Science fiction and the mystery genre differ in the dates of their origins and in certain of their approaches to fiction. Nevertheless, they are similar in being plot-oriented forms of fiction. Authors in both genres assemble casts of characters and focus on patterns of conflict within the constraints of altered, unusual, and odd backgrounds and contexts. Science fiction writers generally select sets of scientific, technological, or sociological assumptions and then extend them in coordinated ways into unknown and hypothetical futures, presents, or pasts. Within the frameworks the writers create, mysteries abound, but within certain constraints.
Some science fiction writers base their assumptions on logical projections of known science, things that are possible given certain discoveries or conditions in the future, or that may have happened in some unrecorded or long-since-forgotten past, or that may exist even now, somewhere. They create probable or possible futures and alternative or imaginary histories. Other writers, through venturesome speculations, create what might be called future fantasies. These writers base their assumptions on logical projections of factors that cannot now be accepted by science but that are suspected to be possible or on yet-to-be-discovered scientific principles that may one day be accepted as at least probable, no matter how uncertain they appear now. These writers seek readers’ acceptance of the premises on which their stories are based. They construct, through careful detail, scientifically plausible explanations or rationales for their altered settings and their consequences or side effects. The altered settings, having their own histories and subsequent futures, may assume any number of forms, in any time and any place, or in dimensions defined by other parameters. They may involve powers and potentials far greater than those of the human race, typifying the ultimate background for human action, the cosmos.