COMPETENCY PROGRAM IN LOGIC & MORAL PHILOSOPHYCagayan State UniversityOffice of the Vice-President for Academic Affairs

CRITICAL THINKING& COMMON ERRORS IN REASONING

ARCHIMEDES C. ARTICULO, MPhil.Chair, Department of Social Sciences & Philosophy

College of Arts & SciencesCagayan State University

For many students, the term “Logic” usually conjures the dreaded images of the Truth Table, Venn’s Diagram, Special Symbols and many others that unfortunately create the impression that it is needlessly and impractically difficult. Unlike any other academic subjects that are taught in school, Logic (most especially the Symbolic part) is very difficult to understand, and they charge that in light of the practical affairs of men, it is highly irrelevant.

This is an unfortunate mistake.

One of the many reasons why this impression is widely held among students is because the teacher, most often than not, fails to explain the significance of studying a particular topic in Logic before they delve on the tables and symbols, or before they discuss propositions and syllogisms. Without telling the students the reason for embarking on a difficult study, the discussion becomes dreadful even before the teacher opens her mouth.

One way of showing the significance of Logic to our students is to show it’s relevance in their everyday life – and the first step of making students appreciate the relevance of Logic as a study is to dispel the popular impression that Logic is purely symbolic, that studying the symbols and the tables are end in themselves, because the study of logical symbols is a mere means to an end.

We use symbols and tables for a purpose. And the main purpose is to promote critical thought among our students. As you have seen in the past few days of our training, Logic employs these special symbols as conceptual tools to prove the Truth and Falsity of claims, to demonstrate the validity or invalidity, and the soundness or unsoundness of arguments. It promotes the cardinal rule in Logic that before we accept the claim to be true, the argument in which it is offered and proved must be shown first to be valid and sound.

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This shows that Logical symbols are not simply symbols, but tools to sharpen the mind, to make it more perceptive, to make it more inquisitive, and to train it to accept only the claims that are true and provable.

There is also a political reason why we must promote Logic and Critical Thinking among our students.

We need to help them think logically and critically if we want our democratic way of life maintained and protected.

If Philippine Democracy, as a Democracy, is ruled by Public Opinion, then we need to have citizens who are capable and able to make intelligent opinions, to argue for or against claims, and to detect and uncover lies and falsities.

The only genuine way to check and to balance the instrumentalities and branches of the Government is participation of an intelligent citizenry.

Although this cannot be provided solely by the study of Logic, for surely it requires the study of other disciplines, once we have done our part in teaching the Principles and Methods of Logic well to our students, the whole endeavor is already half done.

Critical Thinking and Errors in Reasoning

During the previous days of our training, we learned how to evaluate the validity (or invalidity) of arguments. In Categorical Syllogisms we learned that arguments violating the valid forms result to formal fallacies.

Today, we will learn more about fallacies.

Part of learning how to reason logically, is learning how not to reason. And this includes how to distinguish good arguments from those that are faulty. To know how to spot faulty argument is to know what to avoid when we are called to evaluate the arguments of others, or when we ourselves argue. With that, we can know how to construct a strong, if not fault-free, argument.

A faulty argument is worth demolishing. To show that an argument is faulty is to demolish it. Logic prohibits the acceptance of claims presented in a fallacious argument, it is not worthy of belief.

In our discussion, we shall attempt to identify informal fallacies, explain how they are committed, and show how they could be counter-argued.

We start with False Dilemma.

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FALSE DILEMMA

Definition: A limited number of options (usually two) is given, while in reality there are more options. A false dilemma is an illegitimate use of the "or" operator. Putting issues or opinions into "black or white" terms is a common instance of this fallacy (Cedarblom and Paulsen: p.136)Examples:

1. Either you're for me or against me. 2. The human character is either influenced by heredity or environment.

Counter-Argument: Identify the options given and show (with an example) that there is an additional option.

ARGUMENT FROM IGNORANCE (Argumentum Ad Ignorantiam)

Definition: Arguments of this form assume that since something has not been proven false, it is therefore true. Conversely, such an argument may assume that since something has not been proven true, it is therefore false (Copi and Cohen: 93, Davis: 59) This is a special case of a false dilemma, since it assumes that all propositions must either be known to be true or known to be false.) As Davis writes, "Lack of proof is not proof." (p. 59) Examples:

1. Since you cannot prove that ghosts do not exist, they must exist. 2. Since scientists cannot prove that global warming will occur, it probably won't.

