Logical Fallacies

1. Logical Fallacies E.Yearian

2. What is a Logical Fallacy? The term "logical fallacy" refers to the concept of making an error in terms of reasoning. It is crucial to understand logical fallacies so that they can be identified and avoided when attempting to persuade.

3. Argument Structure When we compose logical arguments, they generally follow a specific structure. This structure is composed of two primary parts: one or more premises, and a conclusion. Premise - a proposition which gives reasons, grounds, or evidence for accepting some other proposition, called the conclusion. Conclusion - a proposition, which is purported to be established on the basis of other propositions. Definitions courtesy Lander University

4. Inductive vs. Deductive There are two types of arguments that we will look at: inductive and deductive. A deductive argument is an argument that is intended by the arguer to be deductively valid, that is, to provide a guarantee of the truth of the conclusion provided that the argument's premises are true. An inductive argument is an argument that is intended by the arguer to be strong enough that, if the premises were to be true, then it would be unlikely that the conclusion is false. So, an inductive argument's success or strength is a matter of degree, unlike with deductive arguments. Explanations courtesy University of Tennessee - Martin

5. Soundness and Validity • When we examine logical arguments, generally we assess their worth based off of two concepts: soundness and validity. • An argument can be valid without being sound. It cannot, however, be sound if it is not valid. • Ideally, any argument we make as logical thinkers will prove to be both valid AND sound.

6. Soundness vs Validity Validity - A deductive argument is said to be valid if and only if it takes a form that makes it impossible for the premises to be true and the conclusion nevertheless to be false. Otherwise, a deductive argument is said to be invalid. Soundness - A deductive argument is sound if and only if it is both valid and all of its premises are actually true. Otherwise, a deductive argument is unsound. Explanations courtesy University of Tennessee - Martin

7. FAULTY CAUSE: (post hoc ergo propter hoc) Translates to “after this, therefore because of this” Mistakes correlation for causation Ex. I only failed that test today because a black cat crossed my path on the way to school. Taller people are better readers than shorter people.

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9. SWEEPING GENERALIZATION: (dicto simpliciter) Assumes that what is true of the whole will also be true of the part, or that what is true in most instances will be true in all instances. Ex. This class is loud. Carl is in this class. Therefore, Carl is loud.

10. HASTY GENERALIZATION Bases an inference on too small a sample, or on an unrepresentative sample. Often, a single example or instance is used as the basis for a broader generalization. Ex. The Arkansas Razorbacks won their first two games, they won’t lose a game all season. I was mugged in New York, all New Yorkers are bad people.

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12. FAULTY ANALOGY (Can be literal or figurative) assumes that because two things, events, or situations are alike in some known respects, that they are alike in other unknown respects. Ex. What's the big deal about the early pioneers killing a few Indians in order to settle the West? After all, you can't make an omelet without breaking a few eggs. People who buy stocks are no different from people who bet on horse racing. They both risk their money with little chance of making a big profit.

13. APPEAL TO FORCE (argumentum ad baculum) • An appeal to force is when force, coercion, or even a threat of force is used in place of a reason in an attempt to justify a conclusion. • Often this is because the person making the argument either doesn’t have a good reason to offer, or is too lazy to present their argument. • Ex. Employee: “Why do I have to work this weekend? I requested those days off” Employer: “That’s fine, you don’t have to work. I can just hire somebody else to take your spot here.”

14. APPEAL TO IGNORANCE (argumentum ad ignorantiam) Attempts to use an opponent's inability to disprove a conclusion as proof of the validity of the conclusion, i.e. "You can't prove I'm wrong, so I must be right.“ Ex. The new form of experimental chemotherapy must be working; not a single patient has returned to complain. You don’t have an answer, so my solution must be correct.

15. BIFURCATION (either-or, black or white, all or nothing fallacy) Assumes that two categories are mutually exclusive and exhaustive, that is, something is either a member of one or the other, but not both or some third category. Ex. Either you favor a strong national defense, or you favor allowing other nations to dictate our foreign policy. Either you join our group or you’re a loser.

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17. DAMNING THE SOURCE/ POISONING THE WELL(ad hominem) Attempts to refute an argument by indicting the source of the argument, rather than the substance of the argument itself. Ex. That legislation was proposed by Democrats, so you know it’s bad. Why would you listen to him, he’s a convicted felon!

