RIM: Lesson - Logical Fallacies

Hasty Generalization

A conclusion or judgement made from insufficient evidence. When one piece of evidence or information is used to make a broad conclusion or statement.

Straw Man

An oversimplification of an opposing perspective so that it becomes easy to attack. This is unfair and illogical because when one oversimplifies or inaccurately represents an argument and refutes that oversimplified version, one is not actually addressing the argument.

Red Herring

Changing topics to avoid the point being discussed. This is an argument tactic in which one attempts to change the conversation, often by bringing up information that is not relevant to the claim or point being debated in order to try to control the conversation. This can be a way to avoid having to address or answer the question at hand, and it harms the quality of an argument.

Ad Hominem

Making a personal attack rather than engaging with someone’s ideas, such as the following: “You are an idiot! That’s why you’re wrong!” This type of logical fallacy occurs when an arguer attacks or insults the person making opposing arguments instead of attacking the ideas, the logic, or the evidence within the opposing argument itself.

False Dilemma, Either/Or

An argument that attempts to create a situation of absolutes with no options in between, such as the following: “Either we intervene or we are basically no better than the Nazis.” This thinking is fallacious because it assumes that there are only two options with nothing in between.

Slippery Slope

A fallacy that assumes one thing is going to have a series of consequences or effects–often leading to a worst -case scenario, such as the following: “If we let this happen, then that will happen and then the worst possible thing will happen.” It is false reasoning because 1) it’s impossible to predict the future, 2) it is illogical to suggest that one action will always necessarily lead to the worst possible outcome, and 3) it assumes a very specific chain of future events. This “if we let this happen there will be some horrible end” is a misuse of cause/effect reasoning, often with some pathos (fear) sprinkled in.

Bandwagon

A fallacy that assumes one will follow the crowd, sort of by peer pressure. Consider the old adage, “Everybody’s doing it!” The problem with this type of fallacy is that it assumes the reader/listener will only follow the crowd and not exercise free thought.

False Authority

A fallacy attempting to use credentials of one claim to support another claim even when those credentials are not valid for the argument at hand, such as the following: “Because X says it’s true, it must be true!” For example, someone with a PhD in music theory might know a great deal about genetically modified foods based upon readings; however, citing that person as an expert in the field of food science would be a fallacy.

Post Hoc, Ergo Propter Hoc

A Latin phrase that means, “after this, therefore because of this.” This means that someone makes a claim that one event caused another, when it is instead a correlation. An extreme example of this might be someone claiming that the sunrise causes people to brush their teeth, just because many people brush their teeth in the morning.

Begging the Question

A fallacy occurring when the speaker assumes that the conclusion of his/her argument is valid without proving the lines of reasoning. Many times, the support used for the claim is simply a repetitious restatement of the conclusion. Oftentimes, this type of argument feels circular or redundant.

Non Sequitur (it does not follow)

A fallacy that skips or confuses logical steps thereby making an argument appear to be hollow. The result is often a conclusion that does not follow from the evidence provided.