Counter-Argument:

Identify the proposition in question. Argue that it may be true even though we don't know whether it is or isn't.

SLIPPERY SLOPE

Definition: In order to show that a proposition P is unacceptable, a sequence of increasingly unacceptable events is shown to follow from P. A slippery slope is an illegitimate use of the "if-then" operator (Cedarblom and Paulsen: 137). Examples:

1. If we pass laws against fully-automatic weapons, then it won't be long before we pass laws on all weapons, and then we will begin to restrict other rights, and finally we will end up living in a communist state. Thus, we should not ban fully-automatic weapons.

2. You should never gamble. Once you start gambling you find it hard to stop. Soon you are spending all your money on gambling, and eventually you will turn to crime to support your earnings.

Counter-Argument: Identify the proposition P being refuted and identify the final event in the series of events. Then show that this final event need not occur as a consequence of P.

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COMPLEX QUESTION

Definition: Two otherwise unrelated points are conjoined and treated as a single proposition. The reader is expected to accept or reject both together, when in reality one is acceptable while the other is not. A complex question is an illegitimate use of the "and" operator (Cedarblom and Paulsen: 86, Copi and Cohen: 96)Examples:

1. You should support home education and the God-given right of parents to raise their children according to their own beliefs.

2. Do you support freedom and the right to bear arms?3. Have you stopped using illegal sales practises? (This asks two questions: did you use

illegal practises, and did you stop?)

Counter-Argument: Identify the two propositions illegitimately conjoined and show that believing one does not mean that you have to believe the other.

APPEAL TO FORCE (Argumentum Ad Baculum)

Definition: The reader is told that unpleasant consequences will follow if they do not agree with the author (Cedarblom and Paulsen: 151, Copi and Cohen: 103). Examples:

1. You had better agree that the new company policy is the best bet if you expect to keep your job.

2. Federalism is wrong, and if you don't vote against Pimentel’s Bill then we will vote you out of office.

Counter-Argument: Identify the threat and the proposition and argue that the threat is unrelated to the truth or falsity of the proposition.

APPEAL TO PITY (Argumentum Ad Misericordiam)

Definition: The reader is told to agree to the proposition because of the pitiful state of the author (Cedarblom and Paulsen: 151, Copi and Cohen: 103, Davis: 82). Examples:

1. How can you say that's out? It was so close, and besides, I'm down ten games to two.2. We hope you'll accept our recommendations. We spent the last three months working

extra time on it.

Another example: Foronda (2002), in an unpublished manuscript on Logic, provided a very interesting (and amusing) example. Here’s how he presented this type of fallacy: Imagine a college student wishing to transfer to the University of the Philippines. His Grade Weighted

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Average (GWA) is 4.0 (74 or D). The University requires that a transferee must have a GWA not lower than 2.0 (85 or B). But he appeals his case:

Deariest Mister Rigistrar Sir. I am one orphan only. My mother and father die when I am very young. It is my auntie raising me until I am big. We are very poor. I have no shoes when I am going to school before. Now I am a working student. The little I am earn I am saving for paying tuition. I am not eating brekfast most of the morning. I eat crackers only when lunch. That is all I afford. To add to my miserable living the guidance counsillor in our school before I am go to your UP tell me I have ADHD. She say that it is the cause why I am not think straith, why I have poor memory, why I am not bright, why I have low grades. Sometimes I am asking God why? why? why? I shall remain poor and miserable forever? No one shall help me forever that a poor orphan who try his best to alleviate his poverty living? Its only when I am having a good education that I am having a good chance to have a better living. I believe only UP can give me a good education. I am beg to you. Please! Give me chance. Even president Erap is pity the poor like yours truly. I believe that you are more brighter than president Erap. Therefore I believe you are more pityer the poor like yours truly. Accept me to UP, the only hope of the poor to get an excellent education very well. Very truly yours, Iluminado Kulang-kulang.

The gist of Iluminado’s argument is this:

I have the right to be accepted into the University of the Philippines because I am a poor, pitiful, unfortunate orphan.

Counter-Argument: Identify the proposition and the appeal to pity and argue that the pitiful state of the arguer has nothing to do with the truth of the proposition. As Foronda (Ibid), referring to his example points out, “…being poor and pitiful and unfortunate and orphan or he being in any such pathetic state are not the pertinent criterion that make any transferee’s acceptance to the UP right.”

