Fallacies 2011

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FallaciesFlaws in the Structure of an Argument

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What are fallacies?

Fallacies are defects in an argument.

Fallacies cause an argument to be invalid,unsound, or weak.

Fallacies can be separated into twogeneral groups: formal and informal.

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Formal Fallacies

Formal fallacies are only found in deductive arguments.

Deductive arguments are supposed to be air-tight.

For a deductive argument to be valid, it must beabsolutely impossible for both its premises to be trueand its conclusion to be false. With a good deductiveargument, that simply cannot happen; the truth of the

premises entails the truth of the conclusion.

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Formal Fallacies

The classic example of a deductively validargument is: 1. All men are mortal. (premise)

2. Socrates is a man. (premise) 3. Therefore Socrates is mortal. (guaranteed conclusion)

It is simply not possible that both (1) and (2)

are true and (3) is false, so this argument isdeductively valid.

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Formal Fallacies

Any deductive argument that fails to meet this very highstandard commits a logical error, and so, technically, isfallacious.

This includes many arguments that we would usuallyaccept as good arguments, arguments that make theirconclusions highly probable but not certain.

Arguments that arent deductively valid are said tocommit a formal fallacy.

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Formal Fallacies

Example of a deductive argument with a formal fallacy:1. All humans are mammals. (premise)2. All cats are mammals. (premise)3. All humans are cats. (conclusion)

Both premises in this argument are true but theconclusion is false. The defect is a formal fallacy and canbe demonstrated by reducing the argument to its bare

structure:1. All A are C

2. All B are C

3. All A are B

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Formal Fallacies

With deductive arguments, it can behelpful to reduce an argument to itsstructure.All chickens are feathered animals. (premise)

Clucko is a chicken. (premise)

Therefore Clucko is a feathered animal. (guaranteedconclusion)

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Formal Fallacies

All chickens are feathered animals. (premise)

Quacko is a feathered animal. (premise)

Therefore Quacko is a chicken. (non-guaranteed

conclusion) This argument commits a formal fallacy in that

its form doesnt guarantee the truth of itsconclusion, even if the initial premises are true.

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The Problem of Conclusiveness in an Argument

Real-world arguments address contestableissues of truth and value that cannot be resolvedwith mathematical certainty.

Disputants can create only more or lesspersuasive arguments, never conclusive ones.

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The Problem of Conclusiveness in an Argument

Real-worldArguments

Unpersuasive PersuasiveConclusive

Logically soundAir-tight argument

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Informal Fallacies

They are flaws in the structure of an argument.

They are embedded in many everyday

arguments.

They sometimes make fallacious reasoning seem

deceptively persuasive

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Why Study Informal Fallacies?

Knowledge of informal fallacies is most useful when werun across arguments that we know are wrong, but wecannot quite say why.

Knowledge of informal fallacies can help you locatespecific weaknesses in others arguments . . . and inyour own!

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Warning!

Most students who study fallacies begin to find themplentiful in the arguments of those with whom theydisagree.

Realize that fallacies are most likely being used withequal frequency by you, as well as your friends.

Test your integrity by diligently seeking fallacies in yourown arguments.

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Informal Fallacies: Three Categories

1. Fallacies of Pathos

2. Fallacies of Ethos

3. Fallacies of Logos

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Fallacies of Pathos

Rest on flaws in the way an argument appeals tothe audiences emotions and values

Argument to the People

Appeal to IgnoranceAppeal to Popularity

Appeal to Pity

Red Herring

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Argument to the PeopleAppeal to Stirring Symbols

Appeal to the fundamental beliefs, biases, andprejudices of the audience in order to swayopinion through a feeling of solidarity among

those of a group.

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Argument to the PeopleAppeal to Stirring Symbols

The stirring symbol of the American flag

Allegiance to nationalistic values

Solidarity of American citizens

Ex: Joe Politician delivering a speech while wearing asuit made out material patterned with the American flag.

