An appeal to authority, argument from authority or argumentum ad verecundiam is one method of obtaining propositional knowledge. Some examples of appeals to authority:

  • Referring to the philosophical beliefs of Aristotle.
  • Quotes from religious books such as the Bible.
  • Claiming that some crime is morally wrong because it is illegal.
  • Referencing scientific research published in a peer reviewed journal.
  • Believing what one is told by one's teacher.

Sometimes an appeal to authority is regarded as a logical fallacy. This is the case when a person presenting a position on a subject mentions an authority who also holds that position, but may not be an authority in that area. For instance, the statement "Arthur C. Clarke recently released a report showing it is necessary to floss three times daily" would be unlikely to impress many people, as Arthur C. Clarke is not an expert on dental hygiene. Much of advertising relies on this logical fallacy, for example when Michael Winner promotes car insurance, despite having no expertise in the field of car insurance.

Citing a person who is a recognized authority in the field is likely to carry more weight. In the middle ages, roughly from the 12th century to the 15th century, the philosophy of Aristotle became firmly established dogma, and referring to the beliefs of Aristotle was an important part of many debates. Aristotle's thought became so central to the philosophy of the late Middle Ages that he became known in Latin as Ille Philosophus, "the philosopher," and quotations from Aristotle became known as ipse dixits ("He, himself, has spoken.").

Authoritarian ethics is the ethical theory by which one attains ethical knowledge from an authority, for example from a God or from the law. The bandwagon fallacy can be viewed as a special case of an appeal to authority, where the authority is public opinion.

Five conditions for a legitimate argument from authority

  1. The authority must have competence in an area, not just glamour, prestige, rank or popularity.
  2. The judgement must be within the authority's field of competence
  3. The authority must be interpreted correctly
  4. Direct evidence must be available, at least in principle
  5. A technique is needed to adjucate disagreements among equally qualified authorities.