APPEAL TO CONSEQUENCES

Definition: The author points to the disagreeable consequences of holding a particular belief in order to show that this belief is false (Cedarblom and Paulsen: 100, Davis: 63). Example:

1. You can't agree that evolution is true, because if it were, then we would be equal with monkeys and apes.

2. You must believe in God, for otherwise life would have no meaning. (Perhaps, but it is equally possible that since life has no meaning that God does not exist.)

Counter-Argument: Identify the consequences to and argue that what we want to be the case does not affect what is in fact the case.

PREJUDICIAL LANGUAGE

Definition: Loaded or emotive terms are used to attach value or moral goodness to believing the proposition (Cedarblom and Paulsen: 153, Davis: 62). Examples: 5 | P a g e

1. Reasonable and God-fearing Filipinos will agree with me that we should repeal the law on capital punishment.

2. A reasonable person would agree that our income statement is too low. 3. Senator Turner claims that the new tax rate will reduce the deficit. (Here, the use of

"claims" implies that what Turner says is false.) 4. The proposal is likely to be resisted by the bureaucrats on Parliament Hill. (Compare this

to: The proposal is likely to be rejected by officials on Parliament Hill.)

Counter-Argument: Identify the prejudicial terms used (eg. " Reasonable and God-fearing Filipinos " or "A reasonable person"). Show that disagreeing with the conclusion does not make a person "wrong thinking" or "unreasonable".

APPEAL TO POPULARITY (Argumentum Ad Populum)

Definition: A proposition is held to be true because it is widely held to be true or is held to be true by some (usually upper crust) sector of the population. This fallacy is sometimes also called the "Appeal to Emotion" because emotional appeals often sway the population as a whole (Copi and Cohen: 103, Davis: 62)

Examples:

1. If you were beautiful, you could live like this, so buy Buty-EZ and become beautiful. (Here, the appeal is to the "beautiful people".)

2. Polls suggest that the Liberals will form a majority government, so you may as well vote for them.

Counter-Argument: Point that the claim has no other support then its attempt to appeal to the popularity of the claim.

ATTACKING THE PERSON (Argumentum Ad Hominem)

Definition: The person presenting an argument is attacked instead of the argument itself. This takes many forms. For example, the person's character, nationality or religion may be attacked. Alternatively, it may be pointed out that a person stands to gain from a favorable outcome. Or, finally, a person may be attacked by association, or by the company he keeps (Barker: 166, Cedarblom and Paulsen: 155, Copi and Cohen: 97, Davis: 80) There are three major forms of Attacking the Person:

1. AD HOMINEM (abusive): instead of attacking an assertion, the argument attacks the person who made the assertion.

2. AD HOMINEM (circumstantial): instead of attacking an assertion the author points to the relationship between the person making the assertion and the person's circumstances.

3. AD HOMINEM (tu quoque): this form of attack on the person notes that a person does not practise what he preaches.

Examples: 1. You may argue that God doesn't exist, but you are just following a fad. (ad hominem

abusive)

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2. We should discount what Premier Klein says about taxation because he won't be hurt by the increase. (ad hominem circumstantial)

3. We should disregard Share B.C.'s argument because they are being funded by the logging industry. (ad hominem circumstantial)

4. You say I shouldn't drink, but you haven't been sober for more than a year. (ad hominem tu quoque)

Counter-Argument: Identify the attack and show that the character or circumstances of the person has nothing to do with the truth or falsity of the proposition being defended.

APPEAL TO AUTHORITY (Argumentum Ad Verecundiam)

Definition: While sometimes it may be appropriate to cite an authority to support a point, often it is not. In particular, an appeal to authority is inappropriate if:

1. The person is not qualified to have an expert opinion on the subject, 2. Experts in the field disagree on this issue. 3. The right authority was not being serious

A variation of the fallacious appeal to authority is hearsay. An argument from hearsay is an argument which depends on second or third hand sources (Cedarblom and Paulsen: 155, Copi and Cohen: 95, Davis: 69). Examples:

1. Noted psychologist Dr. Frasier Crane recommends that you buy the EZ-Rest Hot Tub. 2. Economist John Kenneth Galbraith argues that a tight money policy s the best cure for a

recession. (Although Galbraith is an expert, not all economists agree on this point.) 3. We are headed for nuclear war. Last week Ronald Reagan remarked that we begin bombing

Russia in five minutes.(Of course, he said it as a joke during a microphone test.) 4. My friend heard on the news the other day that Canada will declare war on Serbia. (This is a case

of hearsay;in fact, the reporter said that Canada would not declare war.) 5. The Ottawa Citizen reported that sales were up 5.9 percent this year. (This is hearsay; we are not

in a position to check the Citizen's sources.)

