Friday, August 26, 2011


 This is a follow-up or sequel to my last post, a list of classic logical fallacies committed by nearly everyone: students, politicians, racial "spokespersons," advertisers, artists and writers, and the general public. It was a handout that I sometimes gave to my students during my 33 years of teaching at the University of Washington. Take at look at these logical fallacies. Ask yourself which ones you committed today in your speech or writing. Ask yourself how many of these fallacies are regularly committed by our elected officials in Congress. None of these fallacies would be accepted in a court of law, or they shouldn't be. Everyone who takes an "Introduction to Logic" class is tested on these fallacies. (But, sadly, such a course is seldom required today for graduation from our universities and colleges). Share the list with friends.

42 Logical Fallacies
   1. Hasty Generalization (arguing from some to all).

   2. Composition (arguing from each to an organized whole; two

great tennis players do not necessarily make a great tennis


    3. Division (assuming the parts are the same as the whole).

    4. Post hoc (abbreviation of post hoc ergo prompter hoc, “after

this, therefore because of this.” Assumptions about cause and


    5.  Special pleading (presenting one’s case without offering its

drawbacks, faults, limitations or problems).

   6.   Oversimplification.

    7.   Black-or-White fallacy (the false either—or-dilemma).

    8.   Argument of the Beard (reverse of #7, where one argues “One more drink won’t make me a drunk,” i.e., how many hairs make up a beard?)

    9.    Diversion (“the red herring") or wandering away from the subject under discussion.

    10.   Extension (exaggerating an opponent’s argument to make it vulnerable, or to make him defend your misrepresentation of his position).

    11.  Misuse of Humor (to get the audience laughing and therefore forget your opponent’s argument and its seriousness).

    12.  Argumentum ad Ignorantium (lack of evidence to prove your opponent’s position does not prove your own).

    l3. Argumentum ad Baculum (the club; threatening the opponent).

    14. Argumentum ad Hominem (discrediting the man on a personal level to destroy his argument).

    15.     Pettifogging (making an issue of some trivial aspect of an argument, quibbling or evading the point of an argument by unfairly using words of double meaning; arguing over the meaning of a word when there is no reasonable doubt about its meaning; making unreasonably fine distinctions; and wrangling about trivial points in such a way as to obscure the real issue or the important evidence, Applied Logic, p. 22).

    16.     Counterfeit Evidence

1.  Meaning from Association (Ads that juxtaposition cars with roses or prestige objects)

2.  Prestige of Great Names (linking oneself to the great).

3.  Misuse of Authority (citing someone who is competent in one field but not an authority in the one under discussion).

4.  Testimonials.

   17. Repeated Assertion.

   18.     Use of Prestige Jargon (technical or foreign languages simply

to impress the audience).

   19.     Use of a Confident Manner (to make the argument look strong).

    20.     Cliche Thinking.

    21.     Rationalizing (coming up with a good excuse for doing

something which was not the real reason it was done).

    22.     Decision by Indecision (Doing nothing when one must make a

choice, then when no choice can be made claiming it was chosen).

    23.     Misuse of Emotional Words.

24.   Argumentum ad Misericordiam (appeal to pity or sympathy).

25.   Attitude Fitting (shifting the argument to appeal to

different audiences).

  26.     Argumentum ad Populum (appeal to popular sentiment).

  27.     Misuse of the Mean (avoiding an extreme decision by saying we

must always try to compromise. Opposite of  #7.).

28.   Contradictory Assumptions (“If elected, I promise to treat all

citizens alike and work for an increased pension for the aged.’).
 29. Misuse of Analogy.

30.   Begging the Question:

1.   Defining an expression in terms of itself.

2.  Hiding the assumptions of one’s premise.

3.   Reasoning in a Circle.

31.   Poisoning the Well. (If the source of evidence is discounted,

then the evidence from that source becomes impaired in argument.

A variation on ad Hominem).

32.   Hypothesis Contrary to Fact (“If Germany had won World War 1,

we would not have had World War 2.” “If I had not been ill during

the semester, I would have passed all my courses.” The error here

is in the assumption that one can know with certainty what would

have happened.).

33.   Equivocation (using two meanings for the same word).

34.   Obfuscation (lots of talk to say nothing substantial about

the subject; is often combined with ad populum and diversion).

35.   Leading Questions (questions that prejudice the answer).

36.   Lifting Out of Context.

37.   False Obversion (misuse of contrasts or opposites; e.g., “The

young learn fast" doesn’t mean the old learn slow).

38.   False Conversion (pivoting a statement at the verb and 
swinging the subject to predicate position and vice versa).
            1. “All art is entertaining” does not mean that all entertainment is art. (This one is Charles Johnson’s contribution to the field of applied logic and esthetic theory;  I call it the Fallacy of the Hack.)
            2.  Fallacy of the Pharisee (All pious men engage in religious practices).
            3. Fallacy of the Patriot (All patriots proclaim their loyalty).
            4. Fallacy of the Bohemian (All artists lead odd lives).
   39. Fallacy of Accent (Distortion of an opponent’s words by slurring them, or by using a certain negative tone to prejudice a listener hearing the opponent’s argument).
   40. Tu Quoque (“You do this yourself so you can’t argue against me.”)
   41. The General Rule (rigorism: disregard of special circumstances).
   42. The Special Case (“From the one man know them all.”) 

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