Logical Fallacies Origins The word fallacy may derive

Logical Fallacies

Origins �The word “fallacy” may derive from the Latin word fallere meaning, “to deceive, to trip, to lead into error or to trick. ” �The word may also derive from the Greek phelos, meaning “deceitful. ” www. sun-design. com/talitha/fallacies. htm

What is a logical fallacy? �an error in reasoning �faulty logic �flawed statements that often sound true

Why is it important to understand/recognize fallacies?

Think of this as “intellectual kung-fu: the art of intellectual self defense. ” (Logical Fallacies Handlist)

Bandwagon �“Everybody does it. ” �“I should get to go to the show because all my friends are going. ” �“You should buy this product because all the ‘cool’ people have it. ”

Dicto Simpliciter �based on an unqualified generalization �stereotyping �“Exercise is good. Therefore, everybody should exercise. ” �“Women aren’t as strong as men. They aren’t capable of serving in the military. ”

Hasty Generalization �A generalization based on too few instances to support such a conclusion �“You can’t speak French. I can’t speak French. Therefore no one at BHS can speak French. �Based on a survey of 100 people, Pepsi is America’s favorite drink.

Post Hoc Ergo Propter Hoc �Because one thing followed another, the second thing was caused by the first. �Eg. superstitions �“Let’s not take Bill on our picnic. Every time we take him with us, it rains. ” �“I wore my Garfield socks the first time we won. Unless I wear them next time, I’m sure we will lose. ”

Ad Misericordiam �Appeal to sympathy �“Unless you give me an A on this paper I will fail the class and not graduate. I won’t be able to get a job. I’ll probably end up homeless and hungry. ”

False Analogy �Comparing two largely incomparable things �“If doctors get to use x-rays, and carpenters get to use blueprints to do their work, then students should get to use textbooks when they take a test. ”

Hypothesis Contrary to Fact �a prediction based on changing a past event �what might have happened if… �“If Al Gore would have been elected president, we would not be fighting in the Middle East today. ”

Poisoning the Well �attacking the person’s character rather than the issue �“My opponent is a liar. Don’t vote for him. ” �“Don’t go out with Joe. He is a jerk!”

Begging the Question �Circular reasoning �the conclusion is assumed in the premise �“Stealing is against the law because it is illegal. ” �“This restaurant serves the best food in the town because it has the best chef. ”

jc-schools. net/dynamic/LA/activities/Logical. Fallacies. Intro-activities. ppt