RECOGNIZING LOGICAL FALLACIES

Fallacies are lapses in logic that may result from misusing or misrepresenting evidence, from relying on faulty premises, or from distorting the issues.  They may be the result of poor thinking, but they may also be a deliberate attempt to manipulate—as suggested by the origin of the term fallacia which is Latin for “deceit.”  Fallacies are common, especially in persuasive writing.  Here are some of the major forms of fallacies.  Be alert for them in your reading.

(1)  Ad hominem:               Attacking the person who presents an issue rather than dealing logically with

the issue itself.

Faulty                    His arguments might impress us more if he didn’t have false teeth.

                                                [His false teeth have nothing to do with his arguments.]

(2)  Bandwagon: An argument saying, in effect, “Everyone’s doing or saying or thinking this, so

you should too.”

                Faulty                    Everyone else is cheating, so why shouldn’t I? 

[The majority is not always right.]

(3)    Begging the Question:  An assertion that restates the point just made.  Such an assertion is circular

                                                in that it draws as a conclusion a point stated in the premise.

                Faulty                    He is lazy because he doesn’t like to work.

                                                [Being lazy and not liking work mean essentially the same thing.]

(4)    Equivocation:             An assertion that falsely relies on the use of a term in two different senses.

                Faulty                    Your party platform is right about the economy—as far right as you can get.

                                                [“Right” in the first sense implies correct but in the second sense implies a side

                                                of the political spectrum.]

(5)    False Analogy:            The assumption that because two things are alike in some ways, they must be

                                                alike in other ways.

                Faulty                    Since the books are about the same length and cover the same material, one is

                                                probably as good as the other.

                                                [The length and coverage of the books cannot predict whether one is as good as

                                                the other.]

(6)    False Authority:         The assumption that an expert in one field can be a credible expert in another.

Faulty                    The defense budget must be cut, as the country’s leading pediatrician has shown.

                                                [Pediatric medicine is unrelated to economies or political science.]

(7)    False Cause: The assumption that because one event follows another, the first is the cause of

                                                the second.  Sometimes called post hoc, ergo propter hoc (“after this, so

                                                because this”).

                Faulty                    The new tax assessor took office last January, and crime in the streets has

                                                already increased 25 percent.

                                                [The assumption is that having a new tax assessor caused the increase of crime,

                                                an assumption unlikely to be true.]

(8)    False Dilemma:          Stating that only two alternatives exist when in fact there are more than two

                                                (sometimes called either/or fallacy).

                Faulty                    We have only two choices:  to build more nuclear power plants or to be

                                                completely dependent on foreign oil.

                                                [In fact, other possibilities exist.]     

                                               

(9)    Guilt by Association:   An unfair attempt to make someone responsible for the beliefs or actions of

                                                others.

                Faulty                    Senator Barlow must be dishonest because she belongs to the same club as that

                                                judge who was recently disbarred.

                                                [People can belong to the same club—or live in the same neighborhood—

                                                without committing the same crimes.]

(10) Hasty Generalization:  A generalization based on too little evidence or on exceptional or biased

                                                evidence.

                Faulty                    Teenagers are reckless drivers.

                                                [Many teenagers are careful drivers.]

(11) Non sequitur:              A statement that does not follow logically from what has just been said—a

                                                conclusion that does not follow from the premises.

                Faulty                    Billy Joe is honest, therefore, he will get a good job.

                                                [Many honest people do not get good jobs.]

(12) Oversimplification:  A statement or argument that leaves out relevant considerations about an issue.

                Faulty                    People who pass tests are lucky.

                                                [People who pass tests have usually studied and prepared.]

(13) Red herring:                Dodging the real issue by drawing attention to an irrelevant issues (sometimes

                                                called ignoring the question).

                Faulty                    Why worry about a few terrorists when we ought to be doing something about

                                                acid rain?

                                                [Acid rain had nothing to do with the actions of terrorists.]

(14) Slippery slope:            The assumption that if one thing is allowed it will only be the first step in a

                                                downward spiral.

                Faulty                    Handgun control will lead to a police state.

                                                [Handgun control has not led to a police state in England.]

EXERPTED FROM CHAPTER 31G OF THE HARBRACE COLLEGE HANDBOOK

(15) Scare Tactics:

An attempt to convince an audience purely based on the emotional appeal of fear

(15) Sentimental Appeals:

Persuasion based solely on nostalgia or some other emotional sentiment.

(16) Dogmatism:

An argument based on a pre-conceived belief system or religious doctrine.

                                               

(17) Straw Man:

An argument, usually in a debate, based on a paraphrase of an opponents standpoint on an issue—a retelling of their stance on the issue which is easily torn apart or shown to be deficient.