Argument from authority

An argument from authority (Latin: argumentum ab auctoritate, also called an appeal to authority, or argumentum ad verecundiam) is a form of argument in which the opinion of an authority figure (or figures) is used as evidence to support an argument. While all sources agree this is not a valid form of logical proof and therefore obtaining knowledge in this way is fallible, there is disagreement on the general extent to which it is fallible. Historically, opinion on the appeal to authority has been divided: it is listed as a non-fallacious argument as often as a fallacious argument in various sources.

Some consider it a practical and sound way of obtaining knowledge that is generally likely to be correct when the authority is real, pertinent, and universally accepted, while others consider it to be a very weak defeasible argument or an outright fallacy.

Forms

Deductive

This argument is a form of genetic fallacy, in which the conclusion about the validity of a statement is justified by appealing to the characteristics of the person who is speaking, such as in the ad hominem fallacy. For this argument, Locke coined the term argumentum ad verecundiam (appeal to shamefacedness/modesty) because it appeals to the fear of humiliation by appearing disrespectful to a particular authority.

This qualification as a logical fallacy implies that this argument is invalid when using the deductive method, and therefore it cannot be presented as infallible. In other words, it is logically invalid to prove a claim is true simply because an authority has said it. The explanation is: authorities can be wrong, and the only way of logically proving a claim is providing real evidence or a valid logical deduction of the claim from the evidence.

Inductive

When used in the inductive method, which implies the conclusions can not be proven with certainty, the argument can be considered an inductive argument.