What Is Ad Populum Fallacy? | Definition & Examples

Ad populum fallacy refers to a claim that something is true simply because that’s what a large number of people believe. In other words, if many people believe something to be true, then it must be true.

This type of argument is often used when there is no real evidence to back up a certain claim. Ad populum fallacy (also called bandwagon fallacy, appeal to numbers, or appeal to popularity) can be found in advertisements, political speeches, and everyday discussions.

What is ad populum fallacy?

An ad populum fallacy occurs when we use an “argumentum ad populum” (Latin for “argument to the people”), meaning that we make an appeal to what most people think, like, or believe, instead of justifying our position with evidence.

When we are trying to persuade someone about our ideas, preferences, or beliefs, it is often tempting to simply claim that the majority of the people agree with us. Words that imply that many people believe, do, or buy something (such as “the majority,” “lots,” or “most”) are typical to this fallacy.

However, this type of argument is fallacious. Even if the claim is true, popularity alone is not a sufficient reason to accept it as such. The fact that most people may be in favor of the claim is not an adequate substitute for actual evidence (for example, for centuries people believed that the earth was the center of the solar system, but this was ultimately proved to be false).

Ad populum fallacy is a logical fallacy. More specifically, it is an informal fallacy of relevance because no relevant reasons are given to support the claim. In the example above, the premise (i.e., the fact that the book is a bestseller) is not sufficient evidence to accept the conclusion (i.e., you should read it). In logic, the approval of the majority alone cannot substitute the justification for a claim.

When is an ad populum argument legitimate?

It is important to remember that ad populum arguments are not always fallacious. When the belief of the majority is relevant and serves as acceptable evidence for what is true, an ad populum argument is perfectly legitimate.

This is the case when it comes to matters decided by a majority (e.g., the definition of words, jury verdicts, or the outcome of a political election). In such cases, the belief of the majority can be a reasonable basis for accepting the claim. For example, if a friend insists that “magnanimous” means “tall,” and you reply that “magnanimous” means “forgiving” because the majority of dictionaries say so, your argument is not fallacious.

What are different types of ad populum fallacy?

There are three main variations of the ad populum fallacy:

• Bandwagon fallacy 
• Snob appeal
• Appeal to tradition 

Bandwagon fallacy

Bandwagon fallacy (or bandwagon appeal) is the main form of the ad populum fallacy and occurs when someone argues that a belief or action is correct because the majority of people support it. Such arguments take advantage of the “bandwagon effect,” a cognitive bias that causes people to adopt the behaviors or opinions of others due to a desire to fit in and be liked.

Snob appeal

In this variation, the arguer appeals to people’s desire to be part of an exclusive or elite group. Instead of asserting “everyone’s doing it,” the argument suggests “all the best people are doing it.” The snob appeal is often used in advertising.

Appeal to tradition

Appeal to tradition (or appeal to common practice) asserts that a premise must be true or right because people have always believed it or practiced it. Alternatively, it may assert that the premise has always worked in the past, so it will always work in the future. This line of thought conflates tradition with correctness without considering whether it is justified or relevant.

Ad populum fallacy example

Ad populum fallacy is often used to defend habits, actions, or behaviors that are harmful to oneself or others simply because many or most people follow them.

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Frequently asked questions about the ad populum fallacy

How does the ad populum fallacy work?

The ad populum fallacy plays on our innate desire to fit in (known as “bandwagon effect”). If many people believe something, our common sense tells us that it must be true and we tend to accept it. However, in logic, the popularity of a proposition cannot serve as evidence of its truthfulness.

What is an example of ad populum fallacy in politics?

The ad populum fallacy is common in politics. One example is the following viewpoint: “The majority of our countrymen think we should have military operations overseas; therefore, it’s the right thing to do.”

This line of reasoning is fallacious, because popular acceptance of a belief or position does not amount to a justification of that belief. In other words, following the prevailing opinion without examining the underlying reasons is irrational.

What is the difference between ad populum fallacy and appeal to authority fallacy?

Ad populum (or appeal to popularity) fallacy and appeal to authority fallacy are similar in that they both conflate the validity of a belief with its popular acceptance among a specific group. However there is a key difference between the two:

• An ad populum fallacy tries to persuade others by claiming that something is true or right because a lot of people think so.
• An appeal to authority fallacy tries to persuade by claiming a group of experts believe something is true or right, therefore it must be so.