This sidebar quest for experts and expertise reminds me of the fallacy of appeal to authority.

A person becomes a true expert in a field by having expertise in that field. He doesn't need credentials: He can simply demonstrate his expertise.

And instead of his audience relying on some third party to validate those credentials (leading us down the "who watches the watchmen" rabbit hole), each audience member can judge for themselves if he is an expert or not.

I don't think Jay Windley has ever relied on appeals to his own authority to make a case. He does cite his authority on certain subjects, and sometimes on that basis justifies his own personal disagreement with a particular claim. But when it comes time to make his own case, he sets his credentials aside and instead demonstrates the expertise that earned him those credentials.

As for each of us using our own judgement to evaluate demonstrations of expertise, I've found that if I'm not equipped to judge such demonstrations, I'm equally ill-equipped to judge somone's credentials. Most of the time, I'm much better equipped to judge the way a person makes their case and demonstrates their expertise, than I am to judge their credentials.