Ex: Marilyn Manson wiping his butt on an American flag.

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Appeal to Ignorance

Presenting assumptions, assertions, or evidencethat the audience is incapable of examining or

judging.

Maintaining that because a claim has not beendisproved, it must be true.

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Appeal to Ignorance

Ex: Researchers have not conclusively shown that thereis no monster at the bottom of Loch Ness; therefore, weshould expect to see the monster at any time.

Ex: There must be intelligent life on other planets. Noone has proven that there isnt.

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Appeal to Ignorance

Ex: Genetically modified organisms must be dangerousto our health because science has not proved that theyare safe.

Ex: Jones must have used steroids to get those bulging

muscles because he cannot prove that he has not usedsteroids.

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Appeal to PopularityThe Bandwagon Appeal

The argument rests on the assertion that sinceeverybody else is doing something, you should do it too.

These appeals are fallacious because the popularity ofsomething is irrelevant to its actual merits.

These appeals are common in advertising where theclaim that a product is popular substitutes for evidenceof the products excellence.

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Ex: All the popular, cool kids have tattoos; therefore, Ishould get a tattoo.

Ex: Everybody who has a Facebook page has a lot offriends; therefore, I should make a Facebook page.

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Ex: Living together before marriage is the rightthing to do because most couples are now doingit.

Ex: You should buy a Toyota Camry because itis the best-selling car in the world.

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Appeal to Pity

The arguer appeals to the audiencessympathetic feelings in order to support a claimthat should be decided on more relevant or

objective grounds.

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Appeal to Pity

Ex: Professor Rose, Im sorry I couldnt finish myessay. You dont understand how difficult my life is rightnow. My parents could not afford to send me to college,and I have to work two part-time jobs to pay for my

classes and books.

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Appeal to Pity

Ex: Honorable Judge, I should not be fined $250 fordriving 85 mph in a 25 mph zone because I wasdistraught from hearing the news of my brothers illnessand was rushing to see him in the hospital.

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Red Herring

Refers to the practice of throwing an audienceoff track by raising an unrelated or irrelevantpoint.

The name derives from the practice of using a redherring (a very smelly fish) to throw dogs off from ascent that they are supposed to be tracking.

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Red Herring

Ex: Jacks girlfriend asks, Where were you last night?Jack answers, I sure am glad to see you. You lookextra beautiful today!

Ex: Question to politician, Whats your stand on guncontrol? Politicians reply, Im for family values.

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Red Herring

Ex: I dont believe we should elect thiscandidate because she would have to put herchildren in daycare.

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Fallacies of Ethos

Fallacies of Ethos = Rest on a flawedrelationship between the argument and thecharacter of those involved in the argument.

Often these fallacies attack character or usecharacter instead of evidence for proof.

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Appeal to False Authority

The arguer appeals to the authority of a popular personrather than a knowledgeable one.

Many advertisements are based on this fallacy.

Testimony to support an argument should come from aperson competent in the field.

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Kobe Bryant says that Wheaties cereal keeps him on hisgame; therefore, Wheaties cereal is a good cereal.

Real evidence about the quality of Wheaties cereal

would include specific information about its nutritionalcontent rather than testimony from a hired athlete.

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My favorite actor, who appeared in a movie about AIDS,has testified that the HIV virus doesnt really cause AIDSand that there has been a cover-up. So, I think thatAIDS must be caused by something other than HIV, and

the drug companies are hiding it so that they can make

money from expensive anti-HIV drugs. The above argument bases its conclusion on the

testimony of an actor, apparently because he appeared

in a movie on the topic. Legitimate testimony on thenature of AIDS would have to come from doctors orscientists.

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Tom Cruise says that postpartum depression can be besttreated with vitamins because anti-depressant drugs aredangerous. Therefore, all women who claim they havepostpartum depression should stop taking anti-

depressants and start taking vitamins.

