therefore, claim A is true.
    definition:

    Loaded or emotive terms used to attach value or moral goodness to believing the proposition.

    example:

    "All good Catholics know that impure thoughts are the work of the devil, and should be resisted at all costs.."

    The phrase “all good Catholics” is the loaded or prejudicial language being used. The implication is that Catholics who don’t resist impure thoughts are “bad Catholics”, which is not fair - they may just not be as strong willed, or perhaps they don’t agree with the Church's views on sex.

  • 27. Questionable Cause
      AKA:
    • cum hoc ergo propter hoc
    • post hoc ergo propter hoc
    • ignoring a common cause
    • confusing cause and effect
    • false cause
    • reversing causality
      logical form:
    • A is regularly associated with B; therefore, A causes B.
    definition:

    Concluding that one thing caused another, simply because they are regularly associated.

    The Questionable Cause Fallacy is actually a general type of fallacy. Any causal fallacy that involves an error in a reasoning due to a failure to adequately investigate the suspected cause is a fallacy of this type. Thus, fallacies like Post Hoc and Confusing Cause and Effect are specific examples of this type of fallacy.

    example:

    "Every time I go to sleep, the sun goes down. Therefore, my going to sleep causes the sun to set."

  • 28. Red Herring
      AKA:
    • Ignoratio elenchi
    • misdirection
    • irrelevant thesis
    • smokescreen
    • changing the subject
      logical form:
    • Argument A is presented by person 1.
    • Person 2 introduces argument B.
    • Argument A is abandoned.
    definition:

    Attempting to redirect the argument to another issue that to which the person doing the redirecting can better respond. While it is similar to the avoiding the issue fallacy, the red herring is a deliberate diversion of attention with the intention of trying to abandon the original argument.

    example:

    Mike:"It is morally wrong to cheat on your spouse, why on earth would you have done that?"

    Ken:"But what is morality exactly?"

    Mike:"It’s a code of conduct shared by cultures."

    Ken:"But who creates this code?..."

    Ken has successfully derailed this conversation off of his sexual digressions to the deep, existential, discussion on morality.

  • 29. Reducto ad Hitlerum
      AKA:
    • playing the Nazi card
    • Hitler Card
      logical form:
    • Person 1 suggests that Y is true.
    • Hitler liked Y.
    • Therefore, Y is false.

    • Person 1 suggests that Y is true.
    • Person 1’s rhetoric sounds a bit like Hitler’s.
    • Therefore, Y is false.
    definition:

    The attempt to make an argument analogous with Hitler or the Nazi party. Hitler is probably the most universally despised figure in history, so any connection to Hitler, or his beliefs, can (erroneously) cause others to view the argument in a similar light. However, this fallacy is becoming more well known as is the fact that it is most often a desperate attempt to render the truth claim of the argument invalid out of lack of a good counter argument.

    example:

    Peter Gibbons:"It's NOT wrong. INITECH is wrong. INITECH is an evil corporation, all right? Chochkies is wrong. Doesn't it bother you that you have to get up in the morning and you have to put on a bunch of pieces of flair?"

    Joanna:"Yeah, but I'm not about to go in and start taking money from the register."

    Peter Gibbons:"Well, maybe you should. You know, the Nazis had pieces of flair that they made the Jews wear."

    Joanna:"What?"

    The above was from the classic masterpiece film, “Office Space”. Out of desperation, Peter plays the Nazi card in order to make the idea of being made to wear flair more appalling. This somewhat jarring statement misdirects the argument, and the focus is taken off Joanna’s last response, which was quite good.

  • 30. Shifting the burden of proof
      AKA:
    • onus probandi
      logical form:
    • A asserts X is true.
    • B refutes the claim.
    • A demands B to prove it is false.
    definition:

    Placing the burden of proof on the wrong side of the argument. The burden of proof lies with the person who is making a claim. It is not up to someone else to disprove it. The inability to disprove a claim does not validate the claim and since we can never be certain of anything, we can only assign value to any claim based on the available evidence. To dismiss something on the basis that it hasn't been proven beyond all doubt is fallacious reasoning.

    example:

    Sarah:"I think that some people have psychic powers."

    Joanna:"What is your proof?

    Sarah:"Well, can you prove that people do not have psychic powers?"

  • 31. Slippery Slope
      AKA:
    • absurd extrapolation
    • thin edge of the wedge
    • camel's nose
    • domino fallacy
      logical form:
    • If A, then B, then C, ... then ultimately Z!
    definition:

    When a relatively insignificant first event is suggested to lead to a more significant event, which in turn leads to a more significant event, and so on, until some ultimate, significant event is reached, where the connection of each event is not only unwarranted, but with each step it becomes more and more improbable. Many events are usually present in this fallacy, but only two are actually required -- usually connected by “the next thing you know...”

    example:

    "We cannot unlock our child from the closet because if we do, she will want to roam the house. If we let her roam the house, she will want to roam the neighborhood. If she roams the neighborhood, she will get picked up by a stranger in a van, who will sell her in a sex slavery ring in some other country. Therefore, we should keep her locked up in the closet."

