I may have misstated the epistemic problem. It's not important to know who's posing as a scientist. It's important to know who isn't. This may be a more tractable approach.

There are a million ways to lie, but there are only a few ways to tell the truth.

As with Freud, Popper asks the right questions and gets terrible answers.

It's very clear to practicing scientists who is the real thing in their own field, and this "scidar" tends to work in other, quite remote fields.

It's unclear to others, including the posers themselves.

There is something in the praxis of real science that is inculcated without being formally codified. There are complex and subtle cultural and behavoural cues that indicate who actually "gets it".

Is there some insurmountable reason for it remaining implicit?

Scientists expect journalists to interview real scientists and avoid quacks. We feel that we could do it ourselves, and are more than exasperated when they fail.

Today, the failure of journalism to make the distinction is no less than an existential risk to civilisation.

I am convinced that part of the solution is to leave science writing to people who have done some science.

But one could observe that just moves the problem. How are editors and/or readers to distinguish who's actually making sense?