The term ad populum fallacy is used in logic and debate to describe an argument that relies on popular opinion. This is considered to be a weak argument, because it has no evidence to back up its claims. Ad populum arguments are commonly made in daily life, particularly by children hoping to conform to their peers. This concept also is known as an appeal to the masses or a bandwagon fallacy and is very similar to an ad numerum argument. Other fallacious arguments are based on fear, misrepresentation or personal attacks.
Much of the terminology of rhetoric and debate was developed by the ancient Greek philosopher Aristotle in his Organon. This work describes 13 types of argumentative fallacies, or sophistical refutations. The ad populum fallacy is categorized as a type of material fallacy known as an irrelevant conclusion. An ad populum argument does not produce real evidence in support of its thesis, so any conclusions derived from it must be ruled irrelevant. Some private schools still teach Aristotelian-style logic and rhetoric to students as part of a classical education program designed to enhance critical thinking.
Children can be prone to invoking an ad populum fallacy when arguing with their parents. They will often claim that everyone at their school has a certain product or is allowed to engage in a risky activity. The parental response usually asks the child if he would still like to emulate the actions of his or her peers if everyone else was engaged in behavior that was clearly harmful, such as jumping off a cliff. This argument exposes the fallacy behind ad populum arguments by showing that the beliefs of the majority do not provide compelling evidence.
Many debate students in high school and college learn about the ad populum fallacy along with Aristotle’s other sophistical refutations. These fallacies can be recognized by opponents in a debate and used to refute an entire argument. While pointing out these fallacies can help undermine an opponent, they also can provide strong rhetoric and win over some debate judges.
The ad populum fallacy is particularly problematic in a representative democracy. The government derives its power from the people, so arguments based on voter polling and surveys can be difficult to ignore by elected leaders. Ad populum arguments are often used in policy debates to help bolster arguments with little or no factual evidence to back them up. In some cases, this can lead to worse decision-making, because facts are ignored in the face of popular opinion.