The Appeal to Authority Flaw on the LSAT
Citing an expert isn't proof. Learn when an LSAT argument's appeal to authority is a flaw — and when an expert's testimony is legitimately relevant.
2026-06-01 · 6 min read
What the flaw is
An appeal to authority flaw treats an expert's endorsement as proof a claim is true. The error is sharpest when the authority is speaking outside their expertise, when experts disagree, or when the appeal substitutes for actual evidence.
When citing an expert is fine
Relying on a qualified expert within their field is reasonable, not flawed. The flaw appears when the authority is irrelevant to the question, the field is one where consensus does not exist, or the argument leans on status instead of reasons.
Worked example
"A famous physicist says this diet is the healthiest, so it must be." Physics expertise says nothing about nutrition. The argument borrows credibility from the wrong field — a textbook appeal to authority.
Answer choices describe it as "relies on the opinion of an authority whose expertise is not relevant" or "treats an expert's endorsement as conclusive." Verbloom helps you check whether the authority's field actually matches the claim.
Frequently asked questions
Is every reference to an expert a flaw?
No. Citing a relevant expert in their own field is legitimate. It becomes a flaw when the expertise is irrelevant, contested, or used in place of evidence.
How does this relate to the ad hominem flaw?
They are mirror images: appeal to authority accepts a claim because of who endorsed it, while ad hominem rejects a claim because of who made it.
What's the quickest red flag?
An expert cited outside their field, or a conclusion that rests on someone's prestige rather than the reasons they give.
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