It’s Autumn Now!It’s Autumn Now!• Inquiring Minds• report out on homework• fallacies pt1

Zaid Ali AlsagoffZaid Ali Alsagoff

zaid.alsagoff@gmail.czaid.alsagoff@gmail.comom

Module 4:Module 4:Fallacies Fallacies

Man or Woman?Man or Woman?

Source: http://www.coolopticalillusions.com/manwoman.htm

How many legs does this How many legs does this elephant have? elephant have?

Source: http://www.coolopticalillusions.com/elephantlegs.htm

Which officer is the tallest? Which officer is the tallest?

Source: http://www.coolopticalillusions.com/optical_illusions_images_2/giant_man.htm

Is this wave moving? Is this wave moving?

Source: http://www.grand-illusions.com/opticalillusions/oblong_wave/

AirAsia + Girls = Fun

Analyze Analyze + +

EvaluateEvaluate= =

Your Opinion?Your Opinion?Target Audience?Target Audience?

Module 4: FallaciesModule 4: Fallacies1. Fallacies of Relevance

2. Fallacies of Insufficient Evidence

What mistake!!!

4.0 What is a Fallacy?4.0 What is a Fallacy?• A (logical) fallacy is an argument that

contains a mistake in reasoningcontains a mistake in reasoning.

• Fallacies can be divided into two general types:

– Fallacies of RelevanceFallacies of Relevance Arguments in which the premises are logically irrelevant to the conclusion.

– Fallacies of Insufficient EvidenceFallacies of Insufficient Evidence Arguments in which the premises, though logically relevant to the conclusion, fail to provide sufficient evidence for the conclusion.

“There is nothing so stupid as an educated man,if you get him off the thing he was educated in”

- Will Rogers

4.1 Fallacies of Relevance4.1 Fallacies of Relevance• A statement is RELEVANTRELEVANT to another statement if

it provides at least some reason for thinking that the second statement is true or false.

• There are three ways in which a statement can be relevant or irrelevant to another:

– A statement is positively relevant to another statement if it provides at least some reason for thinking that the second statement is true.

– A statement is negatively relevant to another statement if it provides at least some reason for thinking that the second statement is false.

– A statement is logically irrelevant to another statement if it provides no reason for thinking that the second statement is either true or false.

4.1 Fallacies of Relevance4.1 Fallacies of RelevancePersonal Personal AttackAttack

Appeal to PityAppeal to Pity

Attacking the Attacking the MotiveMotive

Bandwagon Bandwagon ArgumentArgument

Look Who’s Look Who’s TalkingTalking

Straw ManStraw Man

Begging the Begging the QuestionQuestion

Red HerringRed Herring

Scare TacticsScare Tactics EquivocationEquivocationTwo Wrongs Make a RightTwo Wrongs Make a Right

4.1.1 Personal Attack4.1.1 Personal Attack

Example:Professor Doogie has argued for more

emphasis on music to facilitate creativity. But Doogie is a selfish bigheaded fool. I absolutely refuse to listen to him.

Personal Attack/Ad HominemPersonal Attack/Ad HominemWhen an arguer rejects a person’s argument or claim

by attacking the person’s character rather than examining the worth of the argument or claim itself.

Personal Attack/Ad HominemPersonal Attack/Ad HominemWhen an arguer rejects a person’s argument or claim

by attacking the person’s character rather than examining the worth of the argument or claim itself.

1. X is a 1. X is a bad person.bad person.2. Therefore X's 2. Therefore X's argument must be bad.argument must be bad.1. X is a 1. X is a bad person.bad person.2. Therefore X's 2. Therefore X's argument must be bad.argument must be bad.

Pattern

4.1.2 Attacking the Motive4.1.2 Attacking the Motive

Example: The Senator claims that congressional salaries should be

raised. He says business executives doing comparable work make much more and that congressional salaries haven't kept pace with inflation. But keep in mind what he does for a living. His self-serving recommendation must be rejected.

Attacking the MotiveAttacking the Motive When an arguer criticizes a person’s motivation for offering a particular argument or claim, rather thanexamining the worth of the argument or claim itself.

Attacking the MotiveAttacking the Motive When an arguer criticizes a person’s motivation for offering a particular argument or claim, rather thanexamining the worth of the argument or claim itself.

1.1. XX has biased or has questionable motives. has biased or has questionable motives.2.2. Therefore, Therefore, X’sX’s arguments or claim should be rejected arguments or claim should be rejected.1.1. XX has biased or has questionable motives. has biased or has questionable motives.2.2. Therefore, Therefore, X’sX’s arguments or claim should be rejected arguments or claim should be rejected.Patter

n

4.1.3 Look Who’s Talking4.1.3 Look Who’s Talking

Example:Doctor: You should quit smoking.Patient: Look who’s talking! I’ll quit when you do, Dr. Smokestack!

How can you tell me I should exercise to lose weight? All you do is sit behind a desk all day. I've never seen you do a lick of exercise

Look Who’s Talking (tu quoque) Look Who’s Talking (tu quoque) When an arguer rejects another person’s argument

or claim because that person is a hypocrite.

Look Who’s Talking (tu quoque) Look Who’s Talking (tu quoque) When an arguer rejects another person’s argument

or claim because that person is a hypocrite.

1.1. X X fails to follow his or her own advice.fails to follow his or her own advice.2.2. Therefore, Therefore, X’X’s claim or argument should be rejected.s claim or argument should be rejected.1.1. X X fails to follow his or her own advice.fails to follow his or her own advice.2.2. Therefore, Therefore, X’X’s claim or argument should be rejected.s claim or argument should be rejected.Patter

n

4.1.4 Two Wrongs Make a 4.1.4 Two Wrongs Make a RightRight

Examples:“I don’t feel guilty about cheating on the quiz. Half the

class cheats.” “Why pick on me, officer? Everyone else is using drugs.”

Two Wrongs Make a RightTwo Wrongs Make a RightWhen an arguer attempts to justify a wrongful act

by claiming that some other act is just as bad or worse.

Two Wrongs Make a RightTwo Wrongs Make a RightWhen an arguer attempts to justify a wrongful act

by claiming that some other act is just as bad or worse.

1. Others are committing worse or equally bad acts. 1. Others are committing worse or equally bad acts. 2. Therefore my wrongful act is justified.2. Therefore my wrongful act is justified. 1. Others are committing worse or equally bad acts. 1. Others are committing worse or equally bad acts. 2. Therefore my wrongful act is justified.2. Therefore my wrongful act is justified. Patter

n

4.1.5 Scare Tactics4.1.5 Scare Tactics

Example:Diplomat to diplomat: I’m sure you’ll agree that

we are the rightful rulers of the Iraq. It would be regrettable if we had to send armed forces to demonstrate the validity of our claim.

Scare TacticsScare TacticsWhen an arguer threatens harm to a reader or listener

and this threat is irrelevant to the truth of the arguer’s conclusion.

Scare TacticsScare TacticsWhen an arguer threatens harm to a reader or listener

and this threat is irrelevant to the truth of the arguer’s conclusion.

Fear is a powerful motivatorFear is a powerful motivator – so powerful that it often causes us to think and behave irrationally.Fear is a powerful motivatorFear is a powerful motivator – so powerful that it often causes us to think and behave irrationally.Rememb

er

4.1.6 Appeal to Pity4.1.6 Appeal to Pity

Example:Student to Lecturer: I know I missed half your classes

and failed all my quizzes and assignments. First my cat died. Then my girlfriend told me she has found someone else. With all I went through this semester, I don’t think I really deserve an F. Any chance you might cut me some slack and change my grade to a C or a D?

Appeal to PityAppeal to PityWhen an arguer attempts to evoke feelings of pity or

compassion, where such feelings, however understandable,are not relevant to the truth of the arguer’s conclusion.

Appeal to PityAppeal to PityWhen an arguer attempts to evoke feelings of pity or

compassion, where such feelings, however understandable,are not relevant to the truth of the arguer’s conclusion.

1.1. P is presented, with the intent to create pity. P is presented, with the intent to create pity. 2. Therefore claim C is true.2. Therefore claim C is true. 1.1. P is presented, with the intent to create pity. P is presented, with the intent to create pity. 2. Therefore claim C is true.2. Therefore claim C is true. Patter

n

4.1.7 Bandwagon Argument 4.1.7 Bandwagon Argument

Example:All the really cool students smoke

cigarettes. Therefore, you should, too.

Bandwagon Argument (Peer Pressure)Bandwagon Argument (Peer Pressure)When an arguer appeals to a person’s desire to be popular,

accepted, or valued, rather than to logically relevant reasons or evidence.

Bandwagon Argument (Peer Pressure)Bandwagon Argument (Peer Pressure)When an arguer appeals to a person’s desire to be popular,

accepted, or valued, rather than to logically relevant reasons or evidence.

1. Most (or a select group of) people believe or do X.1. Most (or a select group of) people believe or do X.2. Therefore, you should believe or do X.2. Therefore, you should believe or do X.1. Most (or a select group of) people believe or do X.1. Most (or a select group of) people believe or do X.2. Therefore, you should believe or do X.2. Therefore, you should believe or do X.Patter

n

4.1.8 Straw Man4.1.8 Straw Man

Example:

Singh and Karen are arguing about cleaning out their closets: Suzie: "We should clean out the closets. They are getting a bit

messy.“Singh: "Why, we just went through those closets last year. Do we

have to clean them out everyday?" Suzie: "I never said anything about cleaning them out every day. You

just want too keep all your junk forever, which is just ridiculous."

Straw ManStraw ManWhen an arguer misrepresents another person’s

position to make it easier to attack.

Straw ManStraw ManWhen an arguer misrepresents another person’s

position to make it easier to attack.

1. 1. Person A has position X. Person A has position X. 2. Person B presents position Y (which is a distorted version of X). 2. Person B presents position Y (which is a distorted version of X). 3. Person B attacks position Y. 3. Person B attacks position Y. 4. Therefore X is false/incorrect/flawed.4. Therefore X is false/incorrect/flawed.

1. 1. Person A has position X. Person A has position X. 2. Person B presents position Y (which is a distorted version of X). 2. Person B presents position Y (which is a distorted version of X). 3. Person B attacks position Y. 3. Person B attacks position Y. 4. Therefore X is false/incorrect/flawed.4. Therefore X is false/incorrect/flawed.

Pattern

4.1.9 Red Herring4.1.9 Red Herring

Example:"I think there is great merit in making the requirements stricter for

the graduation. I recommend that you support it, too. After all, we are in a budget crisis and we do not want our salaries affected."

Red HerringRed HerringWhen an arguer tries to sidetrack his audience by raising

an irrelevant issue, and then claims that the original issue has been effectively settled by the

irrelevant diversion.

Red HerringRed HerringWhen an arguer tries to sidetrack his audience by raising

an irrelevant issue, and then claims that the original issue has been effectively settled by the

irrelevant diversion.

1. Topic 1. Topic AA is under discussion. is under discussion. 2. Topic 2. Topic BB is introduced under the guise of being relevant is introduced under the guise of being relevant to topic A (when topic B is actually not relevant to topic A). to topic A (when topic B is actually not relevant to topic A). 3. Topic 3. Topic A A is abandoned.is abandoned.

1. Topic 1. Topic AA is under discussion. is under discussion. 2. Topic 2. Topic BB is introduced under the guise of being relevant is introduced under the guise of being relevant to topic A (when topic B is actually not relevant to topic A). to topic A (when topic B is actually not relevant to topic A). 3. Topic 3. Topic A A is abandoned.is abandoned.

Pattern

4.1.10 Equivocation 4.1.10 Equivocation

Example:In the summer of 1940, Londoners were bombed almost every night.

To be bombed is to be intoxicated. Therefore, in the summer of 1940, Londoners were intoxicated almost every night.

Hot dogs are better than nothing Nothing is better than steak. Therefore, hot dogs are better than steak.

EquivocationEquivocationWhen an arguer uses a key word in an argument in two

(or more) different senses.

EquivocationEquivocationWhen an arguer uses a key word in an argument in two

(or more) different senses.

Fallacies of Equivocation Fallacies of Equivocation can be difficult to spot becausethey often appear valid, but they aren’t.Fallacies of Equivocation Fallacies of Equivocation can be difficult to spot becausethey often appear valid, but they aren’t.Rememb

er

4.1.11 Begging the Question 4.1.11 Begging the Question

Example:I am entitled to say whatever I choose

because I have a right to say whatever I please.

Begging the QuestionBegging the QuestionWhen an arguer states or assumes as a premise (reason)

the very thing he is seeking to probe as a conclusion.

Begging the QuestionBegging the QuestionWhen an arguer states or assumes as a premise (reason)

the very thing he is seeking to probe as a conclusion.

Arguing in a circleArguing in a circle – A because B, B because A.Arguing in a circleArguing in a circle – A because B, B because A.Reason

I'm trying hard to understand this guy who identifies himself as a security supervisor and criticizes the police officers in this area. I can only come up with two solutions. One, he is either a member of the criminal element, or two, he is a frustrated security guard who can never make it as a police officer and figures he can take cheap shots at cops through the newspaper (adapted from a newspaper call-in column).

Which fallacy?Which fallacy?

A)A) Loaded QuestionLoaded QuestionB)B) Personal AttackPersonal AttackC)C) Bandwagon ArgumentBandwagon ArgumentD)D) Scare TacticsScare Tactics

4.1 Mini Quiz – Question 14.1 Mini Quiz – Question 1

The Red Cross is worried about the treatment of the suspected terrorists held by the U.S. at Guantanamo Bay, Cuba. What do they want the U.S. to do with them, put them on the beaches of Florida for a vacation or take them skiing in the Rockies? Come on, let's worry about the Americans. (adapted from a newspaper call-in column)

Which fallacy?Which fallacy?

A)A) Bandwagon ArgumentBandwagon ArgumentB)B) Personal AttackPersonal AttackC)C) Straw ManStraw ManD)D) Scare TacticsScare Tactics

4.1 Mini Quiz – Question 24.1 Mini Quiz – Question 2

“The foolish and the dead alone never change their opinion.”

- James Russell Lowell

4.2 Fallacies of Insufficient 4.2 Fallacies of Insufficient EvidenceEvidence

Arguments in which the Arguments in which the premises, though premises, though

logically relevant to the logically relevant to the conclusion, conclusion, fail to fail to provide sufficient provide sufficient

evidenceevidence to support the to support the conclusion.conclusion.

Arguments in which the Arguments in which the premises, though premises, though

logically relevant to the logically relevant to the conclusion, conclusion, fail to fail to provide sufficient provide sufficient

evidenceevidence to support the to support the conclusion.conclusion.

4.2 Fallacies of Insufficient 4.2 Fallacies of Insufficient EvidenceEvidence

Inappropriate Inappropriate Appeal to Appeal to AuthorityAuthority

Questionable Questionable CauseCause

Appeal to Appeal to IgnoranceIgnorance

Slippery SlopeSlippery Slope

False False Alternatives Alternatives

Weak AnalogyWeak Analogy

Loaded Loaded QuestionQuestion

InconsistencyInconsistency

Hasty Generalizations Hasty Generalizations

4.2.1 Inappropriate Appeal 4.2.1 Inappropriate Appeal to Authority to Authority

Example:My dentist told me that aliens built the lost city of

Atlantis. So, it’s reasonable to believe that aliens did build the lost city of Atlantis.

Inappropriate Appeal to AuthorityInappropriate Appeal to AuthorityCiting a witness or authority that is untrustworthy.

Inappropriate Appeal to AuthorityInappropriate Appeal to AuthorityCiting a witness or authority that is untrustworthy.

Authority AssessmentAuthority Assessment1. Is the source an authority on the subject at issue?2. Is the source biased?3. Is the accuracy of the source observations questionable?4. Is the source known to be generally unreliable?5. Has the source been cited correctly?6. Does the source’s claim conflict with expert opinion?7. Can the source’s claim be settled by an appeal to expert opinion?8. Is the claim highly improbable on its face?

Authority AssessmentAuthority Assessment1. Is the source an authority on the subject at issue?2. Is the source biased?3. Is the accuracy of the source observations questionable?4. Is the source known to be generally unreliable?5. Has the source been cited correctly?6. Does the source’s claim conflict with expert opinion?7. Can the source’s claim be settled by an appeal to expert opinion?8. Is the claim highly improbable on its face?Tips

4.2.2 Appeal to Ignorance 4.2.2 Appeal to Ignorance

Example:I’ve never seen a rainbow, so there’s no such thing.Yoda must exist. No one has proved that he

doesn’t exist.

Appeal to IgnoranceAppeal to IgnoranceClaiming that something is true because no one has

proven it false or vice versa.

Appeal to IgnoranceAppeal to IgnoranceClaiming that something is true because no one has

proven it false or vice versa.

““Not proven, therefore false”Not proven, therefore false”If such reasoning were allowed, we could prove almostany conclusion.

““Not proven, therefore false”Not proven, therefore false”If such reasoning were allowed, we could prove almostany conclusion.

Remember

AgreAgree I e I do!do!

4.2.3 False Alternatives4.2.3 False Alternatives

Example:The choice in this election is clear: Either we elect my

candidate as our next president, or we watch our country slide into anarchy and frustration. Clearly, we don’t want that to happen. Therefore, we should elect my candidate as our next president.

False AlternativesFalse AlternativesPosing a false either/or choice.

False AlternativesFalse AlternativesPosing a false either/or choice.

Fallacy of false alternatives Fallacy of false alternatives can involve more thanmore thantwo (2) alternativestwo (2) alternatives. It can also be expressed as a conditional (i (if-thenf-then) ) statement.

Fallacy of false alternatives Fallacy of false alternatives can involve more thanmore thantwo (2) alternativestwo (2) alternatives. It can also be expressed as a conditional (i (if-thenf-then) ) statement.Rememb

er

4.2.4 Loaded Question4.2.4 Loaded Question

Example:Lee: Are you still friends with that loser Richard?Ali: Yes.Lee: Well, at least you admit he’s a total loser.

Loaded QuestionLoaded QuestionPosing a question that contains an unfair or unwarranted

presupposition.

Loaded QuestionLoaded QuestionPosing a question that contains an unfair or unwarranted

presupposition.

To respond to a loaded question effectivelyTo respond to a loaded question effectively, , one mustdistinguish the different questions being asked and respondto each individually.

To respond to a loaded question effectivelyTo respond to a loaded question effectively, , one mustdistinguish the different questions being asked and respondto each individually.

Tip

4.2.5 Questionable Cause4.2.5 Questionable Cause

Example:Sarah gets a chain letter that threatens her with dire

consequences if she breaks the chain. She laughs at it and throws it in the garbage. On her way to work she slips and breaks her arm. When she gets back from the hospital she sends out 200 copies of the chain letter, hoping to avoid further accidents.

Questionable CauseQuestionable CauseClaiming, without sufficient evidence, that one thing

is the cause of something else.

Questionable CauseQuestionable CauseClaiming, without sufficient evidence, that one thing

is the cause of something else.

1. 1. A and B are associated on a regular basis. A and B are associated on a regular basis. 2. Therefore A is the cause of B.2. Therefore A is the cause of B. 1. 1. A and B are associated on a regular basis. A and B are associated on a regular basis. 2. Therefore A is the cause of B.2. Therefore A is the cause of B.

Pattern

4.2.6 Hasty Generalization4.2.6 Hasty Generalization

Example:Norwegians are lazy. I have two friends who are from

there, and both of them never prepare for class, or do their homework.

All teenagers are rude and disrespectful.

Hasty GeneralizationHasty GeneralizationDrawing a general conclusion from a sample that

is biased or too small.

Hasty GeneralizationHasty GeneralizationDrawing a general conclusion from a sample that

is biased or too small.

1. A biasedbiased sample is one that is not representative of the target population. 2. The target populationtarget population is the group of people or things that the generalization is about. 3. Hasty generalizations can often lead to false stereotypesstereotypes.

1. A biasedbiased sample is one that is not representative of the target population. 2. The target populationtarget population is the group of people or things that the generalization is about. 3. Hasty generalizations can often lead to false stereotypesstereotypes.

Pattern

4.2.7 Slippery Slope4.2.7 Slippery Slope

Examples:• “The militarily shouldn't get involved in other countries. Once the

government sends in a few troops, it will then send in thousands to die." • If 10th graders are allowed to go out for lunch, they will be late to class,

fail out of school and become wandering vagrants.

Slippery SlopeSlippery SlopeClaiming, without sufficient evidence, that a seemingly

harmless action, if taken, will lead to a disastrousoutcome.

Slippery SlopeSlippery SlopeClaiming, without sufficient evidence, that a seemingly

harmless action, if taken, will lead to a disastrousoutcome.

1.1. The arguer claims that if a certain seemingly harmless action, A, The arguer claims that if a certain seemingly harmless action, A, is permitted, A will lead to B, B will lead to C, and so on to D.is permitted, A will lead to B, B will lead to C, and so on to D.

2.2. The arguer holds that D is a terrible thing and therefore should The arguer holds that D is a terrible thing and therefore should not be permitted.not be permitted.

3.3. In fact, there is no good reason to believe that A will actually In fact, there is no good reason to believe that A will actually lead to D.lead to D.

1.1. The arguer claims that if a certain seemingly harmless action, A, The arguer claims that if a certain seemingly harmless action, A, is permitted, A will lead to B, B will lead to C, and so on to D.is permitted, A will lead to B, B will lead to C, and so on to D.

2.2. The arguer holds that D is a terrible thing and therefore should The arguer holds that D is a terrible thing and therefore should not be permitted.not be permitted.

3.3. In fact, there is no good reason to believe that A will actually In fact, there is no good reason to believe that A will actually lead to D.lead to D.

Pattern