
Ahrens, Sönke. How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking. 2017.
In this short book, Dr. Sönke Ahrens introduces the Zettelkasten method. Zettelkasten is a German word that means “memo box” or “slip box,” which refers to the knowledge management system established and used by the German sociologist Niklas Luhmann (1927–98), one of the most productive academics, who published 50 books and more than 600 articles during his career. Luhmann’s system was called Zettelkasten because he literally used memo boxes to manage and organize his research (see below).

Put simply, Ahrens encourages that researchers (and students) build, grow, and think in an externalized notes management system, whose workflow is (1) FN (fleeting notes) or LN (literature notes) to PN (permanent notes) and (2) PNs into the latticework of knowledge network, from which writings will ooze out (naturally emerge) (pp. 104, 108-9).
The human brain has obvious limits; we cannot store and remember everything. While there do exist exceptional people with exceptional memory, it’s not a norm. Luhmann’s claim that we therefore need a knowledge management system in and with which we think and write continues to hold true. We should not uncritically depend on human ability. We need this “ever-increasing pool of information” (p. 7; i.e. “an external scaffold to think in” [p. 28]) because this is where (a) knowledge connections are generated–“experimental spaces where ideas can freely mingle” (119)–and (b) new ideas are sparked (p. 8). The Zettelkasten is “a permanent reservoir of ideas” (p. 41).
One of the strengths of the Zettelkasten method is that it is a platform-independent concept. You only need a pen and paper (and, of course, place to store your notes). Once you have familiarized yourself with it, you can freely adapt it to serve your purposes and you can also use any devices or apps (e.g., Notion, Obsidian, etc.) to implement the system.
Once you have a mass of Zettels (notes), you begin to see various kinds of connections (“Idea Clusters”) emerging from the mass. My Zettelkasten system can retrieve idea clusters from the following three sources:
- Idea Clusters by related ideas (this is the most important cluster)
- Idea Clusters by reference
- Idea Clusters by tag
In implementing the Zettelkasten method in my doctoral research and reading, I didn’t want to use widely used apps because I always try to evade vendor lock-in. So, I created and am using my own MS Access Zettelkasten database system whose front screen (dashboard) looks as follows:
