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FALLACY “ …arguments, like men, are often pretenders.” Plato

Discover the world of fallacies through logic and reasoning. Understand common fallacies like Appeal to Authority and Slippery Slope. Learn to identify and avoid fallacious arguments.

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FALLACY “ …arguments, like men, are often pretenders.” Plato

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  1. FALLACY“…arguments, like men, are often pretenders.” Plato

  2. Under what discipline would you study fallacies? • Logic

  3. Remember, in forming an argument you may appeal to . . . • Ethos: appeal to ethics, morality, credibility • Pathos: appeal to the emotions • Logos: appeal to reason

  4. But… what exactly is logic? • Logic is the study of the methods and principles used to distinguish factual from faulty reasoning • The purpose of logic to test the validity of arguments.

  5. Fallacy: • An unsound argument in which a mistake is made when moving from a premise to a conclusion.

  6. Yet this definition assumes that we know what premise, conclusion and argument mean?

  7. Premise • A statement supporting a conclusion. • Example: Since no gun powder residue was detected on the terrorist’s clothing or body, . . . • (Words which indicate a premise: since, because, as, for )

  8. Conclusion • A statement concluded from the premise of an argument. • Example: . . . , the FBI concluded he could not have been the murderer. • (Words which indicate a conclusion: therefore, hence, thus, so)

  9. An argument is formed when a conclusion is drawn from a premise. • Example: Since no gun powder residue was detected on his clothing or his body, the FBI concluded he could not have been the murderer.

  10. So… the logical mind will ask? • “Does the conclusion reached follow the premise in a logical manner?

  11. Now let’s take another look at the definition of a fallacy: • A fallacy is an unsound argumentin which the conclusiondoes not follow from the premise.

  12. Appeal to SentimentArgumentum ad Misericordiam • A fallacy committed when pity is appealed to for the sake of getting a conclusion accepted. • Example: But Mr. Gonzalez, I have failed 2,326 times in a row. Don’t you think I deserve to pass it this time around? How many times do I have to fail it before I pass it? • Officer, I know I was speeding, but I just paid for a speeding ticket just last month. Can you give me a break?

  13. Attacking the person Argumentum ad Hominem • It is committed when instead of trying to disprove the truth of what is asserted, one attacks the person who made the assertion. • This argument is fallacious because the personal character of a person is logically irrelevant to the truth or falsehood of what that person says or the correctness or incorrectness of that person’s argument.

  14. Argument from ignorance Argumentum ad ignorantiam • This occurs when it is argued that a proposition is true simply on the basis that it has not been proven false, or that it is false because it has not been proven true. • Example: There must be ghosts because no one has ever been able to prove that there aren’t any. • Since you cannot disprove that there is water on Mars, then there must be water on Mars.

  15. BandwagonArgumentum ad Populum • The attempt to win popular assent to a conclusion by arousing the emotions and enthusiasms of the multitude, rather than by appealing to relevant facts. This fallacy is also known as “jumping on the bandwagon.” • Example: Since so many people are now getting tattoos, it follows that everyone should get one when they turn 17.

  16. Prejudicial Language • Charged, loaded or emotive terms are used to attach value or moral goodness to believing in a particular proposition. • Example: • Anygoodperson would agree that abortion is tantamount to murder. • AnyreasonableIRS agent will agree that our income tax is way too high.

  17. Slippery Slope • On the basis of a sequence of several unacceptable premises, an illegitimate conclusion is drawn. • Example: You should never gamble. Once you start gambling, you will find it hard to stop. Soon, you will spend all your money on gambling, and eventually, you will turn to a life of crime.

  18. False Dichotomy • A limited number of options (usually two) is given while in reality there are more options. Putting issues or opinions into “black and white” terms is a common instance of this fallacy. • Example: • America: Love it or leave it. • Every person is either wholly good or wholly evil. • “Climate deniers” want polluted air and water.

  19. Begging the Question Petitio Principii • If one assumes that part (or all) of what the person claims is proven fact • This occurs when the same proposition is repeated in both the premise and the conclusion. • This is what is commonly referred to as circular reasoning. • I: Your resume looks impressive, but I need a reference. (if impressive, why the need for a reference?) • C: Mrs. L can give me a good reference. • I: Good, but how do I know that she is trustworthy? • C: I can vouch for her. (if your word is that good, why the reference?)