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Ad HominemAppeal to the person

Arguments that attack the character of thearguer rather than the argument itself Name-calling (referring to a disputant by unsavory

names)Appeal to prejudice (applying ethnic, racial, gender,

or religious slurs to an opponent)

Guilt by association (linking the opposition to

extremely unpopular groups or causes) Poisoning the Well (discrediting an opponent or an

opposing view in advance)

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Name-calling Ex: OJ Simpson claims that he is innocent, but hes a

wife beater.

Ex: Hugh Hefner, founder ofPlayboymagazine, hasargued against the censorship of pornography. ButHefner is an immature, self-indulgent millionaire whonever outgrew the adolescent fantasies of his youth.His argument is worthless.

Ex: All wars are not wrong. The people who say soare cowards.

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Appeal to prejudice Ex: Because he is extremely wealthy, our mayor

cannot properly represent this city.

Ex: I reject what Father Rolly has to say about theethical issues of abortion because he is a Catholicpriest. After all, Father Rolly is required to hold suchviews.

Ex: Of course she is in favor of Affirmative Action.What do you expect from a black woman?

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Guilt by Association Ex: Of course you support medical marijuana. All of

your friends are a bunch of pot-head hippies.

Ex: Professor Smith has argued against the theory ofevolution. But hes a member of the Communist

Bikers Association. I refuse to listen to him!

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Poisoning the Well

Ex: You are told, prior to meeting him, that your friends

boyfriend is a poseur and a mooch. When you meethim, everything you hear him say is tainted.

Ex: Before I leave the floor to the next speaker, I mustremind you that persons who oppose my plan do nothave the best interests of the working people in theirhearts.

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Straw Man

Greatly oversimplifying an opponents argumentin order to make it easier to refute or ridicule

Diverts attention from the real issue

The name comes from the practice of stuffing dummies andscarecrows with straw. When one attacks an opponent by puttingwords into the opponents mouth, one makes up a dummyposition. But just as beating up a scarecrow doesnt demonstrateany athletic accomplishment, beating up a straw man in an

argument doesnt demonstrate anything.

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Straw Man

Ex: You many think that levying confiscatory taxes onhomeless peoples cardboard dwellings is the surest wayout of a recession, but I dont.

Ex: While my opponent would like to empty our prisonsof serial killers, I hold to the sacred principles ofcompensatory justice.

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Fallacies of Logos

Rest on flaws in the relationship amongstatements in an argument

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Hasty Generalization

Making a broad generalization on the basis oftoo little evidence

Traditionally, faulty generalizations have beenlabeled either hasty or unrepresentative.

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Ex: Yesterday I met the most remarkable person. He iskind, considerate, sensitive, and thoughtful.

Ex: I talked to five people in my neighborhood, and all

of them said they had guns. The whole city must bearmed.

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Ex: My cousin is a college student, and he doesnt carethe least bit about politics. Students these days areterribly apathetic.

Ex: Jean writes poetry, and shes very sensitive andfrequently depressed. People who write poetry aresensitive and prone to depression.

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Post Hoc, Ergo Propter HocAfter This, Therefore Because of This

Occurs when a sequential relationship ismistaken for a causal relationship

Confusing correlation for cause

Ex: Event A occurred before Event B; therefore,Event A must have caused Event B.

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Ex: Governor X took office in 2008. In 2009,the state suffered a severe recession.Therefore, Governor X should not be re-elected.

Ex: Cramming for a test really helps. Last weekI crammed for a psychology test, and I got an Aon it.

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Superstition is often based on this fallacy.

Ex: Since I walked under that ladder yesterday, Ive lost

my wallet and received a speeding ticket.

Ex: Everything was going fine until the lunar eclipse lastmonth; thats why the economy is in trouble.

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Begging the QuestionCircular Reasoning

Supporting a claim with a reason thatsimply restates the claim in differentwords

Ex: Bungee-jumping is dangerous because itsunsafe.

Ex: Women should not be permitted to join mens

clubs because the clubs are for men only.

