@Sklivvz, yes exactly. Where there is no plausible or apparent scientific theory, one will generally not find pubmed or other reliable literature on the topic – and in those cases requiring an example makes most sense.

The "do/does [ghosts, demons, boogeymen, xenoglossia, gods, turtles all the way down, etc] exist" questions are generally not examined with scientific rigour. The claims are typcially waffly and the evidence unverifiable. The only way to debunk them would be to examine specific instances.

Which I say just to give air to a possible rational for choosing between requiring evidence or specific examples.

@BrianM.Hunt propose it as an answer on meta to @Articuno's question, let's see what comes out of it

I think a pubmed search should suffice to answer?