Fallacies are mistakes or errors within reasoning and arguments. "This differs from a factual error, which is simply being wrong about the facts. To be more specific, a fallacy is an "argument" in which the premises given for the conclusion do not provide the needed degree of support. A deductive fallacy is a deductive argument that is invalid (it is such that it could have all true premises and still have a false conclusion)" (Labossiere, 2013, pg. 1).

Appeal to Ignorance

Uses lack of evidence (for or against) as the basis of the argument. For example, if something can’t be disproven, it must be true!


An either/or fallacy does not acknowledge that opposing claims could both be true, that grey areas may exist between the two alternatives, or that other possibilities exist.

Hasty Generalization

A hasty generalization occurs when a conclusion is drawn from a sample that is too small or selective to represent the subject accurately.


Putting two or more “good” things together does not necessarily mean they will be good together.

Post Hoc Ergo Propter Hoc

Assuming that because "B" follows "A," "A" must have caused "B." This is an easy fallacy to assume because this could happen, but we cannot always assume this happens.

Extravagant Hypothesis

Formulating a complex or unlikely explanation for an event when a simpler explanation would do.

Appeal to Authority

Something is true because person “A” an authority claims it to be true.


The assumption that because things are a certain way, they should always be that way. It could mean because something is not happening it should never happen.

Slippery Slope

An analogy to take the argument in one direction with a series of steps leading to a much more extreme outcome.

Appeal to Tradition

Claiming something is ture or right because it has always been that way.


What is true for the whole has to be true for any of the pieces of the whole as well.

False Analogy

False analogy or a “weak analogy.” This means that the similarities between the two things are not substantial enough to apply to the other.

Circular Reasoning

There is Premise X.
Premise X must be true because of Premise X.


The argument that since something is popular or everybody is doing it, so should you. Think of peer pressure or popularity as being the basis of the argument.