Zettelkasten from "How to take Smart Notes"

April 16, 2022

If you’re trying to get more productive at writing or content creation (especially long-form), I highly recommend checking out How to take Smart Notes. It’s a book by Soenke Ahrens which describes “Zettelkasten”, a system of note-taking and personal knowledge management geared towards writing. Here’s a review and summary of the book, which I think would be more accurately titled “Note-taking to generate ideas for Writing”.

Key Takeaway: Purposeful Note-taking

To date, I’d been focused on the mechanics of Zettelkasten without understanding it’s goals and philosophies. My note-taking was an attempt to make it easier to find and retain information - in effect, creating a personal wiki. So this passage from the book caught my eye:

…it would be rather misleading to think of his slip-box as a personal Wikipedia or a database on paper. The similarities are obviously there, but the subtle differences are what makes this system unique.

Note-taking, in Ahren’s opinion, should be more purposeful. In a Zettelkasten system, the resultant notes should lead to publishable content:

Instead of focusing on the in-between steps and trying to make a science out of underlining systems, reading techniques or excerpt writing, everything is streamlined towards one thing only: insight that can be published.

Eventually, you should be able to get a “critical mass” of notes, such that they become an “idea generator” for your writing:

There is one reliable sign if you managed to structure your workflow according to the fact that writing is not a linear process, but a circular one: the problem of finding a topic is replaced by the problem of having too many topics to write about.

How can our notes achieve this? I like to think of it as building an “idea bank” 🏦, where notes are already processed, potential ideas for future writing. They should also be connected to other relevant notes - this allows us to follow the chain of notes to find related ideas (I like to imagine this as creating literal “trains of thought” 🚂).

I’ve attempted to summarise the process below. Important: The process, while a little abstract, is surprisingly simple. The catch is it depends a lot on you actually processing what you read e.g. rephrasing to develop understanding, connecting the ideas to existing ideas.

Summarising Zettelkasten

“Zettelkasten” means “slip-box” in German. This is in reference to the physical approach of writing on index cards and filing them in a box. Despite the physical roots, it’s still very applicable in today’s digital environment, and can be summarised as follows:

  1. Take “Fleeting Notes” or “Literature Notes”
  2. Write “Permanent Notes”
  3. Connect and Index your Permanent Notes
  4. Expand upon ideas in your Permanent Notes
  5. Write from your ideas

1a. Take Fleeting Notes

These are effectively shower thoughts 🚿, ideas that come to you in random places. Have a way to quickly write them down, and don’t overthink it - they’ll get discarded once processed into Permanent Notes (Step 2) anyway. Note: this isn’t a rigid process - if a thought is already well-formed, it can become a Permanent Note straightaway.

1b. Take Literature Notes

These are notes that you take when reading something, the primary goal being to develop understanding of the text, which will help later in the process. Avoid copying directly - rephrasing helps you develop and check your understanding. Although Ahrens says you are free to use any note-taking methodology or technique, he also suggests to be picky. Since the purpose isn’t to remember everything (you can add a bibliographical reference for that), ideally the notes taken should be concise and relevant to you.

For example, Ahrens read a book about scarcity and how people seem to react irrationally to it (e.g. people with little money spend unnecessarily on luxuries like take-away food):

I took some literature notes collecting reasons how and why humans act so very differently when they experience scarcity. This was step one, done with an eye towards the argument of the book. I had questions in mind like: Is this convincing? What methods do they use? Which of the references are familiar?

Above, we can see that his focus was on understanding the book’s argument (the reasons why humans act differently). The questions at this point are narrower, focused on the text itself.

2. Write Permanent Notes

Here we begin to process the notes in Step 1, converting them into “permanent notes”. This involves thinking about how they relate to your research and interests (which comparing to existing Permanent Notes can help with):

The idea is not to collect, but to develop ideas, arguments and discussions. Does the new information contradict, correct, support or add to what you already have (in the slip-box or on your mind)? Can you combine ideas to generate something new? What questions are triggered by them?

