logical fallacies

The following is taken from Rhetoric Online a comprehensive site on the art of rhetoric. (http://www.usm.k12.wi.us/Upper/AdvComp/InformalFallaciesfinal.htm)

Writers on logic have organized the fallacies into a variety of arrangements.  What follows is an outline devised by S. Morris Engel with a selection of sample fallacies from his books Analyzing Informal Fallacies and The Language Trap.

Informal Fallacies

I. AMBIGUITY-- Confusing sentences / Focus on language

A. Amphiboly -- Use of careless words or faulty sentence construction.

  • Judge to defendant: "I’m not going to send you to prison for attempted robbery. I’m going to give you a second chance.
  • The Witch's prophecy in Shakespeare's Macbeth (Act IV, Scene I):
    Be Bloody, bold and resolute, laugh to scorn
    The power of man, for none of woman born
    Shall harm Macbeth

Recall that Macbeth's enemy Macduff had been born by Caesarian operation--"ripped untimely from his mother's womb"--and thus was not "of woman born.")

  • Croesus, consulting the oracle at Delphi regarding the outcome of a war he was contemplating with Persia, heard that "if he went to war with Cyrus, he would destroy a mighty Kingdom."  Emboldened by the prediction, Croesus launched into battle, only to meet swift defeat.  When he later complained to the oracle about the prediction, the oracle pointed out that Croesus had destroyed a mighty kingdom--his own.

 

B. Accent -- Confusion as to emphasis.

  • Review: Only Hollywood could produce a film like this.
  • Sitcom dialogue: Those people seem to be walking very carefully, so I needn’t slow down for them. After all I was told to watch out for careless pedestrians.
  • "I cannot praise this book too highly."
  • "I shall loose no time in reading your paper."
  • "You never looked better.
  • Note how the sentence "I hit him in the eye yesterday" changes meaning when we insert the word only and then move it around:
    1. Only I hit him in the eye yesterday. 
    2. I only hit him in the eye yesterday.
    3. I hit only him in the eye yesterday.
    4. I hit him only in the eye yesterday.
    5. I hit him in the only eye yesterday.
    6. I hit him in the eye only yesterday.
    7. I hit him in the eye yesterday only.
  • Sometimes certain words (or sentences or paragraphs) are taken out of context and thus are given an emphasis (and therefore a meaning) they were not intended to have:
    The teacher, having told her class that "communism is the best type of government if you care nothing for your liberty or your material welfare," is reported by Johnny to his parents at dinner to have said: "Do you know what Ms. Jones said today? She said communism is the best form of government!"

 

C. Hypostatization -- To attribute to things and animals qualities that, strictly speaking, are applicable only to human beings. Two forms of hypostatization:

  • animism (ascribing human qualities to things) and
  • anthropomorphism (ascribing such qualities to non-human beings).

Nota Bene: Personification is a worthy figure of speech which compares humans and animals in apt, non-distortive ways.  Hypostatization is not as precise.

  • Remark: Science has not produced the general happiness that people expected, and now it has fallen under the sway of greed and power.
  • Editorial: Today big and complicated government has a hand in everybody's business and another in every person's pocket.
  • "The State is the march of God through history."--Georg Wilhelm Hegel, a nineteenth century German philosopher to whom many trace the roots of communism and fascism
  • Nature produces improvements in a race by eliminating the unfit and preventing them from polluting the gene pool of the fit.  Therefore it is only right for us to eliminate these unfit people.

 

D. Equivocation -- Allowing a key term to shift its meaning in the course of the argument.

  • If you believe in the miracles of science, how come you don't believe in the miracles of the Bible.
  • In our democracy all men are equal.  The Declaration of Independence states this clearly and unequivocally.  But we tend to forget this great truth.  Our society accepts the principle of competition.  And competition implies that some men are better than others.  But this implication is false.  The private is just as good as the general, the file clerk is just as good as the corporate executive; the scholar is no better than the dunce; the philosopher is no better than the fool.  We are all born equal.
  • Nota bene: The pun, a figure of speech, makes conscious use of equivocal turns:
    • "If we don't hang together, we will hang separately."--Benjamin Franklin
    • "Milk has something for everybody."--advertisement
    • From a logic text: Some birds are domesticated. My parrot is domesticated. My parrot is some bird.
    • During a the course of a heated dispute: Your argument is sound, nothing but sound
  • Some people read "Freudian slips" as "symptomatic actions" revealed though equivocation.  Freud noted that one of his clients, a woman who was very eager to have children, would consistently read "storks" in the place of "stocks."

