Question: The [Good Subjective/Bad Subjective guidelines](http://blog.stackoverflow.com/2010/09/good-subjective-bad-subjective/) talk a lot about what make for great questions and answers for subjective issues, and it primarily falls around Back It Up!: answers need to cite some kind of relevant material (scholarly works, authoritative discussions, relevant personal experience, something), and questions need to be written such that they encourage such answers.

And, of course, Back It Up! applies to objective questions and answers, too, the resources you use for backing those up just may be somewhat different.

So, we need to be pro-active, from the beginning, about demanding that answers Back It Up! This SE, in particular, I think, is closely tied to a lot of speculative fields – as several meta questions have already discussed, there are a number of SE sites that have significant overlap with this one, *but would not accept our kind of question* because of their speculative nature.

Thus, we need a policy, guideline, or at least discussion of what is too speculative, what questions cannot be answered in a way that Backs It Up! The “Primarily Opinion-Based” close reason exists for this, but we as a community have to decide where to draw the line for using it.

We also, as a community, need to enforce backing things up in answers. Everything about this endeavor is, by definition, highly speculative: the only way to be serious about this, to produce good answers, is to minimize, as much as possible, the “pure” speculation. Cite sources, compare to real-world history, sociology, physics, and so on. And flag or downvote answers that don’t.

Answer: 
I agree with Back It Up!
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We're here to answer questions because they don't fall into the asker's realms of expertise when it comes to world-building. (If they already have the knowledge, why would they come to us?) The Back It Up! policy will provide legitimacy to answers in addition to the legitimacy the voting system can provide. Sources will provide more resources for the askers, making our answers better.

However, there will undoubtedly be questions which can be solved with good old logic, sans references. These answers, while not *strictly* conforming to the Back It Up! policy, should be accepted if the logic is sound. Logical answers should also only be accepted when the logic is laid bare, so anyone can follow it. (Otherwise "logic" should be counted as opinion- not sufficiently backed.)

Given this, **I propose the following supplementary guides for closing questions and judging answers:**

* if an expert or principles in a relevant field cannot provide an answer, vote to close / down-vote
* if logic cannot provide an answer, or provided logic has insufficient explanation, vote to close / down-vote
* if personal *world-building* experience cannot conceivably provide an insight, vote to close / down-vote

Thus, if you can't "logic it" or cite something (experts, experience, or principles) for the answer, it's a bad question or answer for this site.
After some brainstorming on chat I think that there are three kinds of questions, that should have different Back It Up policies for answers:

1. **Hard Science questions:** answers should be properly backed up with documentation or scientific articles, and could potentially be posted on specific scientific-subject sites such as perhaps Astronomy, Biology, Chemistry, etc.
2. **Fantastic science** or **pseudoscience:** answers should be backed up by solid reasoning in the way of (citing @MichaelKjörling) "if we were to assume that Thing X exists and works as hypothesized, then it would be possible to use it to perform Miracle Y by doing A, B and C." This form could be used to explain, for example, how a hypothesized type of particle could be used to perform something which cannot presently be done
3. **Pure fantasy:** answers should be reasonable, and can be based on personal experience, readings or whatever other means.

**All** answers must be internally consistent, as well as in line with the asker's specified requirements, whether those are "hard science only" or "magic fairy dust exists that works like this: ...".