Recognizing Logical Fallacies 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 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 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 Rapists are dangerous because they are menaces.
defining a word in terms of itself 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 vehicles and products that cause it, or we just learn to live with it. Argument from Dubious Authority 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 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 Despite years of effort, no one has proved that ghosts don’t exist; therefore,
rejected because it has not been proved 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. Two Wrongs Make a Right When a person attempts to justify an action against another person because the other person did take or would take the same action against him or her. Jimmy stole Tommy’s lunch in the past. Therefore, it is acceptable for Tommy to steal Jimmy’s lunch today. Special Pleading Applying standards, principles, and/or rules to other people or circumstances, while making oneself or certain circumstances exempt Yes, I do think that all drunk drivers should go to prison, but your honor, he is my son! He is a good boy who
usually connected by “the next thing you know...” should keep her locked up in the closet. Straw Man Substituting a person’s actual position or argument with a distorted, exaggerated, or misrepresented version of the position of the argument. Ted: Biological evolution is both a theory and a fact. Edwin: That is ridiculous! How can you possibly be absolutely certain that we evolved from pond scum! Ted: Actually that is a gross misrepresentation of my assertion. I never claimed we evolved from pond scum. Unlike math and logic, science is based on empirical evidence and, therefore, a scientific fact is something that is confirmed to such a degree that it would be perverse to withhold provisional consent. The empirical evidence for the fact that biological evolution does occur falls into this category. Red Herring Attempting to redirect the argument to another issue that to which the person doing the redirecting can better respond. Mike: It is morally to cheat on your spouse, why on earth would you have done that?
While it is similar to the avoiding the issue fallacy, the red herring is a deliberate diversion of attention with the intention of trying to abandon the original argument. Ken: But what is morality exactly? Mike: It’s a code of conduct shared by cultures. Ken: But who creates this code?... Equivocation Using an ambiguous term in more than one sense, thus making an argument misleading. The priest told me I should have faith. I have faith that my son will do well in school this year. Therefore, the priest should be happy with me. Generalizatino Drawing a conclusion based on a small sample size, rather than looking at statistics that are much more in line with the typical or average situation. My father smoked four packs of cigarettes a day since age fourteen and lived until age sixty-nine. Therefore, smoking really can’t be that bad for you. Cherry Picking When only select evidence is presented in to persuade the audience to accept a position, and evidence that would go against the position is withheld. The stronger the withheld evidence, the more fallacious the argument. My political candidate gives 10% of his income to the needy, goes to church every Sunday, and volunteers one day a week at a homeless shelter. Therefore, he is honest and morally straight. Affirming a Disjunct Either/or Making the false assumption that when presented with an either/or possibility, I am either to bed or watching TV. I am exhausted so