Logical Fallacies

[Miss Isness]

For anyone wishing to brush up on their logic there's lots of good info here: http://www.rexresearch.com/articles/propgnda.htm#greene

In conclusion, in a free and democratic society, it is incumbent upon every citizen to be well informed on propaganda techniques.

 

[doormouse]

Excellent resource. Thank you.

 

[paralleloscope]

I stubled across that site linked above, many good examples of everyday fallacies, served a good read to weed out automatic blunders in daily speech and thougth.

Section A: Habits of Reflective Procedure (Techniques of Self-Deception)

1. Prejudice ~

Example: Nathanael asked (referring to Jesus): "Can anything good come out of Nazareth?", and thus indicated his prejudice against Jesus’ hometown.

Meaning: A prejudice is an unwillingness to examine fairly the evidence and reasoning in behalf of the person or thing which is the object of the prejudice. It is a prejudgment caused by indoctrination, conditioning, or some prior experience of a singularly pleasant or unpleasant character. A prejudice has strong and deep emotional support.

In discussing Prejudice here we are not talking of appeals to known prejudices. These are made from without, as by an advertising man, a salesman, or a politician. Rather, our interest is in how your own Prejudice, unaided by outside support, victimizes you.

Prejudice differs from hasty Generalization in that although hasty Generalization often represents a spontaneous emotional reaction, Prejudice is always a matter of much longer standing. The feeling that operates in the latter case is deep, not superficial, and is often completely hidden from the man in its grip.

2. Academic Detachment ~

Example: "I’ve heard many arguments in favor of the Republican candidate and just as many for the Democratic. Hence I don’t find any reason to prefer one over the other, so I’m going to stay home and not vote for either one".

Meaning: We refuse to commit ourselves when decision or action is demanded. In a situation requiring a stand to be taken, we see (or think we see) persuasive arguments on both sides. But certain situations (e.g., voting) require decision and action of one kind or another. Here, instead of trying to remain neutral, we must make a decision on the basis of which side seems to have the greater weight of evidence.

3. Drawing the Line ~

Example: "Either you tell the truth or you lie".

Meaning: Sharp distinctions are drawn where it is inappropriate to draw sharp distinctions.

It is permissible to draw the line between those who are for you and those who are not for you, those who tell the truth and those who do not tell the truth, and so on. But the error and inclination exhibited by common speech is to fail to realize that the logical class of those who do not tell the truth includes two subclasses that are quite different: (1) those who lie and (2) those who say nothing at all.

4. Not Drawing The Line ~

Example: "If we are allowed to stay out till two o’clock in the morning, why not till three --- one hour doesn’t make that much difference".

Meaning: The existence of differences is denied just because the differences are small and therefore apparently unimportant.

5. Conservatism, Radicalism, Moderatism ~

Example: (1) "This belief is an old one, but I want you to know that the old ways are the best ways".

(2) "What we need is new ideas, completely new ways of thinking; the old is not worthy of our acceptance".

(3) "Vote for me. My program is neither conservative nor radical".

Meaning: These three habits of mind are forms of prejudice. But they are not necessarily such. Prejudices have histories with a beginning. But the neo-conservative, the one who prefers what is old or familiar simply because it is old or familiar, may be born such; it is part of the temperament he brings into the world. Radicalism is the habit of preferring the new or the revolutionary just because of its newness. The moderate habitually chooses middle-of-the-road or compromise ground; he avoids the two extremes. But there is no inherent virtue in moderatism or compromise as such. Actually, there are times when our position should be conservative, and still other times when we should be moderate.

6. Rationalization ~

Example: The student, having failed the test, blames his failure on the classroom’s being so hot that he couldn’t think, whereas in reality he knows that he didn’t spend enough time in study.

Meaning: You cite reasons or causes that will justify action that really has less creditable grounds.

7. Wishful Thinking ~

Example: "My son will win because he ought to win after all his long hard preparation".

Meaning: You believe a proposition to be true because you want it to be true.

When we are forced to admit that our wishes have not become reality, we may then seek comfort in rationalizing. If, in the example cited above, the son does not win and the contest is fair, the parent will feel the necessity of inventing some argument that will excuse the son’s failure.

8. Tabloid Thinking ~

Example: "In college Basil was taught all about evolution --- the apeman theory, you know".

Meaning: To think in tabloids is to oversimplify a complex theory or set of circumstances. The tabloid thinker prefers quick summaries and has the habit of "putting things in a nutshell".

Tabloids concerning people are popular because they offer a neat summary of the character of a prominent person. "Marx? You don’t know who Marx was? Why, he was that philosopher who became impatient and irritable in his old age". It is much easier to remember Marx in this simple fashion than to remember him as a man of many interesting and controversial facets of character and conviction. These human tabloids are frequently emotional, but they are not mere Emotional Terms. To be Tabloid Thinking there must be some indication that someone is trying to sum up another’s character. All stereotypes ("barbers are talkative") are tabloids because they present a certain trait or characteristic, which is really superficial or trivial, as being the essential nature of a given class.

9. Causal Oversimplification ~

Example: "If it were not for the ammunition makers, we would never have wars".

Meaning: A complex event is explained by references to only one or two probable causes whereas many are responsible.

10. Inconceivability ~

Example: "Since Ballhead State has never in its past history won the conference title, I just can’t picture them winning it this year".

Meaning: You declare a proposition to be false simply because you cannot conceive it actualized or possible of realization.

