Circular reasoning, or circular argument, is a logical fallacy in which a person attempts to prove something using circular logic; they use the conclusion as evidence to show that the reasons for the very conclusion are true.
It’s closely related to the fallacy of begging the question, and the two work almost identically in practice. However, the latter is seen as a more specific type of the former.
Circular reasoning occurs when someone makes an argument in which both the premises and the conclusion have to rely on the truthfulness of the other.
As such, the logic of it goes:
- A is true because B is true;
- B is true because A is true.
- “It’s important to argue logically because logic is an essential part of argumentation.”
Here, the point being made is backed up by what preceded it, which, in turn, is supported by the previous point; each part essentially tells us the same thing. Such reasoning creates an endless loop that fails to prove anything useful.
Circular arguments can be quite easy to identify when they are short and it’s clear what the person is trying to convey. However, if the argument involves multiple, more complicated concepts, it becomes increasingly difficult to recognize them.
Furthermore, note that this can also be reasonable and useful when the circle contains a wide variety of relevant concepts, such as a dictionary. As explained here:
For example, a dictionary contains a large circle of definitions that use words which are defined in terms of other words that are also defined in the dictionary. Because the dictionary is so informative, it is not considered as a whole to be fallacious. However, a small circle of definitions is considered to be fallacious.Fallacies, Internet Encyclopedia of Philosophy (link).
- “The best minds in physics have studied physics most of their lives, as it’s necessary to study physics extensively to become a top physicist.”
- Andy: “What is the meaning of life?”. Sarah: “Personal happiness of course.” Andy: “Why do you think so?” Sarah: “Because nothing is as important as being happy!”
- “If an expert says it’s true, it must be true; after all, if experts don’t know, then who does?”
- “Fake news is harmful because it’s bad if the news isn’t real!”
- “You should always do what you are being told because following the rules is important.”