12 Fallacies to Avoid in Communication

12 Fallacies to Avoid in Communication

Sandra and I both love to crochet. She is the Jedi master and I, the humble padawan to whom she taught the craft. As I’ve developed my skills with hook and yarn, I’ve learned different techniques for improving the quality of my creations—and I’ve learned what things to avoid doing.

Rhetoric, defined as “the art of speaking or writing effectively,” also follows a set of dos and donts. These guidelines are especially helpful in the field of apologetics where discussion and dialogue are key activities. In this realm, fallacies are the things to avoid.

Fallacies unravel arguments by replacing sound reasoning and legitimate evidence with faulty logic and bad assumptions. The very word “fallacy” stems from Latin for “deceitful” and “to deceive.” But T. Edward Damer, author of Attacking Faulty Reasoning: A Practical Guide to Fallacy-Free Arguments, points out that “it really doesn’t matter whether the mistake was intended or not; a mistake is a mistake, regardless of the arguer’s intention.”

With a little help from Damer and a lot of help from RTB’s own logic coach Kenneth Samples, I’ve pulled together a list of 12 fallacies to watch out for.

    1. Argumentum ad baculum: “An appeal to force” uses threats to achieve the arguer’s goal. Damer cites the evangelical “threat of eternal damnation” conversion tactic as an example of this fallacy. Ouch! Time to rethink that approach.
    2. Argmentum ad misericordium: “An appeal to pity” stirs up emotions and tugs on our heart strings. Though the evoked emotions don’t change the truth or falseness of the issue at hand, they can cloud our judgment.
    3. Genetic fallacy: This fallacy occurs when people draw a conclusion about something based solely, or primarily, on its origin, without regard to how it has changed over time. For example, Ken points out in an online article that skeptics commit this fallacy when they “suggest that belief in God isn’t objectively true because such beliefs arise [originate] from feelings of loneliness.”
    4. Wishful thinking: Wishful thinking makes the logical error of assuming that just because we want something to be true (or false), then it will be true (or false). Relativistic thinking succumbs to this fallacy. (Listen to episode 42 of Ken’s podcast, Straight Thinking.)
    5. Post hoc ergo propter hoc (“after this, therefore because of this”): As Ken explains in his book A World of Difference, “This type of reasoning insists that because A precedes B, then A must have caused B.” For example, research shows that linking standard immunization shots with the rise in autism mistakenly assumes that simply because some cases of autism were detected after administration of a vaccination that the vaccination must some how be a cause of autism.
    6. Argumentum ad ignorantiam: “An appeal to ignorance” argues that something must be false because it has not yet been proven true. In A World of Difference, Ken notes that atheists frequently use this kind of fallacy to argue against God’s existence. They insist that since God’s existence has not been proven, God must not exist.
    7. Slippery slope: Also known as the “domino fallacy,” this tactic predicts that dire consequences will inevitably result from a certain belief or course of action. For example, someone might argue that drinking an occasional glass of wine eventually leads to alcoholism.
    8. Hasty generalization: This fallacy pops up everywhere—in politics, religion, social issues, etc. It makes sweeping judgments about a group of people based on an insufficient sample of group members. For example, CEOs are often typecast as greedy, heartless profit-mongers based on the deplorable actions of a few CEOs.
    9. Argumentum ad hominem: “Attacking the man” methods aim to smear an opponent’s character, rather than answer the challenge of his or her arguments. (Listen to episode 10 of Straight Thinking.)


      Name-calling, mudslinging, whatever you want to call it, this rhetorical tactic is rude and offensive.

Poisoning the well:

      This attack, as Ken puts it, attempts to “discredit a person’s motives.” This is a challenge RTB’s scholars frequently face when opponents charge them with having insidious reasons for believing in an old Earth.

Tu quoque

      (“you too”): This form of

ad hominem

    turns the tables in order to avoid criticism. It is, essentially, the old childhood tactic of declaring, “Well, you do it, too!”

  1. Attacking the straw manIt’s much easier to knock down a scarecrow than an actual human being. Likewise, it’s easier to set up and defeat an exaggerated, simplified, or otherwise misrepresented version of an opponent’s argument rather than his or her true views. (Listen to episode 9 of Straight Thinking.)
  2. Suppressed evidence: This fallacy occurs when an arguer cherry-picks evidence and ignores or dismisses legitimate evidence that either challenges his or her own view or supports the opponent’s.
  3. Diversionary humor or ridicule: Everyone enjoys a good joke, but in a debate setting humor can be misused to avoid the real issue or ridicule an opponent unfairly.

Now before we go accusing rhetoricians (politicians and pundits come to mind) of fallacious reasoning, keep in mind Damer’s admonishment to listeners and readers:

In most cases, fallacies are mistakes made by those who construct or present arguments for our consideration. However, those to whom such arguments are addressed may also be guilty of faulty reasoning if they accept the conclusion of a faulty argument. If they accept the bad argument as a good one, they are, in effect, making the same argument and thus bear the same responsibility for its problems. Similarly, a person who accepts the conclusion of a good argument is, in effect, making the same argument and should be recognized as a good thinker.

Yikes! I don’t know about you, but I know I probably need to reevaluate the arguments I put forward and the ones I accept.

— Maureen

Resources: This list mentions just 12 fallacies, but there’s plenty more where these came from. Ken outlines 22 in A World of Difference and Damer’s Attacking Faulty Reasoning discusses even more. Check out these two helpful books for more info on fallacies and how to avoid them.