Defining science fiction has long been inherent to the genre itself, as authors of science fiction have proposed what makes the genre distinct from naturalistic fiction and other kinds of fiction other than simple thematic concerns. One such attempt that I find useful in thinking through the nature of science fiction is a theoretical framework proposed by Samuel Delany in his book of essays The Jewel-Hinged Jaw. Delany proposes that what defines science fiction is the linguistic distance it has from reality, from the world of the reader. He calls this framework “subjunctivity,” or “the tension on the thread of meaning that runs between word and object.” Where reportage is what is actually happened in the world, naturalistic or so-called realist fiction is defined by the possibility that it could happen. If in reportage, we read that “The man disappeared,” we read this with the understanding that the man actually disappeared, and likely in ways that are entirely explainable. He was a victim of some kind, he ran away from his life, etc. Comparably, the speculative genre of fantasy violates the real, representing events that could not happen. Delany argues fantasy inverts the subjunctivity of naturalistic fiction. However, science fiction is defined by it’s representing that which has not yet happened. It does not divorce itself entirely from reality as in fantasy, nor does it simply represent reality as in reportage or naturalistic fiction. Instead, science fiction’s subjunctivity is defined by maintaining a relationship to reality while also forcing the reader to encounter possibilities beyond the boundaries of our reality. Joanna Russ speaks to this when she says that sf “must neither be impossible nor possible.” In this case, the line “The man disappeared” might refer to something slightly beyond the easily explainable. For example, a wormhole, time travel, literal identity and body morphing, or even possession of some kind.