Appeal to authority can be a perfectly valid inductive method when used as a statistical syllogism. It is only a fallacy in the realm of formal logic, where the truth or falsehood of a statement is independent of its source.

This is a common but quite annoying misconception. The following is a perfectly valid deduction: 1. Authority A is correct on matters in subject X p percect of the time. 2. A claims Y regarding a matter in subject X. --> Therefore, Y is correct with probability p.