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CHAPTER 7
INFORMAL FALLACIES
A deductive fallacy is committed whenever it is suggested that the truth of the conclusion of an argument necessarily follows from the truth of the premises given, when in fact that conclusion does not necessarily follow from those premises. An inductive fallacy is committed whenever it is suggested that the truth of the conclusion of an argument is made more probable by its relationship with the premises of the argument, when in fact it is not. We will cover two kinds of fallacies: formal fallacies and informal fallacies. An argument commits a formal fallacy if it has an invalid argument form. An argument commits an informal fallacy when it has a valid argument form but derives from unacceptable premises. A. Fallacies with Invalid Argument Forms Consider the following arguments: (1) All Europeans are racist because most Europeans believe that Africans are inferior to Europeans and all people who believe that Africans are inferior to Europeans are racist. (2) Since no dogs are cats and no cats are rats, it follows that no dogs are rats. (3) If today is Thursday, then I'm a monkey's uncle. But, today is not Thursday. Therefore, I'm not a monkey's uncle. (4) Some rich people are not elitist because some elitists are not rich.
These arguments have the following argument forms: (1) Some X are Y All Y are Z All X are Z. (2) No X are Y No Y are Z No X are Z (3) If P then Q not-P not-Q (4) Some E are not R Some R are not E Each of these argument forms is deductively invalid, and any actual argument with such a form would be fallacious. There are many other forms that an argument might have that would make it invalid (and thereby fallacious), and it was the purpose of Chapters 1, 2, 3, and 4 to provide us with procedures for describing and testing the formal validity of argument forms. One common kind of formal fallacy derives from the use of ambiguous terms. In Chapter 3, we explored how such fallacies derived from a faulty middle term in a syllogism. Thus, “Every lion is ferocious and Haile Sellassie was the Lion of Judah so Haile Sellassie must have been ferocious” has the syllogistic form: All L are F (major premise) All HS are L’ (minor premise) All HS are F (conclusion)
The first example involves an equivocation on the word “bank” and its meaning as: (a) a financial institution for storing and preserving money and valuables, and (b) as the sides of a stream, river, lake, sea or other substantial body of water. Example (2) involves equivocation on the phrase “government that is divided.” The phrase is used initially to suggest the meaning “Government that is divided between warring factions” but afterwards, it is used to mean “government that is divided into branches with different functions.” The final example involves an equivocation on the term “kid,” which is used initially to mean “a young human being”, but subsequently is used to mean "a young goat.”
- A. 1. Exercise: Explain how the terms pitcher, bat, bank, spoke, fish, dig, square, bad, could be ambiguous. Try to formulate arguments in which these terms are used ambiguously. A common way of describing groups is in terms of group averages. But different concepts of averages can be used equivocally to lead to a particular conclusion that in fact does not follow. Thus, suppose firm A has 10 employees where 9 make $10,000 p/y and the president makes $110,000 p/y. The total salary is $2,00,000 for the 10 employees, gives an average salary of $2 0 ,000 per employee. The president of a firm can truthfully say that the average salary is $20,000 p/y. The average being used by the president is the mean, which is the total amount paid in salaries divided by the total number of workers. But the mean tells us nothing about how salaries are distributed in firm A. On the other hand, the union will stress that the average salary is 1/11 the salary of the president. Suppose that firm B has 10 employees, each making $20,000 p/y. B also has a mean salary of $20,00 p/y. but the mean in firm B is much more indicative of what the
‘average’ worker actually earns. The mean, mode and median are different ways of talking about group averages. The mean salary is the total paid in salaries divided by the number of individuals paid. The modal salary is the salary that most employees make. The modal salary for A is $10,000 p/y. The modal salary for firm B is $20,000, twice the modal salary in A. Yet each has the same average in terms of the mean. Another way of characterizing a group is in terms of percentages. Equivocation in using percentages occurs when a percentage calculated on one base is used as if it applied equally to a different base. Consider the following examples: Claim: A survey showed that people who use Pepodent have 20% fewer cavities. Therefore, if you use Pepodent you will probably have 20% fewer cavities than if you didn’t use Pepodent. Analysis: It may be true that Pepodent users have 20% fewer cavities on average than non- Pepodent users. But this does not imply that using Pepodent will cause each user to have 20% fewer cavities. Claim: People who go to college make 50% more income. Therefore, if you go to college you’ll make 50% more income than if you didn’t go to college. Analysis: The class of people who go to college may make 50% more income. But going to college may not lead each graduate to make 50% more than if they had not gone to college. Claim: Suppose a merchant spends $9 on merchandise each day that she then sells for $10. Her total sales for the year are $3650. With a profit of $365, this gives her a return (on total sales) of 10%. But with an initial investment of $9 and a final profit of $365, the percentage return (on initial investment) is 500%. The company made 10% return on total sales but a 50 0 % return on initial investment. Analysis: The above fallacies involve calculating a percentage on one base, then then applying it to a different base.
