Good logic is critical to sound argument. The tighter the logic, the better the argument. But poor logic often sounds good. Politicians use nice sounding phrases and reasonable-sounding assertions to hide poor logic. If we had not tools for figuring out good vs. bad logic, we might simply accept all those “nice-sounding” arguments. Logical fallacies are flaws in the structure of an argument that make a claim valid. A fallacy is a falsehood, so a logical fallacy is a logical falsehood that makes no sense within a given situation:
- Ad hominem (Latin for to the person) fallacies are personal attacks. Instead of responding to the ideas someone has put forth, the arguer attacks the person. Personal attacks are common in politics and in everyday life. In politics, personal attacks are used to draw attention away from important policy debates and to focus it instead on character.
- Straw person fallacies involve misrepresenting a position and then proving it wrong. In this type of fallacy, an arguer sets up a straw person that is easy to knock over or beat up. If someone argues that dogs should be kept on leashes when they are walked down Main Street, and someone else responds that dogs need to run and should not always be leashed, the response misrepresents the original position.
- Post hoc, ergo propter hoc (faulty cause-effect) fallacies claims that if one thing happened before another, then the first thing must have caused the second. Such arguments are false because they confuse a temporal (time) relationship with a cause-effect one. If a rooster crows just before the sun rises, claiming that the rooster caused the sun to rise is a post hoc fallacy.
- Either/or fallacies oversimplify an issue by claiming that only two options exist, when in fact there are more options to choose from. The old slogan “Love it or leave it” suggests only two choices.
- Hasty generalizations draw conclusions based on too little evidence. For example, generalizing about a city because you drove through it on a Sunday morning can be dangerous, because cities are quieter and have less traffic on Sunday mornings. Claiming that Santa Rosa is a sleepy little town, based on one Sunday morning is not accurate. People often make broad generalizations about places, people, and things.
- Slippery slope fallacies claim that a certain way of thinking or acting will necessarily lead to more of the same—that once you begin sliding down a slippery slope, you will keep sliding. While one action may in fact lead to similar actions, the slippery slopes fallacy appeals to fear by claiming that taking certain moderate actions will lead to more extreme actions.
- Begging the question (also called circular reasoning) involve supporting an assertion by restating the assertion itself. So support is provided. Tim would be a good president, because he is presidential material is circular reasoning.
- Red herring fallacies are deliberate attempts to change the subject. Instead of dealing with the actual argument, the arguer introduces and argues irrelevant points as a way of distracting the audience. A red herring is like rattling keys in front of a crying baby.
- Association fallacies claim that two people or things share a quality just because they are somehow associated, connected, or related. One type of association argument is guilty by association.