Appeal to Belief is a fallacy that has this general pattern:
Premise 1: Most people believe claim X is true.
Conclusion: Therefore, X is true.
The Appeal to Belief fallacy derives its influence from psychological rather than logical force. People are often inclined to accept a claim is true when they think most people believe it. The usual illustration of this is that at one time most people in Europe believed that the earth was the center of the solar system. However, this belief turned out to be false.
This reasoning is fallacious because the fact that most people believe a claim does not, by itself, serve as evidence that a claim is true. There are, however, two general exceptions.
There are some cases when belief in a claim can indicate it is true. For example, suppose that when visiting Maine, you are told by several Mainers that anyone over 16 who wants to fish needs to buy a fishing license. Barring reasons to doubt them, it would be reasonable to accept their claim. In such cases, the reasoning is a good Argument from Authority rather than an Appeal to Belief.
There are also cases in which belief makes a claim true. For example, the truth of claims about manners seems to depend on what people believe to be good manners. The truths of language, such as what words mean, also seem to be a matter of majority belief. Another example is the case of community standards, which is often defined in term of what most of the community believes. As an illustration, obscenity might be defined in terms of community standards. In this case, the claim “x is obscene” will be true if most people in that community believe x is obscene. In such cases it is still prudent to question the justification of the individual beliefs.
This fallacy is sometimes modified slightly to better match its intended target. In these cases, the appeal is made to the (alleged) beliefs of people the target looks at favorably. For example, a teacher’s union might say that most teachers believe that a bill should be supported to influence teachers. This approach can improve the persuasive force of the fallacy but does not impact its logical force.
Ted: “Did you do your taxes yet?”
Ken: “Yeah. Got a tiny rebate.”
Ted: “That is because you were honest. You should cheat on your taxes.”
Ken: “That seems wrong. Also, illegal. I mean, for people like us.”
Ted: “Nah, most people think it is okay to lie a bit to the IRS. So it is okay.”
God must exist. After all, I just saw a poll that says 85% of all Americans believe in God.
Of course, there is nothing wrong with drinking. Ask anyone, he’ll tell you that he thinks drinking is just fine.
Edward: “What do you think about that new bill?”
Willamina: “The one that lets parents decide what books will be allowed for use in public education?”
Edward: “Yup, that one. You know that most teachers like you think it is a bad idea and oppose it.”
Willamina: “Well, I was not sure until now. But if my fellow teachers think it is a bad bill, I agree with them.”