Gives an overview of logical fallacies and several examples

1. Don’t get duped:understanding Logical fallacies By Ken Barry for Speech 104 26JAN2011

2. What is a Logical Fallacy? A logical fallacy can occur between two people arguing or one person examining an occurrence themself. Logical fallacies attempt to make invalid connections appear valid. The fallacies use a skewed sense of logic that when examined does not hold up. Logical fallacies may appear quite appealing and sensible. Be sure to scrutinize any point.

3. So, what of logical fallacies? There are many different types logical fallacies. Additionally, there are many subsets of logical fallacies that differ in exact execution but the gist is the same. While there are too many logical fallacies to expand on all, we will be looking at some of the common ones in this presentation.

4. 1. Post Hoc Ergo Propter Hoc Follows the thinking that A happened then B happened therefore A must have caused B. This type of thinking would lead one to believe that since the first time Joe ever tried Pepsi he got hit by a car, the drinking of Pepsi was responsible for Joe’s getting hit by the car.

5. 2. Correlation =/= Causation Draws conclusions where no evidence of causation exists. States that if two things happen at the same time one must be responsible for the other. Joe wake up with hisshoes on and a pounding headache. Sleeping with shoes on must cause headaches. In reality Joe had drank too much the night before and both were symptoms of that.

6. 3. Straw Man This is a method of arguing. By using a straw man approach an arguer twists his/her opponent’s position to make it easier to attack. Person A: I support the Roe v. Wade decision. Person B: You want to use abortion as a primary form of birth control.

7. 4. Ad hominem In an ad hominem attack the credibility of a person is called into question so as to weaken the validity of their position. Person A: We should get out of Iraq. Person B: You’re an ex-con, why should anyone listen to you?

8. 5. Moving the Goalposts A method of arguing where once one’s conditions for satisfaction are met the conditions are then changed. Politician: If heads of the military favor repealing DADT we should repeal it. Heads of the military: We are in favor. Politician: We need to survey the servicemen for their opinion before we repeal it!

9. 6.Ad-hoc Reasoning Puts special conditions on subjects. Favorable data is kept and unfavorable data is scrapped for an arbitrary reason. Person A: I’m not bad at poker, I didn’t do well at the table because I was wearing a green shirt. Person B: Last week you didn’t do well and you were wearing a blue shirt. Person A: Well both blue and green must be unlucky for me then.

10. 7. Tautology Tautology allows for the use of circular reasoning. If A says B is true and B says A is true then that is proof.

11. This concludes the presentation Hopefully this presentation has piqued your interest to analyze what you immediately assume as valid and what others try to impress upon you as valid. A quick search online will bring up a fount of information on the subject. Utilize and enjoy your critical thinking skills. Thanks to curefaith.com for the napkin image.