When one argues in circles, one uses a conclusion to prove itself. "She has written several books on the subject because she is an authority." ..."How do I know she is??? Well, she has written several books on the subject."

An example of someone talking in circles to make their point.

All I know is that we have got to stick together, if we stick together we will get what we need and when we get what we need it will prove that sticking together really worked.