Appeals to authority fallaciously argue that a claim is true, or is very likely to be true, because some particular authoritative person says that it is true, or also believes the claim to be true. Such an inference is invalid since a claim can be false even if many noted authorities believe it to be true, and visa-versa. For instance, it was once almost universally believed that the sun orbited about the Earth, which is now known to be false.
Appeal to authority is one of the most contentious and often misunderstood logical fallacies, since citing authorities is a very common argumentative technique. Indeed, much of our knowledge about matters beyond our direct experience is derived by believing what is told to us by some authority. As such, it is not necessarily fallacious to argue that a claim has warrant because it is endorsed by somebody with relevant expert or authority. Such appeals are only fallacious under particular circumstances, including:
- When the authority has no relevant expertise or special insight into the claim being made. Citing a physicist who disputes the theory of evolution by natural selection, for example, would generally be an irrelevant appeal to authority since physicists have no special knowledge or expertise about the evidence for evolution. Determining exactly who has relevant expertise in a given situation can be difficult, but nevertheless it is clear that an appeal to be valid, authority must have expertise specifically relevant to the claim being made.
- When many equivalently-qualified authorities disagree with the authority one is citing. In a highly contested field such as philosophy, for example, citing one ethicist who states that utilitarianism is deeply flawed as an ethical theory would likely be an instance of a fallacious appeal to authority, since many equally eminent ethicists hold that utilitarianism is not deeply flawed. Appealing to authorities is in general quite difficult when authorities sharply disagree with one another.
- When the authority has been misquoted or taken out of context. This may seem quite obvious, but it is surprising how often famous figures are misquoted, or their quotes misunderstood or misused to defend positions they themselves never defended. Figures such as Plato, Socrates, Buddha, Einstein, and others are particularly likely to have inaccurate quotations attributed to them. Whenever authorities are cited in the form of a quotation it is important to carefully source that quotation and check the context in which it was made, so as to ensure the figure in question really did endorse the views being attributed to them.
- When the authority’s opinion or statements are granted excessive weight in the argument. For example, an eminent scholar in a particular field may have recently published a paper making some specific argument. In this situation, it would be invalid to argue that the claims are overwhelmingly likely to be true merely because they have been made by one eminent scholar, as the degree of justification provided by the opinion of a single scholar (even an eminent one) is simply great enough to warrant such a high degree of confidence, given that in any field individual scholars are quite often wrong when they are advancing novel arguments.
Appeal to authority: overview from Logical Fallacies
Appeal to authority: overview from Logically Fallacious
Appeal to authority: overview from the Nikor Project
Argumentum ad verecundiam: more detailed discussion with examples of correct and incorrect usage
Argument from authority: overview and discussion from The Logical Place
Appeal to authority breakdown: a small website devoted to providing analysis and examples of appeals to authority