Almost the whole of modern medical practice leans on this concept at the core of Sterile Technique, where the practitioner is always tracking, for each object, a binary `is_sterile` flag. They’re also tracking every time an object touches another, and when an object touches a non-sterile object, it becomes non-sterile. They explicitly train you to mentally track this.
Oh wait there’s a huge one: Sterility!
Almost the whole of modern medical practice leans on this concept at the core of Sterile Technique, where the practitioner is always tracking, for each object, a binary `is_sterile` flag. They’re also tracking every time an object touches another, and when an object touches a non-sterile object, it becomes non-sterile. They explicitly train you to mentally track this.