- Slides: 16
Introduction to Logical Fallacies Morales English 101/120 Goya’s “Sleep of Reason Produces Monsters”
Why Study Logical Fallacies? • Even if you could count on reasoning correctly 100% of the time, you cannot cy” falla ical “log a and ake mist a is acy” “fall A count on others doing so. In logical selfg able to spot poor reasonin is a mistake defense, youinneed to be 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)
Hasty Generalization/Overgeneralization • Women make bad bosses. --Don’t make judgments based on insufficient evidence. • Politicians are crooked. --Don’t assume that all members of a group have the qualities of some. • British people are very cold and uptight. --Never use “all” or “none” statements. • African-Americans can sing beautifully.
The Argument Based on Tradition --Tradition doesn’t The death penalty is nothing new. necessarily make it People have been executed for moral or ethical. thousands of years, in many societies. --Such arguments mayfor over two hundred Slavery has existed not address years andthe current negro is accustomed to his lifestyle of servitude. What would become of situation him without it? --The needs of society may great society has provided state have. Every changed. funding for art and culture.
Ad Hominen Attack --Don’t resort to cheap shots. Why should we trust George Bush’s ideas about foreign policy when he is nothing --Tackle the tough points. more than a recovering cocaine addict? --Do your homework; find the facts. How can Susan Sarandon, an actress, blabber about issues like the death --Attack the issues, not the person! penalty when she hasn’t even been to college? ?
Begging the Question This must be proven 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.
Post Hoc, Ergo Propter Hoc (after Today a black cat caused me to break my this, therefore, this) ankle! It crossed in because front of me, of and ten minutes later, I tripped on the curb! --Don’t assume that an earlier event Evercaused since Villaraigosa became mayor, the situation. crime rate has increased! He’s going to ruin our city! factors may have --What other contributed to the situation? Most rapists read pornography; therefore, --You must prove the connection pornography causes violence against women. two events between
Either/Or Fallacy Either you’re with us, or you’re against us Gerda Reith is convinced that superstition can be a positive force. "It gives youmore a sense than of controltwo by --There are usually making you think you can work out what's going options. America. Love it or leave it. to happen next, " she says. "And it also makes you feel lucky. And to take a risk or to enter into a chancy situation, are you really have to believe in --Arguments complex your own luck. In that sense, it's a very useful way of thinking, because the alternative is fatalism, --Don’t your audience’s which isunderestimate to say, 'Oh, there's nothing I can do. ' At least superstition makes people do things. " intelligence (Source: David Newnham, "Hostages to Fortune“)
Slippery Slope If we legalize marijuana, the next thing we know, kids will be shooting up heroin, smoking crack, and going crazy with LSD. --Don’t assume that one event will Iflead we make homosexual marriages legal, to another. pretty soon it’ll be acceptable to marry one’sconnections uncle or one’s father, an --These must or beeven proven. animal! --If you can, in fact, show a connection, then it’s not a fallacy.
Card Stacking/ Slanting Georgeignore Washington, the “father” of our -- Don’t evidence that may weaken your argument. country, was actually a slaveholder and a Acknowledge pot-smoker. Whyit! do celebrate his birthday as a national holiday? --Don’t use words that show extreme prejudice and disapproval. Gay marriage should not be legalized because homosexuality a sin and --Treat your opponentsis with respect. homos are disgusting perverts.
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
I lost my wallet yesterday. I knew that walking under that ladder would be trouble! POST HOC: ONE EVENT DID NOT NECESSARILY CAUSE Yesterday, THE OTHER 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? Hasty Generalization: Not enough evidence 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! Hasty Generalization: judgment based on stereotype Of course she’s poor. Look at that torn coat she’s wearing. Hasty Generalization/ Stereotype How can George Bush understand the plight of poor people? He was born with a silver spoon in his mouth. Cardstacking: Ad Hominem Attack
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,
If we pass laws against fully-automatic weapons, then it won't b before we pass laws on all weapons, and then we will begin to other rights, and finally we will end up living in a communist st 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 li You are a Mormon after all. You may argue that God doesn't exist, but you are just a big fat "Adding meat to his diet helped make him physically stronger, " Twiss, an officer of the team. "The doctors convinced him he n meat. "
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 nonreligious 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 marriage 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
The only policy that effectively reduces public shootings is right-to-carry laws. Allowing citizens to carry concealed ha reduces violent crime. In the 31 states that have passed right-to-carry laws since t mid-1980 s, the number of multiple-victim public shootings violent crimes has dropped dramatically. Murders fell by 7. rapes by 5. 2%, aggravated assaults by 7%, and robberies b