Logical FallaciesLogical Fallacies

10/24/07

What is a fallacy?What is a fallacy?Fal*la*cyFal*la*cy |ˈfaləsē| |ˈfaləsē| noun ( pl. noun ( pl. -cies-cies))

a mistaken belief, esp. one based a mistaken belief, esp. one based on unsound argument : on unsound argument : the notion the notion that the camera never lies is a fallacy.that the camera never lies is a fallacy. ･ ･

Logic Logic a failure in reasoning that a failure in reasoning that renders an argument invalid.renders an argument invalid.

174--Say What?!174--Say What?! There are over 174 different types of There are over 174 different types of

logical fallacies. We will discuss 5 of logical fallacies. We will discuss 5 of them today. them today.

Ad Hominem Post hoc Strawman Bandwagon Emotional Appeal

Ad Hominem This argument is when you make a This argument is when you make a

personal attack on your opponent. The personal attack on your opponent. The fallacy lies in the assumption that the fallacy lies in the assumption that the attack destroys your opponent’s attack destroys your opponent’s argument.argument. Example:What she says about Johannes Kepler's

astronomy of the 1600's must be just so much garbage. Do you realize she's only fourteen years old?

Ad Hominem In order for an argument to be labeled “Ad

Hominem” the attack must be irrelevant.

Attacking someone for their immoral sexual practices during a debate about mathematical equations is irrelevant. Ergo: Ad Hominem

Attacking someone for their immoral sexual practices during a debate over which opponent should be elected to the school board.

Post Hoc This argument is when you make an This argument is when you make an

assumption that because B happened assumption that because B happened after A, therefore, A caused B.after A, therefore, A caused B.

Example: You were the last to use the telephone. Then the phone stopped working, therefore you broke the telephone.

Straw Man This argument happens when you twist or This argument happens when you twist or

distort your opponent’s view, ignoring distort your opponent’s view, ignoring their actual argument. Or you take your their actual argument. Or you take your opponent’s weakest argument and you opponent’s weakest argument and you exaggerate it.exaggerate it.

Example: The Democrats’ insistence on pulling the troops from Iraq is a sheer disregard for the safety of both the countries of Iraq and America. It is ideology such as theirs that perpetuates terrorism.

Bandwagon This argument happens when you to This argument happens when you to

convince your opponent that he or she is convince your opponent that he or she is the only one who disagrees with your the only one who disagrees with your point of view. EVERYONE else agrees point of view. EVERYONE else agrees with your point of view.with your point of view.

Example: You’re not going to the party? You have to go to the party! Everyone will be there!

Emotional Appeal This argument is when you try to This argument is when you try to

manipulate your reader’s emotions. You manipulate your reader’s emotions. You try to get them to agree with your point of try to get them to agree with your point of view by using emotions rather than using view by using emotions rather than using facts and logical reasoning.facts and logical reasoning.

Example: You want to convince your mother to let you borrow the car. Instead of listing good reasons that are valid and logical (such as you will be a responsible and careful driver), you appeal to your mother’s guilt by saying “Remember, you let my brother borrow the car more than me!”

Create your own examples

With a partner, take a look at With a partner, take a look at advertisements, news articles, etc advertisements, news articles, etc online. See if you can locate online. See if you can locate examples of each type of argument. examples of each type of argument. OR see if you can create your own OR see if you can create your own examples.examples.