A fallacy is a type of argument that is psychologically persuasive but completely invalid. Among the many different types of logical fallacies are the following:

1. Appeal to Force occurs when one uses or threatens to use force—whether physical, psychological or legal—in an attempt to coerce another person to accept their conclusion.

• "Oh Senators, I would strongly advise you to make Claudius our next emperor.  The Praetorian guard has already rallied around him, and I fear for this august body if you thwart their desires."
• "If you don’t convict this murderer, one of you may be his next victim."

2. Ad Hominum Attack: An attempt to refute the another’s position by attacking the person rather than the argument

• "I don’t think we should accept the councilman’s arguments in favor of Sunday shopping in our town. He’s a godless communist after all."
• "You shouldn’t listen to Billy-Bob’s argument because he spent a year in prison."

3. Argument from Ignorance: An attempt to argue that a proposition is true because it hasn’t be proven false or that a certain proposition is false because it hasn’t been proven true.

• "God is clearly the creator of the moral order. Try as hard as they may, ethicists have been unable to come up with any other explanation of the source of universal moral principles or why moral principles are binding on us."
• "The superb quality of her character can be demonstrated by the fact that I have never heard a word spoken against her."

4. Appeal to (Inappropriate) Authority involves using the testimony of someone who is an expert or authority in another field than the one under discussion.

• "My priest says that genetic engineering and in vitro fertilization are dangerous. Therefore, all experiments in this field should be stopped immediately."
• All this talk about global warming is a lot of hooey.  Why I just heard Rush Limbaugh say today that we have absolutely nothing to worry about."

5.  Hasty Generalization occurs when one uses unusual or atypical cases to support a general point covering all cases.

• "I know for a fact that drinking alcohol is evil. My father was an alcoholic and his drinking damned near ruined our family."
• I have a friend who lives near Bookhaven National Laboratories, who has just been diagnosed with breast cancer.  I think that we can safely conclude, then,  that the research being done at Brookhaven is responsible for the high rate of breast cancer on Long Island.

6.  Begging the Question occurs when a person assumes what the argument is trying to prove. [i.e., when the conclusion and premises are rewordings of each other]

• "To allow complete, unfettered freedom of speech is advantageous to the interests of the state. For it is clearly helpful to the community to have each individual freely express his or her own point of view."
• "You can’t expect eighteen-year-olds to vote intelligently, because they are too young to have good judgment about the issues."

7. Straw Man: An attempt to substitute for your opponents argument a simplistic caricature. By defeating the caricature (the straw man), the fallacious impression is created that you have defeated your opponent’s position.

• "Of course the Equal Rights Amendment must be defeated. Do you want men and women sharing the same toilet facilities?"

        Ex.  4:  Logical Fallacies