LOGICAL FALLACIES English 11

REMEMBER…  Only take notes on slides that have an arrow.  You will be tested on these fallacies…TAKE GOOD NOTES.

LOGICAL FALLACIES  logical fallacies are flaws in reasoning that lead to faulty, illogical statements  they are unreasonable argumentative tactics named for what has gone wrong during the reasoning process

LOGICAL FALLACIES Often difficult to spot fallacies. They are meant to manipulate readers by reaching their emotions instead of their intellects.

WHY STUDY LOGICAL FALLACIES? Learning to recognize these will:  Strengthen your own arguments  Help you critique other’s arguments

LIST OF MOST POPULAR FALLACIES Ad hominem Hasty Generalization False Dilemma Begging the Question Post Hoc Weak Analogy

AD HOMINEM – ARGUMENT TO THE PERSON  An attack on the person proposing an argument rather than on the argument itself.  May attack a person’s appearance, personal habits, or character rather than focusing on the merit of the issue at hand.  Reason: if something is wrong with this person, whatever he/she says must be wrong.

AD HOMINEM: EXAMPLE Sarah has never had a boyfriend for more than a year, so whatever relationship advice she gives you can’t be good. Sara’s relationship status has nothing to do with the quality of her advice.

HASTY GENERALIZATION  a conclusion based on insufficient or unrepresentative evidence  making assumptions about a whole group of range of cases based on a sample that is inadequate (stereotypes)

HASTY GENERALIZATION: EXAMPLE The only redheads I know are rude. Therefore, all redheads must have bad manners. My roommate said her philosophy class was hard, and the one I’m in is hard, too. All philosophy classes must be hard.

FALSE DILEMMA  A false dilemma asserts that a complex situation can have only two possible outcomes and that one of the options is necessary.  The arguer sets up the situation so it looks like there are only two choices.

FALSE DILEMMA:EXAMPLE The school building is in bad shape. Either we tear it down and put up a new building, OR we continue to risk students’ safety. Since we shouldn’t risk anyone’s safety, we need to tear down the building. The argument doesn’t mention the possibility of repairing the building. It acts as if there are only two options. Tear down building or risk students’ safety.

BEGGING THE QUESTION  A kind of circular argument where the support only restates the claim.  Asks the reader to accept the conclusion without providing real evidence.

BEGGING THE QUESTION: EXAMPLE Wrestling is dangerous because it is unsafe. Jogging is fun because it is enjoyable. Students should not be allowed to park in the lots reserved for faculty because those lots should be for faculty only.

POST HOC  The assumption that because one event follows another, the first is the cause of the second.  Assuming that because B comes after A, A cause B.

POST HOC: EXAMPLE President Jones raised taxes, and then the rate of violent crime went up. Jones is responsible for the rise in crime. Since Governor Jones took office, unemployment of minorities in the state has decreased by seven percent. Governor Jones should be applauded for reducing unemployment among minorities.

WEAK ANALOGY  when two things being compared aren’t really alike in the relevant respects, the analogy is a weak one  comparing apples and oranges

WEAK ANALOGY: EXAMPLE If we can put a man on the moon, why can’t we find the cure for a common cold? Guns are like hammers—they’re both tools with metal parts that could be used to hurt someone.

FALLACY REVIEW Grab a partner, a whiteboard, a dry erase markers, and an orange eraser. When you see the example…write down the corresponding logical fallacy.

WHICH LOGICAL FALLACY IS THIS? Plagiarism is deceitful because it is dishonest.

WHICH LOGICAL FALLACY IS THIS? Plagiarism is deceitful because it is dishonest. Begging the question

WHICH LOGICAL FALLACY IS THIS? Water fluoridation affects the brain. Citywide, student’s test scores began to drop five months after fluoridation began. I think we know the cause.

WHICH LOGICAL FALLACY IS THIS? Water fluoridation affects the brain. Citywide, student’s test scores began to drop five months after fluoridation began. I think we know the cause. Post Hoc

WHICH LOGICAL FALLACY IS THIS? I know three grad students who spend way too much time studying. All grad students are nerds.

WHICH LOGICAL FALLACY IS THIS? I know three grad students who spend way too much time studying. All grad students are nerds. Hasty Generalization

WHICH LOGICAL FALLACY IS THIS? Supreme Court Justice Byron White was an All- American football player while in college, so how can you say that all athletes are dumb?

Hasty generalization WHICH LOGICAL FALLACY IS THIS?

The book Investing for Dummies really helped me understand my finances better. The book Chess for Dummies was written by the same author, was published by the same press, and costs about the same amount, so it would probably help me understand my finances as well. WHICH LOGICAL FALLACY IS THIS?

The book Investing for Dummies really helped me understand my finances better. The book Chess for Dummies was written by the same author, was published by the same press, and costs about the same amount, so it would probably help me understand my finances as well. Weak Analogy

Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for awhile. WHICH LOGICAL FALLACY IS THIS?

Look, you are going to have to make up your mind. Either you decide that you can afford this stereo, or you decide you are going to do without music for awhile. False dilemma

Justin Bieber can’t be a good musician. He has been in and out of rehab too many time. WHICH LOGICAL FALLACY IS THIS?

Justin Bieber can’t be a good musician. He has been in and out of rehab too many time. Ad hominem