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19. TU QUOQUE (AKA 2 Wrongs = Right) Pointing to a similar wrong or error committed by another. Ex. Gee, Mom and Dad, how can you tell me not to do drugs when you both smoke cigarettes and drink alcohol? The United States has no business criticizing the human rights policies of the Third World nations, not as long as discrimination and segregation continue to exist in the United States.

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21. EQUIVOCATION: Allows a key word or term in an argument to shift its meaning during the course of the argument. The result is that the conclusion of the argument is not concerned with the same thing as the premise(s). Ex. A warm soda is better than a cold soda. After all, nothing is better than a cold soda, and a warm soda is better than nothing. Sure philosophy helps you argue better, but do we really need to encourage people to argue? There's enough hostility in this world.

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23. BEGGING THE QUESTION Entails making an argument, the conclusion of which is based on an unstated or unproven assumption. In question form, this fallacy is known as a COMPLEX QUESTION. Ex. Of course smoking causes cancer. The smoke from cigarettes is a carcinogen. Prosecutor to defendant: So how did you feel when you killed your wife?

24. TAUTOLOGY / CIRCULAR REASONING Defining terms or qualifying an argument in such a way that it would be impossible to disprove the argument. Often, the rationale for the argument is merely a restatement of the conclusion in different words. Ex. You are a disagreeable person and, if you disagree with me on this, it will only further prove what a disagreeable person you are. Parent: “It’s bed time, go to bed.”Child: “Why?”Parent: “Because I said so.”

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27. APPEAL TO IMPROPER AUTHORITY Attempts to justify an argument by citing a highly admired or well-known (but not necessarily qualified) figure who supports the conclusion being offered. Ex. If it's good enough for (insert celebrity's name here), it's good enough for me. My 5th grade teacher once told me that girls will go crazy for boys if they learn how to dance.  Therefore, if you want to make the ladies go crazy for you, learn to dance.

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29. APPEAL TO TRADITION Based on the principle of "letting sleeping dogs lie". We should continue to do things as they have been done in the past. We shouldn't challenge time-honored customs or traditions. Ex. Of course we have to play "pomp and circumstance" at graduation, because that's always been the song that is played. Dave: For five generations, the men in our family went to Stanford and became doctors, while the women got married and raised children.  Therefore, it is my duty to become a doctor. Kaitlin: Do you want to become a doctor? Dave: It doesn’t matter -- it is our family tradition.  Who am I to break it?

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31. APPEAL TO THE CROWD (ad populum) Refers to popular opinion or majority sentiment in order to provide support for a claim. Often the "common man" or "common sense" provides the basis for the claim. This can sometimes be referred to informally as a “bandwagon” fallacy. Ex. Why did I get in trouble for talking in class? Everyone else was talking, too. Professor Windplenty's test was extremely unfair. Just ask anyone who took it.

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33. STRAW MAN Stating an opponent's argument in an extreme or exaggerated form, or attacking a weaker, irrelevant portion of an opponent's argument. Ex. What woman in her right mind could truly desire total equality with men? No woman wants the right to be shot at in times of war, the right to have to pay alimony, or the right to have to use the same restrooms as men. They proposed stricter gun control laws. Can you believe they want to take everybody’s guns now? "Senator Jones says that we should not fund the attack submarine program. I disagree entirely. I can't understand why he wants to leave us defenseless like that.“

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35. SLIPPERY SLOPE Suggests that if one step or action is taken it will invariably lead to similar steps or actions, the end results of which are negative or undesirable. A slippery slope always assume a chain reaction of cause-effect events which result in some eventual dire outcome. Ex. We cannot unlock our child from the closet because if we do, she will want to roam the house.  If we let her roam the house, she will want to roam the neighborhood.  If she roams the neighborhood, she will get picked up by a stranger in a van. Therefore, we should keep her locked up in the closet.

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37. NON SEQUITUR In a general sense any argument which fails to establish a connection between the premises and the conclusion may be called a non-sequitur. In practice, however, the label non-sequitur tends to be reserved for arguments in which irrelevant reasons are offered to support a claim. Ex. I wore a red shirt when I took the test, so that is probably why I did so well on the test. Mr. Boswell couldn't be the person who poisoned our cat, Truffles, because when I used to take Truffles for walks he always smiled and said "Hello" when we walked by.

