LOGICAL FALLACIES

What are logical fallacies? When trying to make a case or argument where logic is missing or something in the case is not clear When trying to make a case or argument where logic is missing or something in the case is not clear Is not necessarily a false statement Is not necessarily a false statement Can be useful in debates Can be useful in debates

Why learn logical fallacies? Point them out when an opponent uses one or offer reasoning if you use them Point them out when an opponent uses one or offer reasoning if you use them Make you look smart Make you look smart Impresses judges Impresses judges Can remove an argument from the table not just weaken it Can remove an argument from the table not just weaken it You can know when you are using them and prepare for your opponents argument rather than being taken off guard and unprepared You can know when you are using them and prepare for your opponents argument rather than being taken off guard and unprepared

How do you point them out? State the name of fallacy in Latin and English making sure to use the phrase “logical fallacy” State the name of fallacy in Latin and English making sure to use the phrase “logical fallacy” Tell everyone what the fallacy means and why it is wrong but do it without sounding pedantic (smarter than everyone else) Tell everyone what the fallacy means and why it is wrong but do it without sounding pedantic (smarter than everyone else) Give a really obvious example of why the fallacy is incorrect, preferably the example should also be an unfavorable analogy for your opponents case Give a really obvious example of why the fallacy is incorrect, preferably the example should also be an unfavorable analogy for your opponents case Point out why the fallacy matters to the debate round Point out why the fallacy matters to the debate round

Argumentun ad antiquitatem The argument to antiquity or tradition The argument to antiquity or tradition Argument that a policy, behavior or practice is right or acceptable because “its always been done that way” Argument that a policy, behavior or practice is right or acceptable because “its always been done that way” Example: “every great civilization in history has provided states subsidies for art and culture” Example: “every great civilization in history has provided states subsidies for art and culture” Try to avoid it but if you do use it, try to give a reason why it should be considered Try to avoid it but if you do use it, try to give a reason why it should be considered

Argumentum ad hominem Argument directed at the person Argument directed at the person Attacking the character or motives of a person who has stated and idea rather than the idea itself; can also be an attack on the source of information Attacking the character or motives of a person who has stated and idea rather than the idea itself; can also be an attack on the source of information “my opponents are fascists” or “Richard Nixon was liar and a cheat” “my opponents are fascists” or “Richard Nixon was liar and a cheat” Can also be used when the person talking has something to gain from the policy (example: Bill Gates talking against anti-trust legislation) Can also be used when the person talking has something to gain from the policy (example: Bill Gates talking against anti-trust legislation)

Argumentum ad ignorantiam Argument to ignorance Argument to ignorance Assuming something is true simple because it hasn’t been proven false (example: global warming is true because nobody has demonstrated conclusively it is not) Assuming something is true simple because it hasn’t been proven false (example: global warming is true because nobody has demonstrated conclusively it is not) Which ever team/person has “burden of proof” (usually affirmative) has to be more careful in using this fallacy Which ever team/person has “burden of proof” (usually affirmative) has to be more careful in using this fallacy Example: Prosecution who says that no alibi means guilty vs.. Defense saying prosecution didn’t prove case so defendant is not guilty Example: Prosecution who says that no alibi means guilty vs.. Defense saying prosecution didn’t prove case so defendant is not guilty

Argument ad logicam Argument to logic Argument to logic Assuming that something is false simply because proof or argument that someone has offered for it is invalid Assuming that something is false simply because proof or argument that someone has offered for it is invalid Also known as Straw Man argument Also known as Straw Man argument Burden of proof determines whether it is fallacy or not (if affirmative team fails to provide sufficient support for its case, the burden of proof dictates they should lose the debate even if there exist other arguments not presented that could have supported the case) Burden of proof determines whether it is fallacy or not (if affirmative team fails to provide sufficient support for its case, the burden of proof dictates they should lose the debate even if there exist other arguments not presented that could have supported the case)

