[PL 211] Arguments from Authority

Introductory textbooks to critical thinking and informal logic usually include a chapter about arguments from authority (see, for example, Salmon's Introduction to Logic and Critical Thinking and Hurley's A Concise Introduction to Logic).

Treatments of arguments from authority (AKA "appeals to authority") usually include the following conditions, without which an argument from authority would be fallacious:

1. The authority must be a genuine expert on the subject matter in question. If the authority that says that p is not an expert in the subject matter to which p is related, then the argument from authority is fallacious.
2. There must be an agreement among experts concerning the claim in question. If there is disagreement among experts regrading p, then the argument from authority would be fallacious.

But when, if ever, is the mere fact that an expert says that p sufficient reason to believe that p is true (or probable)? Is the mere fact that an expert says that p make it more likely that p is true?

Recent research has shown that experts are wrong more often than not. If this is true, can we trust experts?