In the first example, the statement “Hush said the terrorists must be stopped before rising from his desk” is ambiguous between: (a) a situation in which Hush said “The terrorists must be stopped” before he arose from his desk; and (b) a situation in which Hush said that the terrorists must be stopped before they arose from his desk. Without a doubt, (b) depicts a rather bizarre state of affairs while (a) is perfectly ordinary. In the second example, the proposition “All men are not sexist” is ambiguous between “Some men are not sexist” and “No men are sexist.” The conclusion of the argument makes use of the second meaning though it is probably the first meaning that leads Ms. B to accept the ambiguous statement as a premise. In the third example, the locution “X will lose no time in doing Y” is ambiguous between “X will not do Y” and “X will begin doing Y immediately.” III. Fallacy of Accent When interpretations of a statement can be changed by placing emphasis on different syllables or terms in the statement, the statement is accent-ambiguous. The fallacy of accent is committed when one interpretation is used to gain acceptance of the premise but a different interpretation is used in drawing the conclusion. In the following examples, the statement, “I believe that all men are created equal” is ambiguous in at least five different ways, depending on what word is accented in using the statement as a premise. (1) I believe that all men are created equal. However, that does not require that you believe that all men are created equal. Therefore, you are not obligated to practice non-discrimination as I do. (2) I believe that all men are created equal. However, what I believe need not be the case. Therefore, it may be that in fact all men are not equal. (3) I believe that all men are created equal. But this certainly does not extend to women. Therefore, I oppose the Equal Rights Amendment to the constitution. The Founding Fathers didn't believe women were equal to men either.
(4) I believe that all men are created equal. But once their creation is finished, some men work harder than others. The social equalities we see between men are no more created by God than the mighty skyscrapers we see as we drive through our nation's capital. But just because God didn't create skyscrapers during the six days he took to create the solar system, that doesn't mean that we should therefore destroy them. And neither should we destroy social inequalities. (5) I believe that all men are created equal. That means that no person has a right to certain kinds of opportunity that other people do not have an equal right to. Therefore, I believe that if a man can be operated on so that he is implanted with a functional womb, then he should be allowed the opportunity to give birth to a baby. B. Category Fallacies This group of fallacies - the fallacy of division and the fallacy of composition- involves equivocation between: (a) using a term to refer to a class as a whole and (b) using the term to refer to a member of that class. The fallacy of division takes what is true of the whole to be true of all the parts. The fallacy of division arises when a concept is used as a collective unit in the premise, then a conclusion (based on the truth of that premise) is drawn in which the same concept is applied to an individual unit of the collection. (1) America is the richest country in the world. Since you are an American, you must be rich. (2) Smith has a better basketball team than Wellesley. Mary is a player on Smith's team. Phyllis is a player on Wellesley’s team. Therefore, Mary is a better basketball player than Phyllis. The fallacy of composition derives from taking what is true of a part to be true of the whole. This is the reverse of the fallacy of division. Here a claim is made about the
- The average American family has two and a half children. You are an average American family, therefore, you have two-and-a-half children.