Argumentum ad misericordian Argument or appeal to pity Argument or appeal to pity Example: “Think of all the poor, starving people in Ethiopia. How can we not help them?” Example: “Think of all the poor, starving people in Ethiopia. How can we not help them?” This doesn’t mean you can’t argue for something like aid to Ethiopia, what it does mean is that you can’t just use emotional pleas This doesn’t mean you can’t argue for something like aid to Ethiopia, what it does mean is that you can’t just use emotional pleas Do not use it unless the opposition has ONLY offered emotional pleas Do not use it unless the opposition has ONLY offered emotional pleas

Argumentum ad nauseam Argument to the point of disgust (repetition) Argument to the point of disgust (repetition) Trying to prove something by saying it again and again Trying to prove something by saying it again and again Stating a main point over and over again instead of real arguments Stating a main point over and over again instead of real arguments Make sure you SUPPORT your main points Make sure you SUPPORT your main points

Argumentum ad numerum Argument or appeal to numbers Argument or appeal to numbers Attempt to prove something by showing how many people think that it’s true Attempt to prove something by showing how many people think that it’s true Example: 70% of all Americans support restrictions on access to abortions Example: 70% of all Americans support restrictions on access to abortions Don’t confuse this with argumentum ad populum Don’t confuse this with argumentum ad populum

Argumentum ad populum Appeal to people or to popularity Appeal to people or to popularity Trying to prove something by showing that the public agrees with you Trying to prove something by showing that the public agrees with you Narrowly designates an appeal to the opinions of people in the immediate vicinity like your judges Narrowly designates an appeal to the opinions of people in the immediate vicinity like your judges

Argumentum ad verecundiam Argument or appeal to authority Argument or appeal to authority Someone tries to demonstrate the truth of a proposition by citing some person who agrees, even though that person may have no expertise in the given area Someone tries to demonstrate the truth of a proposition by citing some person who agrees, even though that person may have no expertise in the given area Example: Quoting Einstein on politics Example: Quoting Einstein on politics Only use this when they don’t use qualified quotes to support the same point and/or imply some policy is right because so-and-so thought so Only use this when they don’t use qualified quotes to support the same point and/or imply some policy is right because so-and-so thought so

Circulus in demonstrando Circular argument Circular argument Someone uses what they are trying to prove as part of the proof of that thing Someone uses what they are trying to prove as part of the proof of that thing Always illegitimate but hard to spot Always illegitimate but hard to spot

Complex Question Question that implicitly assumes something to be true by its construction Question that implicitly assumes something to be true by its construction Example: Have you stopped beating your wife” or “Inasmuch as the majority of black Americans live in poverty, do you really think that self-help within the black community is sufficient to address their problems?” Example: Have you stopped beating your wife” or “Inasmuch as the majority of black Americans live in poverty, do you really think that self-help within the black community is sufficient to address their problems?” Only a fallacy when used for something that hasn’t been proved Only a fallacy when used for something that hasn’t been proved

Cum hoc ergo propter hoc With this, therefore because of this With this, therefore because of this Mistaking correlation for causation (because two things occur simultaneously, one must be a cause of the other) Mistaking correlation for causation (because two things occur simultaneously, one must be a cause of the other) Example: President Clinton has great economic policies, just look at how great the economy is Example: President Clinton has great economic policies, just look at how great the economy is Usually called post hoc Usually called post hoc

Dicto simpliciter Sweeping generalization Sweeping generalization Making a sweeping statement and expecting it to be true of every specific case; aka “stereotyping” Making a sweeping statement and expecting it to be true of every specific case; aka “stereotyping” Example: Women on average are not as strong as mean and less able to carry a gun. Therefore women can’t pull their weight in a military unit. Example: Women on average are not as strong as mean and less able to carry a gun. Therefore women can’t pull their weight in a military unit. When pointing it out in a round, try not to use the Latin and just attack the generalization When pointing it out in a round, try not to use the Latin and just attack the generalization

Nature, appeal to Assuming that whatever is natural or consistent with nature is good or that whatever conflicts with nature is bad Assuming that whatever is natural or consistent with nature is good or that whatever conflicts with nature is bad Fairly rare, but usually seen in environmentalist argument Fairly rare, but usually seen in environmentalist argument

