Read about it in Inside the Box, but of course I’ve known of this idea from before. Like, when I wrote somewhere that, unimaginable is usually imaginable, truly unimaginable things are impossible to imagine. I read about a similar idea in Abundance, where they talked about who gets funded for new research - it’s not truly new research, it’s familiar research. Though the story was different there. This basically means throwing a rope to the reader (for example) when you’re doing truly unique work. So the wilder the setting, the more the plot needs to be something we already know...