In this necessarily brief review it would be impossible to discuss all the fallacies listed by logicians, but we can examine the ones most likely to be found in the arguments you will read and write. Fallacies are difficult to classify, first, because there are literally dozens of systems for classifying, and second, because under any system there is always a good deal of overlap. Our discussion of the reasoning process, however, tells us where faulty reasoning occurs.

The first group of fallacies (called "inductive") result from the wrong use of evidence: That is, the arguer leaps to a conclusion on the basis of an insufficient sample, ignoring evidence that might have altered his or her conclusion. A second group of fallacies (called "deductive"), on the other hand, result from a failure to follow the logic of a series of statements. Here the arguer neglects to make a clear connection between the parts of his or her argument. One of the commonest strategies is the introduction of an irrelevant issue, one that has little or no direct bearing on the development of the claim and serves only to distract the reader.

Even if you cannot name particular fallacies, you can learn to recognize them.  Looking for fallacies in your readings can help you develop ideas for papers, and knowing what the fallacies are will help you avoid them in your writing.


1. Hasty Generalization

It is dangerous to draw conclusions on the basis of insufficient evidence--we call this "hasty generalization." In fact, many of our prejudices are a result of hasty generalization. A prejudice is literally a judgment made before the facts are in. On the basis of experience with two or three members of an ethnic group, for example, we may form the prejudice that all members of the group share the characteristics that we have attributed to the two or three in our experience (Allport, "The Nature of Prejudice," 135).


Superstitions are also based in part on hasty generalization. As a result of a very small number of experiences with black cats, broken mirrors, Friday the thirteenth, or spilled salt some people will assume a cause-and-effect relation between these signs and misfortunes. Superstition has been defined as "a notion maintained despite evidence to the contrary.” The evidence would certainly show that, contrary to the superstitious belief, in a lifetime hundreds of such “unlucky" signs are not followed by unfortunate events. To generalize about a connection is therefore unjustified.

2. Faulty Use of Authority

Faulty use of authority is the attempt to bolster claims by citing the opinions of experts.  Both writers and readers need to be especially aware of the testimony of authorities who may disagree with those cited. In circumstances where experts disagree, you are encouraged to undertake a careful evaluation and comparison of credentials.

3. Post Hoc or Doubtful Cause

The entire Latin term for this fallacy is post hoc, ergo propter hoc, meaning, "After this, therefore because of this."  The arguer infers that because one event follows another event, the first event must be the cause of the second. But proximity of events or conditions does not guarantee a causal relation. The rooster crows every morning at 5:00 and, seeing the sun rise immediately after, decides that his crowing has caused the sun to rise. A month after A-bomb tests are concluded, tornadoes damage the area where the tests were held, and residents decide that the tests caused the tornadoes. After the school principal suspends daily prayers in the classroom, acts of' vandalism increase, and some parents are convinced that failure to conduct prayer is responsible for the rise in vandalism. In each of these cases, the fact that one event follows another does not prove a causal connection. The two events may be coincidental, or the first event may be only one, and an insignificant one of many causes that have produced the second event. The reader or writer of causal arguments must determine whether another more plausible explanation exists and whether several causes have combined to produce the effect. Perhaps the suspension of prayer was only one of a number of related causes: a decline in disciplinary action, a relaxation of academic standards, a change in school administration, and changes in family structure in the school community.

In the previous section we saw that superstitions are the result not only of hasty generalization but also of the willingness to find a cause-and-effect connection in the juxtaposition of two events. A belief in astrological signs also derives from erroneous inferences about cause and effect. Only a very few of the millions of people who consult the astrology charts every day in newspapers and magazines have submitted the predictions to statistical analysis. A curious reader might try this strategy: Save the columns, usually at the beginning or end of the year, in which astrologers and clairvoyants make predictions for events in the coming year, allegedly based on their reading of the stars and other signs. At the end of the year evaluate the percentage of predictions that were fulfilled. The number will be very small. But even if some of the predictions prove true, there may be other less fanciful explanations for their accuracy.

In defending simple explanations against complex ones, philosophers and scientists often refer to a maxim called Occam's razor, a principle of the medieval philosopher and theologian William of Occam. A modern science writer says this principle "urges a preference for the simplest hypothesis that does all we want it to do."

Bertrand Russell, the twentieth-century British philosopher, explained it this way: "It is vain to do with more what can be done with fewer. That is to say, if everything in some science can be interpreted without assuming this or that hypothetical entity, there is no ground for assuming it. I have myself found this a most fruitful principle in logical analysis."

