What Does Post Hoc Mean?

The Latin term "post hoc" is a short form of the phrase "Post hoc, ergo propter hoc," which means "after this, therefore because of this." The term is used as an adjective to describe reasoning, a statement or an argument made using the "post hoc fallacy." This logical fallacy is the act of claiming one event or situation was caused by another just because it occurred after it.

Post hoc reasoning is described as the following: "Event B happened after event A. Therefore A caused B." This is a fallacy, because one thing happening after another does not necessarily mean the two events are related. This type of reasoning is often seen in political debates and discussions of controversial issues. For example, concerning gun ownership, you may say, "States that have passed right-to-carry laws have seen a decrease in violent crimes." This statement -- in which the passed laws are event A and the decrease in crime is event B -- is an example of post hoc, because the decrease in crime may be unrelated to the passage of right-to-carry laws. A variety of other causes might be responsible for the decrease, including employment opportunities and increased public security.