However the fallacy is so common it deserves special mention. A variation on this fallacy is the appeal to rumour. Because the source of a rumour is typically not known, it is not possible to determine whether to believe the rumour. Very often false and harmful rumours are deliberately started in order to discredit an opponent. A government official said today that the new gun law will be proposed tomorrow.
Experts agree that the best way to prevent nuclear war is to prepare for it.
It is held that there are more than two million needless operations conducted every year. Rumour has it that the Prime Minster will declare another holiday in October. Argue that because we don't know the source of the information we have no way to evaluate the reliability of the information.