BY JULIE FAULKNER

LOGICAL

FALLACIES

ESSENTIAL QUESTIONS

What techniques to advertisers, writers,

and speakers use to persuade their

audiences?

How can being aware of these techniques

make us more critical thinkers and

digesters of information rather than just

consumers?

WHAT IS A LOGICAL FALLACY?

A logical fallacy is a mistake in

reasoning, a flawed argument used just

to win a debate, a distraction from the

actual argument, or a foundational

weakness in reasoning.

FEAR

FEAR

FEAR

Click to watch an example of appeal to fear.

https://www.youtube.com/watch?v=SfAxUpeVhCg

AD HOMINEM

[LATIN: “TO (AGAINST) THE PERSON”]

Ad hominem is an argument

that attacks the character of

a person rather than his

opinions or arguments.

AD HOMINEM

[LATIN: “TO (AGAINST) THE PERSON”]

Example:

Oprah’s donations to worthy causes

are useless because she can’t possibly

know about poverty as a rich and

arrogant celebrity.

AD HOMINEM = PERSONAL ATTACK

AD HOMINEM = PERSONAL ATTACK

AD HOMINEM = PERSONAL ATTACK

AD HOMINEM = PERSONAL ATTACK

Click the link to watch a video where the speaker employs personal

attack.

https://www.youtube.com/watch?v=AppHOYxpquQ

FALSE DILEMMA/SITUATION

Presents only two choices and forces

someone to choose from the two

choices when in reality there are

plenty more options out there.

FALSE DILEMMA– ONLY TWO CHOICES

Example:

If you drive without car insurance, then you’re an accident waiting to

happen.

Stay protected with Auto Union insurance.

Fa lse ana log ies use com par isons or m etaphors

to re la t e ideas o r s i tua t ions tha t a re no t

rea l l y tha t s im i la r .

*Be sure tha t the two ideas you ’ re com par ing

are rea l l y re la t ed .

FALSE ANALOGY

Example: Students and nails are the same. As it is

necessary to hit nails on the head in order

to make them work, the same must be done

with students.

FALSE ANALOGY

FALSE

ANALOGY

FALSE

ANALOGY

FALSE ANALOGY

• Slippery slope is a conclusion based on the premise that if A happens, then eventually through a series of small steps B, C, D….X, Y, and Z will happen too.

• This basically equates A and Z.

• If we don’t want Z to occur, then A must not be allowed to occur either.

Example:

Parents who do not set a curfew for their children

are setting them up for failure. Their children will

stay out late at night, become involved in self-

destructive activities, develop dangerous habits, get

arrested, and wind up in a life of crime, resulting in

long-term imprisonment.

Example:

If we ban Hummers because they are

bad for the environment, then

eventually the government will ban

all cars; therefore, we should not ban

Hummers.

SLIPPERY SLOPE

SLIPPERY

SLOPE

SLIPPERY SLOPE

Click to watch the Direct TV ad:

https://www.youtube.com/watch?v=u9vbXpMKz6I

NON SEQUITUR

[LATIN: “IT DOES NOT FOLLOW” OR NOT

IN SEQUENCE]

One point or argument does not follow

logically from the preceding one, i.e., no

logical relationship exists between two or

more supposedly connected ideas.

NON SEQUITUR

[LATIN: “IT DOES NOT FOLLOW” OR NOT

IN SEQUENCE]

Example: He has my vote for senator, because

he has the best shirts.

(What does a campaign organization have to

do with qualifications?)

NON SEQUITOR

Click the link to watch a series of commercials from Old Spice that

demonstrate the non sequitor fallacy.

https://www.youtube.com/watch?v=KXuho3eRfh4

FALSE AUTHORITY

F a l s e a u t h o r i t y i s a t a c t i c u s e d m a i n l y i n

a d ve r t i s i n g t h a t p r e s e n t s p e o p l e a s

“ a u t h o r i t i e s ” o n p r o d u c t s o r i s s u e s .

. H o w e ve r, a n a u t h o r i t y i n o n e f i e l d m a y k n o w

n o t h i n g o f a n o t h e r f i e l d .

• B e i n g k n o w l e d g e a b l e i n o n e a r e a d o e s n ’ t

c o n s t i t u t e k n o w l e d g e i n o t h e r a r e a s .

• U s u a l l y c e l e b r i t i e s a n d s p o r t s f i g u r e s a r e u s e d

i n t h i s t a c t i c .

FALSE AUTHORITY Example:

“My uncle is a podiatrist, and he only takes Sweet Valley

daily chewable vitamin C, and so should you.”

•A podiatrist is a foot doctor.

•What does a foot doctor know about the best vitamin

supplement brands on the market?

•A foot doctor would be an authority on products related

to foot care (i.e. corn pads, arch supports, etc.).

POST HOC

LATIN: “OCCURRING AFTER THIS,

THEREFORE RESULTING FROM IT”

Post hoc is a conclusion that assumes a cause/effect relationship between two sequential events. (i.e. If A occurred after B, then B must have caused A.)

A cause and effect relationship between two sequential events; often very unreasonable

POST HOC

LATIN: “OCCURRING AFTER THIS,

THEREFORE RESULTING FROM IT”

Example: “Eating five candy bars and drinking two sodas before a test helps me get better grades. I did that and got an A on my last test in history.” * This ignores other possible causes like how much this student studied or how easy the test was.

POST HOC – FAULTY

CAUSE/EFFECT • A man ate pizza everyday. That man lived to be 100. Eating pizza

everyday will make you live a long life.

STRAW MAN

Misrepresents the context from which a

quotation is taken; putting words or

ideas in people’s mouth/head; creating

a “dummy” or fake or falsified

argument or situation so you can attack

it .

It appears to be a human. It draws the

attention of animals without even really

being anything more than a fixture. It

isn't real, yet the animals are concerned

about it.

STRAW MAN

Bill and Jill are arguing about cleaning out their

closets:

Jill: "We should clean out the closets. They are getting

a bit messy."

Bill: "Why, we just went through those closets last

year. Do we have to clean them out everyday?"

Jill: "I never said anything about cleaning them out

every day. You just want too keep all your junk forever,

which is just ridiculous."

STRAW MAN

"Senator Jones says that we should not fund the attack submarine

program. I disagree entirely. I can't understand why he wants to leave us

defenseless like that."

In this example, Senator Jones‘s position is misrepresented as one that

wants to leave the country defenseless. The antagonist is making the

assertion that: "Do not fund the attack submarine program" = "Leave the

country defenseless." However the two statements are not equal, and it

takes more work to argue against the former statement than the latter.

BALL TOSS REVIEW If the ball comes your way, say the definition to the following term:

Straw man

Post hoc

False authority

Non sequitur

Slippery slope

False analogy

False Dilemma

Ad hominem

Appeal to Fear

THANK YOU!

By Julie Faulkner, 2013

www.teacherspayteachers.com/Store/Julie-Faulkner