Logical Fallacies

A logical fallacy is an inaccurate misleading misapplication of logic. It is an element of an argument that is flawed, essentially rendering the line of reasoning, if not the entire argument, invalid. In Argumentative essays, rational thought is strong persuader. If essay is based on emotion or feelings, or if rational thought is flawed, the argument loses its strength. There are some logical errors commonly made by students in argumentative essays.

1. Hasty Generalization     : Jumping to conclusions.

It means hasty generalizations occur when you draw a conclusion from too few cases, instances or examples.  The few examples you have may be good evidence for your argument, but you must have enough typical cases in order to prove your point.

Example: "A bear lives at the zoo, therefore, all bears live at zoos."

Solution: avoid words like “everybody, all and nothing,” and qualify statements

2. Stereotype                    : A form of hasty generalization applied to people.

A stereotype is a special and especially dangerous form of the hasty generalization.  If you find that a few people in a certain group share certain characteristics and then generalize that all people in that group will have the same characteristics, you are guilty of the fallacy of stereotyping.  There are national, regional, religious, racial and many other kinds of stereotypes.  All are dangerous because they encourage thinking of people in terms of groups rather than as individuals.

Example:   “After being in New York for a week, I can tell you: all New Yorkers are rude.”

Solution: Qualify and specify your statements; prove with valid evidence.

3. Oversimplification         : Severe reduction of choices, sometimes limited to an either / or dilemma.

This is a conclusion that oversimplifies the argument by reducing it to only two sides or choices.

Example: “We can either stop using cars or destroy the earth.”

In this example where two choices are presented as the only options, yet the author ignores a range of choices in between such as developing cleaner technology, car sharing systems for necessities and emergencies, or better community planning to discourage daily driving.

4. Post Hoc Ergo Propter Hoc      : X happened before Y; therefore Y caused X

This fallacy is committed when it is concluded that one event causes another simply because the proposed cause happened before the proposed effect. More formally, the fallacy involves concluding that A causes or caused B because A happens before B and there is not sufficient evidence to actually warrant such a claim. The mistake of assuming that, because event a is followed by event b, event a caused event b.

 Example: It rained today because I washed my car.

Solution: make sure that time is not the only thing linking cause and effects.

5. Red Herring                  : A statement that has no direct relevance to the topic.

A Red Herring is a fallacy in which an irrelevant topic is presented in order to divert attention from the original issue. The basic idea is to "win" an argument by leading attention away from the argument and to another topic. This sort of "reasoning" has the following form:

• Topic A is under discussion.
• Topic B is introduced under the guise of being relevant to topic A (when topic B is actually not relevant to topic A).
• Topic A is abandoned.

Example: "I think there is great merit in making the requirements stricter for the graduate students. I recommend that you support it, too. After all, we are in a budget crisis and we do not want our salaries affected."

 : How can he be expected to manage the company? Look at how he manages his wife!

Solution: Be precise in distinguishing the relevant from the irrelevant.

6. False Authority : Arguing that a person who is competent in one field will necessarily be competent in another.

Example: Toni is a good teacher. Therefore he would be a good president.

Solution:  Be certain that your sources are authorities in their field

7. Statistics                       : False use of numbers proves nothing

Example: Super-Slim artificial Yogurt will help you lose weight because it has only 50 calories per ounce.

Solution: ask yourself specific questions about statistics; source.

8. Vice and virtue words   : The use of words that connote bad or good emotional reaction in the reader.

Solution: use connotative words, but sure that you have logical proof to support what you say.

Fundamentals for Logical Analysis

1.                  Always remember never to say always and never (and all and everyone and nobody and none). Reasonable thinking should be reflected in reasonable language. All inclusive statements can rarely be proved. Qualify and specify.

2.                  Even if you are sure that one thing is cause of another, it may not be the only cause. Be careful not to oversimplify.

3.                  Suspicious words like undoubtedly and obviously are often followed by hasty generalizations and oversimplifications.

4.                  Any opinion you have must be qualified and specified, and must be supported completely with facts, examples, or personal experience.