Rhetorical trick
Moving the Goalposts
Raise the bar for proof each time the current bar gets met.
Example
"Show me one peer-reviewed study." (shown one) "Well, one study isn't enough, show me a meta-analysis from the last year."
Moving the goalposts sets one standard of evidence, then quietly raises it the moment that standard is satisfied, so the conclusion can never actually be reached.
This isn’t the same as reasonably asking follow-up questions. The tell is that the new standard wasn’t mentioned until after the old one was already met.
Ask the person to state, up front, exactly what evidence would change their mind. If that keeps shifting after each answer, the goalposts are moving.