Even the long running (2013) zettelkasten.de website credits Niklas Luhmann as being the "original creator" of the zettelkasten.

sigh

We really need to track down the origin of linking one idea to another. Obviously writers, and especially novelists, would have had some sort of at least linear order in their writing due to narrative needs in using such a system. What does this tradition look like on the non-fiction side?

Certainly some of the puzzle stems from the commonplace book tradition, but this is more likely to have relied on natural memory as well as searching and finding via index methods.

Perhaps looking more closely at Hans Blumenberg's instantiation would be more helpful. Similarly looking at the work of Claude Lévi-Strauss and his predecessors like Marcel Mauss may provide at least an attack on this problem.

My working hypothesis is that given the history of the Viennese numbering system, it may have stemmed from the late 1700s and this certainly wasn't an innovation by Luhmann.

link to: https://hyp.is/hLy7NNtqEeuWQIP1UDkM6g/web.archive.org/web/20130916081433/https://christiantietze.de/posts/2013/06/zettelkasten-improves-thinking-writing/ for evidence of start of zettelkasten.de

Benedictine abbot Franz Stephan Rautenstrauch (1734 – 1785) in creating the Catalogo Topographico for the Vienna University Library created a nine point instruction set for cataloging, describing, and ordering books which included using paper slips.

Interesting to note that the admonishment to leave the backs of the slips (pagina aversa), in the 1780's seems to make its way into 20th century practice by Luhmann and others.