Counter-Argument: Show that either (i) the person cited is not an authority in the field, or that (ii) there is general disagreement among the experts in the field on this point.

ANONYMOUS AUTHORITIES

Definition: The authority in question is not named. This is a type of appeal to authority because when an authority is not named it is impossible to confirm that the authority is an expert. However the fallacy is so common it deserves special mention. A variation on this fallacy is the appeal to rumour. Because the source of a rumour is typically not known, it is not possible to determine whether to believe the rumour. Very often false and harmful rumours are deliberately started in order to discredit an opponent (Davis: 73).Examples:

1. A government official said today that the new gun law will be proposed tomorrow. 2. Experts agree that the best way to prevent nuclear war is to prepare for it. 3. It is held that there are more than two million needless operations conducted every year.

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4. Rumor has it that the President will declare other official holidays in December, The Born Again Day, The Iglesia ni Cristo Day and the Ang Dating Daan Day.

Counter-Argument: Argue that because we don't know the source of the information we have no way to evaluate the reliability of the information.

STYLE OVER SUBSTANCE

Definition: The manner in which an argument (or arguer) is presented is taken to affect the likelihood that the conclusion is true (Davis: 61)Examples:

1. FPJ lost the presidential debate because of the sweat on his forehead. 2. Ate Glo received twenty-two standing ovations. What she said must be right. 3. Why don't you take the advice of that nicely dressed young man?

Counter-Argument: While it is true that the manner in which an argument is presented will affect whether people believe that its conclusion is true, nonetheless, the truth of the conclusion does not depend on the manner in which the argument is presented. In order to show that this fallacy is being committed, show that the style in this case does not affect the truth or falsity of the conclusion.

HASTY GENERALIZATION

Definition: The size of the sample is too small to support the conclusion (Barker: 189, Cedarblom and Paulsen: 372, Davis: 103).

Examples:

1. Fred, an Ilokano, stole my wallet. Thus, all Ilokanos are thieves. (Of course, we shouldn't judge all Ilokanos on the basis of one example.)

2. I asked six of my friends what they thought of my chances of winning the SBO vice-presidential position and they said I will win. Therefore, I will be the next vice-president of the Student Body Organization.

Counter-Argument: Identify the size of the sample and the size of the population, then show that the sample size is too small. Note: a formal proof would require a mathematical calculation. This is the subject of probability theory. For now, you must rely on common sense.

UNREPRESENTATIVE SAMPLE

Definition: The sample used in an inductive inference is relevantly different from the population as a whole (Barker: 188, Cedarblom and Paulsen: 226, Davis: 106). Examples:

1. To see how Filipinos will vote in the next election, we polled a hundred people in Metro Manila. This shows conclusively that FPJ will sweep the polls. (People in Metro Manila tend to be more Pro-FPJ, and hence more likely to vote FPJ, than people in the rest of the country.)

2. The apples on the top of the box look good. The entire box of apples must be good. (Of course, the rotten apples are hidden beneath the surface.)

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Counter-Argument: Show how the sample is relevantly different from the population as a whole, and then show that because the sample is different, the conclusion is probably different.

FALSE ANALOGY

Definition: In an analogy, two objects (or events), A and B are shown to be similar. Then it is argued that since A has property P, so also B must have property P. An analogy fails when the two objects, A and B, are different in a way which affects whether they both have property P (Barker: 192, Cedarblom and Paulsen: 257, Davis: 84). Examples:

1. Employees are like nails. Just as nails must be hit in the head in order to make them work, so must employees (But there are model employees out there who can work without being forced to work).

2. Government is like business, so just as business must be sensitive primarily to the bottom line, so also must government. (But the objectives of government and business are completely different, so probably they will have to meet different criteria.)

Proof: Identify the two objects or events being compared and the property which both are said to possess. Show that the two objects are different in a way which will affect whether they both have that property.

