Latin: argumentum ad verecundiam
An Appeal to Authority is the general name for any argument that rests on who provides some evidence, rather than on the content of the evidence. The name also refers to the specific practice of citing expert opinion.
There are some matters for which an appeal to an expert is perfectly reasonable. If faced with a task of carpentry, mathematics, or bureaucracy, one is wise to consult an expert and trust the guidance received.
In informal logic, however, the opinion of an expert is seldom conclusive in itself. It may be appropriate to list expert opinion as evidence, but only after establishing that such opinion is relevant, available, trustworthy, and not contradicted by other experts, simple experimentation, or common sense. The key question to ask is: is this opinion falsifiable? The carpenter or mathematician cannot afford to give bad advice, since the quality of their advice will become apparent with use. The fortune teller or political pundit ... not so much.
The trustworthiness of an expert must also be considered with respect to the burden of proof. That is, to the extent that an argument rests on the opinion of the expert, the argument also rests on the level of respect that expert commands to the listener. As a special case, the believability of an expert varies inversely with an audience's perception of his bias relative to his opinion.
Conversely, to show that an Appeal to Authority is fallacious (or at least to counter it), it is only necessary to show that one of the following:
- The opinion is taken out of context or misquoted
- This or another expert has given contradictory opinions on the same subject
- The expert is a crackpot (ad hominem versus ad verecundiam is a draw)
- Actual facts or simple, solid reasoning that controvert the opinion
Ad verecundiam is a Latin phrase that actually means "(appeal) to modesty." However, it is generally referred to as "Appeal to Authority." The arguments in this family appeal to the modesty, i.e. lack of knowledge or expertise, of the listener (and also generally of the speaker). Since the listener is too modest to claim to be an expert in the subject under discussion, the speaker attempts to settle the question by citing the authority of someone who is an expert.Thompson lists these as examples of ad verecundiam:
- Invincible Authority
- Unidentified Experts
- Celebrity Endorsement
- Appeal to Confidence
- Appeal to Popularity (Ad Populum)
- Appeal to Rugged Individualism (Speak Truth to Power)
- Appeal to Tradition
- Appeal to Novelty