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Begging the QuestionCircular Reasoning

Ex: Abortion is murder because it is theintentional taking of the life of a human being.

Because murder is defined as the intentional taking ofthe life of a human being, the argument is circular.

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False Dilemma Either/Or

Oversimplifying a complex issue so that only two choicesappear possible

No alternative, middle-ground, or compromise positionsare acknowledged.

Often one of the choices is made to seem unacceptable ,so the only remaining option is the other choice. Ex: Its my way or the highway.

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Ex: Love football or youre not a man.

Ex: A woman can either be a mother or have a

career.

Ex: Either we get tough with drug users, or we

legalize all drugs.

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Ex: Either we allow embryonic stem cellresearch, or we condemn persons with diabetes,Parkinsons disease, or spinal injuries to a life

without a cure.

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Slippery Slope

Based on the fear that once we put a foot on aslippery slope heading in the wrong direction,we will have to keep going.

The controlling metaphor is of a slickmountainside without places to hold on ratherthan of a staircase with numerous stoppingplaces.

Often functions as a scare tactic

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Slippery Slope

Ex: Look, Joe, no one feels worse about yourneed for open-heart surgery than I do. But Istill cannot let you turn this essay in late. If I

were to let you do it, then I would have to leteveryone turn essays in late.

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Slippery Slope

Ex: We dont dare legalize marijuana. If we do,well have to legalize cocaine, then ecstasy, andthen heroin. Finally, all hard hard drugs will be

available anywhere to anybody.

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False Analogy

Arguments by analogy use a comparison asthough it were evidence to support a claim.

An argument by analogy is only as strong as thecomparison on which it rests. The false analogyfallacy is committed when the comparison is notstrong enough.

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False Analogy

Ex: There is no convincing evidence to showthat cigarette smoking is harmful. Too much ofanything is harmful. Too much Jell-O is harmful.

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False Analogy

Ex: Mountain climber talking to hismother, I dont want to die falling off arock. But you can kill yourself falling in

the bathtub, too.

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False Analogy

Ex: In his autobiography, Tommy Chong writesthat when DEA (Drug Enforcement

Administration) agents raided his house he saw

himself as Anne Frank talking to Herr Mengele.. . For the first time, I felt like I couldunderstand what the Jews suffered under Hitler,and this was happening in America in 2003.

N S i

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Non SequiturIt Does Not Follow

Making a claim that does not follow logicallyfrom the premises or is supported by irrelevantpremises.

The arguer seems to make an inexplicablyillogical leap.

There is a disconnect between the reasons andthe claim.

N S it

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Ex: Violent video games have some socialvalue because the Army uses them forrecruiting.

There may be an important idea emerging here,

but too many logical steps are missing.

N S it

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Ex: Our university has one of the best facultiesin the U.S. because a Nobel Prize winner used toteach here.

How does the fact that a Nobel Prize winner used toteach at our university make its present faculty one ofthe best in the U.S.?

N S it

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Ex: Its a beautiful day! We dont need to be inclass.

Ex: The professor in the Hawaiian shirt and flipflops must be an easy grader.

N S it

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Ex: The man with the powerful new computermust be highly skilled in the use of computertechnology.

Ex: Emily is on academic probation, but herhours at work have changed, so she will dobetter in her classes now.

N S it

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Ex: Donald Trump, the billionaire real-estate developer,in considering a run for president in 2000, told aninterviewer: My entire life, Ive watched politicians bragging about how poor they are, how

they came from nothing, how poor their parents and grandparents were. And I

said to myself, if they can stay so poor for so many generations, maybe this isntthe kind of person we want to be electing to a higher office. How smart canthey be? Theyre morons. Do you want someone who gets to be president andthats literally the highest paying job hes ever had?

As a brief glance at U.S history shows, it does not followthat men of small success in the world of commerce are

unfit to make sound decisions about matters of state.

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Fallacies 2011

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Fallacies 2011