Lesson Eight - Reasoning Errors and Fallacies

When studying logic and arguments it is very important to remember that applying valid logic to an argument will result in a valid conclusion. There are, however, mistakes called fallacies that disrupt this process. Fallacies are incorrect argumentation or reasoning errors that result in misconceptions, presumptions, and invalid conclusions. There are so many fallacies that we cannot explain or illustrate all of them. The ones that we do cover in this section can also be found by different names depending on which resource you consult. Therefore, in addition to examining specific fallacies in detail, this section also focuses on recognizing and responding to a logical fallacy.

In some cases, fallacies cause someone to believe something is true without enough evidence or to follow an incorrect argument. For example, imagine that your friend concludes that the new teacher in the Hawaiian shirt is an easy grader.

In this case, the fallacy leads one to believe that the teacher’s clothes indicate how he or she will grade. Clothing has nothing to do with grading. This type of fallacy is called non sequitur, which is Latin for “it does not follow,” meaning the conclusion does not follow the evidence.

By accident or design, fallacies may exploit emotional triggers in the listener, take advantage of social relationships between people, or simply mislead the argument. Fallacies can use strong feelings such as anger, sadness, or excitement. Fallacies may rely on the authority of a teacher or politician to make their argument. They may come in a well or confidently spoken manner, which is used to cover up the fact that the argument lacks logical reasoning. In other words, fallacies are virtually everywhere in many different forms, and it is important to know how to recognize them and respond to them.

  1. The fallacy of Hasty Generalization – occurs when someone attempts to use a special case as evidence to prove a general rule.
    - “Everyone I met here speaks English. There must be no foreigners in the entire state of California.”
    -Problem: Those who have been met are only a subset of the entire set.
    - Since there are some people in the state of California that the person has not met, they are generalizing the population. This fallacy occurs often in the form of stereotyping and prejudice. Remember, a generalization tries to use a special case to prove a general rule.
  2. The fallacy of Irrelevant Conclusion – diverts attention away from a fact in dispute rather than addressing it directly. There are a number of fallacies in this category.
    1. Appeal to Authority involves arguing on the basis of having a more powerful position.
      -Mom says: “Take off your dirty shoes before you walk in the house.”
      You ask: “Why?”
      Mom says: “Because I am the mom, and I said so.”

      -Problem: Mom is using her position of authority to force an action. The real argument here is that it is much more work to clean the floor than to take off your shoes. So please take off your shoes.
    2. The fallacy of Popular Sentiment – occurs when many other people think or feel that a conclusion should be correct.
      -“Everyone here agrees that there should be no school on Friday!”
      -Problem: A popular idea is not necessarily a logical one.
    3. The appeal to Fear or Emotion – makes an argument for something based on danger or other strong emotion.
      -You need a strong lock for the door, or else someone is going to break into your home.
      -Problem: There are other deterrents from someone breaking into your home.
    4. The fallacy of Affirming the Effect – ignores other possible causes for the outcome.
      -If people have the flu, they cough. Tom is coughing. Therefore, he has the flu.
      -Problem: People cough for reasons other than the flu.
      -If it rains, the ground is wet. The ground is wet. Therefore, it rained.
      -Problem: There are other ways the ground could have gotten wet.
    5. The fallacy of Denying the Cause – draws a conclusion from a result that does not necessarily support that conclusion.
      -If it is raining outside, it must be cloudy. It is not raining outside. Therefore, it is not cloudy.
      -Problem: There does not have to be rain for it to be cloudy.
  3. The Straw Man fallacy– happens when someone attributes an argument to an opponent and refutes it to look like he has won an argument.
    -“Some would say that I am not qualified to be mayor. But that’s not true because I have spent 8 years on city counsel.”
    -Problem: No one ever said he was inexperienced. So when speaker brings up his experience to refute it, it seems like he wins a point. The Straw Man suggests competence where it might not actually exist.
  4. The Begging the Question fallacy– restates the conclusion without offering any support or proof.
    -“Emily ate the cookies because I know she did!”
    -Problem: There is no evidence to support these claims. It begs the question, “How do you know she ate the cookies?”
    -The oil company has done the best they can to clean up the environment, because they said they did.
    -Problem: There is no support to actually prove this claim. It begs the question, “What have they done?”
  5. The Either – Or fallacy– falsely oversimplifies an argument by offering only two solutions to a problem: either this or that.
    -This country can have either a strong military or a strong welfare program.
    -Problem: This ignores alternative positions or a middle-ground perspective.
    -A woman can either be a mother or have a career.
    -Problem: There is no acknowledgement of an alternative possibility.
  6. The Slippery Slope fallacy– is a scare tactic that claims if we accept one thing, then there will be further negative consequences. This gives the image that if one thing is allowed to “slip”, everything will “slip” down the hill to disaster. Often the arguer will mention the most detrimental result.
    -If you give a mouse a cookie, he’ll ask for a glass of milk. If you give him a glass of milk, he will ask for a napkin, and so on.
    -If we allow loggers to cut down a few trees, we will soon have no forest
    -Raising taxes requires employers to pay more, forcing them to cut jobs.
    -Problem: Taking a particular action will not necessarily result in the most undesirable outcome.
  7. The Guilty By Association fallacy– suggests a conclusion based on the characteristics of those nearby. Often someone’s character is defined by the character of the people they hang out with
    -A member of a school board is a bad person because the school district just fired some teachers.
    -Problem: The board member may not have been involved in or may have opposed firing teachers.
    -Sam lives with his brother, a known criminal. Sam must be a criminal, too.
    -Problem: Living with his brother does not make him a criminal.
  8. The Ad Hominem fallacy– means “to the man” in Latin and attacks a person’s character instead of their ideas. Politicians circulate advertisements that attack a candidate’s personal life or past decisions to discredit the person before the public.
    -Mom: Please take off your shoes before coming into the house.
    -You: Are you in a bad mood today?
    -Problem: Mom’s mood has nothing to do with her asking you to take your shoes off. Cleaning the floor takes more work than taking off shoes.
  9. The Red Herring fallacy– refers to the tactic of providing irrelevant and misleading information that pulls the listener away from the real argument. A red herring is meant to distract the listener into believing or following an incorrect argument.
    -“I don’t think we should hire this person for the job because she will have to put her children in day care.”
    -Problem: Bringing up someone’s personal responsibilities has nothing to do with their job qualifications. A red herring occurs when irrelevant information is inserted into the argument, either intentional or accidental, and meant to distract the listener into following an incorrect, invalid, or irrelevant argument.

During a case in which a rich celebrity is accused of murder, the defense brings up the fact that the sports star donated lots of money to charity. They argue that the celebrity is morally a good person. While this may be true, it has nothing to do with whether or not the celebrity committed murder. The lines of argument suddenly cross, and you are thrown off the original argument.

In this case, focusing on the idea that the celebrity has for many years donated money diverts attention from the more important and relevant claims. Bringing the red herring into the argument could provide an opportunity to persuade the jury. This is just one example of how the diversions can occur.

This example shows how distracting and irrelevant information can be used to divert attention, even momentarily, away from the real issue and expand an incorrect line of argument. When your attention has been diverted, there may be a different conclusion. So be alert when someone says something random or irrelevant.

You will encounter fallacies in political debates, conversations with others, advertisements, news articles, textbooks, and many other places. When making an argument or supporting a position, you should avoid sources that contain fallacies, because fallacies weaken your argument as well as your reputation as an arguer. Recognize fallacies by asking such questions as Is this information relevant to the issue at hand? Is it acceptable? Does it support the claim?