Appeal to belief
The logical fallacy of appeal to belief is committed when an argument infers the truth (or plausibility) of a proposition merely from the fact that it is widely believed. The fallacy is most commonly found in arguments over ethics:
- Most Americans hold that the Vietnam War was morally indefensible. Therefore, the Vietnam War was morally indefensible.
- Southern segregationists didn't see anything wrong with what they were doing. Therefore, it must not have been wrong. (or: Therefore, it wasn't wrong to them.)
- Just about everyone in Ptolemy's day was convinced that the Sun travelled around the Earth. Therefore, the Sun travelled around the Earth in Ptolemy's day.
- Throughout history, most people have believed in some sort of God. Therefore, you should also believe in God.
Further, as with appeals to authority or to tradition, there are some limited circumstances in which an argument from belief may not be a fallacy. For example, when the subject being considered are the results of democratic processes, points of etiquette, or other matters of social convention, arguments of the following form may be valid:
- Most people in Russia think that it is polite for men to kiss each other in greeting. Therefore, it is polite for men to kiss each other in greeting in Russia.
- Nearly all Americans think that you should drive on the right side of the road. Therefore, you should drive on the right side of the road in the United States.