  20. Appeal to Authority Argumentum ad verecundiam An authority is appealed to for testimony in matters outside the province of that authority’s special field. For example, an appeal to the opinion of a great physicist like Einstein to settle a political or economic argument would be fallacious. He may be an authority in science, but he would not be an authority in government. Example: President Obama has assured us that everyone will receive improved and more affordable healthcare.

  21. Anonymous Authority • The fallacy of anonymous authority is similar to the fallacy of appeal to authority, but in this particular fallacy the authority appealed to is not specified. The authority is anonymous or unknown and thus unreliable. • Example: Government experts have reported that anthrax has been found in 95% of federal government buildings.

  22. Non Sequitur • Any pretended jump in logic that doesn't work cleanly, perhaps because of unfounded premises, unmentioned complicating factors, or alternative explanations, such as 'This war is righteous because we are French!' or 'You will do what I say because !'" • No Logical Connection – Completely Random • Or my personal favorite… • While packing the car for vacation, I overheard my 7-year-old daughter have this exchange with her 9-year-old brother. • Taylor: Morgan, zip up your suitcase before you put it in the trunk. • Morgan: Duh, Taylor. I’m not the dumbest person alive. That would be Picasso! • Taylor: Morgan, Picasso is dead. • Morgan: Well, yeah … just because he cut off his ear!

  23. Straw man • One way of making our own arguments stronger is to anticipate and respond in advance to the arguments that an opponent might make. • So 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 the ability 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. • Example: “Those people in favor of the temporary ban on immigrants from the seven designated middle-east countries want to ban all Muslims everywhere from immigrating to the U.S. because they are all bigoted Islamophobes!” • The argument is made weak by being overstated— one cannot assume that most people who want a better review process for immigrants coming from countries with strong ties to terrorism prejudiced against Muslims. It may be that they are concerned about the increase of terrorist incidents throughout Europe as the number of refugees from terror-sponsored countries has increased.

  24. Faulty Analogy • Many arguments rely on an analogy between two or more objects, ideas, or situations. • If the two things that are being compared aren't really alike in the relevant respects, the analogy is a fallacy • Example: "Guns are like hammers—they're both tools with metal parts that could be used to kill someone. And yet it would be ridiculous to restrict the purchase of hammers—so restrictions on purchasing guns are equally ridiculous." • While guns and hammers do share certain features, these features (having metal parts, being tools, and being potentially useful for violence) are not the ones at stake in deciding whether to restrict guns. • Rather, we restrict guns because they can easily be used to kill large numbers of people at a distance. This is a feature hammers do not share—it'd be hard to kill a crowd with a hammer. Thus, the analogy is weak, and so is the argument based on it. Now a large heavy truck on the other hand……

  25. Hasty generalization • 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, smart and wear glasses," "wealthy people are snobs," etc.) are a common examples 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 to base a conclusion. • "Some philosophy classes are hard for some students" would not be a hasty generalization.

  26. Ones that don’t need as much explanation • Dogmatism: Does Not Allow for discussion because the speaker believes that his/her beliefs are beyond question. Stating an opinion as if it is a known fact. • Equivocation: Telling PART of the truth Aka:Lying by Omission. Also, purposely using a term with ambiguous meaning in order to mislead

  27. Post Hocor Post Hoc Ergo Propter Hoc • A logical fallacy that states “Since event Y followed event X, event Y must have been caused by X.” After this, therefore because of this.” • The rooster crowed and the sun came up. • Therefore, the sun rises because the rooster crows.

  28. Misleading Statistics

  29. Red Herring • An attempt to redirect the argument to another “more agreeable” issue. A red herring is a pungent smelling fish used to redirect hounds away from the fox at the end of a hunt.

  30. Appeal to Emotionaka Demagoguery • “Leader of the mob…” • A leader in a democracy who gains popularity by exploiting prejudice and ignorance among the common people, whipping up the passions of the crowd and shutting down reasoned deliberation. “Hands up; don’t shoot.” “We are going to build a wall…..”

  31. False Dilemma • A fallacy of false alternatives in which a person claims a something to be an either/or situation with no other options. • Politician: “We must decide if we are going to support the funding for construction of a new school or continue to prop up a failing, deteriorating structure.”

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