 

E. Division -- Extending properties from wholes to parts.

  • It is predicted that the cost-of-living index will rise again next month. Consequently you can expect to pay more for butter and eggs next month.
  • From a logic text: All of the trees in the park make thick shade; this tree is one of them and therefore makes a thick shade.
  • Since the city revenues have fallen off, I propose a 20-percent across-the-board cuts for all city departments.  We'll just have to get along with four-fifths of the service we've been used to.
  • Nineteenth Century German philosopher Arthur Schopenhauer held deeply pessimistic views: "From the first dawn of my thought I have felt myself in discord with the world.  The more I see men the less I like them."  He saw the world as a product of a blind and aimless Will in which the individual counts for nothing.  He used examples from nature to support his claim:
In this example we see what spirit animates nature.   That an animal is surprised and attacked by another is bad; still we can console ourselves for that; but that such a poor innocent squirrel sitting beside its next with its young is compelled, step by step, reluctantly battling with itself and lamenting, to approach the wide open jaws of the serpent and consciously throw itself into them is revolting and atrocious.  What monstrous kind of nature is this to which we belong?
  • "Certain forms of racial (as well as many other kinds of) prejudice...seem to exemplify the fallacy of division.  At the root of the problem very often is the attempt to attribute to individuals in a certain group those qualities believed to be possessed by the group.  The sad thing is that not only is it unjust and unfair (and logically unsound to suppose) that each member of a group possesses the qualities of the group, but it is often doubtful and sometimes simply false that the group."   (Engel, The Language Trap, 52-53)
 

 

F. Composition -- The reverse of division: attempting to apply to the whole what is true of the part

  • Some day humans will disappear from earth, for we know that every human is mortal.
  • No one of this committee is especially outstanding in ability. It is impossible for the committee, therefore, to bring in an able report.
  • It is not going to help the energy crisis to have people ride busses instead of cars.  Busses use more gas than cars.
  • Each manufacture is perfectly free to set his own price on the product he produces.  So there can be nothing wrong with all manufactures getting together to fix the prices of the articles made by all of them.

 

 

II. PRESUMPTION -- Misrepresenting facts / Focus on thought

A. Overlooking the facts

1. Sweeping generalization; Accident; Argumentum a dicto impliciter ad dictum secundum quid (arguing from a statement made simply to a statement made under some special condition) -- Assuming that what is true under certain conditions must be true under all conditions.

  • Everyone enjoys a good joke. I am sure, therefore, that Jones won’t mind us playing one on him.
  • The president should get rid of his advisors and run the government by himself. After all, too many cooks spoil the broth.
  • Narcotics are habit forming. Therefore, if you allow your physician to ease your pain with an opiate, you will become a hopeless drug addict.

 

2. Hasty generalization; Converse accident; Argumentum a dicto secundum quid ad dictum simpliciter (arguing from a statement made under some special condition to a statement made simply) -- Misusing a generalization in a particular situation. Senses of misuse:

a. The particular case is not representative of the cases that would warrant the conclusion in question

  • Overheard: When you think of what some people have accomplished without a college education, you will agree with me that it will be a waste of time for anyone to spend our years there.

 

b. An insufficient number of cases have been used to arrive at the conclusion in question.

  • The clerks in Mason’s Department Store are incompetent. They got two of my orders mixed up during the last Christmas season.

 

c. There is no essential connection between the particular case and the generalization it is called in to support.

  • Edmond Rostand’s Cyrano de Bergerac, act 1, scene 1: Cyrano: A great nose indicates a great man.

 

d. Important contrary evidence that would tend to cast doubt on the conclusion drawn has not been considered

  • To fail children who do poorly upsets them and disturbs class morale. The only thing to do is to promote everyone.

 

3. Bifurcation; Either/or fallacy; Black or white fallacy -- Presuming a certain distinction or classification is exhaustive and exclusive when other alternatives are possible. The fallacy often has its source in confusion over contradictories (dead/alive) and contraries (rich/poor)--a statement consisting of contraries put forward as if it contained contradictories.

  • Nietzsche: What does not destroy me makes me stronger.
  • Old adage: All that is good in the world is either illegal, immoral, or fattening.
  • Patrick Henry: Give me liberty or give me death.

