TEN STEPS TO ADVANCINGCOLLEGE READING SKILLS

Chapter 10c:Errors in Reasoning

John Langan

© 2010 Townsend Press

RECOGNIZING ERRORS IN REASONING

Fallacies are errors in reasoning that take the place of the real support needed in an argument.

RECOGNIZING ERRORS IN REASONING

A valid point is based on a rock-like foundation of solid support.

A fallacious point is based on a house of cards that offers no real support at all.

RECOGNIZING ERRORS IN REASONING

Two common fallacies were discussed in Chapter 9, “Argument”:

• Changing the subject distracts us from the issue by presenting irrelevant support that actually has nothing to do with the argument.

• Hasty generalization is a fallacy in which a point has inadequate support. Drawing a conclusion based on insufficient evidence is the same as making a hasty generalization.

RECOGNIZING ERRORS IN REASONING

Three Fallacies That Ignore the Issue

Six Common Fallacies

•Circular Reasoning•Personal Attack •Straw Man

Three Fallacies That Oversimplify the Issue

•False Cause•False Comparison •Either-Or

RECOGNIZING ERRORS IN REASONINGFallacies That Ignore the Issue: Circular Reasoning

Circular reasoning repeats the point instead of giving evidence for it. Circular reasoning is also known as begging the question.

Ms. Jenkins is a great manager because she is so wonderful at managing.

Example

The supporting reason (“she is so wonderful at managing”) is really the same as the conclusion (“Ms. Jenkins is a great manager”).

RECOGNIZING ERRORS IN REASONINGFallacies That Ignore the Issue: Circular Reasoning

Which item contains an example of the circular reasoning fallacy?

A. Sports cars continue to be popular because so many people like them.

B. My wife wants to participate in the local amateur theater group, but I don’t want all those actors flirting with her.

RECOGNIZING ERRORS IN REASONINGFallacies That Ignore the Issue: Circular Reasoning

Which item contains an example of the circular reasoning fallacy?

A. Sports cars continue to be popular because so many people like them.

B. My wife wants to participate in the local amateur theater group, but I don’t want all those actors flirting with her.

Saying that many people like sports cars is another way of saying that sports cars are popular. (Item B is straw man.)

RECOGNIZING ERRORS IN REASONINGFallacies That Ignore the Issue: Personal Attack

Personal attack ignores the issue and concentrates instead on the character of the opponent.

Our mayor’s opinions about local crime are worthless. Last week, his own son was arrested for disturbing the peace.

Example

The arrest of his son would probably have embarrassed the mayor, but it has nothing to do with the value of his opinions on local crime.

RECOGNIZING ERRORS IN REASONING

Which item contains an example of personal attack?

A. Mr. Casey was fined for drinking while driving and should not be allowed to teach math.

B. Barry cannot make up his mind easily because he is indecisive.

Fallacies That Ignore the Issue: Personal Attack

RECOGNIZING ERRORS IN REASONING

The statement attacks Casey for his poor judgment about driving, not for his ability to teach math. (Item B is circular reasoning.)

Fallacies That Ignore the Issue: Personal Attack

Which item contains an example of personal attack?

A. Mr. Casey was fined for drinking while driving and should not be allowed to teach math.

B. Barry cannot make up his mind easily because he is indecisive.

RECOGNIZING ERRORS IN REASONINGFallacies That Ignore the Issue: Straw Man

Straw man falsely claims that an opponent holds and extreme position and then opposes that position.

The candidate for mayor says she’ll cut taxes, but do you really want fewer police officers protecting your city?

Example

The candidate does not support having “fewer police officers.” Her plan calls for reducing taxes by privatizing the the city’s trash collection, not reducing the police force.

RECOGNIZING ERRORS IN REASONING

Which item contains an example of straw man?

A. The school board is considering building a swimming pool, but I don’t like the idea of kids hanging out there all day and neglecting their studies.

B. Pearl is a poor choice for the position of salesperson—she’s a lesbian.

Fallacies That Ignore the Issue: Straw Man

RECOGNIZING ERRORS IN REASONING

The school board is not advocating that kids hang out all day and neglect their studies. (Item B is personal attack.)

Fallacies That Ignore the Issue: Straw Man

Which item contains an example of straw man?

A. The school board is considering building a swimming pool, but I don’t like the idea of kids hanging out there all day and neglecting their studies.

