Argumentum ad populum (ad populum error, reason of the majority, reason of the people, appeal to the masses, appeal to the majority, appeal to beliefs, argument from consensus, argument from universal consent, demagogic argument, populist argument or error of the people) refers to the claim that something is true simply because it is what a large number of people believe. In other words, if many people believe something to be true, then it must be true.
The ad populum fallacy is a logical fallacy. More precisely, this is an informal fallacy of relevance, as no relevant reason is given to support this claim.
Cause
An ad populum fallacy occurs when we use an "argumentum ad populum" (from the Latin "argument to the people"), meaning we appeal to what most people think, like, or believe, instead of justifying our position by evidence.
When we try to persuade someone of our ideas, preferences, or beliefs, it is often tempting to simply pretend that the majority of people agree with us. Words that imply that many people believe, do, or buy something (such as "the majority," "many," or "most") are typical of this fallacy.
However, this type of argument is fallacious. Even if this statement is true, popularity alone is not a sufficient reason to accept it as such. The fact that most people favor this claim is not an adequate substitute for actual evidence (e.g., for centuries people believed that Earth was the center of the solar system, but this ultimately turned out to be true). fake).
There are three main variations of the ad populum fallacy: Bandwagon fallacy, Snobbish appeal, Appeal to tradition.
The bandwagon fallacy (or bandwagon calling) is the primary form of ad populum fallacy and occurs when someone maintains that a belief or action is correct because the majority of people support it. Such arguments take advantage of the “ripple effect,” a cognitive bias that causes people to adopt the behaviors or opinions of others because of the desire to fit in and be liked.
In the snob appeal or appeal to elitism, the arguer appeals to people's desire to be part of an exclusive or elite group. Instead of stating that “everyone does it,” the argument suggests that “all the best do it.” The snob appeal is often used in advertising.
The appeal to tradition (or appeal to common practice) asserts that a premise must be true or right because people have always believed or practiced it. Alternatively, he can claim that the premise has always worked in the past and will therefore always work in the future. This line of thinking confuses tradition with correctness without asking whether it is justified or relevant.
How to avoid populist arguments
It is important to remember that ad populum arguments are not always fallacious. When the majority's belief is relevant and constitutes acceptable evidence of what is true, an ad populum argument is perfectly legitimate.
This is the case when it comes to questions decided by majority (e.g. definition of words, jury verdicts or result of a political election). In such cases, the majority's belief may provide a reasonable basis for accepting the claim. For example, if a friend insists that "magnanimous" means "great", and you respond that "magnanimous" means "forgiving" because the majority of dictionaries say so, your argument is not fallacious.
In general, to prevent an argument from becoming populist, it is possible to avoid personal attribution of the argument by referring to a paper of research. This way, the reader can learn more about your argument.
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