Well, sure, you have a relatively high opinion of authority. But even a vague claim needs the expert to be significantly better than chance to be promoted to your attention.

(And, well, this guy isn't a physicist. He's involved in medicine. There's less likely to be clear-cut experimental proof the expert can simply point out in order to overcome your prior. Instead, you get a huge, enormous pile of famous cases where The Experts Screwed Up.)