\begin{definition}[Definition:Argumentum ad Verecundiam]
'''Argumentum ad verecundiam''', or '''argument from authority''', is a logical argument that infers something is true on the basis that a knowledgeable and well-reputed person has said it.
An '''argument from authority''' may be valid or invalid, depending on the circumstances.
If the trustworthy person is also an expert in the field, and is free to speak their mind about the matter, then the argument has some validity. Otherwise, it generally does not.
That said, '''argumentum ad verecundiam''' can never serve as a (mathematical) proof, since no authority could ever be infallible.
Thus, in the context of {{ProofWiki}}, such an argument should be considered fallacious.
\end{definition}