B. Pearl is a poor choice for the position of salesperson—she’s a lesbian.

RECOGNIZING ERRORS IN REASONINGFallacies That Oversimplify the Issue: False Cause

False cause assumes that because event A came before event B, event A caused event B.

The baseball team was doing well before Paul Hamilton became manager. Clearly, he is the cause of the decline.

Example

Event A: Paul Hamilton became manager. Event B: The baseball team is losing games. But Paul Hamilton has been the manager for only a year. There may be other causes responsible for the team’s losses, such as the fact that several key players are past their prime.

RECOGNIZING ERRORS IN REASONING

Which item contains an example of false cause?

A. The waiter went off duty early, and then the vase was discovered missing, so he must have stolen it.

B. In Vermont we leave our doors unlocked all year round, so I don’t think it’s necessary for you New Yorkers to have three locks on your front doors.

Fallacies That Oversimplify the Issue: False Cause

RECOGNIZING ERRORS IN REASONING

The waiter going off work early does not indicate that he stole the vase. He may have gone home sick. (Item B is false comparison.)

Fallacies That Oversimplify the Issue: False Cause

Which item contains an example of false cause?

A. The waiter went off duty early, and then the vase was discovered missing, so he must have stolen it.

B. In Vermont we leave our doors unlocked all year round, so I don’t think it’s necessary for you New Yorkers to have three locks on your front doors.

RECOGNIZING ERRORS IN REASONINGFallacies That Oversimplify the Issue: False Comparison

False comparison assumes that two things being compared are more alike than they really are.

When your grandmother was your age, she was already married and had four children. So why aren’t you married?

Example

The situations are different in two respects: (1) society, when the grandmother was young, encouraged early marriage; (2) the grandmother was not working outside the home or attending college. The differences are more important than the similarities, so this is a false comparison.

RECOGNIZING ERRORS IN REASONING

Which item contains an example of false comparison?

A. A week after a new building supervisor took over, the elevator stopped working. What a lousy super he is!

B. All of my friends like my tattoo and pierced tongue, so I’m sure my new boss will too.

Fallacies That Oversimplify the Issue: False Comparison

RECOGNIZING ERRORS IN REASONING

There are probably many differences between the speaker’s friends and the speaker’s boss—including differences in taste. (Item A is false cause.)

Which item contains an example of false comparison?

A. A week after a new building supervisor took over, the elevator stopped working. What a lousy super he is!

B. All of my friends like my tattoo and pierced tongue, so I’m sure my new boss will too.

Fallacies That Oversimplify the Issue: False Comparison

RECOGNIZING ERRORS IN REASONING

Either-or assumes that there are only two sides to a question.

People who support gun control want to take away our rights.

Example

This argument ignores the fact that a person can support gun control and believe that hunters and others have the right to own guns.

Fallacies That Oversimplify the Issue: Either-Or

RECOGNIZING ERRORS IN REASONING

Which item contains an example of the either-or fallacy?

A. Why can’t we have a big dog in this apartment? You had a Great Dane when you were growing up on the farm.

B. Eat your string beans, or you won’t grow up strong and healthy.

Fallacies That Oversimplify the Issue: Either-Or

RECOGNIZING ERRORS IN REASONING

There are other ways to grow up healthy and strong besides eating one’s string beans. (Item A is false comparison.)

Fallacies That Oversimplify the Issue: Either-Or

Which item contains an example of the either-or fallacy?

A. Why can’t we have a big dog in this apartment? You had a Great Dane when you were growing up on the farm.

B. Eat your string beans, or you won’t grow up strong and healthy.

CHAPTER REVIEW In this chapter, you learned that critical readers evaluate an author’s support for a point and determine whether that support is solid or not. Critical reading includes the following three abilities:

• Separating fact from opinion. A fact is information that can be proved true through objective evidence. An opinion is a belief, judgment, or conclusion that cannot be proved objectively true. Much of what we read is a mixture of fact and opinion, and our job as readers is to arrive at the best possible informed opinion. Textbooks and other effective writing provide informed opinion—opinion based upon factual information.

• Detecting propaganda. Advertisers, salespeople, and politicians often try to promote their points by appealing to our emotions rather than our powers of reason. To do so, they practice six common propaganda techniques: bandwagon, testimonial, transfer, plain folks, name calling, and glittering generalities.

• Recognizing errors in reasoning. Politicians and others are at times guilty of errors in reasoning—fallacies—that take the place of the real support needed in an argument. Such fallacies include circular reasoning, personal attack, straw man, false cause, false comparison, and either-or.