Logical Fallacies

A logical fallacy is a weak argument

Ad hominem You attack the person rather than his or her statements The phrase is Latin for “to the man”

Example No wonder “Hills Like White Elephants” is an awful story: everyone knows Hemingway was an alcoholic.

Ad populum You appeal to the audience’s devotion to country or family The phrase is Latin for “to the people”

Example North American cars are better than foreign cars because they are built right here by our own people.

Appeal to fear You attempt to persuade by playing on the audience’s fears.

Example If you allow this alleged murderer to go free, your own children will be in mortal danger.

Appeal to ignorance You assert that since something has never been proven, it must not be true.

Example Since we have never found evidence of life on Mars, there must not be any.

Appeal to pity You attempt to persuade by substituting sympathy for logic.

Example One look at these malnourished children should convince you to give all of your money to our charity.

Bandwagon You assert that something is right or acceptable because everyone is doing it.

Example Cheat on your taxes; everyone I know already does.

Begging the question You present an opinion as a given fact

Example Homeless people contribute nothing to society. They should be denied welfare. (Do homeless people contribute nothing? Why should they be denied welfare?)

Complex question Forces the audience to admit something that may not be true, because the question asked contains an unproven assumption

Example Have you quit smoking? (to say yes is to admit that you used to smoke; to say no is to admit you still smoke.) The question is unfair if directed at someone who still smokes.

Enthymeme Not a fallacy, but a common form of argument in which either one of the premises or the conclusion is missing The phrase is Latin for “in the mind”

Example Mowing the lawn is a waste of time, because the grass never stops growing anyway. This argument overlooks that fact that regular mowing maintains an attractive lawn.

False dichotomy You deny the possibility of more than two alternatives.

Example There are two kinds of exams: bad and awful! There are two seasons in Canada: winter and construction!

Hasty generalization: You deny exceptions

Example All police officers are unthinking bullies.

Non sequitur The conclusion does not follow from the premises Phrase is Latin for “it does not follow”

Example All men are mortal Gloria is not a man Therefore Gloria is not mortal (The mistake arises form the assumption that the first premise also means “Only men are mortal.”

Overgeneralization The effects are attributed to actions that may not be the complete cause, or may not be the cause at all

Example To get rid of crime, get rid of all the drug users.

Post hoc ergo propter hoc An affect is attributed to an action simply because the action came first Latin for “after this, therefore because of this.)

Example The escalation of baseball players’ salaries is responsible for the recent melting of the polar ice caps.

Red Herring You try to distract the audience from your argument by introducing something unrelated.

Example Of course, that team’s owner is losing millions of dollars. However, the team has won four games in a row, and the owner would never sell the team while it is winning. The winning streak is the red herring. If the owner loses enough money, he/she will sell the team regardless of its performance.)

Slanted language You use the connotations of words to portray similarities as substantial differences.

Example I am a strong conswervative, eager to protect the state and its people by limiting immigration and introducing racial segregation. My opponent, however, is a fascist.

Tautology An argument that proves nothing since something is just defined in different terms ( also called a circular argument.)

Example All unmarried men are bachelors. Hanif is an unmarried man. Therefore, Hanif is a bachelor. ( Comment: Bachelorhood is the defining feature of unmarried men. It is not a quality such as mortality, greed, generosity, and so on.)

Testimonial An expert in one field offers his or her opinion in another field.

Example: We should all drive the new SUV because that Olympic winner drives one.

Undistributed Middle Holds that because two agents perform some action, they share each other’s qualities. Used a lot by advertisers.

Example Successful people drive SUVs. If you drive an SUV, you will be a successful person.