Zettelkasten — Wikipedia
Neutral reference adding concrete scale and mechanism facts to the zettelkasten page, which had drawn only on the zettelkasten.de practitioner guide.
What it establishes
- Scale. niklas-luhmann built his slip-box from 1952–53 to roughly 90,000 index cards, and produced with it about 50 books and 550 articles — the standing evidence that the method scales productively.
- Addressing mechanism. Cards were linked by “a unique index number based on a branching hierarchy” — a fixed alphanumeric address (e.g. 21/3d7) that lets a new note be inserted between existing ones without renumbering, so the structure grows organically rather than being pre-planned.
- The method predates Luhmann. It descends from commonplace-book traditions; Conrad Gessner (1516–1565) made early organizational innovations, and Thomas Harrison designed “the first early modern card cabinet” in the 1640s. Luhmann popularized but did not invent the slip-box.
- As a partner. Luhmann framed it as a thinking/communication partner in his essay “Kommunikation mit Zettelkästen” (Communication with Slip Boxes).
- Digitized 2019. Luhmann’s archive was digitized and put online in 2019.
Tier
T2 — Wikipedia, neutral encyclopedic source for a historical method.