Luhmann considered referencing to be the crucial feature of his system. He believed that the quality of the note is determined by the quality, not quantity, of its references.

Quality comes from the network of links with other notes, not from the content itself, because following the links through the web of thoughts will enrich our thinking with unexpected discoveries in a way re-reading the content of separated notes never will.

Therefore, references must be very selective.

The reference represents more than just a relation between two notes. It says that two notes are contextually congruent.

if they are just related, but not contextually harmonious, they might tackle a similar topic or share the same keyword, but their combination doesn’t carry greater meaning than their individual meanings. This is an important aspect that distinguishes the Zettelkasten from a Wiki database.

If we are working toward the communication with the slip box, we must look for references which are unexpected. It is worthwhile to think of problems that connect disparate thoughts.

if I look for references only in the same area of interest, I am limiting the potential for future discoveries.

in what context these two notes can be combined in a meaningful way?

There is no point in finding idea out of context that has no value to our current questions. This is why it is important to form references around shared context, not around general and broad concepts that are relevant to too many other notes.

“The communication with the slip box becomes rewarding only at a high level of generalization, specifically while unveiling relations of relations. And it becomes valuable only at the moment of observation, thus it is bound to a specific moment and is to a high degree accidental.”

True value of the slip-box becomes clear when we combine ideas and take them to the higher level of abstraction to articulate an answer to our question by creating relations of relations type of references between previously unconnected ideas, references relevant to that specific query that couldn’t be anticipated before.