Fallacies in Argumentation

There are different kinds of logical fallacies that people make in presenting their positions.  This is a list of some of the major fallacies.  It is a good idea to be familiar with them so that you can point them out in a discussion thereby focusing the issues where they belong while exposing error.

Argument from False Authority When a person making a claim is presented as an expert who should be trusted when his or her expertise is not in the area being discussed. Logical Form: Expert A gives her view on issue B. Expert A's area of expertise has little or nothing to do with issue B. Expert A's opinion influences how people feel about issue B. Example: My accountant says that within the next 90 days, the president will be impeached! So, we should take this claim seriously. Example: Of course she's guilty. The police arrested her, didn't they? They're experts when it comes to crime.

False Dilemma (false choice, false dichotomy) When only two choices are presented yet more exist, or a spectrum of possible choices exists between two extremes.  False dilemmas are usually characterized by “either this or that” language, but can also be characterized by omissions of choices. Logical Form: Either X or Y is true.    Example:  You either did knock the glass over or you did not.  Which is it? Example: You are either with God or against him. Example:  Do you still beat your wife?

Faulty Analogies (aka weak, false, etc.) When an analogy is used to prove or disprove an argument, but the analogy is too dissimilar to be effective, that is, it is unlike the argument more than it is like the argument. Logical Form: X is like Y. Y has property P. Therefore, X has property P. (but X really is not too much like Y) Example: Smoking cigarettes is just like ingesting arsenic into your system. Both have been shown to be causally related to death. So if you wouldn’t want to take a spoonful of arsenic, I would think that you wouldn’t want to continue smoking. Example: Believing in the literal resurrection of Jesus is like believing in the literal existence of zombies.

Appeal to Fear When fear, not based on evidence or reason, is being used as the primary motivator to get others to accept an idea, proposition, or conclusion. Logical Form: If you don’t accept X as true, something terrible will happen to you. Therefore, X must be true. Example:  If you don't want to get beat up, you will agree with what I say. Example: If we don’t bail out the big automakers, the US economy will collapse. Therefore, we need to bail out the automakers.

Ad hominem Attacking the person making the argument, rather than the argument itself, when the attack on the person is completely irrelevant to the argument the person is making. Logical Form: Person 1 is claiming Y. Person 1 is a moron. Therefore, Y is not true. Example: I figured that you couldn't possibly get it right, so I ignored your comment. Example: My opponent suggests that lowering taxes will be a good idea -- this is coming from a woman who eats a pint of Ben and Jerry’s each night!

Bandwagon Appeals A threat of rejection by one's peers (or peer pressure) is substituted for evidence in an argument. Logical Form: Everybody is doing X. Therefore, X must be the right thing to do. Example: A 2005 Gallup Poll found that an estimated 25% of Americans over the age of 18 believe in astrology—or that the position of the stars and planets can affect people's lives. That is roughly 75,000,000 people. Therefore, there must be some truth to astrology! Example: Zippo – the grand old lighter that’s made right here in the good old U.S. of A.

Non Sequitur Comments or information that do not logically follow from a premise to the conclusion. In more informal reasoning, it can be when what is presented as evidence or reason is irrelevant or adds very little to support to the conclusion. Logical Form: Claim A is made. Evidence is presented for claim A. Therefore, claim C is true. Example:  People generally like to walk on the beach.  Beaches have sand.  Therefore, having sand floors in homes would be a great idea! Example: Buddy Burger has the greatest food in town.  Buddy Burger was voted #1 by the local paper.  Therefore, Phil, the owner of Buddy Burger, should run for President of the United States.

Slippery Slope When a relatively insignificant first event is suggested to lead to a more significant event, and so on, until some ultimate, significant event is reached. With each step, it becomes more and more improbable. Logical Form: If A, then B, then C, ... then ultimately Z! Example: “We cannot unlock our child from the closet because if we do, she will want to roam the house.  If we let her roam the house, she will want to roam the neighborhood.  If she roams the neighborhood, she will get picked up by a stranger in a van, who will sell her in a slavery ring in some other country.  Therefore, we should keep her locked up in the closet.” Example: "The US shouldn't get involved militarily in other countries. Once the government sends in a few troops, it will then send in thousands to die."

Straw Man Argument Example: Substituting a person’s actual position or argument with a distorted, exaggerated, or misrepresented version of the position of the argument. Logical Form: Person 1 makes claim Y. Person 2 restates person 1’s claim (in a distorted way). Person 2 attacks the distorted version of the claim. Therefore, claim Y is false. Example:  Senator: “We use many dollars from taxpayers to help the poor, but we don’t have a ‘poor tax’ necessarily.” Protestor: “Wrong, Senator. Because it doesn't have a tax specifically to support the poor, the government hates all poor people.” Example: Child: "Can we get a dog?“ Parent: "No.“ Child: "It would protect us.“ Parent: "Still, no.“ Child: "Why do you want to leave us and our house unprotected?”

Other popular logical fallacies Red Herring Fallacy Hasty Generalization Fallacy Slothful Induction Fallacy Correlation/Causation Fallacy Anecdotal Evidence Fallacy Texas Sharpshooter Fallacy **You can receive extra credit if you learn these and are able to recognize them in an argument.