Logical Fallacies are the results of faulty (incorrect / unreliable) reasoning or logic. Although they are incorrect, they can still be compelling or convincing as arguments because at first glance they seem plausible. It is when they are investigated or discussed that it becomes clear that an error in reasoning has occurred at some point. Perhaps the arguer wasn’t careful when choosing the support for their position, or perhaps their sources are unreliable.
Here is a list of the most common logical fallacies:
Bandwagon: Ever heard of “hopping on the bandwagon?” It’s an expression that means someone is doing, believing, or saying something because it happens to be popular. The bandwagon argument is when the arguer tries to persuade the audience by noting that "it is what everyone else is doing."
Post hoc: “Post hoc” literally means “after this,” which might help you remember this fallacy. The arguer has assumed that because A comes before B, A is the cause of B. Keep in mind: Just because you ate tuna salad before you crashed your bike doesn’t mean that tuna salad causes bike accidents.
Either/or: The either/or fallacy assumes that there are only two possible (and often opposite) outcomes for a specific event or action. Rarely are there only two outcomes for an event, and it is even less probable that those outcomes will be exact opposites of each other. The arguer will often present the preferred outcome in a positive way and then present the opposing option negatively. The arguer has narrowed the field of discussion to make their argument seem valid because it is now the better out of two options.
Hasty Generalization: Hasty Generalization is also known as “jumping to conclusions.” The arguer is making dramatic and drastic assumptions about the audience, the sequence of events, or any other part of their argument. A common hasty generalization occurs when a couple of people associated with a specific group are seen behaving in a certain way and then it is assumed that everyone in that group behaves that way.
For example, some people might make the generalization that all child actors end up in rehab. Just because some child actors do not make much of themselves doesn't mean that every child actor will end up that way.
Begging the Question: An arguer begs the question when their conclusion masquerades as a support for their position, or when their argument is only valid when you assume the conclusion is true. It is similar to attempting to define a word by using the word itself: the support cannot be the conclusion and the conclusion cannot be the support.
A common case of begging the question is the following:
"You can't give me an F, I'm an A student." This argument assumes that the student is incapable of getting an F because they are an A student. But A student's don't normally get F's and there the student stands with an F. The claim and conclusion rely too much on each other's truth to stand as true on their own.
Ad Hominem: Literally means "to the man." Whenever an arguer makes critical or disrespectful comments about the author of another argument (or supporter of another argument) and then uses those comments to claim that the position is false, or the argument is invalid they have employed the Ad Hominem logical fallacy. It does not matter if you do not care for the supporter of an argument because the focus is on the argument itself.
Appeal to False Authority: It is important to appeal to authorities on a subject matter when developing an argument; however, arguers need to make sure their chosen experts are actually experts or respected figures in that particular area of knowledge. Using unreliable experts or pretending someone is an expert on your topic is appealing to false authority. Additionally, whenever a writer sites themselves as an expert (x is true because I say so), or sites someone as an expert simply because the writer deems them to be an expert (x is true because y said so, and I believe y, so x is true), they are also appealing to a false authority.
Equivocation: Arguers equivocate when they attempt to support their argument or conclusion by shifting between several definitions of an ambiguous term. “Well A means B, oh I mean A means Q, you say Q is invalid? I meant to say B, but only after C.” An arguer can also equivocate by telling only half truths or making a lie look as though it is true. Again, this is done by shifting language. It is circular logic that goes nowhere, fast.
Straw man: First think of how a traditional scarecrow (straw man) is made to look like a real person, and how crows tend to attack scarecrows. The straw man fallacy is when you attack the misrepresentation of an argument rather than the actual argument. This is a waste of energy because even if you defeat the straw man / fake argument, the real one is still waiting for you.
False Analogy: A great way to remember this fallacy is to think of making an analogy between apples and oranges: there are enough relevant differences between the two that just because you can make a claim about one of them doesn’t mean you should make the same claim about the other. Whenever you use an analogy as support in an argument, make sure that you can create a one to one ratio, meaning there is an overwhelming amount of similarities to the point that any differences there might be between the two subjects will seem irrelevant.
In any case, logical fallacies should be avoided at all costs! Think of logical fallacies like a cavity in your tooth. You might not see it at first, but a detailed x-ray will show the resulting decay in your tooth, or argument. Arguments that rely on logical fallacies are hollow statements.