See more on faulty thinking.
Logical fallacies are common mistakes in thinking that may lead to wrong conclusions or distort evidence. Here are a few familiar logical fallacies.
| Term | Explanation | Example |
| Non Sequitur | Stating a claim that doesn’t follow from your first premise or statement; Latin for “It does not follow” | Jenn should marry Mateo. In college he got all A’s. |
| Oversimplification | Offering easy solutions for complicated problems | If we want to end substance abuse, let’s send every drug user to prison for life. (Even aspirin users?) |
| Post Hoc Ergo Propter Hoc | Assuming a cause-and-effect relationship where none exists, even though one event preceded another; Latin for “after this, therefore because of this” | After Jenny’s black cat crossed my path, everything went wrong, and I failed my midterm. |
| Allness | Stating or implying that something is true of an entire class of things, often using all, everyone, no one, always, or never | Students enjoy studying. (All students? All subjects? All the time?) |
| Proof by Example or Too Few Examples | Presenting an example as proof rather than as illustration or clarification; overgeneralizing (the basis of much prejudice) | Armenians are great chefs. My neighbor is Armenian, and can he cook! |
| Begging the Question | Proving a statement already taken for granted, often by repeating it in different words or by defining a word in terms of itself | Rapists are dangerous because they are menaces. |
| Happiness is the state of being happy. | ||
| Circular Reasoning | Supporting a statement with itself; a form of begging the question | He is a liar because he simply isn’t telling the truth. |
| Either/Or Reasoning | Oversimplifying by assuming that an issue has only two sides, a statement must be true or false, a question demands a yes or no answer, or a problem has only two possible solutions (and one that’s acceptable) | What are we going to do about global warming? Either we stop using all of the energy-consuming vehicles and products that cause it, or we just learn to live with it. |
| Argument from Dubious Authority | Using an unidentified authority to shore up a weak argument or an authority whose expertise lies outside the issue, such as a television personality selling insurance | According to some of the most knowing scientists in America, smoking two packs a day is as harmless as eating oatmeal cookies. |
| Argument ad Hominem | Attacking an individual’s opinion by attacking his or her character, thus deflecting attention from the merit of a proposal; Latin for “against the man” | Diaz may argue that we need to save the polar bears, but he’s the type who gets emotional over nothing. |
| Argument from Ignorance | Maintaining that a claim has to be accepted because it hasn’t been disproved or that it has to be rejected because it has not been proved | Despite years of effort, no one has proved that ghosts don’t exist; therefore, we should expect to see them at any time. |
| No one has ever shown that life exists on any other planet; clearly the notion of other living things in the universe is absurd. | ||
| Argument by Analogy | Treating an extended comparison between familiar and unfamiliar items, based on similarities and ignoring differences, as evidence rather than as a useful way of explaining | People were born free as the birds; it’s cruel to expect them to work. |
| Bandwagon Argument | Suggesting that everyone is joining the group and that readers who don’t may miss out on happiness, success, or a reward | Purchasing the new Global Glimmer admits you to the nation’s most elite group of smartphone users. |