- The jury was unable to come to a verdict as to whether the defendant was guilty. Therefore each of the jurors was unable to make up his or her mind.
- Rights within the State should always be balanced by responsibilities to the State. Therefore, those with the most civil rights ought to shoulder most of the responsibilities of government.
- Rights within the State should always be balanced by responsibilities to the State. Therefore, those who make the least contribution to the State should have the least civil rights.
- John said that he would give Tom and Mary $5,000.00. John always tells the truth. Therefore John will give Tom $5,000.00.
- Whooping cranes are becoming extinct. That bird is a whooping crane. Therefore, that bird is becoming extinct.
- A brick is very small. Therefore, a building made of brick must be very small.
- Flour tastes horrible. And since it is the main ingredient in bread, bread must taste horrible.
- Much religious teaching is contained in the Bible. The Bible is a word of five letters. Therefore, much religious teaching is contained in a word of five letters.
- The Consumer Report says: “We cannot recommend this car too highly.” Therefore, I should not buy that car.
- The killing of the hunters is regrettable, my neighbor said. Therefore, my neighbor must be against hunting.
- College graduates make on the whole more money than non-college graduates. Thus, since you are a college graduate and I am not, you must make more money than me.
- A feather is very light. Therefore, a mountain of feathers is very light.
- Mr. Senator, individual liberty is not being threatened or abused by the CIA because it authorizes only twenty categories of domestic and international espionage. This is a smaller number than any other country in the world. (The suggestion is that there were only twenty cases of domestic and international espionage carried out by the CIA).
- Since I lifted each piece of wood that went into making this table, I must be able to lift the table.
- The boss interviewing an young attractive secretary told her she could expect frequent advances. Therefore, she readily accepted the job.
- Both hydrogen (H) and oxygen (O) are highly flammable. Therefore, H2O must be highly flammable.
- The house that you live in is large so it must have large closets.
- I'm not worried that the six Beasley boys are coming to fight me. I've whipped each of than, so I know I'll be able to whip them again. C. Fallacies With Valid Argument Forms Formal fallacies are arguments that are defective because they have invalid argument forms. But while all invalid arguments are fallacious, it is not the case that all fallacious arguments are invalid. Indeed, many fallacious arguments have valid argument forms. For instance, the argument “All dogs are from outer space because all dogs are cats and all cats are from outer space” is fallacious, even though it has a valid argument form. It is fallacious because its premises are unacceptable and therefore do not lead us to accept the conclusion as true. Whenever a conclusion is asserted to have a certain truth-value on the basis of premises that are unacceptable, the argument is unsound and therefore fallacious. Many informal fallacies are a species of unsound arguments. Generally, informal fallacies involve arguments that have faulty premises. Typically, the premises of such arguments are not stated explicitly (enthymemes), and the listener is led to accept them without careful examination. In what follows, we will introduce some of the most common forms of informal fallacies. I. Appeal to the Person (Ad Hominem) The fallacy of ad hominem is committed when the conclusion of an argument is rejected, not because of objections to the premises or steps connecting the premises to the
The statements in (4b) speak to whether certain statements alleged to be true by the witness are in fact true. If a person is known to misrepresent truth for personal gain, psychological release, or whatever reason, then the probability increases that under current circumstances he may be misrepresenting the facts. And if the truth-value of the premises is indeterminate, then the truth-value of the conclusion of that argument is also indeterminate. On the other hand, if there is no question as to the authenticity of all the evidence presented, then it is only to the validity of the argument into which that evidence is incorporated that criticism can be directed. In this case, one must show that the facts do not fit together in one's opponent's argument. It is no good to attack the character of the opposing attorney, as in (4a). The opposing attorney may be scrupulous in presenting witnesses that tell the truth and a genius at constructing clever arguments, yet be a scoundrel in her personal life. 4a. If A has a bad character then A’s argument should be rejected. A has a bad character. A’s argument should be rejected 4b. If A has a bad character then A’s argument should be suspect. A has a bad character. A’s argument should be suspect. 4a is an invalid argument, because an argument cannot be discredited by attacking its maker. An argument can only be challenged on two fronts: the truth-value of its premises and the validity of its form. If the truth of the assumptions proposed is guaranteed by someone whose truthfulness is suspect, then that person's guarantee is suspect. Thus, those assumptions may be considered insufficient to establish the truth of the conclusion in question. The other basis for rejecting the argument is whether the argument form is valid. But the validity of an argument form is independent of the trustworthiness of the maker of the argument, because the validity of an argument form is independent of the actual truth or falsity of the statements that make it up.
