Logical Fallacies

Definition & Facts  Defects that weaken arguments weaken arguments  Common in politics and politics and advertisements advertisements  Often very persuasive persuasive

Don’t weaken your argument with faulty reasoning!

 When you attempt to employ logic to support claims in your papers, your reasoning is sometimes weakened because you are presenting fallacious arguments.  It is important for you to be able to identify and eliminate fallacies in your writing.

Check this out! This fallacy is very common in advertising, as in this simple example.

Unchanged Since 1899 (Reader's Digest, March, 1999, p. 15)

Hershey’s Advertisement Appeal to Tradition Appeal to Tradition Any argument that defends a behavior or choice by pointing out that the behavior or choice is a longstanding practice. Unfortunately, many foolish and destructive behaviors are also very traditional, such as slavery, forced prostitution, and punishing children by hitting them with belts. belts.

What the heck does this mean? bandwagon

bandwagon: logical fallacy in which the writer uses the argument that because everyone believes in something, it must be true.

Example “I’m going to the party because all my friends are going!”

What the heck does this mean? begging the question

begging the question: logical fallacy in which the writer presents an assertion that simply restates the point just made

Example "Exposure to asbestos is carcinogenic because it causes cancer.”

Example Circular reasoning is bad mostly because it’s not very good!

What the heck does this mean? ad hominem

ad hominem: logical fallacy in which the writer attacks the person who presents the issue rather than deal logically with the issue itself.

Example “After Sally presents an eloquent and compelling case for a more equitable taxation system, Sam asks the audience whether we should believe anything from a woman who isn’t married, was once arrested, and smells a bit weird."

What the heck does this mean? either-or fallacy

either-or fallacy: logical fallacy in which the writer states that only two alternatives exist when in fact there are more than two.

Example The EHS Literature building is in bad shape. Either we tear it down and put up a new building, or we continue to risk students’ safety. Obviously we should not risk anyone’s safety, so we must tear the building down." The EHS Literature building is in bad shape. Either we tear it down and put up a new building, or we continue to risk students’ safety. Obviously we should not risk anyone’s safety, so we must tear the building down."

What the heck does this mean? red herring

red herring: logical fallacy in which the writer dodges the real issue by drawing attention to an irrelevant issue (ignoring the question).

red herring: In literature, this fallacy is often used in detective or suspense novels to mislead readers or characters or to induce them to make false conclusions. In literature, this fallacy is often used in detective or suspense novels to mislead readers or characters or to induce them to make false conclusions.

red herring: The term red herring means a kind of dried red fish, which has a pungent smell. In fox hunting, hounds are prevented from catching the fox by distracting them with the strong scent of red herring. Similarly, a person can be stopped from proving his point in an argument by distracting him with an irrelevant issue. The term red herring means a kind of dried red fish, which has a pungent smell. In fox hunting, hounds are prevented from catching the fox by distracting them with the strong scent of red herring. Similarly, a person can be stopped from proving his point in an argument by distracting him with an irrelevant issue.

Example Example: "A teacher catches a student cheating during a test. The student in response says, “I know I’ve made a mistake. But think of my parents. They’re going to kill me”. "A teacher catches a student cheating during a test. The student in response says, “I know I’ve made a mistake. But think of my parents. They’re going to kill me”.Analysis: The student uses a red herring in his response. He tries to appeal to pity to distract his teacher from the real issue. The student uses a red herring in his response. He tries to appeal to pity to distract his teacher from the real issue.

Example Real World Example: "No, no, he's a friend of mine. He's not a moron at all -- he's a friend. I had a good time with him today." Canadian Prime Minister Jean Chretien, responding to reports that his chief spokesman had called President George W. Bush a moron. (Newsweek, 2 Dec. 2002) Analysis: Perhaps it's true that Bush is his friend. Perhaps it's true that they had a good time together. What has that information got to do with answering the charge that Bush is a moron? Chretien is changing the subject instead of talking about Bush's intelligence.