Circular reasoning

Circular reasoning is an infromal fallacy in which the proposition is supported by the premises, which is supported by the proposition, creating a circle in reasoning where no useful information is being shared.

Circular reasoning is often of the form: 'A is true because B is true; B is true because A is true.' Circularity can be difficult to detect if it involves a longer chain of propositions. Academic Douglas Walton used the following example of a fallacious circular argument:
Wellington is in New Zealand.
Therefore, Wellington is in New Zealand.