SLOTHFUL INDUCTION

Definition: The proper conclusion of an inductive argument is denied despite the evidence to the contrary (Barker: 189). Examples:

1. Hugo has had twelve accidents in the last six months, yet he insists that it is just a coincidence and not his fault. (Inductively, the evidence is overwhelming that it is his fault. This example borrowed from Barker, p. 189)

2. Poll after poll shows (from 1914-2003) that the Cure Phlegm Party of Northern Philippine Area (CPP-NPA) will win fewer than two seats in Congress. Yet the party leader insists that the party is doing much better than the polls suggest (from 1914-2003).

Counter-Argument: About all you can do in such a case is to point to the strength of the inference.

FALLACY OF EXCLUSION

Definition: Important evidence which would undermine an inductive argument is excluded from consideration. The requirement that all relevant information be included is called the "principle of total evidence" (Davis: 115)Examples:

1. Jones is Visayan, and most Visayans vote Roco, so Jones will probably vote Roco. (The information left out is that Jones lives in Pangasinan, and that most people in Pangasinan vote Ramos.)

2. The Ginebra team will probably win this game because they've won nine out of their last ten. (Eight of the Ginebra’s wins came over last place teams, and today they are playing the first place team.)

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Counter-Argument: Give the missing evidence and show that it changes the outcome of the inductive argument. Note that it is not sufficient simply to show that not all of the evidence was included; it must be shown that the missing evidence will change the conclusion.

EXERCISES

1. He is a school drop-out, how could he know anything about Politics?2. She supports Ramos because he is from Pangasinan.3. Mr. Juan De Jesus keeps on telling us not to get absent but he is the one who always

misses the class.4. Condoms are good defense against colds, because that’s what my teacher in Logic told

the class.5. According to Kris Abunda, the husband of the President was seen dating Mahal in a

secluded place in the Luneta Park.6. According to some school administrators, there will be no classes the whole semester

next school year.7. He never blinked when he said, my one and only wife. It must be true that he is

monogamous.8. How could you believe her, she’s a kapampangan!9. Fifteen Filipinos has responded to our nationwide product survey. They don’t like the

product. So, my dear board of directors, we better design another one if we want to stay in business.

10. One hundred Landowners all over the country were randomly selected and interviewed about the real condition of their tenants. 99% of them claimed that their tenants are generally happy and living well.

11. Women are like roller coasters - their mood swings unpredictably.12. Accidents are accidents, no one wants them to happen. It is true that I accidentally

kicked your face ten times already – but that’s that: an accident.13. An old woman came to our house uninvited and declared that the pain I’m feeling in my

knees is connected to breast cancer. She does not know me personally and it was my first time to meet her. But she know that my knees are in pain. You see, it’s so mysterious, it’s unexplainable. Therefore it is true that I have a breast cancer.

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COINCIDENTAL CORRELATION (Post Hoc Ergo Propter Hoc)

Definition: The name in Latin means "after this therefore because of this". This describes the fallacy. An author commits the fallacy when it is assumed that because one thing follows another that the one thing was caused by the other (Cedarblom and Paulsen: 237, Copi and Cohen: 101). Examples:

1. Immigration to Alberta from Ontario increased. Soon after, the welfare rolls increased. Therefore, the increased immigration caused the increased welfare rolls.

2. I took EZ-No-Cold, and two days later, my cold disappeared.

Counter-Argument: Show that the correlation is coincidental by showing that: (i) the effect would have occurred even if the cause did not occur, or (ii) that the effect was caused by something other than the suggested cause.

JOINT EFFECT

Definition: One thing is held to cause another when in fact both are the effect of a single underlying cause. This fallacy is often understood as a special case of post hoc ergo prompter hoc (Cedarblom and Paulsen: 238). Examples:

1. We are experiencing high unemployment which is being caused by a low consumer demand. (In fact, both may be caused by high interest rates.)

2. You have a fever and this is causing you to break out in spots. (In fact, both symptoms are caused by the measles.)

Counter-Argument: Identify the two effects and show that they are caused by the same underlying cause. It is necessary to describe the underlying cause and prove that it causes each symptom.

GENUINE BUT INSIGNIFICANT CAUSE

Definition: The object or event identified as the cause of an effect is a genuine cause, but insignificant when compared to the other causes of that event. Note that this fallacy does not apply when all other contributing causes are equally insignificant (Cedarblom and Paulsen: 238).

. Examples:

1. Smoking is causing air pollution in Edmonton. (True, but the effect of smoking is insignificant compared to the effect of auto exhaust.)

2. By leaving your oven on overnight you are contributing to global warming. Proof: Identify the much more significant cause.