    In this example, it starts out with reasonable effects to the causes. For example, yes, if the child is allowed to go free in her room, she would most likely want to roam the house -- 95% probability estimate[1]. Sure, if she roams the house, she will probably want the freedom of going outside, but not necessarily “roaming the neighborhood”, but let’s give that a probability of say 10%. Now we start to get very improbable. The chances of her getting picked up by a stranger (.05%) in a van (35%) to sell her into sex slavery (.07%) in another country (40%) is next to nothing when you do all the math:.

    .95 x .10 x .0005 x .35 x .0007 x .4 = about 1 in 25,000,000.

    Morality and legality aside, is it really worth it to keep a child locked in a closet based on those odds?

  • 32. Special Pleading
      AKA:
    • -
    definition:

    Applying standards, principles, and/or rules to other people or circumstances, while making oneself or certain circumstances exempt from the same critical criteria, without providing adequate justification. Special pleading is often a result of strong emotional beliefs that interfere with reason.

    example:

    "Yes, I do think that all drunk drivers should go to prison, but your honor, he is my son! He is a good boy who just made a mistake!"

    The mother in this example has applied the rule that all drunk drivers should go to prison. However, due to her emotional attachment to her son, she is fallaciously reasoning that he should be exempt from this rule, because, “he is a good boy who just made a mistake”, which would hardly be considered adequate justification for exclusion from the rule.

  • 33. Spotlight
      AKA:
    • -
      logical form:
    • Xs with quality Q receive a great deal of attention or coverage in the media.
    • Therefore all Xs have quality Q.
    definition:

    The Spotlight fallacy is committed when a person uncritically assumes that all members or cases of a certain class or type are like those that receive the most attention or coverage in the media. This line of reasoning is fallacious since the mere fact that someone or something attracts the most attention or coverage in the media does not mean that it automatically represents the whole population. For example, suppose a mass murderer from Old Town, Maine received a great deal of attention in the media. It would hardly follow that everyone from the town is a mass murderer.

    example:

    Bill:"Jane, you say you are a feminist, but you can't be."

    Jane:"What! What do you mean? Is this one of your stupid jokes or something?"

    Bill:"No, I'm serious. Over the summer I saw feminists appear on several talk shows and news shows and I read about them in the papers. The women were really bitter and said that women were victims of men and needed to be given special compensation. You are always talking about equal rights and forging your own place in the world. So, you can't be a feminist."

    Jane:"Bill, there are many types of feminism, not just the brands that get media attention."

    Bill:"Oh, sorry."

  • 34. Strawman Fallacy
      AKA:
    • -
      logical form:
    • Person 1 makes claim Y.
    • Person 2 restates person 1’s claim (in a distorted way).
    • Person 2 attacks the distorted version of the claim.
    • Therefore, claim Y is false.
    definition:

    Substituting a person’s actual position or argument with a distorted, exaggerated, or misrepresented version of the position of the argument.

    example:

    Ted:"Biological evolution is both a theory and a fact."

    Edwin:"That is ridiculous! How can you possibly be absolutely certain that we evolved from pond scum!"

    Ted:"Actually that is a gross misrepresentation of my assertion. I never claimed we evolved from pond scum. Unlike math and logic, science is based on empirical evidence and, therefore, a scientific fact is something that is confirmed to such a degree that it would be perverse to withhold provisional consent. The empirical evidence for the fact that biological evolution does occur falls into this category."

    Edwin has ignorantly mischaracterized the argument by a) assuming we evolved from pond scum (whatever that is exactly), and b) assuming “fact” means “certainty”.

  • 35. Weak Analogy
      AKA:
    • false analogy
    • faulty analogy
    • false metaphor
      logical form:
    • X is like Y.
    • Y has property P.
    • Therefore, X has property P.
    • (but X really is not too much like Y)
    definition:

    When an analogy is used to prove or disprove an argument, but the analogy is too dissimilar to be effective, that is, it is unlike the argument more than it is like the argument.

    example:

    "Not believing in the literal resurrection of Jesus because the Bible has errors and contradictions, is like denying that the Titanic sank because eye-witnesses did not agree if the ship broke in half before or after it sank."

    There are several problems with this analogy, including:

    • The Titanic sank in recent history
    • We know for a fact that the testimonies we have are of eye-witnesses
    • We have physical evidence of the sunken Titanic
  • 36. Wishful Thinking
      AKA:
    • appeal to consequences
      logical form:
    • I wish X were true.
    • Therefore, X is true.
    definition:

    When the desire for something to be true is used in place of/or as evidence for the truthfulness of the claim. Wishful thinking, more as a cognitive bias than a logical fallacy, can also cause one to evaluate evidence very differently based on the desired outcome.

    example:

    "I know in my heart of hearts that our home team will win the World Series."

    No, you don’t know that, and what the heck is your “heart of hearts” anyway? This is classic wishful thinking -- wanting the home team to win so pretending that it is/has to be true.