 

B. Evading the facts

1. Begging the question -- To assume (instead of prove) the point at issue. In its most elementary form it is simply a matter of repeating what was said (affirming something while implying, or believing, one has confirmed it).

a. "A is so because it is (or A says so)"

  • Overheard: We can believe what it says in the catalog because the catalog itself says it is the official publication of the college

 

b. "A is so because of B (where B is the same as A)."

  • Letter to the editor: There’s no question but that the deterioration in modern moral values is to be attributed to people’s inability to distinguish what is right and what is wrong.

 

c. " A is so because of B (where B is dependent on A)."

  • Overheard:
    • Bill: I enjoy reading good books.
    • Tom: How do you know when they’re good?
    • Bill: If they’re not good, I don’t enjoy them.

 

d. "A is so because of B (where B is even more suspect than A)."

  • Overheard: The crime this man committed is the result of his childhood environment; for all such crimes are rooted in childhood environment, as this man’s case proves.

 

e. Smuggled-in undercutting assumptions

  • Overheard: Smith cannot have told you a lie when she said she was my cousin, for no cousin of mine would ever tell a lie.

f. Wit and madness

  • Famous remark by Joe E. Lewis: I don’t want to be a millionaire; I just want to live like one!
  • The clown in Hamlet (act 5, scene 1) upon being asked how the prince has gone mad, replies: By losing his wits.

 

2. Emotive language; question-begging epithets; Name calling; Loaded words, Controversial phrases; Verbal Suggestion;; "libel by label" (Marshall McLuhan); "mudslinging" -- A descriptive label or tag which we attach to a person, a thing, or an idea in an effort to condemn it out-of-hand. Uncomplimentary labels are called dyslogistic terms; complimentary terms, eulogistic.

  • Witness: The scoundrel hounded his wife to the grave.
  • Editorial: This is a proposal that is offensive to every enlightened conscience.
  • Editorial: This measure is calculated to subvert the just aspirations of our people

 

3. Loaded question; complex question;; Trick question; Leading question; False question; Fallacy of many questions -- A question phrased so that it cannot be answered without granting a particular answer to some question at issue: "Have you stopped beating your wife yet?"

a. Handle by exposing the hidden assumption

  • Overheard: Why was the new building not given to the school?

 

b. Handle by dividing the question

  • Editorial: Is this policy going to lead to ruinous deflation?

 

c. Handle by combining complex question with question-begging epithets

  • Interviewer: Senator, why is it so hard for you to come to a conclusion?

 

d. Handle by asking for explanations for "facts" that are either untrue or not yet established

  • Old riddle: What time was it before time began?

 

e. Examples of the Complex Question in advertising and sales:

i. Presenting the positive merits of the product

  • Cosmetic advertisement: Are your lashes as beautiful as they used to be?

 

ii. Attempting to help us make up our minds to buy the product

  • Sales representative: Would you like me to make this contract out for twelve or eighteen months?

 

iii. Playing on our fears

  • Commercial: Would your wife and children have security if you died today? If not, shouldn’t you buy more insurance?

 

f. Example of Complex Question in interpersonal relations

  • From Thomas Harris:
    • Husband: Where did you hide the can opener?
    • Wife: I hid it next to the tablespoons, darling.

    Thomas A. Harris, I’m OK--You’re OK (New York: Avon Books, l973), pp. 114.

 

4. Special pleading -- Thinking of ourselves as being special and therefore subject to a different standard than one we are inclined to apply to others.

  • Overheard: Speaking of not trusting people, it’s no wonder you can’t trust anyone nowadays. I was looking through the desk of one of my roomers, and you won’t believe what I found.
  • Sultan Khaled Hethelem, crown prince of the Ujman tribe of Saudi Arabia:
    • Interviewer: Some people criticize the Arabs for using oil to blackmail; how do you feel about this?
    • Sultan: We are not trying to blackmail Western Europe or Japan; we are just trying to convince them to help us.
  • Commercial: Phillips 66. The Performance Company. Phillips Petroleum Company.

 

C. Distorting the facts

1. False analogy -- A comparison between two unlike things in which the two things resemble each other only in trifling ways and differ in important ones.

  • From a logic textbook: Why should we criticize and punish human beings for their actions? Whatever they do is an expression of their nature, and they cannot help it. Are we angry with the stone for falling, and the flame for rising?
  • Sitcom dialogue:
    • Jeff: That stuff’s not my regular beer!
    • Sue: That beer was on sale, so I bought it!
    • Jeff: If dirty socks were on sale, would you buy them?
  • Overheard: If we find it necessary to tip waiters and other hotel servants, why should we not similarly reward the bus driver, the clerk, or the doctor? Either they should be included or hotel tipping should be abolished.