WRONG DIRECTION

Definition: The relation between cause and effect is reversed (Cedarblom and Paulsen: 238). Examples:

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1. Cancer causes smoking. 2. The increase in AIDS was caused by more sex education. (In fact, the increase in sex education

was caused by the spread of AIDS.)

Counter-Argument: Give a causal argument showing that the relation between cause and effect has been reversed.

COMPLEX CAUSE

Definition: The effect is caused by a number of objects or events, of which the cause identified is only a part. A variation of this is the feedback loop where the effect is itself a part of the cause Cedarblom and Paulsen: 238. Examples:

1. The car accident was caused by the heavy rain. (True, but it wouldn't have occurred had the driver not been drunk and the pedestrian not been jaywalking.)

2. The Challenger explosion was caused by the cold weather. (True, however, it would not have occurred had theO-rings been properly constructed.)

3. People are in fear because of increased crime. (True, but this has lead people to break the law as a consequence of their fear, which increases crime even more.)

Counter-Argument: Show that all of the causes, and not just the one mentioned, are required to produce the effect.

BEGGING THE QUESTION(PETITIO PRINCIPII)

Definition: The truth of the conclusion is assumed by the premises. Often, the conclusion is simply restated in the premises in a slightly different form. In more difficult cases, the premise is a consequence of the conclusion (Barker: 159, Cedarblom and Paulsen: 144, Copi and Cohen: 102, Davis: 33). Examples:

1. Since I'm not lying, it follows that I'm telling the truth. 2. We know that God exists, since the Bible says God exists. What the Bible says must be true, since

God wrote it and God never lies. (Here, we must agree that God exists in order to believe that God wrote the Bible.)

Counter-Argument: Show that in order to believe that the premises are true we must already agree that the conclusion is true.

IRRELEVANT CONCLUSION (IGNORATIO ELENCHI)

Definition: An argument which purports to prove one thing instead proves a different conclusion (Copi and Cohen: 105). Examples:

1. You should support the new housing bill. We can't continue to see people living in the streets; we must have cheaper housing. (We may agree that housing s important even though we disagree with the housing bill.)

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2. I say death penalty does not deter crime. Only a handful of countries today still impose the death penalty. Death penalty cannot bring back the life of the victim. The legal system is flawed, only the poor are convicted in the death row because they cannot hire good lawyers and they cannot buy the judges. Life imprisonment is a far much better deterrence to crime than death penalty (all the premises may be acceptable, but they have nothing to say about the conclusion – that is, death penalty, In fact, does not deter crime).

Counter-Argument: Show that the conclusion which the author has set to prove is not the conclusion that the author’s premises prove. Meaning, demonstrate that the author’s premises failed to establish his conclusion.

STRAW MAN

Definition: The author attacks an argument which is different from, and usually weaker than, the opposition's best argument (Cedarblom and Paulsen: 138). Examples:

1. People who opposed the Charlottetown Accord probably just wanted Quebec to separate. But we want Quebec to stay in Canada.

2. We should have conscription. People don't want to enter the military because they find it an inconvenience. But they should realize that there are more important things than convenience.

Counter-Argument: Show that the opposition's argument has been misrepresented by showing that the opposition has a stronger argument. Describe the stronger argument.

EQUIVOCATION

Definition: The same word is used with two different meanings or senses. (Barker: 163, Cedarblom and Paulsen: 142, Copi and Cohen: 113, Davis: 58). Examples:

1. Criminal actions are illegal, and all murder trials are criminal actions, thus all murder trials are illegal. (Here the term "criminal actions" is used with two different meanings. Example borrowed from Copi.)

2. The sign said "fine for parking here", and since it was fine, I parked there. 3. All child-murderers are inhuman, thus, no child-murderer is human. (From Barker, p. 164; this is

called "illicit obversion") 4. A plane is a carpenter's tool, and the Boeing 737 is a plane, hence the Boeing 737 is a carpenter's

tool. (Example borrowed from Davis, p. 58) Counter-Argument: Identify the word which is used twice, then show that a definition which is appropriate for one use of the word would not be appropriate for the second use.

AMPHIBOLY

Definition: An amphiboly occurs when the construction of a sentence allows it to have two different meanings (Copi and Cohen: 114). Examples:

1. Last night I shot a burglar in my pyjamas.

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2. The Oracle of Delphi told Croseus that if he pursued the war he would destroy a mighty kingdom. (What theOracle did not mention was that the kingdom he destroyed would be his own. Adapted from Heroditus, TheHistories.)

