It’s not important to know then all, but just to know a few well. You don't need to know all the museum when you go to a museum, but only a few paintings. In my case, in fact, for example, I know three paintings by Cezanne very well. It didn't do me any good at all to the museum all the time, but to reflect concretely on a limited amount of work. That’s culture, as they say. It does not consist of having it all, but in having reflected concretely on a few things.Jean-Marie Straub quoted here via here.
The question is which few to know.