 

2. Post Hoc Ergo Proper Hoc; False cause -- An argument that suggests events are causally connected when in fact no such causal connection has been established.

 

a. Superstition

  • From Shakespeare’s King Lear act 1, scene 2:
Earl of Gloucester: The late eclipses in the sun and moon portend no good to us: though the wisdom of nature can reason it thus and thus, yet nature finds itself scourged by the sequent effects: love cools, friendship falls off, brothers divide: in cities, mutinies, in countries, discord; in palaces, treason; and the bond crackt ‘twixt son and father.

 

b. Immediate succession

  • Advertisement for sound equipment: Don’t ever let anyone tell you that stars aren’t made. It happens every day. Professional sound equipment can make it happen a lot sooner.

 

c. Remote succession

  • From David Reuben: Adolph Hitler slipped three cents to a Viennese whore in 1910 (that was the going rate for street girls then) and she slipped him a few million bacilli of syphilis. Ironically, that one case of syphilis besmirched a cultured and civilized nation with depravity and sadism previously unknown in the history of the world
David Reuben, How to Get More Out of Sex. New York: David McKay Co., 1975, p. 222.

 

d. Reversal of cause and effect

  • From early Greek physics: Night is the cause of the extinction of the sun, for as evening comes on, the shadows arise from the valleys and blot out the sunlight.

 

e. Effects of a common cause

  • Letter to the editor: If religion prevented crime, the cities, where churches abound, would show a lower crime rate than the ten thousand rural communities said to be without churches. Actually the city rate is higher.

 

3. Red herring; Irrelevant thesis; Irrelevant conclusion; Ignoring the issue; Befogging the issue; Diversion; -- An attempt to prove a thesis or a conclusion that is not the one at issue or, alternately, to refute a thesis different from the one at issue in the other person’s argument.

a. Plain irrelevance

  • Henry Kissinger, talking about the 1972 war between India and Pakistan over Bangladesh: There have been some comments that the administration is anti-Indian. This is totally inaccurate. India is a great country.

 

b. Gross exaggeration

  • Overheard: I regret I find myself unable to support this no doubt deserving cause. It is quite impossible for me to respond to all the charitable appeals that are made to me.

 

c. Humor

  • From James Boswell

    We talked of the education of children; and I asked him what he thought was best to teach them first.

    JOHNSON. "Sir, it is no matter what you teach them first, any more than what leg you shall put into your breeches first. Sir, you may stand disputing which is best to put in first, but in the meantime your breech is bare. Sir, while you are considering which of two things you should teach your child first, another boy has learned them both.

James Boswell, The Life of Samuel Johnson (1791), (New York: Random House), p. 273.

 

d. Anger

  • From Eric Berne:
    • Little girl: Mommy, do you love me?
    • Mother: What is love
Eric Berne, Games People Play: The Psychology of Human Relationships (New York: Grove Press, 1976), p. 94.
 

 

III. Relevance -- Feelings passing for argument / Focus on emotion

A. Personal attack (prejudice)

1. Genetic fallacy -- An attempt to prove a conclusion false by condemning its source or genesis.

  • Overheard: Religion began with magic and animism. Religion is therefore nothing but nonsense.

 

2. Abusive ad hominem -- The attempt not only to condemn the source of an argument but also to shower the source with abuse.

 

a. Raise suspicions about a person

  • Overheard: This idea was introduced by a person who has been declared by a court as mentally incompetent. There cannot be much to the idea.

 

b. Try to make a person look ridiculous

  • Speaker: We shall reject Mr. Jones’s suggestion for increasing the efficiency of our colleges. As a manufacturer, he cannot be expected to realize that our aim is to educate the youth, not to make a profit.

 

c. To show contempt

  • America has always been able to find jobs for the unskilled. Look at all the people we’ve sent to congress. -- The Comedy Center, Wilmington, Delaware.

 

d. To charge a person with being inconsistent

  • He is an American and thus should believe that Americans make the finest soldiers in the world.

 

3. Circumstantial ad hominem -- An attempt to undercut opponents’ positions by suggesting that in advancing their views they are merely serving their own interests.