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39. RED HERRING Attempting to hide a weakness in an argument by drawing attention away from the real issue. A red herring fallacy is thus a diversionary tactic or an attempt to confuse or fog the issue being debated. Ex. Accused by his wife of cheating at cards, Ned replies "Nothing I do ever pleases you. I spent all last week repainting the bathroom, and then you said you didn't like the color.“ Daughter: "I'm so hurt that Todd broke up with me, Mom." Mother: "Just think of all the starving children in Africa, honey. Your problems will seem pretty insignificant then."

40. Examples Red Herring example: https://www.youtube.com/watch?v=f_ttbfTGs48

41. Not Fallacies, but related… The following concepts are not fallacies themselves, but can assist in determining the validity and/or soundness of an argument. They can help you to avoid falling for fallacies. So, for example, while Occam’s Razor is not 100% full proof, it’s a good starting point in figuring out what should probably be believed. Keep in mind, in any argument or debate, the burden of proof belongs on somebody that is making a claim (whether positive or negative). For that reason, Hitchen’s Razor comes into play. In the case of Hitchen’s Razor, just because something is asserted without evidence, doesn’t mean it isn’t true. However, if you aren’t given evidence to believe something, it may be best not to believe it until evidence is provided. With that being said, let’s look at those two concepts.

42. Occam’s Razor If two competing theories explain a single phenomenon, and they both generally reach the same conclusion, and they are both equally persuasive and convincing, and they both explain the problem or situation satisfactorily, the logician should always pick the less complex one. The one with the fewer number of moving parts, so to speak, is most likely to be correct. The idea is always to cut out extra unnecessary bits, hence the name "razor." An example will help illustrate this.

43. Examples Suppose you come home and discover that your dog has escaped from the kennel and chewed large chunks out of the couch. Two possible theories occur to you. (1) Theory number one is that you forgot to latch the kennel door, and the dog pressed against it and opened it, and then the dog was free to run around the inside of the house. This explanation requires two entities (you and the dog) and two actions (you forgetting to lock the kennel door and the dog pressing against the door). (2) Theory number two is that some unknown person skilled at picking locks managed to disable the front door, then came inside the house, set the dog free from the kennel, then snuck out again covering up any sign of his presence, and then relocked the front-door, leaving the dog free inside to run amok in the house. This theory requires three entities (you, the dog, and the lock picking intruder) and several actions (picking the lock, entering, releasing the dog, hiding evidence, relocking the front door). It also requires us to come up with a plausible motivation for the intruder--a motivation that is absent at this point.

44. Hitchens's Razor Hitchens's Razor simply states that “what can be asserted without evidence can be dismissed without evidence.” This means that if somebody posits something without providing any evidence to show it is indeed true, a listener is logically free to dismiss it without providing any evidence that it isn’t true.

45. Example While leaving the mall, a haggard old man with tattered clothes walks up to you and informs you that he is a billionaire. Do you believe him? You could ask for him to show you some sort of proof, but until proof is given, logic dictates that there is no reason to consider this to be likely true. This is closely related to the idea that extraordinary claims require extraordinary evidence.

46. Example If a man walks up to you and says his name is Fred, that would be considered an ordinary claim because there are numerous people named Fred. You could still ask for evidence, but most people would be okay with taking him at his word in most cases. However, if I told you that I have an invisible green giraffe in my backyard that farts out nickels, you probably shouldn’t believe me. You should require proof. If I pulled a nickel out of my pocket would that be enough evidence? Of course not. Extraordinary claims require extraordinary evidence.

47. Examples of Fallacious Arguments • https://www.youtube.com/watch?v=8DC0tHZ78iQ

48. Sources Thanks to faculty from Cal State Fullerton, Tennessee-Martin, and Texas State University for definitions and examples. Access their Fallacy pages here: Fullerton: http://commfaculty.fullerton.edu/rgass/fallacy3211.htm Texas State: http://www.txstate.edu/philosophy/resources/fallacy-definitions Tennessee – Martin: https://www.iep.utm.edu/val-snd/