Here is a proposal. It is based on the example question "Are there any white crows?"
First, I explain the current system, then I propose a new form of acceptable answer.
Currently, the following are acceptable, in order of preference:
Yes, there are white crows. [Ref with examples]
Assuming it is true, this is the best answer because, hey, we all love being surprised by the world.
No, there are no white crows. This was proven by a careful examination of every single crow that is alive. [Ref detailing method of global experiment]
This answer is unlikely because of the infeasibility, but if it were true, it would be acceptable.
Experts have looked for evidence of white crows. They found none. If white crows existed, we would have expected the various bird-watching expeditions to have seen one by now. Absense of evidence where evidence has been predicted is evidence of absense. We should provisionally accept white crows don't exist until evidence turns up to the contrary. [Ref to literature review describing the copious expeditions and the lack of evidence, or to expert declaring that they have been unable to find any literature.]
This answer is less satisfying because (a) it isn't a 100% definitive answer and (b) it relies on expert opinion. Nonetheless, we have a history of accepting such answers, as they are the best we can expect in the real world. Citing an expert shows it isn't just the answerer's inept Google-searching that failed to find evidence.
Leaving the question unanswered.
We have questions that I expect will never be answered; in theory they are waiting for science to catch up, but science is unlikely to ever achieve that goal.
Currently, the following are unacceptable.
There are no white crows. No-one's ever found one. Trust me.
This has no references, and cannot be verified. It might be the posted by someone incompetent, a troll, a shill for Big Crow, etc.
According to my Bayesian model of bird movements and twitcher behaviour, the probability of there being an unseen white crow is 1 in 10,000,000.
Original research isn't trusted. Mathematical models aren't trusted without a lot of support for the assumptions, premises and the appropriateness of the calculations performed.
None of these answers match the majority view amongst the skeptics. The skeptical position is to provisionally accept that there are no white crows, but to be open to having our mind changed if sufficiently robust evidence was produced.
We should be able to say that. Leaving an obviously false claim unanswered is indistinguishable from us having no position at all, and the question simply being ignored.
I propose that we allow a placeholder answer, copied from a community-approved template.
It would briefly explain (with a FAQ meta-question link for a fuller explanation) that we don't have evidence to prove a claim is false, but the onus is on the claimant to provide empirical evidence that that the claim is true. Until then, we provisionally accept it as false.
The answer should be Community Wiki; no-one deserves real rep for cutting-and-pasting a boiler-plate. Nonetheless, it is likely to be voted up, as people agree that that is their position.
If a counter-answer appears, with evidence, the templated answer is wrong and should be flagged and deleted.
This isn't a great form of answer. I would prefer any of the acceptable answers, above. However, the answer serves to
- explain to the OP and other interested visitors how skepticism works and what the onus is on the believers,
- takes the question off the unanswered list, so the questions that are addressable with research get more attention,
- removes the pressure to close/delete questions that are unfalsifiable, but are still of interest to the Internet.