3. Save soap and waste paper. (From Copi, p. 115)

Counter-Argument: Identify the ambiguous phrase and show at least two possible interpretations.

UNTESTABILITY

Definition: The theory advanced to explain why some phenomenon occurs cannot be tested. We test a theory by means of its predictions. For example, a theory may predict that light bends under certain conditions, or that a liquid will change colour if sprayed with acid, or that a psychotic person will respond badly to particular stimuli. If the predicted event fails to occur, then this is evidence against the theory (Cedarblom and Paulsen: 161).A theory cannot be tested when it makes no predictions. It is also untestable when it predicts events which would occur whether or not the theory were true.Examples

1. Aircraft in the mid-Atlantic disappear because of the effect of the Bermuda Triangle, a force so subtle it cannot be measured on any instrument.(The force of the Bermuda Triangle has no effect other than the occasional downing of aircraft. The only possible prediction is that more aircraft will be lost. But this is likely to happen whether or not the theory is true.)

2. I won the lottery because my psychic aura made me win.(The way to test this theory to try it again. But the person responds that her aura worked for that one case only. There is thus no way to determine whether the win was the result of an aura of of luck.)

3. The reason why everything exists is that God created it.(This may be true, but as an explanation it carries no weight at all, because there is no way to test the theory. No evidence in the world could possibly show that this theory is false, because any evidence would have to be created by God, according to the theory.)

4. NyQuil makes you go to sleep because it has a dormative formula.(When pressed, the manufacturers define a "dormative formula" as "something which makes you sleep". To test this theory, we would find something else which contains the dormative formula and see if makes you go to sleep. But how do we find something else which contains the dormative formula? We look for things which make you go to sleep. But we could predict that things which make you sleep will make you sleep, no matter what the theory says. The theory is empty.)

Counter-Argument: Identify the theory. Show that it makes no predictions, or that the predictions it does make cannot ever be wrong, even if the theory is false.

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LIMITED SCOPE

Definition: The theory doesn't explain anything other than the phenomenon it explains (Cedarblom and Paulsen: 163). Examples

1. There was hostility toward hippies in the 1960s because of their parents' resentment toward children.(This theory is flawed because it explains hostility toward hippies, and nothing else. A better theory would be to say there was hostility toward hippies because hippies are different, and people fear things which are different. This theory would explain not only hostility toward hippies, but also other forms of hostility.)

2. People get schizophrenia because different parts of their brains split apart.(Again, this theory explains schizophrenia - and nothing else.)

Counter-Argument: Identify the theory and the phenomenon it explains. Show that the theory does not explain anything else. Argue that theories which explain only one phenomenon are likely to be incomplete, at best.

LIMITED DEPTH

Definition: Theories explain phenomena by appealing to some underlying cause or phenomena. Theories which do not appeal to an underlying cause, and instead simply appeal to membership in a category, commit the fallacy of limited depth (Cedarblom and Paulsen: 164)Examples

1. My cat likes tuna because she's a cat.(This theory asserts only that cats like tuna, without explaining why cats like tuna. It thus does not explain why my cat likes tuna.)

2. Ferdinand Marcos is militaristic because he was Ilokano.(True, he was Ilokano, but what was it about being Ilokano that made him militaristic? What caused him to act in this way? The theory does not tell us, and hence, does not offer a good explanation.)

3. You're just saying that because you belong to the union.(This attempt at dismissal tries to explain your behaviour as frivolous. However, it fails because it is not an explanation at all. Suppose everyone in the union were to say that. Then what? We have to get deeper - we have to ask why they would say that - before we can decide that what they are saying is frivolous.)

Counter-Argument: Theories of this sort attempt to explain a phenomenon by showing that it is part of a category of similar phenomenon. Accept this, then press for an explanation of the wider category of phenomenon. Argue that a theory refers to a cause, not a classification.

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Final Note on the Fallacies

Of course it is difficult to be experts in spotting faulty arguments overnight. The skills required cannot be perfected by mere memorization of the types of fallacies and the counter-arguments. The key however is constant practice and constant application in real life situations.

It is hoped that armed with this knowledge, we become more logical and reasonable, more comfortable and secured when we confront the propositional marketplace that lies outside the four walls of our classrooms.

Truth, they say, is out there. But it depends on how well we recognize one when we meet one.

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