A Zettelkasten is a German word that translates to “slip box.” The term became used to describe a particular workflow that Niklas Luhmann used to publish about 50 books and 550 articles over his career.

Many great articles are out there describing Niklas Luhmann’s Zettelkasten system. As well as a few books, so I won’t go into those details here. Instead, I want to focus on the key concepts I realized about a Zettelkasten over time.

A Zettelkasten is a box of notes. Luhmann’s workflow to take and organize notes became synonymous with Zettelkasten. When we hear the word Zettelkasten today, we think of the workflow process, not necessarily a box of index cards.

Sönke Ahrens helped make the Zettelkasten popular with his book How To Take Smart Notes. Sönke introduced the names of the various types of notes, Fleeting, Literature, Permanent, and Project, to describe the various phases of Luhmann's workflow. However, these names were never part of Luhmann’s vocabulary to describe his system (in fact, Luhmann rarely talked about his workflow).

Digital tools try to mimic the Zettelkasten workflow that Luhmann used. However, digital tools have many advantages that make some parts of his analog workflow seem wasteful, such as numbering and limiting space to what fits on a 4x6 card. We can now easily connect notes using Wiki Links, see connections using Backlinks, see a graph of notes related to the current note, and even see a visual of the entire system to identify clusters of information. Not to mention full-text search and hyperlinks!

While we can take advantage of these digital tools, we need to remember the fundamental purpose of the Zettelkasten. It’s not to make as many notes and connections as we can to grow an enormous graph that will somehow start answering all of our questions and do the writing for us.

Luhmann’s Zettelkasten system worked because it forced him to slow down and think about each idea and how it relates to the other ideas. Numbering each card to connect it to another card was a painstaking process, which required him to spend more time organizing his notes than actually writing his publications. This gave him the time (in his head) to make real connections and insights. Digital tools can easily abstract this from us if we’re not careful.
Another reason Luhmann created so much content is that throughout his process, he spent time creating output that would be used in his work. Rather than capturing and making quick notes, he spent the time writing out his interpretation in his own words. When writing his publications, his thinking was already done, and he could focus on creating a draft.

Quotes

“Of course, I do not think of all this on my own; it mostly happens in my file. ... In essence, the filing system explains my productivity. ... Filing takes more of my time than writing the books” - Niklas Luhmann
"What Luhmann appeared to have done instead was to immediately write his own thoughts on whatever he read in a way that would be as close to being publishable as possible. That's what allowed him to be so productive, he was constantly creating output, rather than accumulating knowledge in a way that may lead to future output, which is what most of us do when taking notes." (level 1, Zettelkasten is NOT a note-taking system(?))
"Write all your notes and quotes on separate three-by-five-inch cards. Then, when you get ready to organize your thinking, just spread them all out on the floor, see the natural structure that emerges, and figure out what’s missing." (David Allen, Getting Things Done)

Additional Reading