LOGICAL FALLACIES Errors in Reasoning

LOGIC The science of how to evaluate arguments and reasoning Logic allows us to distinguish correct reasoning from poor reasoning Logic helps us to reason correctly

FALLACY (noun) A failure in reasoning that makes an argument invalid Fallacious (adjective) *wrong, untrue, inaccurate, flawed

WHAT IS AN ARGUMENT? A connected series of statements intended to establish a definite assertion An argument is never made up of a simple statement! An argument needs to offer reasons and evidence for the purpose of establishing the truth.

Argument cont. Made of 3 parts: A) a claim/assertion – the position statement that can be proven true or false B) a warrant – the statement after the claim, that is used to support it or demonstrate evidence for it C) a conclusion – the final assertion in the argument

Ad Hoc When you make up a defense to your argument that does not really make sense for the counter argument you have just been given EX: CLAIM: That boy likes me. But, he has a girlfriend. WARRANT: He has a girlfriend and he is only dating her to make me jealous.

Ad Hominem When you attack the character of the person making the claim EX: CLAIM: Sally says that people should never kill animals for food. WARRANT: Well, Sally is a sissy crybaby that loves animals too much.

Hasty Generalization When you use an idea based on a small sample of a larger population EX: CLAIM: All short students are really smart. WARRANT: All of the short students in my class are getting As in every subject.

Slanting When you emphasize one side of the evidence (usually the favorable info) EX: CLAIM: Polar bears are not becoming extinct. WARRANT: The number of polar bears in this small Alaskan town has reached record high numbers.

Begging the Question When you make the assumption that something is correct because something else is correct EX: CLAIM: These rules are important and must be followed. WARRANT: If these rules were not important enough to be followed, then no one would have invented them.

Straw Man When you misrepresent an argument to make it easier to attack EX: CLAIM: You want our country to be taken over. WARRANT: You said you believe that our country should spend more money on education. This means that you want the military to suffer.

Slippery Slope When you say that if A happens, then Z will definitely happen. Therefore, A should not happen. EX: CLAIM: Students should have homework even on the weekends. WARRANTL: Students that do not complete weekend homework become lazy and unmotivated.

Post Hoc Ergo Propter Hoc (Post Hoc) When you assume that because something occurred before another, the first caused the second (After this, therefore, because of this) EX: CLAIM: This charm made me do well on my tests. WARRANT: After I bought the charm, I did well on a test.

False Analogy When you make a comparison of two things which is inaccurate EX: CLAIM: Women are like delicate flowers. WARRANT: Women, like flowers, must be cut from their foundations and placed into crystal vases.

Red Herring When you introduce a totally different topic in order to take attention away from the real argument EX: CLAIM: Hunting must be outlawed to preserve wildlife in California. WARRANT: Hunting causes thousands of accidents every year that takes the lives of young children.

Questionable Cause The idea that if 2 things always occur together, then 1 must cause the other EX: CLAIM: Rap music causes violence. WARRANT: ever since rap became popular, kids have become more violent.

Appeal to the Consequences of a Belief Something is true because if it were not, then there would be negative consequences Also known as Wishful thinking EX: CLAIM: Unicorns exist. WARRANT: Unicorns exist, because if they did not, millions of children would be very sad.

Appeal to Authority Using an “expert” to prove a claim EX: CLAIM: One Direction is the best boy band ever. WARRANT: My little sister, Mary, is obsessed with all boy bands and she says that One Direction is the best!

Appeal to Common Practice The idea that ‘everyone’ does something and that makes it okay EX: CLAIM: At St. Anthony’s, I don’t have to tuck in my shirt. WARRANT: I know I don’t have to tuck in my shirt, because most of the kids in my class don’t tuck theirs in.

Appeal to Emotion The idea that something feels good and that makes it okay to do EX: CLAIM: Drinking Gatorade makes you feel good. WARRANT: Drinking Gatorade will make you a better athlete because it makes you feel stronger and faster.

Appeal to Fear The idea that if something scares you, you should not do it EX: CLAIM: Children should never be taught to use a stove. WARRANT: Children that use stoves will definitely burn themselves.

Appeal to Flattery The idea that a compliment makes something right EX: CLAIM: Mr. Brown, you are the best teacher ever! WARRANT: Mr. Brown should totally give us extra points because we think he is the best.

Appeal to Tradition/Appeal to Novelty The idea that all old or new things are always better EX: CLAIM: This restaurant is the best. WARRANT: My family has been eating here for five generations! EX: CLAIM: This restaurant is really good. WARRANT: I heard they use this new cooking technology that does not even use heat to cook the food.

Burden of Proof The introduction of a claim that the other side must prove EX: CLAIM: Unicorns exist. WARRANT: You cannot prove that unicorns do not exist, so they must be real.

QUIZ TIME!