It's hard to actually feel the effects of a Zettelkasten. So even while using one, you start to wonder whether you're doing it right. That's why I want to offer some criteria for saying, "If you're using it like this, you're fine."
1. Literature Notes - You Can Find the Reference
When we recall an idea or thought we read a long time ago, we remember the idea itself, not where it came from. That is, unless we read the source recently or it really moved us. What I mean is, when an idea comes to mind, we forget which book or video it came from. This becomes a problem when you have to cite sources for a book or paper, or when you want to go back and understand that idea more deeply.
But if you've written your literature notes properly and linked them to your permanent notes, you can tell where each thought came from. This helps when you need to cite a source, and it also tells you what to consult when you want to look into an idea in more detail.
2. Literature Notes - You Can Connect External Knowledge to Your Mental Models
If you connect the outside knowledge you gain from reading to your own mental models, you're making good use of your literature notes. Connecting literature notes to mental models makes learning easier. After all, you're linking knowledge to your own context. This is also called elaboration: connecting new information to an existing schema.
To experience the power of connection, let me give an example. Arteries, which carry blood out of the heart, are thicker and more elastic. Veins, on the other hand, are thinner but have valves. If you tried to simply memorize these facts, it would be hard.
But arteries receive blood pumped out by the heart, so they have to withstand higher pressure. Veins, where the pressure has dropped as the blood has flowed along, only need to withstand lower pressure, but because they have to prevent backflow at that lowered pressure, they have valves.
This fits two mental models we already hold: the greater the force something receives, the more material is needed to support that force and all movement meets resistance, so its force diminishes. Once the facts are connected to mental models like this, the characteristics of arteries and veins become easy to memorize.
In the same way, connecting what's in a literature note to your existing mental models or permanent notes makes it easier to remember. The literature note above says that when hiring developers, years of experience isn't what matters; asking about a part of the work they would actually do matters more. If you just read this, it would be hard to recall later. Would you even think of it when actually interviewing developers?
But it connected to a permanent note I already had, A good test is one that is close to the real situation, so I was able to remember it easily. That permanent note expresses my mental model that it's best to practice as if it were the real thing, and that's why I was able to remember the book's content.
3. Permanent Notes - You Can Continue Your Thinking
To think deeply about an idea, writing it down somewhere is essential. Otherwise your thinking becomes fragmented. When thinking is fragmented, you end up thinking the same thoughts again, or you don't know what to think about next. Then you can't think deeply and are left with only shallow thoughts. This matches the case for a second brain, not just for a Zettelkasten.
The Zettelkasten solves the problem of fragmented thinking. A Zettelkasten that works helps you carry your thinking forward. It helps you form your own thoughts from literature notes, and lets your thinking branch out from one permanent note to another. And structure notes tell you what to think about.
I believe this connection of thoughts is the key factor that decides whether a Zettelkasten is effective. Beginners branch out shallowly from one note to many. That's because they're used to top-down thinking. Experienced Zettelkasten users, by contrast, end up with notes that stretch out deeply, and those long chains of notes connect with each other.
Below is my own permanent notes in Obsidian's graph view. You can't see a pattern; you can see the notes densely and extensively connected to one another. In other words, they are closely related to each other. 1
A visible pattern like the one below may look pretty, but it's probably not a Zettelkasten that works. When notes are connected to each other over long distances, the pattern disappears. A Zettelkasten that doesn't work looks like this: thoughts radiate out from one note, and those thoughts aren't connected to each other.
4. Permanent Notes - You Can Use Them to Produce Output
The Zettelkasten became famous, after all, because of Niklas Luhmann's prolific output. I believe a Zettelkasten ultimately pays off only when you use it for production. If you don't use it to produce output, there's no reward for the effort of writing literature notes and permanent notes. However you use it, if you ultimately use it to produce output, isn't that a Zettelkasten that works?
Finally, Let Me Clear Up a Few Misconceptions About the Zettelkasten
- You don't need 1,000 notes to feel the effects
There's a narrative that to feel the effects of a Zettelkasten, notes have to pile up, and you need 1,000 of them. I think this narrative started with the book How to Take Smart Notes. I believe what matters for a Zettelkasten's effectiveness is the density of the notes rather than their total number. Even just 100 notes on a single topic and line of thought are enough to produce plenty of online content. (The point isn't that 100 is the magic number; I'm stressing that you don't need that many notes.) A single piece of content would draw on about 5–10 notes. And even with 1,000 notes, if the topics are all scattered and the notes aren't properly connected, you won't feel any effect. The content made that way probably won't be particularly distinctive, either.
- A Zettelkasten won't improve your writing skill
And because the Zettelkasten is a tool for writing, you might expect it to sharpen your prose. If you're using a Zettelkasten to build writing skill, I think you're headed in the wrong direction. A Zettelkasten deepens the substance of your writing; it isn't a tool that makes your writing sparkle. For one thing, I can't say with confidence that I'm a good writer myself.
Of course, if you write a lot, your prose may improve somewhat. But to really improve your writing, I think you need deliberate practice with feedback. The Zettelkasten workflow has no deliberate practice in it.
Footnotes
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Actually, it only looks patternless to the eye; there is a pattern. It's called a Small World Network, and... ↩