[JulianK]

I very much agree that you don't have to understand the details of how something works for it to be useful. Whether that's a theory, a car or a computer, the world is full of things that are too complex for me to understand _fully_.

But if you don't truly understand something, I think you've given up control of that thing to someone else. Someone else has to do the thinking for you.

Once that happens, you'll have a hard time doing something new in that area, or even applying whatever it is you're supposed to know to new areas.

Understanding isn't the only thing that matters, but it still matters.