Section E: The Fault May Be With The Form (Techniques of Form)

1. Concurrency ~

Example: "Who was president at the time of World War I? Wilson, a Democrat. Who was President at the time of World War II? Roosevelt, a Democrat. Who was President at the time of the Korean War? Truman, a Democrat. Obviously, the Democratic party is the war party".

Meaning: Because things exist or appear simultaneously, it is claimed that one is the cause of the other. The form of the argument is: A is present along with B; therefore A is the cause of B. But two concurrents could never be the cause of one another, for a cause is something antecedent in time.

2. Post Hoc ~

Example: "The bankers are the source of our troubles. You will notice that every depression is preceded by bank failures".

Meaning: Because two events (or things) follow one another in close temporal succession the first event is claimed to be the cause of the second. The form of the argument is: A precedes B; therefore A is the cause of B. We may take as a hypothesis for testing, that A is a (or the) cause of B, but we should not forget that any one of a score of other preceding events is equally worthy of consideration.

3. Selected Instances ~

Example: Someone says, "All professors are conceited". When asked for his evidence he replies, "Well, how about Professor Smith, Professor Jones, and Professor Brown. Everybody knows they’re as conceited as they come". But he deliberately skips over Professor Black whom he knows to be a model of humility.

Meaning: Support is drawn for a position by choosing only those cases or instances which can back it up and disregarding those cases or instances which either contradict or do not support the position. The form of the argument is: All A is B; because A1, A2, A3 and A4 are B. the form is invalid; the arguer knows that at least A5 is not B.

4. Hasty Generalizations ~

Example: Having observed five women to be poor drivers, Jones generalizes and declares all women are poor drivers.

Meaning: The arguer jumps to a general or blanket conclusion about members of a given group on the basis of an unrepresentative or insufficient number of cases. The form of the argument is: A1, A2, A3 are B; therefore all A is B.

Selected Instances and Hasty Generalization have much the same effect. There are important differences, however. Hasty Generalization typically occurs on an emotional basis, while selected instances is typically coldly calculating. In the former case there is, at the time at least, no awareness of opposed instances; in the latter case, there is. Selected Instances is not merely crooked thinking but dishonesty. On the surface the two are apt to look alike, and until we have evidence that the arguer is really deliberately closing his eyes to contradictory cases, we cannot label the technique as Selected Instances.

5. Faulty Analogy ~

Example: "Last quarter I had a student by the name of Orzymski who did good work. This quarter I have another student by that name, and I’m expecting good work from him".

Meaning: To reason analogically is to reason that because two of more things or types of things are alike in some one or more respects (we may call this the antecedent resemblance), they will therefore be found alike in some other respect(s) --- the consequent resemblance. In cases of reliable analogies the antecedent factor is already known to have some bearing on the consequent factor. In faulty analogies such knowledge is lacking. The form of the argument is: A is like B in respect c; therefore A is like B in respect d.

In our example, while it is true that Orzymski is a rare name in English-speaking societies and while it is even probable that a second Orzymski enrolled at the same college would be related to the first, we need evidence that heredity is a decisive factor in scholastic performance. But an analogy is no stronger than its linking generalization, which in this case is "Heredity determines scholastic performance". Since our experience contains an abundance of cases of relatives with widely different scholastic records, we can have no confidence in an analogy based on such a linking generalization.

Some arguments take the form of alleging a complete analogy: two things are alike to the point of identity. The argument is: A (or all A) is c and B (or all B) is c; therefore B is A (or A is B). "Communists will not take the oath of allegiance and neither will Jones. Therefore he must be a Communist". The absurdity of this argument becomes readily evident when we see it is just like saying, "Dogs have tails; this cat has a tail; so this cat is a dog".

In discussing Metaphor and Simile the point was made that neither one, especially Metaphor, should be used in controversial situations. That remains true. But a metaphor or simile appearing by itself is to an argument, and is very uncertain in meaning. Analogies make use of simile and make clear how A is compared to B, but it still must be said that analogical argument is strong only when A and B are essentially the same thing, and A has a property deriving from its essential nature, therefore B must have the same property.

6. Composition ~

Example: "He’s a nice boy; she’s a nice girl. I’m sure they’ll make a nice married couple".

Meaning: We reason as if the properties of elements or individuals were always (i.e., necessarily) the properties of the wholes which they constitute. But the assumption that what holds true of a part is automatically true of the whole cannot be justified. The form of the argument is: A is part of B and A is c; therefore B is c.

7. Division ~

Example: "How dare you criticize any member of the Harvard faculty? Don’t you know that this faculty has the highest reputation of any university faculty in the United States?".

Meaning: We reason as if the properties of any whole are always (i.e., necessarily) properties of each part. But the assumption that what holds true of a whole is automatically true of its parts cannot be justified. The form of the argument is: A is part of B and B is c; therefore A is c.

8. Non Sequitur ~

Example: "Your children deserve the best milk. Buy Lorden’s".

Meaning: The conclusion is not necessitated by the premise(s).

Strictly speaking, all the techniques so far covered where the conclusion is invalid are Non Sequiturs. There is, therefore, no one form for a Non Sequitur. In the example cited above no more reason is given to buy Lorden’s milk than to buy Healtest or any one of a hundred other brands of milk.

Since the Non Sequitur label can be applied to so many other techniques, the label will be reserved on for those invalidities that cannot be classified under some other heading. They are, at least, Non Sequiturs.