  • The senator is really sponsoring the amendment primarily as a way to gain national recognition in his bid for the presidency.

 

4. Tu quoque -- Colloquial equivalent: "Hey, look who’s talking!" (or "You too!"). Two forms:

a. Attacking the other person for acting in a manner that contradicts the very position he or she advocates.

  • Letter to the editor: I find it incredible that Turkey, which has been one of the world’s producers of opium for heroin, would sentence three Americans to life imprisonment for supposedly smuggling marijuana into Turkey. This is surely a travesty of justice and an act of hostility toward the American People.

 

b. Defending oneself for engaging in the particular questionable activity by arguing that the other person engages in it too.

  • Speaker: It is strange that you should think it inhuman of me to take much pleasure in hunting; you don’t seem to mind feeding on the flesh of harmless animals.

 

5. Poisoning the well -- The attempt to place one’s opponent in a position from which he or she is unable to reply. Its purpose is therefore to avoid opposition by precluding discussion

  • Clich�: Don’t listen to him; he’s a liar.
  • Clich�: If you disagree with me, you don’t understand what I am saying.
  • From Hidden Meanings:
    • "I don’t think I really matter to you."
    • "Now why are you saying that? I’m doing the best I can."
    • "Well, I just feel taken for granted."
    • "I think you are insatiable. There is never enough."
    • "See, this is proof of what I just said. I don’t really matter to you. If I did you wouldn’t talk this way to me."
Gerald Walker, Hidden Meanings (Millbrae, California: Celestial Arts, 1977), pp. 134-35.

 

B. Mob appeal (flattery and envy) -- To use highly explosive or emotional words in the hope of substituting feeling for logical thinking.

  • Advertisement by Licensed Beverage Industries Inc.: One American custom that has never been changed: a friendly social drink.

 

C. Appeal to pity -- The attempt to win over people by appealing to the emotion of sympathy.

 

[Note: To substitute feeling for argument constitutes the fallacy of Appeal to Pity. But to support an argument with an image or story that evokes an emotion such as pity is a time-honored method of persuasion, called Pathos by Aristotle.--JCH]

  • Defense attorney: My client is the sole support of his aged parents. If he is sent to prison, it will break their hearts, and they will be left homeless and penniless. You surely cannot find it in you hearts to reach any other verdict than "not guilty."

 

D. Appeal to authority or, more properly, Misappeal to authority -- Citing someone who is not an authority (an expert or a specialist) on the subject in "proof" of a position.

  • Billboard: Eat American Lamb. Ten Million Coyotes Can’t be Wrong.

 

E. Appeal to ignorance -- To attempt to shift the burden of proof by using an opponent’s inability to disprove a conclusion as proof of the conclusion’s correctness.

  • Overheard: You can’t prove he was to blame for the misfortune, so it must actually have been someone else who was responsible.

 

F. Appeal to fear; Swinging the big stick; The scare technique; in Latin, Argumentum ad baculum (intimidation) -- The attempt to influence people by threatening them with unpleasant consequences of some kind if they do not agree.

  • Interchange:
    • Seller: This one is better, but you can’t afford it.
    • Buyer: That’s the one I’ll take.

OUTLINE OF INFORMAL FALLACIES (After Engel)
OF AMBIGUITY--confusing sentences (focus on language)
Amphibole
Accent
Hypostatization
animism
anthropomorphism
Equivocation
Division
Composition (reverse of Division)
OF PRESUMPTION--misrepresenting facts (focus on thought)
Overlooking the facts
Sweeping generalization
Hasty generalization (converse accident)
Evading the facts
Begging the question
Question-begging epithets (name calling)
Complex question
Special pleading
Distorting the facts
False analogy
False cause (post hoc ergo proper hoc)
Irrelevant thesis (red herring)
OF RELEVANCE--Feelings passing for argument
Personal attack
Genetic fallacy
Abusive ad hominem
Circumstantial ad hominem
Tu quoque
Poisoning the well
Mob appeal
Appeal to pity (overturning reason)
Appeal to authority (misappeal)
Appeal to ignorance
Appeal to fear (argumentum ad baculum)

Engel, S. Morris.  Analyzing Informal Fallacies. Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1980.

Engel, S. Morris.  The Language Trap: How to Defend Yourself Against the Tyranny of Words.  Englewood Cliffs, New Jersey: Prentice-Hall, Inc., 1984.

The keeper of that page is John Horlivy --  [email protected] and the above should not be used without giving him credit.

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