In other words, choose the simpler, more credible explanation wherever possible.

We all share the belief that scientific experimentation and research can answer questions about a wide range of natural and social phenomena: evolutionary development, hurricanes, disease, crime, poverty. It is true that repeated experiments in controlled situations can establish what seem to be solid relations suggesting cause and effect. But even scientists prefer to talk not about cause but about an extremely high probability that under controlled conditions one event will follow another.

In the social sciences cause-and-effect relations are especially susceptible to challenge. Human experiences can seldom be subjected to laboratory conditions. In addition, the complexity of the social environment makes it difficult, even impossible, to extract one cause from among the many that influence human behavior.


4. False Analogy

Many analogies are merely descriptive and offer no proof of the connection between the two things being compared. In recent years a debate has emerged between weight-loss professionals about the wisdom of urging overweight people to lose weight for health reasons. Susan Wooley, director of the eating disorders clinic at the University of Cincinnati and a professor of psychiatry, offered the following analogy in defense of her view that dieting is dangerous:

We know that overweight people have a higher mortality rate than thin people. We also know that black people have a higher mortality rate than white people. Do we subject black people to torturous treatments to bleach their skin? Of course not. We have enough sense to know skin-bleaching will not eliminate sickle-cell anemia. So why do we have blind faith that weight loss will cure the diseases associated with obesity?
But it is clear that the false analogy between black skin and excessive weight does not work. The color of one's skin does not cause sickle-cell anemia, but there is an abundance of proof that excess weight influences mortality.
Historians are fond of using analogical arguments to demonstrate that particular circumstances prevailing in the past are being reproduced in the present. They therefore feel safe in predicting that the present course of history will follow that of the past. British historian Arnold Toynbee argues by analogy that humans' tenure on earth may be limited.
On the evidence of the past history of life on this planet, even the extinction of the human race is not entirely unlikely. After all, the reign of man on the Earth, if we are right in thinking that man established his present ascendancy in the middle paleolithic age, is so far only about100,000 years old, and what is that compared to the 500 million or 900million years during which life has been in existence on the surface of this planet? In the past, other forms of life have enjoyed reigns which have lasted for almost inconceivably longer periods - and which yet at last have come to an end.
Toynbee finds similarities between the limited reigns of other animal species and the possible disappearance of the human race. For this analogy, however, we need to ask whether the conditions of the past, so far as we know them, at all resemble the conditions under which human existence on earth might be terminated. Is the fact that human beings are also members of the animal kingdom sufficient support for this comparison?

5. Ad Hominem

The Latin term ad hominem means "against the man" and refers to an attack on the person rather than on the argument or the issue. The assumption in such a fallacy is that if the speaker proves to be unacceptable in some way, his or her statements must also be judged unacceptable. Attacking the author of the statement is a strategy of diversion that prevents the reader from giving attention where it is due—to the issue under discussion.

You might hear someone complain, "What can the priest tell us about marriage? He's never been married himself." This ad hominem accusation ignores the validity of the advice the priest might offer. In the same way, an overweight patient might reject the advice on diet by an overweight physician. In politics it is not uncommon for antagonists to attack each other for personal characteristics that may not be relevant to the tasks they will be elected to perform. They may be accused of infidelity to their partners, homosexuality, atheism, or a flamboyant social life. Even if certain accusations should be proved true, voters should not ignore the substance of what politicians do and say in their public offices.

This confusion of private life with professional record also exists in literature and the other arts. According to their biographers, the American writers Thomas Wolfe, Robert Frost, and William Saroyan—to name only a few—and numbers of film stars, including Charlie Chaplin, Joan Crawford, and Bing Crosby, made life miserable for those closest to them. Having read about their unpleasant personal characteristics, some people find it hard to separate the artist from his or her creation, although the personality and character of the artist are often irrelevant to the content of the work.

Ad hominem accusations against the person do not constitute a fallacy if the characteristics under attack are relevant to the argument. If the politician is irresponsible and dishonest in the conduct of his or her personal life, we may be justified in thinking that the person will also behave irresponsibly and dishonestly in public office.


6. False Dilemma

As the name tells us, the false dilemma, sometimes called the black-white fallacy, poses an either-or situation. The arguer suggests that only two alternatives exist, although there may be other explanations of or solutions to the problem under discussion. The false dilemma reflects the simplification of a complex problem. Sometimes it is offered out of ignorance or laziness, sometimes to divert attention from the real explanation or solution that the arguer rejects for doubtful reasons.

