A logical fallacy is any form of incorrect or faulty reasoning. These fallacies are often committed during the course of an argument or debate when one person is trying to convince another that their viewpoint or opinion on a particular matter is correct. There are several particular mistakes in logic that are so frequently seen that they are given individual names and definitions. Circular arguments fall under the category of fallacies that contain false premises.
A logical argument normally starts with at least one statement known as a premise. The premise is typically something that is considered to be true, and which will be used to establish the validity of the argument. However, in circular reasoning, the premise contains the conclusion that the argument is supposed to prove. Essentially, this form of reasoning assumes that the conclusion of the argument is true before the argument is even made, by inserting the conclusion into the premise.
There are numerous examples of circular reasoning. One such example is the series of statements "I should get an A on this test because I'm a good student. I know I'm a good student because I always get A's." Another example is "My uncle tells me he is never wrong. He always tells the truth. Therefore my uncle is never wrong." Common themes in such examples are that the conclusion and premise are only true in relation to one another and that the argument often contains statements that simply say the same things in different ways.
Circular reasoning is often considered as interchangeable with the fallacy known as "begging the question." Some philosophers, however, consider the two slightly different. The distinction is subtle, but typically begging the question implies rather than states the conclusion of the argument in the premise. An example of this would be the premise "Useless courses such as English should be dropped from the college program." This premise assumes without proof that English is a useless course, and from there may go on to try to show why it should be dropped (to save money, for instance).