The Begging the Question fallacy is a type of logical fallacy that occurs when an argument's conclusion is assumed by its premises. In other words, the truth of the conclusion must already be accepted in order for the premises to hold, making the argument circular and non-informative. This fallacy is also referred to as "circular reasoning" or by its Latin name, "petitio principii."
Begging the question can take several forms. In its most obvious form, the premise simply restates the conclusion in different words. For example, "Freedom of speech is important because people should be allowed to say what they want" merely rephrases the same idea without providing independent support.
A subtler form occurs when a chain of reasoning loops back on itself. For example, "We know this news source is trustworthy because it has a reputation for accuracy, and we know it has a reputation for accuracy because it is a trustworthy source." Here, each claim depends on the other, and neither is independently supported.
Begging the question can also be hidden within complex arguments where the circular dependency between premise and conclusion is obscured by additional language or intermediate steps. This makes it one of the harder informal fallacies to detect in practice.
To avoid begging the question, ensure that your premises provide independent support for your conclusion—support that does not require the listener to already accept the conclusion as true. Asking yourself "Would someone who doubts my conclusion also doubt this premise?" is a useful test.
