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Introduction to Logical Fallacies Morales English 101/120 Goya’s “Sleep of Reason Produces Monsters”

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Presentation on theme: "Introduction to Logical Fallacies Morales English 101/120 Goya’s “Sleep of Reason Produces Monsters”"— Presentation transcript:

1 Introduction to Logical Fallacies Morales English 101/120 Goya’s “Sleep of Reason Produces Monsters”

2 Why Study Logical Fallacies? Even if you could count on reasoning correctly 100% of the time, you cannot count on others doing so. In logical self- defense, you need to be able to spot poor reasoning, and—more importantly—to understand it. To be able to correct others' mistakes, or to refute them convincingly, you need to understand why they are wrong. (fallacyfiles.com) A “fallacy” is a mistake and a “logical fallacy” is a mistake in reasoning

3 Hasty Generalization/Overgeneralization Women make bad bosses. Politicians are crooked. British people are very cold and uptight. African-Americans can sing beautifully. -- Don’t make judgments based on insufficient evidence. --Don’t assume that all members of a group have the qualities of some. --Never use “all” or “none” statements.

4 The Argument Based on Tradition The death penalty is nothing new. People have been executed for thousands of years, in many societies. Slavery has existed for over two hundred years and the negro is accustomed to his lifestyle of servitude. What would become of him without it? Every great society has provided state funding for art and culture. --Tradition doesn’t necessarily make it moral or ethical. --Such arguments may not address the current situation --The needs of society may have changed.

5 Ad Hominen Attack Why should we trust George Bush’s ideas about foreign policy when he is nothing more than a recovering cocaine addict? How can Susan Sarandon, an actress, blabber about issues like the death penalty when she hasn’t even been to college? --Don’t resort to cheap shots. --Tackle the tough points. --Do your homework; find the facts. --Attack the issues, not the person ! ?

6 Begging the Question We shall justify making abortion illegal. 1. Abortion is unjust murder. 2. Murder is illegal. 3. Therefore abortion should be made illegal, since it is murder. This must be proven

7 Post Hoc, Ergo Propter Hoc (after this, therefore, because of this) Today a black cat caused me to break my ankle! It crossed in front of me, and ten minutes later, I tripped on the curb! Ever since Villaraigosa became mayor, the crime rate has increased! He’s going to ruin our city! Most rapists read pornography; therefore, pornography causes violence against women. --Don’t assume that an earlier event caused the situation. --What other factors may have contributed to the situation? --You must prove the connection between two events

8 Either/Or Fallacy Either you’re with us, or you’re against us America. Love it or leave it. --There are usually more than two options. --Arguments are complex --Don’t underestimate your audience’s intelligence Gerda Reith is convinced that superstition can be a positive force. "It gives you a sense of control by making you think you can work out what's going to happen next," she says. "And it also makes you feel lucky. And to take a risk or to enter into a chancy situation, you really have to believe in your own luck. In that sense, it's a very useful way of thinking, because the alternative is fatalism, which is to say, 'Oh, there's nothing I can do.' At least superstition makes people do things." (Source: David Newnham, "Hostages to Fortune“)"Hostages to Fortune“

9 Slippery Slope If we legalize marijuana, the next thing we know, kids will be shooting up heroin, smoking crack, and going crazy with LSD. If we make homosexual marriages legal, pretty soon it’ll be acceptable to marry one’s uncle or one’s father, or even an animal! --Don’t assume that one event will lead to another. --These connections must be proven. --If you can, in fact, show a connection, then it’s not a fallacy.

10 Card Stacking/ Slanting George Washington, the “father” of our country, was actually a slaveholder and a pot-smoker. Why do celebrate his birthday as a national holiday? Gay marriage should not be legalized because homosexuality is a sin and homos are disgusting perverts. -- Don’t ignore evidence that may weaken your argument. Acknowledge it! --Don’t use words that show extreme prejudice and disapproval. --Treat your opponents with respect.

11 Major Fallacies Review Overgeneralization/ Hasty Generalization Argument Based on Tradition Ad Hominem Attack Ignoring (begging) the Question Post Hoc, Ergo Propter Hoc Either/Or Fallacy Slippery Slope Card Stacking/ Slanting

12 I lost my wallet yesterday. I knew that walking under that ladder would be trouble! Yesterday, my neighbor’s sixteen-year old son zoomed out of the driveway and almost hit my little daughter. Last week, a teenager rear-ended my car. When are we going to raise the driving age to 21? How can she be guilty of that crime? She has such a lovely family—they go to church regularly and they are such friendly people! Of course she’s poor. Look at that torn coat she’s wearing. How can George Bush understand the plight of poor people? He was born with a silver spoon in his mouth. POST HOC: ONE EVENT DID NOT NECESSARILY CAUSE THE OTHER Hasty Generalization: Not enough evidence Hasty Generalization: judgment based on stereotype Hasty Generalization / Stereotype Cardstacking: Ad Hominem Attack

13 This unfair rule of making students do useless community service work must be changed. We should either pay our children’s teachers better salaries or just admit that we don’t give a damn about education. How do you know that life doesn’t exist on other planets? Christopher Columbus should not be considered a hero. He massacred Native Americans and stole their land. If the exam is too difficult, students will fail, and then they’ll want to drop out of school.

14 If we pass laws against fully-automatic weapons, then it won't be long before we pass laws on all weapons, and then we will begin to restrict other rights, and finally we will end up living in a communist state. Thus, we should not ban fully-automatic weapons. If I make an exception for you then I have to make an exception for everyone. You claim that Mr. Jones is innocent, but why should anyone listen to you? You are a Mormon after all. You may argue that God doesn't exist, but you are just a big fat idiot. "Adding meat to his diet helped make him physically stronger," says Jeff Twiss, an officer of the team. "The doctors convinced him he needed meat."

15 Smith, who is from England, decides to attend graduate school at Ohio State University. He has never been to the US before. The day after he arrives, he is walking back from an orientation session and sees two white (albino) squirrels chasing each other around a tree. In his next letter home, he tells his family that American squirrels are white. The Brookings Institute sampled 500 liberal non-religious males living in San Francisco regarding the issue of gay marriage in America. Most of them approved, therefore most Americans everywhere must approve of gay marriageSan Francisco Marriage is one of humanity’s oldest institutions, and it wouldn’t have survived so long as an integral part of every culture if it were not for the fact that it is vital for our survival. Therefore, we shouldn’t tamper with it or do anything that might harm it.

16 The only policy that effectively reduces public shootings is right-to-carry laws. Allowing citizens to carry concealed handguns reduces violent crime. In the 31 states that have passed right-to-carry laws since the mid-1980s, the number of multiple-victim public shootings and other violent crimes has dropped dramatically. Murders fell by 7.65%, rapes by 5.2%, aggravated assaults by 7%, and robberies by 3%.


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