For questions that ask if a given concept is consistent, or being used consistently, in the context of the referenced world rules. Answers should say yes or no, with supporting info. This tag should not be used with the science-based, hard-science, or science-fiction tags. Comparisons to the real world should use the science-based tag. This tag may not be used alone. This tag may not be used with the science-fiction, science-based, or hard-science tags.

Unlike questions tagged with the , or tags, questions tagged may be unrelated to real world science or the rules of the real world — or may depend on specifically defined modifications to real world science or real world rules. The approach for questions with this tag should be to ensure logical consistency with established rules of the OP's imaginary world. In short, does the concept/idea/assertion make sense, given the specified rules?

Answers to the question should determine whether or not the presented concept, circumstance, situation, condition, or application are appropriate or consistent with the specified rules of the world, or, contrarily, are likely to break a user's or reader's suspension of disbelief. Said another way, the question is testing the questioner's rules and/or the consistent use of the rules and not just asking about the plausibility, feasibility, or believablity of something vs. the rules. Although details are appreciated, answers should be of the form:

  • Yes, because (explain how the proposition or assertion is supported by the specified rules).

  • No, because (explain how the concept violates the specified rules and, if possible, how the rules or concept can be modified to make them consistent).

  • This tag is not used to test ideas against the real world. To ask questions concerning the reality, realism, believability, feasibility, plausibility, etc. of an idea, concept, or rule vs. the real world, users should use the or tags (the tag is preferred, and the tag is a synonym of it).

People answering questions should remember that the test is not against the real world, but against the specified rules of the OP's imaginary world. If the OP has not clearly specified the rules to be tested or used to judge the assertion or proposition, the question should be closed for lacking details.

Rejecting the premise put forth in the question (e.g., the specified rules or fundamental context of the assertion or proposition) is only allowed if it is to point out logical inconsistencies with the rules of the imaginary world, and offering a solution is recommended.

This tag frames the answer, not the question. As such, it cannot be the only tag attached to the question. One or more subject-specific tags mus be included or the question will be closed as needing more details.


  • If you want a fanciful or imaginative answer based on real world science (vs. magic or the pure invention of world rules, aka, a "plausible" or suspension-of-disbelief answer), use the tag.

  • If you want scientifically realistic answers (aka, a "reality check") that meet suspension-of-disbelief but aren't necessarily proven (or need to be proven) as fact, use the tag.

  • If you want only scientifically supported answers, including citations, meaning the answers must be factual real world solutions to the problem that definitively exceed suspension-of-disbelief, use the tag.


For details concerning the conversion of this tag from its original name, , to its present name, , and the assignment of the tag as a synonym of , see the following meta post: If we can't burn the "reality check" tag, can we rename it?