Naturalistic Fallacy Trying to derive conclusions about what is right or good (about values) from statements of fact alone Trying to derive conclusions about what is right or good (about values) from statements of fact alone Any inference of fact is another fact NOT a value Any inference of fact is another fact NOT a value “The medicine will prevent you from dying” does not lead to ‘you should take this medicine” “The medicine will prevent you from dying” does not lead to ‘you should take this medicine” Examples include argumentum ad antiquities or appeal to nature Examples include argumentum ad antiquities or appeal to nature

Non Sequitur It does not follow It does not follow Stating as a conclusion, something that does not strictly follow from the premises Stating as a conclusion, something that does not strictly follow from the premises Example: Racism is wrong, therefore, we need affirmative action” Example: Racism is wrong, therefore, we need affirmative action” Try to to use this for every argument but use it when the opposition is trying to construct A lead to B leads to C without justifying each step in the chain Try to to use this for every argument but use it when the opposition is trying to construct A lead to B leads to C without justifying each step in the chain

Petitio Principii Begging the question Begging the question Assuming, when trying to prove something, what it is that your are trying to prove Assuming, when trying to prove something, what it is that your are trying to prove Very similar to circular argument Very similar to circular argument Occurs when a question has been asked before in the discussion then a conclusion is reached on a related matter without the question having been answered Occurs when a question has been asked before in the discussion then a conclusion is reached on a related matter without the question having been answered Example: “The fact that we believe pornography should be legal means that it is valid form of free expression. And since it’s free expression, it shouldn’t be banned” Example: “The fact that we believe pornography should be legal means that it is valid form of free expression. And since it’s free expression, it shouldn’t be banned”

Post hoc ergo propter hoc After this, therefore because of this After this, therefore because of this Assuming that A caused B simply because A happened prior to B Assuming that A caused B simply because A happened prior to B Example: most rapists read pornography when they were teenagers; obviously, pornography causes violence toward women. Example: most rapists read pornography when they were teenagers; obviously, pornography causes violence toward women. Similar to cum hoc ergo prompter hoc Similar to cum hoc ergo prompter hoc

Red herring Introducing irrelevant facts or arguments to distract from the question at hand Introducing irrelevant facts or arguments to distract from the question at hand Example: The opposition claims that welfare dependency leads to higher crime rates - but how are poor people supposed to keep a roof over their heads without our help? Example: The opposition claims that welfare dependency leads to higher crime rates - but how are poor people supposed to keep a roof over their heads without our help? It is not fallacious to argue that benefits of one kind may justify incurring costs of another kind It is not fallacious to argue that benefits of one kind may justify incurring costs of another kind

Slippery slope Not always a fallacy Not always a fallacy Argument that says adopting one policy or taking one action will lead to a series of other policies or actions also being taken without showing a causal connection between the advocated policy and the consequent policies Argument that says adopting one policy or taking one action will lead to a series of other policies or actions also being taken without showing a causal connection between the advocated policy and the consequent policies Example: If we legalize marijuana, the next thing you know we’ll legalize heroin, LSD and crack cocaine. Example: If we legalize marijuana, the next thing you know we’ll legalize heroin, LSD and crack cocaine.

Straw man Refuting a caricatured or extreme version of somebody’s argument rather than the actual argument they’ve made Refuting a caricatured or extreme version of somebody’s argument rather than the actual argument they’ve made Putting words into someone else’s mouth or misinterpreting something said Putting words into someone else’s mouth or misinterpreting something said

Tu quoque You too You too Defending an error in one’s reasoning by pointing out that one’s opponent has made the same error Defending an error in one’s reasoning by pointing out that one’s opponent has made the same error Example: They accuse us of making unjustified assertions. But they asserted a lot of things, too. Example: They accuse us of making unjustified assertions. But they asserted a lot of things, too. Can be helpful if both sides have done a bad job of debating and you want to point that out to the judges Can be helpful if both sides have done a bad job of debating and you want to point that out to the judges