Logical Fallacies
AP Language and Composition

Often, a speaker or writer resorts to "unfair practices" in seeking to persuade an audience. Sleazy appeals to emotion designed to inspire guilt are very common among advertisers and politicians. Because we humans are emotional (as well as rational) beings, it is often hard to protect ourselves from the power of such appeals. We are moved, for example, by the pictures of ill-clothed, dirty, but endear­ing children who look beseechingly at us from the pages of magazines or the screens of televisions, pleading with us to help by contributing to a charitable organization. If our emotions are vulnerable, our reason should be more resistant.  If we are aware of the way in which reason is violated, we can become a more wary audience since wariness is an important form of self-protection. The following common logical fallacies are worth your attention. Logical fallacies are fun to learn (and to teach!), and they are a part of a well-rounded, fully grounded curriculum in rhetoric. But they are not the be-all and end-all of an AP English curriculum. There may be occasional questions on the multiple-choice portion of the examination, and there may be opportunities for students to use their knowledge of fallacies in the free responses. Logical fallacies are, after all, fallacies, and they can lead student thinkers to new levels of persuasion by contrast and indirection; that is, by avoiding fallacies, students will become more cogent arguers. Although logical fallacies are not as fundamental to the curriculum as classical appeals, rhetorical modes, and literary devices, they have a place in the knowledge bank of the students who aim for the fullest education in rhetorical analysis.


Argumentum ad ignorantiam. The argumentative appeal to ignorance claims that a position must be true since no one can prove it is false. It is often used for health claims of home remedies such as herbal teas or metal bracelets.

Argumentum ad hominem. In Latin, ad hominem means "against the person." This fallacy is committed when a writer or speaker argues for or against a claim by presenting statements, such as attacks on char­acter, about the claimant that are not relevant to the discussion: "She is arrogant and self-centered. Her theories of economic behavior cannot possibly be valid."


In All the King's Men, Willie Stark comments on why fallacies persist in our language:

The Boss knew all about the so-called fallacy of the argumentum ad hominem. “It may be a fallacy," he said, "but it is shore-God useful. If you use the right kind of argumen­tum you can always scare the hominem into a laundry bill he didn't expect." (231)


Bandwagon. Jumping on the bandwagon suggests that large numbers or ever-increasing numbers will give credibility to a product, a cause, or an assertion: "Everybody does or believes this, so you should, too." Bandwagon advertising techniques can be positive ("Join the cool group!") or negative ("You wouldn't want to be the kind of person who subjects your family to germs, would you?").


Begging the Question. This fallacy occurs when the writer assumes in the premises of the argument something that ought to be proved. Begging the question is often signaled by empty starter phrases such as, "All thinking people would agree that ... ," “It is commonly held that ... ," and “It is obvious that .... "

The term is often misused to mean "bringing up the question." Note the difference. Begging the question, a logical fallacy, assumes what must be proven. Bringing up a question is often an effective rhetorical device that sequentially leads an audience to a new point or shows that an opponent has not considered all alternatives.

Circular Reasoning. A circular argument takes as evidence what it claims to prove. "The candidate did not win the election because not enough people voted for him." Implicit in the idea of an election is vot­ing; therefore, explaining an election loss in terms of insufficient votes is like saying, "He didn't get enough votes because he didn't get enough votes."


Either/Or. The Either/Or fallacy is also known as the Black/White Fallacy, Faulty Dilemma, or False Dichotomy. The Latin term, tertium quid ("the third thing"), refers to the fact that a third, often a middle, compromising, position is missing. The most common of these is the cliche, "Either you are for us or against us." Another example, from the Cold War, is "Better dead than Red." These statements do not acknowledge the possibilities of neutral, compromising, or middle positions.


False Analogy. Analogies can be effective, but sometimes the dissimilarities between two things are so much greater than their similarities that their connection by analogy is unjustified. These are called "false" or "faulty analogies." II Gene-splicing is really no different from creating a new recipe by com­bining familiar foods in a novel way/' The differences between these processes and their potential out­comes are certainly more significant than their similarities.


Hypothesis Contrary to Fact. This fallacy is all too common in student writing and should be, one would think, easy to eliminate. The writer begins with a premise that is not true and then draws conclusions therefrom: "If Huck and Jim had recognized Cairo and had traveled up the Ohio River, they never would have developed their deep friendship." The premise in the if-clause is contrary to fact:

Mark Twain didn't write that plot. He did, conveniently enough, however, write a plot where Huck and Jim did continue down the Mississippi and did develop a deep and trusting relationship. The writer should explore that reality instead of trying to prove something that never happened in the novel.


Ipse dixit. In Latin, this phrase means "he himself has spoken" and ipse dixit holds in cases where there is an appeal to an unqualified "expert." Why should an actor who plays a doctor on a soap opera know anything special about analgesics? Why would we buy a product or an idea that is endorsed by a celebrity?


Non sequitur. Non sequitur in Latin means "it does not follow" and refers to any argument whose conclusion does not follow from its premises. "She would make an excellent senator because she knows her way around Washington." It does not follow. Many newcomers to the capital city have become excellent senators.


Post hoc; ergo propter hoc. Another Latin phrase, meaning "after this; therefore because of this." This fallacy, also called "false cause" or "faulty cause/' is committed when a sequential relationship is mis­interpreted as a causal one. "He drank three large glasses of water and soon after became ill. Drinking too much water always leads to illness."


Red Herring. Just as a smelly fish could be drawn across a trail to distract a hunter (or a dog), a argu­mentative red herring introduces an irrelevant point to distract the audience from the main or current argument. To call the Strategic Defense Initiative "Star Wars" introduces the elements of fantasy and unreality by comparison to George Lucas' popular films and distracts the audience from hearing the details of SDI in order to evaluate the program on its own merits or flaws.


Simple Cause. This fallacy, also called" only reason/, results when it is assumed that one reason alone is sufficient to explain a situation. “If school were more interesting, our country would not have a problem with high school dropouts." There are many factors that account for students dropping out of high school, only one of which may be lack of student interest.


Straw-Man. In a straw-man argument, the writer denounces an easier, less defensible argument than the one at hand. "Many schools are converting from year-long schedules to semester block schedules. But if you spend half the time on a course, you'll learn half as much-it's as simple as that." The arguments supporting conversion to a semester block schedule are more numerous (only cause) and more complex (simple cause) than one would make by simply comparing the number of days in each course.


Undistributed Middle. The first premise and the conclusion are said to be related because they share a common property, expressed in the middle term. II All seniors are required to take exams. There was cheating on the exams. Therefore, all seniors are cheaters." The middle term (cheating on exams) does not apply to the first term (all seniors take exams).