This is perhaps the most abstract step of the process - how do you know what is worth keeping, especially in the beginning when you have few notes to compare with? Though he doesn’t explicitly say this, Ahrens talks about “what interests you” a lot, and I think that’s a decent heuristic - write about what you find “interesting”. If it interests you, there’s a higher chance you’d want to expand on it in the future.

Another suggested approach for writing Permanent Notes is to write about why something seemed important to you. Following on the previous Literature Note example in Step 1b - since Ahrens was interested in “a theory of society” (🤷‍♂️), his Permanent Note was:

“Any comprehensive analysis of social inequality must include the cognitive effects of scarcity. Cf. Mullainathan and Shafir 2013.”

Still pretty vague? Unfortunately, yes (at least to me). There is a further example in the book’s appendix which I’ll attempt to break down in a future post.

3. Connect and Index Permanent Notes

The next step is to file/store your Permanent Notes, making sure to add links to and/or from other relevant notes. This will help us find related ideas later when writing.

To further aid discoverability, keep an “index” of topics or keywords, and make sure the new Permanent Note can be reached from the index. This can be done by adding a link to the note directly next to the topic, or linking it from another note that can be reached through the index.

The above index might seem irrelevant given the searching functionality in digital solutions, but Ahrens suggests our keywords be more situational instead of purely for categorisation (“In which circumstances will I want to stumble upon this note, even if I forget about it?”). His example was the following note:

“Tversky/Kahneman (1973) showed in an experiment that people are more likely to overestimate the likelihood of an event to happen if they are able to conceive it well and in detail than if it were abstract.”

If we took a categorisational approach, the keyword could be “misjudgements” or “experimental psychology”, which he doubts could be turned into a structured argument. Instead, we should look through existing notes and think about trains of thought and questions.

If the writer was an economist working on decision-making, he or she might be thinking about how management prefers projects with easily-visible outcomes, even if they’re less profitable. A good keyword could then be “capital allocation problems”.

As a topic develops, you may want to add an “Overview Note” - a note which starts to structure thoughts and links to relevant Permanent Notes. Unfortunately the book doesn’t give a clearer example of this, though Ahrens says it could be an in-between step to the development of a manuscript (e.g. laying out the arguments for the topic).

4. Develop ideas in Permanent Notes

Ahrens talks about developing topics, questions and projects “bottom up” from the system. To my understanding, this is more about mindset than a mechanical difference from Step 3 - instead of starting “top down” like brainstorming topics to write about, look into your notes and expand upon what looks promising (e.g. where clusters of notes form).

What you end up writing about may be very different from what originally interested you! I love his example about how DNA’s structure was discovered - the original research project was to find a treatment for cancer. As they researched, the scientists were able to pivot to the most promising path.

5. Write from your ideas

When an topic is developed far enough, you can copy notes to an outliner and re-order them. This helps you identify what’s missing for further research and note-taking, as well as remove redundant information. At this stage, it’s also easy to try out different ideas and structures for articles. Then… write!

The Review

✅ This book gets the wasabi stamp of approval, especially since I’m trying to get better at writing. If the summary above intrigued you, please give the book a read! There’s a lot of detail and nuance that I didn’t cover (and honestly, still trying to process how it applies to me). One point worth re-emphasis - the system summarised above is just a skeleton. Processing what you read and thinking about how it connects is what’s actually important.

Here’s some other thoughts:

  • Time Commitment: Low. Amazon says that this book takes just above 4 hours to read. Personally, I took longer for a first read-through, but was still able to finish it with a few days of intermittent reading (probably < 10 hours).
  • Depth: I think the content is pretty dense, in a good way. There’s a lot to ponder about. I like how Tiago Forte puts it: “Every paragraph has a point, and I struggled to leave anything out of this summary.” However, I did feel that the book was more abstract and spoke mostly in terms of principles. I could have used more concrete examples to visualise and understand the process.
  • Writing Style: You can see the influence of academia in citations and references to other papers, but I thought overall the writing was simple to read. The words weren’t unnecessarily flowerly or complex.

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By Nick, a Business grad turned Software Engineer, living in sunny 🇸🇬. I write mostly about Ruby and Rails, not wasabi (sorry!).