The ad hominem fallacy is also committed is in what is called the “You also!” (Tu quoque) argument. Here, the accused defends herself by charging the accuser of having committed the same act she is being prosecuted for. The erroneous premise of such arguments is that the accused should not be held responsible for doing x if others have done x without being held equally responsible. (5) Members of the American military should not be prosecuted for killing civilians during the war in Iraq. Al Qaeda has practiced the killing of civilians as part of its holy war tactics. Yet, Al Qaeda sympathizers have not condemned Al Qaeda. So, members of the American military should not be condemned and punished when others are doing the same thing. (6) Senator X has accused me of being financed by Big Business. Well, in reply let me point out that much of the money for Senator X’s campaign has come from Big Business. (7) American presidents defended legalized segregation by pointing out that many other countries violated the rights of certain groups of their own citizens. Observe that, in the tu quoque (you also!) argument, A argues that B’s accusation about A should be rejected because B is guilty of a similar offense. Thus, attention is redirected from the charge to the maker of the charge. But even if the counter-accusation is true, this does not imply that the original accusation was false. To answer an allegation of misconduct by citing the accuser's similar misconduct is only a means of confusing the issue. What is needed in order to meet an accusation is not a counter accusation, but an argument showing that the accusation being made is unwarranted. II. Appeal to Authority (Ad Verecundiam) In this fallacy, reverence for a particular authority is used to gain acceptance of a particular conclusion, without due consideration of the reasons advanced by the authority in support of that conclusion. The corrective to the fallacy of appealing to authority is to
Some further examples of appeal to authority are: (4) Hyrd station wagons are superior to other brands of station wagons because Knut Ruckney, football coach of Notre Dame, drives a Hyard and says that Hyrd makes the best station wagon in the world. (5) Doxema is the best shave cream on the market because Eli Kanning, the well-known quarterback, uses it. These examples illustrate how the proposition “If authority A says that P is true, then P is true” is not always true. The fact that Knut Ruckney might be an authority on football does not mean that he is an authority on automobiles. An authority in one field is not necessarily an authority in another. Yet, advertising suggests that an authority in one field is equally an authority in another when individuals who excel in one area (sports, music, science, etc.) are asked to testify concerning issues in an entirely different area. III. Appeal to Ignorance (Ad Ignorantiuam) This fallacy arises when an argument is accepted (or rejected), not as a result of an examination of the relationship between its premises and conclusion, but rather as a result of ignorance of key concepts used in the argument. Because of the need for specialized knowledge, this fallacy is often combined with an appeal to authority. (1) Amplifier A has 25 KMI per channel. Amplifier B has 40 KMT per channel. They cost the same. Therefore, Amplifier B is the best buy. (more examples needed) IV. Appeal to the Mob (Ad Populum) This fallacy is committed when an audience is induced to accept a certain conclusion on the basis of appeal to interests, preferences, and values common to the speaker and the audience. Such arguments have the following general form:
If we have the same values and interests, then P is true. We have the same values and interests. P is true. Speaker: “Do you want freedom of speech?” Crowd: “Yes!” Speaker: “Do you want to be ruled by a dictatorship?” Crowd: “No!” Speaker: “Do you want a decent 1iving?” Crowd: “Yes!” Speaker: “Then we want the same things. So vote for me and let's make the world safe for democracy.” Rufus Dufus was caught at the scene of the crime. A good, upstanding woman just like our wives, sisters and mothers, said she was assaulted. Is this what we want for our womenfolk? Is this what we are going to allow our daughters to face when they grew up. No! We must have law and order and safety for our loved ones. We have to let vicious criminals know that we will not stand for such atrocities. So let's string Rufus up now and set an example that such will not be tolerated in this town. V. Appeal to Pity (Ad Misericordiam) Compassion is an important human emotion. It is good and necessary that we should feel concern for the plight of others. But this does not mean that our actions must always be guided by our feelings. Unfortunately, there is often sincere confusion on this point. To illustrate, suppose A is approached by a handicapped beggar and A gives him money. She might explain her action by saying that she was moved by pity to help the beggar. The framework for her action would then be given the following argument: If I feel pity for x, then I should help x. I feel pity for x. I should help x.
