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 general 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.
A lot of people believe X.
Therefore, X must be true.
Up until the late 16th century, most people believed that the earth was the center of the universe. This was seen as enough of a reason back then to accept this as 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.
Mark: Do you believe in virgin births?
Sue: You mean that babies are born virgins?
Mark: I mean birth without fertilization.
Mark: 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.