There are many people (at least that from the developers I know) who need to understand things fully before they 'can' use them. One of my friends is mentally stuck for 30 years on a platform because he cannot use what he does not fully understand. He tried Haskell (a few years ago) but instead of going through exercises or just trying to implement something, he read a book and noticed he did not understand basic (monads and such...) things and quit. He cannot touch a computer unless understanding arrives first. He is an extreme case but many (especially non-entrepreneurial in my experience) people I know have this in some ways.

So they're essentially non-functional with today's technology stack? I think it's safe to declare the entire thing essentially incomprehensible to a single person. Sure - you can understand all the basics, and achieve expertise in a lot of it, but modern software and computing is essentially fractal in its complexity. Even when you think you understand, it often ends up being an abstraction which is re-written by some routine further down, deep within some area which raises even more questions.

Why would they be non-functional with today's technology stack? The whole stack is complex, but everything depends in general on very basic principles (eg: basic information knowledge about parallelism, how a compilation works, etc.. and hardware knowledge : how parallelism is handled, why do we need asynchronous jobs and how they work, etc..). Any complex piece of software can be decomposed into basic principles and very often without a lot of work. The only softwares that require more time to understand are the ones that solve some physical or mathematical problems IMO, as you need to understand the math underlying them. But again, this is not an impossible task

Ask him to explain in full detail how the flushing mechanism of a WC works. Then ask him if he uses any alternative solution he understands better.

I think it is quite common, even for people who want to understand things at a fundamental level, to just use stuff without said understanding.

What sort of hidden knowledge do you see in the flushing mechanism? It’s pretty straightforward.

(If you don’t want to go into how plastics are made, &c — but that stretches the metaphor way too far)

I would personally have trouble naming all of the pieces in the flushing mechanism and being able to put y them together if I asked someone to buy them for me. That’s seems to be the same for many people I know.

It is not because you cannot name something that you don't understand something, even in profound levels.. the knowledge of the name is only conventional against the underlaying mechanism. It suffice to repair one wc, one time to have a pretty good idea on how it work without much effort

It’s easy to do. You should get at least some more handy friends — or become one yourself: it will broaden your understanding of your environment, most things are very easy to fix and change.

It is not so consistent; I guess when they think about it consciously, they want to understand it. For all the rest (more low level, a WC etc) they, inconsistently, do not care. It is not really for me to change their behaviour, I just know that some of them are really crippled by this.

I agree, there is no point in trying to change their behavior, we can at best understand them and offer alternatives

Has he got any luck on that Quantum Mechanics and General Relativity harmonization or he simply avoids using a computer in a gravity wheel?