DO NOW: (answer in at least 4 complete sentences)

What do you think of the following argument? Are each persons points/logic valid? Why or why not?DO NOW: (answer in at least 4 complete sentences)Polly: My friend Nicole said that when her parents extended her curfew, her grades actually went up! You should let me stay out later.Mother: Who cares? Nicole isnt exactly a reliable source of information!Polly: Mom! All my friends are going to laugh at me if you keep making come home at 9:30 on Saturday nights. My boyfriend will break up with me, and I will be the most unhappy teenager on the planet. Is that what you WANT?Mother: If I extend your curfew by half an hour youll just ask me again, and again, and again to extend it later.

What are logical fallacies?Defects that weaken argumentsLook and sound like logic, but are notLearning to look for them strengthens your ability to evaluate the arguments of othersLearning to look for them strengthens the arguments you make

Thats a Fallacy! I object!Correlation does not mean CausationAd Hominem (arguing to the man)Slippery SlopeHasty GeneralizationStraw ManFalse ChoiceCircular ReasoningArgument from IgnoranceArgumentum Ad Populum (Bandwagon)Appeal to PityAppeal to AuthorityThe Fallacy Files (11 common examples of logical fallaciesthere are more!)Fallacy #1: Correlation does not mean Causation.

ArgghIts getting too hot to be a pirate, matey! What does this graph prove?Fallacy #1: Correlation does not mean Causation. Correlation: A relationship between two sets of data. For example, when the economy is thriving, people are happier.

Causation: Being responsible for an action or result.

Answer: Nothing! The pirates and the weather have nothing to do with eachother.Fallacy #1: Correlation does not mean Causation. Example:Researchers at the Aabo Akademi found that Finns who speak Swedish were up to 25 percent less likely to fall ill than those who do not.

Fallacy #2 Ad Hominem (to the man!)http://www.youtube.com/watch?v=ebT1Oo6yDMI&NR=1

Fallacy # 3: Slippery SlopeThe arguer claims that a sort of chain reaction, usually ending in some dire consequence, will take place, but there's really not enough evidence for that assumption. The arguer asserts that if we take even one step onto the "slippery slope," we will end up sliding all the way to the bottom; he or she assumes we can't stop halfway down the hill.

Fallacy # 3: Slippery SlopeExample: If I let you use your phones in the last 5 minutes of class, pretty soon youll have them out in class all the time, and eventually students will be having full-blown conversations about weekend plans while Im trying to teach about logical fallacies

Slippery SlopeExample: "Animal experimentation reduces our respect for life. If we don't respect life, we are likely to be more and more tolerant of violent acts like war and murder. Soon our society will become a battlefield in which everyone constantly fears for their lives. It will be the end of civilization. To prevent this terrible consequence, we should make animal experimentation illegal right now." Since animal experimentation has been legal for some time and civilization has not yet ended, it seems particularly clear that this chain of events won't necessarily take place. Even if we believe that experimenting on animals reduces respect for life, and loss of respect for life makes us more tolerant of violence, that may be the spot on the hillside at which things stopwe may not slide all the way down to the end of civilization. And so we have not yet been given sufficient reason to accept the arguer's conclusion that we must make animal experimentation illegal right now.

Slippery Slope Guyhttp://www.youtube.com/watch?v=jT-iU5-czlU&feature=BF&list=PL36C80229BFDE0671&index=7

Fallacy #4: Hasty GeneralizationDefinition: Making assumptions about a whole group or range of cases based on a sample that is inadequate (usually because it is atypical or just too small). Stereotypes about people ("librarians are shy and smart," "wealthy people are snobs," etc.) are a common example of the principle underlying hasty generalization. Example: "My roommate said her philosophy class was hard, and the one I'm in is hard, too. All philosophy classes must be hard!" Two people's experiences are, in this case, not enough on which to base a conclusion.

ExamplesALL my friends get to stay out until midnight, just ask Jill her parents let her stay out.

I dont have an A, you dont have an A, she doesnt have an A nobody gets an A in Miss Figs class.

Fallacy 5: Straw ManDefinition: One way of making our own arguments stronger is to anticipate and respond in advance to the arguments that an opponent might make. In the straw man fallacy, the arguer sets up a wimpy version of the opponent's position and tries to score points by knocking it down. But just as being able to knock down a straw man, or a scarecrow, isn't very impressive, defeating a watered-down version of your opponents' argument isn't very impressive either.

Fallacy 5: Straw ManExamples:

Jill: "We should clean out the closets. They are getting a bit messy." Bill: "Why, we just went through those closets last year. Do we have to clean them out everyday?" Jill: "I never said anything about cleaning them out every day. You just want too keep all your junk forever, which is just ridiculous."

Clip from Thank You For Smokinghttp://www.youtube.com/watch?v=DrnZdFFovBE

Fallacy 6: False ChoiceDefinition: In false choice, the arguer sets up the situation so it looks like there are only two choices. The arguer then eliminates one of the choices, so it seems that we are left with only one option: the one the arguer wanted us to pick in the first place. But often there are really many different options, not just twoand if we thought about them all, we might not be so quick to pick the one the arguer recommends!

Example: "Caldwell Hall is in bad shape. Either we tear it down and put up a new building, or we continue to risk students' safety. Obviously we shouldn't risk anyone's safety, so we must tear the building down." The argument neglects to mention the possibility that we might repair the building or find some way to protect students from the risks in questionfor example, if only a few rooms are in bad shape, perhaps we shouldn't hold classes in those rooms.

Fallacy 6: False ChoiceMy boss wants me to work later. You can extend my curfew, or Ill have to quit my job.

America: love it or leave it.

Fallacy 7: Circular ReasoningDefinition: Basically, an argument that is circular asks the reader to simply accept the conclusion without providing real evidence; the argument either relies on a premise that says the same thing as the conclusion or simply ignores an important (but questionable) assumption that the argument rests on.

Examples:I have a right to say what I want, therefore you shouldnt silence me!

Assisted suicide is morally acceptable because it is the right thing to do to help another human being avoid suffering.

Fallacy 8: Argument from IgnoranceDefinition: In the appeal to ignorance, the arguer basically says, "Look, there's no conclusive evidence on the issue at hand. Therefore, you should accept my conclusion on this issue."

Example: There is no evidence to prove that the Greek and Roman Gods existed, therefore, they did not exist.Fallacy 9: Argument Ad PopulumDefinition: The Latin name of this fallacy means "to the people." There are several versions of the ad populum fallacy, but what they all have in common is that in them, the arguer takes advantage of the desire most people have to be liked and to fit in with others and uses that desire to try to get the audience to accept his or her argument. One of the most common versions is the bandwagon fallacy, in which the arguer tries to convince the audience to do or believe something because everyone else (supposedly) does.

Ad Populum Examples:ALL my friends are allowed to stay out late! I should be too!

Fallacy 10: Appeal to PityDefinition: The appeal to pity takes place when an arguer tries to get people to accept a conclusion by making them feel sorry for someone. Example: "I know the exam is graded based on performance, but you should give me an A. My cat has been sick, my car broke down, and I've had a cold, so it was really hard for me to study!"

Fallacy 11: Appeal to AuthorityDefinition: Often we add strength to our arguments by referring to respected sources or authorities and explaining their positions on the issues we're discussing. If, however, we try to get readers to agree with us simply by impressing them with a famous name or by appealing to a supposed authority who really isn't much of an expert, we commit the fallacy of appeal to authority.

Fallacy 11: Appeal to AuthorityExample: We should repeal the Dont Ask Dont Tell policy in the military; Lady Gaga thinks so.