You may encounter the either-or situation in dilemmas about personal choices. "At the University of Georgia," says one writer, "the measure of a man was football. You either played it or worshiped those who did, and there was no middle ground."  Clearly this dilemma - "Love football or you're not a man" - ignores other measures of manhood.

Politics and government offer a wealth of examples. In an interview with the New York Times in 1975, the Shah of Iran was asked why he could not introduce into his authoritarian regime greater freedom for his subjects. His reply was, "What's wrong with authority? Is anarchy better?" Apparently he considered that only two paths were open to him - authoritarianism or anarchy. Of course, democracy was also an option, which, perhaps fatally, he declined to consider.

7. Slippery Slope

If an arguer predicts that taking a first step will lead inevitably to a second, usually undesirable step, he or she must provide evidence that this will happen. Otherwise, the arguer is guilty of a slippery-slope fallacy. Asked by an inquiring photographer on the street how he felt about censorship of a pornographic magazine, a man replied, "I don't think any publication should be banned. It's a slippery slope when you start making decisions on what people should be permitted to read.... It's a dangerous precedent." Perhaps. But if questioned further, the man should have offered evidence that a ban on some things leads inevitably to a ban on everything.

Predictions based on the danger inherent in taking the first step are commonplace: Legalization of abortion will lead to murder of the old and the physically and mentally handicapped. The Connecticut law allowing sixteen-year-olds and their parents to divorce each other will mean the death of the family. If we ban handguns, we will end up banning rifles and other hunting weapons.

Distinguishing between probable and improbable predictions -that is, recognizing the slippery-slope fallacy - poses special problems because only future developments can verify or refute predictions. For example, in 1941 the imposition of military conscription aroused some opponents to predict that the draft was a precursor of fascism in this country. Only after the war, when 10 million draftees were demobilized, did it become clear that the draft had been an insufficient sign for a prediction of fascism. In this case the slippery-slope prediction of fascism might have been avoided if closer attention had been paid to other influences pointing to the strength of democracy.

Slippery-slope predictions are simplistic. They ignore not only the dissimilarities between first and last steps but also the complexity of the developments in any long chain of events.


8. Begging the Question

If the writer makes a statement that assumes that the very question being argued has already been proved, the writer is guilty of begging the question. In a letter to the editor of a college newspaper protesting the failure of the majority of students to meet the writing requirement because they had failed an exemption test, the writer said, "Not exempting all students who honestly qualify for exemption is an insult." But whether the students are honestly qualified is precisely the question that the exemption test was supposed to resolve. The writer has not proved that the students who failed the writing test were qualified for exemption. She has only made an assertion as if she had already proved it.

In an effort to raise standards of teaching, some politicians and educators have urged that master teachers be awarded higher salaries. Opponents have argued that such a proposal begs the question because it assumes that the term master teachers can be or has already been defined.

Circular reasoning is an extreme example of begging the question: "Women should not be permitted to join men's clubs because the clubs are for men only." The question to be resolved first, of course, is whether clubs for men only should continue to exist.


9. Straw Man

The straw-man fallacy consists of an attack on a view similar to but not the same as the one your opponent holds. It is a familiar diversionary tactic. The name probably derives from an old game in which a straw man was set up to divert attention from the real target that a contestant was supposed to knock down.

One of the outstanding examples of the straw-man fallacy occurred in the famous Checkers speech of Senator Richard Nixon. In1952 during his vice-presidential campaign, Nixon was accused of having appropriated $18,000 in campaign funds for his personal use. At one point in the radio and television speech in which he defended his reputation, he said:

One other thing I probably should tell you, because if I don't they will probably be saying this about me, too. We did get something, a gift, after the election.  A man down in Texas heard Pat on the radio mention the fact that our two youngsters would like to have a dog, and, believe it or not, the day before we left on this campaign trip we got a message from Union Station in Baltimore saying they had a package for us. We went down to get it. You know what it was? It was a little cocker spaniel dog, in a crate that he had sent all the way from Texas, black and white, spotted, and our little girl, Tricia, the six-year-old, named it Checkers. And, you know, the kids, like all kids, loved the dog, and I just want to say this, right now, that regardless of what they say about it, we are going to keep it.
Of course, Nixon knew that the issue was the alleged misappropriation of funds, not the ownership of the dog, which no one had asked him to return.


10. Two Wrongs Make a Right

The two-wrongs-make-a-right fallacy is another example of the way in which attention may be diverted from the question at issue.


After President Jimmy Carter in March 1977 attacked the human rights record of the Soviet Union, Russian officials responded:

"As for the present state of human rights in the United States, it is characterized by the following facts: millions of unemployed, racial discrimination, social inequality of women, infringement of citizens' personal freedom, the growth of crime, and so on."'
The Russians made no attempt to deny the failure of their human rights record; instead they attacked by pointing out that the Americans are not blameless either.

11. Non Sequitur

The Latin term non sequitur, which means "it does not follow," is another fallacy of irrelevance. An advertisement for a book, Worlds in Collision, whose theories about the origin of the earth and evolutionary development have been challenged by almost all reputable scientists, states:

Once rejected as "preposterous"! Critics called it an outrage! It aroused incredible antagonism in scientific and literary circles. Yet half a million copies were sold and for twenty-seven years it remained an outstanding bestseller.
We know, of course, that the popularity of a book does not bestow scientific respectability. The number of sales, therefore, is irrelevant to proof of the book's theoretical soundness - a non sequitur.


12. Ad Populum

Arguers guilty of the ad populum fallacy make an appeal to the prejudices of the people (populum in Latin). They assume that their claim can be adequately defended without further support if they emphasize a belief or attitude that the audience shares with them. One common form of ad populum is an appeal to patriotism, which may allow arguers to omit evidence that the audience needs for proper evaluation of the claim. In the following advertisement the makers of Zippo lighters made such an appeal in urging readers to buy their product.

It's a grand old lighter. Zippo - the grand old lighter that's made right here in the good old U.S.A.

We truly make an all-American product. The raw materials used in making a Zippo lighter are all right from this great land of ours.

Zippo windproof lighters are proud to be Americans.


13. Appeal to Tradition

In making an appeal to tradition, the arguer assumes that what has existed for a long time and has therefore become a tradition should continue to exist because it is a tradition. If the arguer avoids telling his or her reader why the tradition should be preserved, he or she may be accused of failing to meet the real issue.

The following statement appeared in a letter defending the membership policy of the Century Club, an all-male club established in New York City in 1847 that was under pressure to admit women. The writer was a Presbyterian minister who opposed the admission of women.

I am totally opposed to a proposal which would radically change the nature of the Century.... A club creates an ethos of its own over the years, and I would deeply deplore a step that would inevitably create an entirely different kind of place. A club like the Century should surely be unaffected by fashionable whims.

14. Faulty Emotional Appeals

In some discussions of fallacies, appeals to the emotions of the audience are treated as illegitimate or "counterfeit proofs." All such appeals, however, are not illegitimate. Appeals to the values and emotions of an audience are an appropriate form of persuasion. You can recognize fallacious emotional appeals if (1) they are irrelevant to the argument or draw attention from the issues being argued or (2) they appear to conceal another purpose. Here we treat two of the most popular appeals--to pity and to fear.

Appeals to pity, compassion, and natural willingness to help the unfortunate are particularly hard to resist. The requests for aid by most charitable organizations--for hungry children, victims of disaster, stray animals--offer examples of legitimate appeals. But these appeals to our sympathetic feelings should not divert us from considering other issues in a particular case. It would be wrong, for example, to allow a multiple murderer to escape punishment because he or she had experienced a wretched childhood. Likewise, if you are asked to contribute to a charitable cause, you should try to learn how many unfortunate people or animals are being helped and what percentage of the contribution will be allocated to maintaining the organization and its officers. In some cases the financial records are closed to public review, and only a small share of the contribution will reach the alleged beneficiaries.

Appeals to fear are likely to be even more effective. But they must be based on evidence that fear is an appropriate response to the issues and that it can move an audience toward a solution to the problem. (Fear can also have the adverse effect of preventing people from taking a necessary action.) Insurance companies, for example, make appeals to our fears of destitution for ourselves and our families as a result of injury, unemployment, sickness, and death. These appeals are justified if the possibilities of such destitution are real and if the insurance will provide relief. It would also be legitimate to arouse fear of the consequences of drunk driving, provided, again, that the descriptions were accurate. On the other hand, it would be wrong to induce fear that fluoridation of public water supplies causes cancer without presenting sound evidence of the probability. It would also be wrong to instill a fear of school integration unless convincing proof were offered of undesirable social consequences.

An emotional response by itself is not always the soundest basis for making decisions. Your own experience has probably taught you that in the grip of a strong emotion like love or hate or anger you often overlook good reasons for making different and better choices. Like you, your readers want to be given the opportunity to consider all the available kinds of support for an argument.