Common Logical Fallacies

Brief Definitions of Informal Fallacies With Links to Examples and Discussions

Straw man is a fallacy in which an opponent's argument is overstated or misrepresented in order to be more easily attacked or refuted. (Dimitri Otis/Getty Images)

For those who need a little refresher, here are some of the most common informal logical fallacies.

It may have happened to you while reading comments on a blog, watching a political commercial, or listening to a talking head on a chat show. A mental alarm goes off signaling that what you're reading, watching, or listening to is utter claptrap and twaddle.

For me, the BS alert sounded when I ran across these random observations in the "Vox Populi" column of the local newspaper:

  • Learning how to swim does not guarantee you won't drown. I'm 55 years old, have never learned to swim and I haven't drowned.
  • We need to pass a law that stupid people are not allowed to own pets.
  • I'm aggravated with spaghetti sauce with vegetables. I love vegetables, but I don't want them in my spaghetti sauce. Where's our freedom going?
  • Regarding the person who had to "tote" stuff at Wal-Mart; tote? Carry. What is wrong with people? You don't "tote" stuff, you carry it.
  • The English language is the only language that should be spoken in the open and none other. This is the United States of America.
  • Those of us who are true taxpaying, working Americans need to stand up and demand that people should have certain education, I.Q. and income levels to be able to vote for president or any major political office.
  • Anyone who thinks that interest in books is waning hasn't paid much attention. I love the show Face the Nation and they recently had eight authors on!
  • Isn't it amazing that Savannah is ranked as 10 on America's most snobbish city [list] and that 10 percent of Savannah's population are Yankees?
  • Obama shouldn't go to Martha's Vineyard. Every time he does, something major happens.

At these head-slapping moments, it may help to recall some of those informal logical fallacies that we once studied in school. At least then we can put a name to the nonsense.

In case you need a little refresher, here are 12 common fallacies. For examples and detailed discussions, click on the highlighted terms.

  1. Ad Hominem
    A personal attack: that is, an argument based on the perceived failings of an adversary rather than on the merits of the case.
  2. Ad Misericordiam
    An argument that involves an irrelevant or highly exaggerated appeal to pity or sympathy.
  3. Bandwagon
    An argument based on the assumption that the opinion of the majority is always valid: everyone believes it, so you should too.
  4. Begging the Question
    A fallacy in which the premise of an argument presupposes the truth of its conclusion; in other words, the argument takes for granted what it's supposed to prove. Also known as a circular argument.
  5. Dicto Simpliciter
    An argument in which a general rule is treated as universally true regardless of the circumstances: a sweeping generalization.
  6. False Dilemma
    A fallacy of oversimplification: an argument in which only two alternatives are provided when in fact additional options are available. Sometimes called the either-or fallacy.
  7. Name Calling
    A fallacy that relies on emotionally loaded terms to influence an audience.
  8. Non Sequitur
    An argument in which a conclusion doesn't follow logically from what preceded it.
  9. Post Hoc
    A fallacy in which one event is said to be the cause of a later event simply because it occurred earlier.
  10. Red Herring
    An observation that draws attention away from the central issue in an argument or discussion.
  11. Stacking the Deck
    A fallacy in which any evidence that supports an opposing argument is simply rejected, omitted, or ignored.
  12. Straw Man
    A fallacy in which an opponent's argument is overstated or misrepresented in order to be more easily attacked or refuted.