There are no privileged places in the note-card system, every card is as important as every other card, and no hierarchy is super-imposed on the system. The significance of each card depends on its relation to other cards (or the relation of other cards to it). It is a network; it is not "arboretic." Accordingly, it in some ways anticipates hypertext and the internet.
Niklas Luhmann's zettelkasten system doesn't impose a heirarchy upon it's contents and in some ways its structure anticipates the ideas of hypertext and the internet's structure.
Also similar to the idea from Umberto Eco: https://hypothes.is/a/jqug2tNlEeyg2JfEczmepw