Logical Fallacies

Flaws in appeals

Types of appeals

To understand logical fallacies, you first have to understand appeals, or methods of persuasion.

ETHOS

• Credibility or ethical appeal• Means convincing by character. We tend to

believe people we respect.

• Example: Michelle Kramer, director of research at St. Jude, agrees that more money should be spent to look into childhood leukemia.

• Angelina Jolie agrees that adoption is beneficial to the children.

PATHOS

• Emotional• Means persuading by appealing to emotions

• Leukemia affects thousands of children. Their pain and suffering cannot be comprehended. It could be your child.

• Some children have no future without adoption.

LOGOS

• Logical• Persuasion through reason

• Leukemia affects one in four children. Money should be spent to research so that we can help those children.

• 40,000 children live in orphanages and need good homes. People should explore adoption.

DEDUCTIVE REASONING

• General to specific• All cats have fur. Xena is a cat. Therefore, Xena

has fur.

INDUCTIVE REASONING

• Specific to general• Suzy is a doctor. Doctors are smart. Therefore,

Suzy is smart.

AD HOMINEM

Non-Sequitur

APPEAL TO FEARX is a circumstance to fear. Y should be taken to prevent circumstance X

Nazis are scary. Buy war bonds to prevent them from taking over your child

Also:

“A vote for him is like a vote for terrorists.”.

FALSE DILEMMA

FALSE ANALOGY

SLIPPERY SLOPE• Threatens dire consequences from taking a simpler course of action.

• Mom: Those look like bags under your eyes. Are you getting enough sleep?• Jeff: I had a test and stayed up late studying.• Mom: You didn’t take any drugs, did you?• Jeff: Just caffeine in my coffee, like I always do.• Mom: Jeff! You know what happens when people take drugs! Pretty soon

the caffeine won’t be strong enough. Then you will take something stronger, maybe someone’s diet pill. Then, something even stronger. Eventually, you will be doing cocaine. Then you will be a crack addict! So, don’t drink that coffee.

• THINK DIRECT TV

FALSE AUTHORITY

• Cites an authority who is not qualified to have an expert opinion.

• Cites an expert when other experts disagree on the issue.

• Cites and expert by hearsay

• Example: My 5th grade teacher once told me that girls will go crazy for boys if they learn how to dance. Therefore, if you want to make the ladies go crazy for you, learn to dance.

RED HERRING• A fallacy of distraction, and is committed when a listener attempts to

divert an arguer from his argument by introducing another topic.

• Example:• Will the new tax in Senate Bill 47 unfairly hurt business? I notice that

the main provision of the bill is that the tax is higher for large employers (fifty or more employees) as opposed to small employers (six to forty-nine employees). To decide on the fairness of the bill, we must first determine whether employees who work for large employers have better working conditions than employees who work for small employers. I am ready to volunteer for a new committee to study this question. How do you suppose we should go about collecting the data we need?

CIRCULAR ARGUMENT

• Restates the argument rather than proving it.

• Example• “Women have rights,” said the Bullfighters

Association president. “But women shouldn’t fight bulls because a bullfighter is and should be a man.”

AD POPULUM• Emotional appeal that speaks positive or negative concepts rather

than the real issue at hand (large numbers of people who are often elite are more likely to be right)

• Can be compared to snob appeal, emotional appeals, and bandwagon.

• Examples– You should turn to channel 6. It’s the most watched channel this year.– "But officer, I don't deserve a ticket; everyone goes this speed. If I went

any slower, I wouldn't be going with the stream of traffic.”– It is well recognized by most persons that the present technological

revolution has affected the ethical basis of the nation's institution of education. Since this belief is so widely held, there can be little doubt of its accuracy.

STRAW MAN• Oversimplifies an opponents viewpoint and then attacks that

hollow argument.• Example• Opponent: Because of the killing and suffering of Indians that

followed Columbus’s discovery of America, the City of Berkeley should declare that Columbus Day will no longer be observed in our city.

• Speaker: This is ridiculous, fellow members of the city council. It’s not true that everybody who ever came to America from another country somehow oppressed the Indians. I say we should continue to observe Columbus Day, and vote down this resolution that will make the City of Berkeley the laughing stock of the nation.

Identify the fallacy

• A: We should liberalize the laws on beer.• B: No, any society with unrestricted access to

intoxicants loses its work ethic and goes only for immediate gratification.

• Straw Man

ID

• "If you continue to drink, you will die early as your father did.”

• Appeal to fear

ID

• "To his dying day, Governor Marvin Mandel will never understand what was wrong in accepting more that $350,000 worth of gifts from wealthy friends who happened to engage in business ventures that benefited from his gubernatorial influence. The governor has lots of company … And to a man they have cried in bewilderment that ‘everybody does it,’ that politics survives on back scratching.”

• Ad populum

ID

• "Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for a while.”

• False Dilemma

ID

• "We have to stop the tuition increase! The next thing you know, they'll be charging $40,000 a semester!”

• Slippery Slope

ID

• "Argument" for making grad school requirements stricter:

• "I think there is great merit in making the requirements stricter for the graduate students. I recommend that you support it, too. After all, we are in a budget crisis and we do not want our salaries affected.”

• Red Herring

ID

• President Reagan was a great communicator because he had the knack of talking effectively to the people.’

• Circular Argument

ID

• Kintaro: "I don't see how you can consider Stalin to be a great leader. He killed millions of his own people, he crippled the Soviet economy, kept most of the people in fear and laid the foundations for the violence that is occuring in much of Eastern Europe." Dave: "Yeah, well you say that. However, I have a book at home that says that Stalin was acting in the best interest of the people. The millions that were killed were vicious enemies of the state and they had to be killed to protect the rest of the peaceful citizens. This book lays it all out, so it has to be true.”

• False Authority

ID

• "There are seven windows given to animals in the domicile of the head: two nostrils, two eyes, two ears, and a mouth. . . . From this and many other similarities in Nature, too tedious to enumerate, we gather that the number of planets must necessarily be seven.”

• False Analogy

ID

• The school in which my child goes to school is big. The classroom must be big.

• Non Sequitur

ID

• "Lincoln knew the reactions of frontiersmen, who made up the jury. When his turn came, his plea was brief: 'Gentlemen of the jury, because I have justice on my side, I am sure you will not be influenced by this gentleman's pretended knowledge of the law. Why. he doesn't even know which side of his shirt ought to be in front!’

• Ad Hominem

In real life

• Thinking people don’t accept an argument just because they hear it. They don’t let prejudice taint their ability to listen to another person. Think about what you hear. Determine if it is fallacious or not.