The ability to use one’s own understanding is a challenge, not a given. Luhmann stresses the importance of permanent notes in this regard:

“The problem with reading academic texts seems to be that we need not the short-term memory, but the long-term memory to develop reference points for distinguishing the important things from the less important, the new information from the mere repeated. But it is of course impossible to remember everything. That would be rote learning. To put it differently: One has to read extremely selectively and extract widespread and connected references. One has to be able to follow recurrences.

But how to learn it if guidance is impossible? […] Probably the best method is to take notes – not excerpts, but condensed reformulated accounts of a text. Rewriting what was already written almost automatically trains one to shift the attention towards frames, patterns and categories in the observations, or the conditions/assumptions, which enable certain, but not other descriptions. It makes sense to always ask the question: What is not meant, what is excluded if a certain claim is made?