Appeal to Authority

Definition

Let:

• $X$ : A person
• $P$ : A claim made by $X$
• $\text{Expertise}(X,P)$ : $X$ has relevant expertise regarding $P$

Then an argument commits the Appeal to Authority fallacy if and only if it asserts:

$$X\text{ is an authority}⟹P\text{ is true}\text{when }\neg \text{Expertise}(X,P)$$