Appeal to Authority: When It’s Fine, When It’s Not
Citing an expert is not automatically a fallacy. The fallacy occurs when the expert isn’t really an expert on the question, or when the citation substitutes for engagement with the evidence.
The appeal to authority is one of the most commonly invoked fallacies, and also one of the most commonly misunderstood. Citing an expert is not, by itself, a logical error. Expertise is generally a good reason to take a claim seriously. The fallacy occurs in specific circumstances that are narrower than the term’s casual usage suggests.
When it’s legitimate
If a cardiologist tells you that a particular medication has cardiac side effects, you should generally take that seriously. The cardiologist has training, experience, and access to literature relevant to the claim. Trusting their judgment, in the absence of equally credentialed contradicting opinions, is reasonable.
This kind of citation is not a fallacy. It is a legitimate use of expertise. Most knowledge in most domains is acquired through deference to experts, because most of us cannot independently verify most claims in most fields.
When it’s a fallacy
The appeal becomes fallacious in three main circumstances.
First, when the authority is not actually an expert on the question. A Nobel Prize-winning physicist’s opinion on nutrition is not authoritative simply because they won a Nobel Prize in physics. Their expertise does not transfer.
Second, when the authority is cited despite disagreement among other authorities. If the cardiologist’s view is contradicted by most other cardiologists, citing the cardiologist as authoritative is misleading. The fact of disagreement is itself important information.
Third, when the citation substitutes for engagement with the evidence. “Expert X said so” is sometimes the end of an argument when it should be the beginning. The relevant question is usually why the expert said so — what evidence they relied on, what reasoning supports the claim. A citation without the evidence behind it is weaker than the citation alone suggests.
Celebrity endorsements
A particularly common version of the fallacy involves celebrity endorsements. An actor’s opinion on a political matter is not authoritative because they are an actor. A successful businessperson’s opinion on epidemiology is not authoritative because they are a successful businessperson. The expertise does not transfer.
This becomes a fallacy when the celebrity status is being used to lend credibility to the claim. The same claim, from an anonymous source with the same reasoning, would be assessed on its merits. The celebrity packaging is doing argumentative work that the claim itself does not warrant.
How to handle authority claims
When you encounter an appeal to authority, ask three questions:
Is this person actually an expert on this specific question? Does their credential align with the claim being made?
Are other experts in the field in agreement, or is this a contested area? If contested, how does this expert’s position fit into the broader debate?
What is the evidence behind the claim? Can you, at least in outline, follow why the expert believes what they believe?
If you can answer all three positively, the appeal is in good shape. If not, the citation is doing more work than it should.
