Argumentum ad populum

In argumentation theory, an argumentum ad populum (Latin for "appeal to the people") is a fallacious argument that concludes that a proposition is true because many or most people believe it: "If many believe so, it is so."

This type of argument is known by several names, including appeal to the masses, appeal to belief, appeal to the majority, appeal to democracy, appeal to popularity, argument by consensus, consensus fallacy, authority of the many, and bandwagon fallacy (also known as a vox populi), and in Latin as 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 Chinese proverb "three men make a tiger" concerns the same idea.