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Appeal to Common Belief

argumentum ad populum

(also known as: appeal to accepted belief, appeal to democracy, appeal to widespread belief, appeal to the masses, appeal to belief, appeal to the majority, argument by consensus, consensus fallacy, authority of the many, bandwagon fallacy, appeal to the number, argumentum ad numerum, argumentum consensus gentium, appeal to the mob, appeal to the gallery, consensus gentium, mob appeal, social conformance, value of community, vox populi)

Description: When the claim that most or many people in general or of a particular group accept a belief as true is presented as evidence for the claim. Accepting another person’s belief, or many people’s beliefs, without demanding evidence as to why that person accepts the belief, is lazy thinking and a dangerous way to accept information.

Logical Form:

A lot of people believe X.

Therefore, X must be true.

Example #1:

Up until the late 16th century, most people believed that the earth was the center of the universe.  This, of course, is not true.

Explanation: The geocentric model was an observation (limited) and faith-based, but most who accepted the model did so based on the common and accepted belief of the time, not on their own observations, calculations, and/or reasoning.  It was people like Copernicus, Galileo, and Kepler, who refused to appeal to the common belief and uncovered a truth not obvious to the rest of humanity.

Example #2:

How could you not believe in virgin births?  Roughly two billion people believe in them, don’t you think you should reconsider your position?

Explanation: Anyone who believes in virgin births does not have empirical evidence for his or her belief.  This is a claim accepted on faith, which is an individual and subjective form of accepting information, that should not have any effect on your beliefs.  Don’t forget that there was a time that the common beliefs included a flat earth, earth-centered universe, and demon possession as the cause of most illness.

Exception: Sometimes there are good reasons to think that the common belief is held by people who do have good evidence for believing.  For example, if virtually all of earth scientists accept that the universe is approximately 13.7 billion years old, it is wise to believe them because they will be able to present objective and empirical evidence as to why they believe.

Tip: History has shown that those who break away from the common beliefs are the ones who change the course of history.  Be a leader, not a follower.


Wagner, R. H. (1938). Handbook of argumentation. Nelson.

Registered User Comments

Joe Walker
Saturday, January 21, 2017 - 12:04:20 PM
I disagree with the exception. How could you possibly know when to make an exception or not. Scientists had always believed that the universe was eternal, or infinite, or had no beginning based upon what they thought at the time was empirical evidence just to find out later that they were wrong. Again, how could you know when or when not to believe them.

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Bo Bennett, PhD
Saturday, January 21, 2017 - 12:11:13 PM
Hi Joe, many (maybe even most) scientists still think the cosmos is eternal... (multi-verse, or some other theory). But these are scientific hypotheses with little support based on the available data, just like before the Big Bang theory. All scientific conclusions are not equal. The key is to know enough about the scientific method to know the difference between a scientific consensus and just a belief that most scientists hold.

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Rob Petersen
Wednesday, May 31, 2017 - 03:09:24 PM
@Bo Bennett, PhD: Well said with one exception, science is not about consensus, remember that in Galileo's time the consensus was that the sun revolved around the earth. Consensus is not truth, it's just a common belief.

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Bo Bennett, PhD
Wednesday, May 31, 2017 - 03:11:46 PM
@Rob Petersen: Sure, but "consensus" is not "scientific consensus." The two are very different.

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