There’s the Fermi Paradox, which wonders where the aliens are. There’s also the Fermi Problem, which considers piano tuners in Chicago. These two are related to each other and also to what we will call Fermi Knowledge.
This story is from The Last Man Who Knew Everything and is told by a family friend who lent a teenage Enrico Fermi a book.
For instance, I remember that when he returned the calculus book by [Ulisse] Dini I told him that he could keep it for another year or so in case he needed to refer to it again. I received this surprising reply: “Thank you, but that won’t be necessary because I’m certain to remember it. As a matter of fact, after a few years I’ll see the concepts in it even more clearly than now, and if I need a formula I’ll know how to derive it easily enough.”
That’s a deep understanding to aspire to. Reading about Fermi, or Feynman, it makes me wonder how much of insight is due to seeing the world through first principles and then verifying a new idea works.