A concept from theater about what sort of thing helps a narrative make sense. (In that case, to an actor, but it also matters to an audience.)
Contrast to Boxcar Story.
There’s a cliche that “life is just one damn thing after another.” Generally speaking, we don’t much like our stories to be like that. When a character reacts in a particular way in a particular scene, we want that to *make sense* in light of all that character’s previous actions and reactions. That doesn’t mean that, say, a character’s reaction to a tornado suddenly devastating her home town might not be surprising in the moment, but we should have the feeling that, yeah, if you think about it, she *would* act that way. And we’re generally best pleased if the tornado was a surprise-but-not-a-surprise. That is, the author put little hints in the text so that we didn’t *expect* a tornado, but – looking back – we think, “Oh yeah, there were little bits early on that weren’t spoilers but made the event seem both surprising *and*, yes, exactly what should have happened.” Example: James Hynes' /Next/
Authors of technical works – if they’re presenting a narrative – should strive for the same: each paragraph the reader hits should *make sense* in terms of what came before. Ideally, it should feel inevitable once the paragraph’s been read: *this* is the right place to introduce that idea.
There are some forms of Non-Narrative Explanation, but an awful lot of technical writing has a narrative form, which makes sense. Human beings love stories with a beginning, middle, and end.