In some cases the status of a claim is objectively unknown, e.g. if research indicates that we definitively do not know the answer, or if research leads to no information one way or the other (these are two different cases, mind you).
For example (these are meant to be illustrative and hopefully don't distract from the point, if they are not strong examples just ignore them; full disclosure: I authored these, if linking them is considered poor form feel free to remove links or replace with other examples):
- Research in to "are multivitamins healthy or not" could lead to "it's still open for debate and actively being studied" (or "there are too many variables to ever know", depending on your interpretation).
- Research in to To get husbands, pastor undresses and kisses female church members behinds at beach leads to "we can not know, no information on the primary source is available" (i.e. "the information required to confirm/debunk is not available to us"). This answer has a related discussion regarding its quality, which I still am not sure of.
My question is: What makes a good "we do not / can not know" answer here? How deep / exhaustive should the research be? How can bias be avoided? At what point can we say "we do not know" in a way that satisfies this site's demand for concrete, sourced, accurate answers?