Understanding Logical Fallacies

Understanding Logical Fallacies Dire c t e d L e arning Ac t iv it y —C rit ic al Thinking 05

Essential Question What is a logical fallacy and how do I spot fallacies in a visual?

Purpose This activity is designed to strengthen your knowledge of five common logical fallacies and how to

recognize them in literary works.

This DLA should take approximately 30 to 45 minutes to complete.

Directions Read the information below taken directly from “Fallacies” by The Writing Center, University of North

Carolina at Chapel Hill, and Beyond Feelings: A Guide to Critical Thinking by Vincent Ryan Ruggiero, then

do the activity on the next page. You only need to print the activity page.

Hasty Generalization Definition: Making assumptions about a whole group or range of cases based on a sample that is

inadequate (usually because it is atypical or too small). Stereotypes about people (“librarians are shy

and smart,” “wealthy people are snobs,” etc.) are a common example of the principle underlying hasty

generalization.

Example: “My roommate said her philosophy class was hard, and the one I’m in is hard, too. All

philosophy classes must be hard!” Two people’s experiences are, in this case, not enough on which to

base a conclusion.

Slippery Slope Definition: The arguer claims that a sort of chain reaction, usually ending in some dire consequence, will

take place, but there’s really not enough evidence for that assumption. The arguer asserts that if we

take even one step onto the “slippery slope,” we will end up sliding all the way to the bottom; he or she

assumes we can’t stop partway down the hill.

Example: “Animal experimentation reduces our respect for life. If we don’t respect life, we are likely to

be more and more tolerant of violent acts like war and murder. Soon our society will become a

battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent

this terrible consequence, we should make animal experimentation illegal right now.”

False Analogy Definition: Many arguments rely on an analogy between two or more objects, ideas, or situations. If the

two things that are being compared aren’t really alike in the relevant respects, the analogy is a weak

one, and the argument that relies on it commits the fallacy of weak analogy.

Example: “Guns are like hammers—they’re both tools with metal parts that could be used to kill

someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on

purchasing guns are equally ridiculous.”

 

 

Either/Or (False Dichotomy) Definition: In false dichotomy, the arguer sets up the situation so it looks like there are only two choices.

The arguer then eliminates one of the choices, so it seems that we are left with only one option: the one

the arguer wanted us to pick in the first place. But often there are really many different options, not just

two—and if we thought about them all, we might not be so quick to pick the one the arguer

recommends.

Example: “Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we

continue to risk students’ safety. Obviously we shouldn’t risk anyone’s safety, so we must tear the

building down.”

Irrational Appeal to Tradition Definition: An irrational appeal urges maintaining the tradition merely because we’ve always done so.

Example: For many years, doctors refused to accept indisputable evidence that washing their hands

between patients curtailed the spread of disease simply because washing hands between patients was

not part of the medical tradition (Ruggiero 131).

Exercise Now that you have read about five common logical fallacies, read the excerpts below, indicate which

fallacy is at play (if any), and then explain why.

1) “That’s all there is,” my father said. “War and peace with nothing in between. It’s always one or

another.” (Taken from “Because My Father Always Said. . .” by Sherman Alexie)

2) Scout says, “Until I feared I would lose it, I never loved to read. One does not love breathing.”

(Taken from To Kill a Mockingbird by Harper Lee)

3) “Damn pack of crazy fools,” says Old Man Warner after being told that some people want to

give up the lottery. “Next thing you know, they’ll be wanting to go back to living in caves,

nobody work any more. Live that way for awhile.” (Taken from “The Lottery” by Shirley Jackson)

4) “There’s always been a lottery,” asserts Old Man Warner in defense of keeping the lottery.

(Taken from “The Lottery” by Shirley Jackson)

5) As my white friends revived me and prepared to take me to the emergency room where doctors

would later diagnose my diabetes, the Chicano teacher ran up to us. “Hey,” he said. “What’s

that boy been drinking? I know all about these Indian kids. They start drinking real young.”

(Taken from “Indian Education” by Sherman Alexie)

Review your answers with an instructor or tutor in the Virtual Writing & Reading Center. Be sure you can

answer the essential question above.