Logical Fallacy: Argumentum ad populum
In logic, an argumentum ad populum (Latin: "appeal to the people") is a fallacious argument that concludes a proposition to be true because many or all people believe it; it alleges: "If many believe so, it is so."
This type of argument is known by several names, [1] including appeal to the masses, appeal to belief, appeal to the majority, appeal to the people, argument by consensus, authority of the many, and bandwagon fallacy, and in Latin by the names argumentum ad populum ("appeal to the people"), argumentum ad numerum ("appeal to the number"), and consensus gentium ("agreement of the clans"). It is also the basis of a number of social phenomena, including communal reinforcement and the bandwagon effect, the spreading of various religious beliefs, and of the Chinese proverb "three men make a tiger".