Verisimilitude

Verisimilitude, from the Latin verum ("truth") and similis ("similar"), is the "lifelikeness" or believability of a work of fiction. The philosopher Steve Neale splits it into cultural verisimilitude, plausibility against the real world's norms, and generic verisimilitude, plausibility within the genre's own rules, which is why characters in a musical can sing their feelings. The article traces the idea to classical mimesis, ties it to the reader's willingness "to suspend their disbelief", and records its later shift from external credibility to a story's "internal logic," its own established rules.

For writers that is the discipline: readers grant wild premises, then hold the story to what it established, so verisimilitude and suspension of disbelief are two ends of one bargain, and worldbuilding is largely the practice of writing down rules worth believing. The article's anecdote: director Richard Donner kept a picture of Superman wearing a sash that read "verisimilitude," so the 1978 film's fantasy would feel "intuitively real."