For questions that allow fanciful, creative or imaginative solutions based on or rationalized by real world science, but not necessary limited by real world science. Entirely magical solutions must use the magic tag instead. This tag should not be used with the science-based, hard-science, or internal-consistency tags. This tag should never be the only tag on a question, because this tag frames how a question should be answered, not the topic.
Similar to questions using the science-based or hard-science tags, questions tagged science-fiction expect answers related to science as understood by humanity at a specified time (and, if possible, in a specified place) in human history. However, unlike the science-based and hard-science tags, the science-fiction tag allows for fanciful, creative, and imaginative uses of real world science.
An example of such a question would be one that asks, given the technology of Europe in the 1500s, could a deep-sea investigation could be conducted? An answer may refer to present-day bathyspheres and extrapolate a plausible (meeting the expectation of suspension-of-disbelief) solution using 1500s materials.
The goal of this tag is not to encourage fantasy or otherwise patently unrealistic or impossible-to-believe solutions, but to express in it's most creative form the highest goal of science fiction: What if?
An example using commercial science fiction would be the question "How could I remove a screw without touching it?" with one answer suggesting magnetism, referring to the magnetic screwdriver seen in the movie Mission Impossible (1996) (a near-plausible suspension-of-disbelief solution). Another answer may suggest using sound waves and refer to Dr. Who's famous Sonic Screwdriver (a less-plausible suspension-of-disbelief solution). In both cases, science (magnetism and sound waves) were used to develop creative, imaginative, and fanciful solutions with varying degrees of suspension-of-disbelief.
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 must be included or the question will be closed as needing more details.
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 science-based 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 hard-science tag.
If you want to test an idea, assertion, condition, situation, circumstance, or application of rules against the rules of your fictional or imaginary world, use the internal-consistency tag.