A wonderful analysis of an important part of world-building in science fiction.
As most of you probably know, filmmakers use the term “MacGuffin” to stand for some object that various characters in the tale are competing for. A secret paper, a formula, a stunning gem, a statue of a Maltese falcon…
In Fantasy and SF novels we have a slightly different convention—a special device or procedure or organism with special powers that affect the flow of the story. The writer very often works backwards, that is, they get some visually or conceptually interesting thing happening in their story, and only then posits a gimmick that will make the effects possible.
There must be some standard generic name for these gimmicks, and if so, I’ve probably heard it, but for whatever reason, I can’t think of a completely apt and standard phrase today. Deus ex machina isn’t quite right, as that’s more specifically a miraculous something that saves your characters. Pixie dust is fairly accurate, but it doesn’t have the technological feel that I’d like.