home to his sick mother. I ask you, ladies and gentlemen of the jury, not to impose yet another burden on my client. I ask you to find him not guilty of the crime he is accused of.” (2b) Prosecutor: “Ladies and gentlemen of the jury, I share with the defense a concern for the misfortunes that the accused has suffered. But that has nothing to do with the actual fact of whether or not he committed the crime he is accused of. All the evidence points to the conclusion that he did commit that crime. Therefore, we are bound by law to find the defendant guilty.” In example (1b) the professor may believe that the student deserves aid because of her unfortunate situation, but he is expressly forbidden by the code of the university from offering a passing grade as aid. Likewise, the members of the jury in example (2b) may feel compassion for the defendant, but they too are expressly forbidden by the codes of law from acquitting the defendant purely on the basis of their feeling of compassion and belief that he deserves aid. These examples show how the kind of aid we are allowed to give is often limited by the codes, principles, and rules governing our social roles. The professor is prohibited from giving a grade on any criteria except that of classroom performance. A jury is prohibited from acquitting a defendant on any grounds except insufficient evidence. The fact that a store clerk feels or believes that the destitute person outside the store needs help is not a legitimate justification for giving that person merchandise that has not been paid for. VI. Appeal to Force (Ad Baculum) When it is suggested to a person that dire consequences will befall her if she does not accept (or reject) a given conclusion, we have an appeal to force. In such cases, the conclusion is accepted (or rejected) on the basis of fear induced by a suggested threat. If you do not wish to suffer harm, then you will do x. You do not wish to suffer harm. You will do x.
While this is a valid argument, there are nonetheless many situations in which one is expressly forbidden from acting on the basis of the premise “If you do not wish to suffer harm, then you will do x.” (1a) Student: “Professor, I beat a man up real bad who didn’t give me what I wanted. Therefore, you'd better give me a passing grade in this course.” (1b) Professor: “I certainly do not want to be beaten up. But nonetheless I am expressly forbidden from awarding you a passing grade in this course for such a reason.” (2) Mr. B: “Jones, you've been an employee of mine for a 1ong time and I know you want to keep your job. Therefore, I hope you'll find time to help my friend, Senator Tydings, in his re-election campaign.” (3) Mafia Boss: “Ms. Smith, you've had this store for many years without any serious accidents. I know you want to keep it that way. But a number of store owners who don't carry my insurance policy have recently experienced horrible fires that have closed down their businesses. I hope you’ll buy my insurance policy.” VII. Appeal to Pride In the appeal to pride, the attempt is made to influence a person's acceptance or rejection of a certain conclusion by making that conclusion appear as a reflection of the person's character. The person's desire to improve and enhance his or her self-image becomes the primary factor determining the acceptance or rejection of the conclusion in question. Arguments that appeal to pride generally have the following form:
