How to Take Smart Notes

Last updated: 2020-09-23

How to Take Smart Notes

Author: Sönke Ahrens

Who should read: The #roamcult, academics, aspiring writers, personal knowledge management newbies, mental model aficionados

Rating: 7 / 10

When it comes to knowledge, most of us live paycheck to paycheck.

We might consume information that enriches our conversations for a while, but over time, it doesn’t stick. New insights come in, and we’re onto the next hot Twitter topic.

In How to Take Smart Notes, Sönke Ahrens changes this. Instead of letting information fade, he teaches us how we can “bank” our knowledge, and most excitingly, compound its value over time.

If you like accumulating mental models, you’ll love this book.

The Tools

At the core of this book is something called the “slip box”, which was utilized by Niklas Luhmann to become one of the most insightful (and prolific) sociologists of the 20th century.

Ahrens sings the praises of the slip box (or “zettelkasten”, as Luhmann called it). And much of the book is about how to use a zettelkasten as your second brain.

However, it’s now 2020, and each year (month?), we get better tools. I use Roam, but I also recommend Obsidian. Others love Notion, which is a fine choice as well. (Especially considering the introduction of backlinking - not to mention, Notion is built on blocks, so Roam's beloved block references should be possible).

Roam, Obsidian, Notion, all fine options

All fine options

I think any tool with [[backlinks]] will do. The goal is to make your notes easier to stumble upon in the future. The bi-directional references accomplishes that beautifully, they double how connected your notes are - with absolutely no work on your part.

The Philosophy

The core philosophy of the book is rather relaxing:

“Just follow your interest and always take the path that promises the most insight.” (p. 25).

Instead of forcing yourself to learn about topics you’re supposed to know, work on what you love. Read what you find most interesting and jump around. Ask questions, debate ideas, and only work hard to understand things you want to understand. Do stuff that gives you energy.

"I never force myself to do anything I don't feel like. Whenever I am stuck, I do something else" - Niklas Luhmann

This is liberating to hear, but for many of us, we're skeptical upon hearing this. Working on stuff only when you feel like it is an attitude shared by the least productive people as well. So what else must we do?

Ahrens provides a direction: “work as if nothing else counts than writing”. In other words, when it comes to learning, you must write:

"everything is streamlined towards one thing only: insight that can be published." (p. 38)

With such a crystal clear objective function, it starts to make sense why incessant jumping from topic to unrelated topic won’t lead us anywhere. We wouldn’t accumulate enough insights to produce writing worth reading. And thus writing is a lens which focuses our exploration efforts. You may not know where you’re going, but if you know you’re going to have to tell a damn good story by the end of the trip, you’ll wander with adventurous intent.

So far so good. Be curious. And write. Is that it?

No, that just sets the stage for the title of the book: taking smart notes.

Smart Notes

Ahrens does a great job of summarizing the process of taking smart notes in this Quora post.

The nugget of insight for taking smart notes is the two step process:

You have to have a two-step process in place. First, don’t worry too much about the notes you take while you are doing something else... Now, to the important second step: as quick notes are only reminders of an idea, you need to turn them (ideally within a day) into permanently understandable notes”

Let’s unpack this.

The first step is what Ahrens calls in the book “fleeting notes”. In this step we make notes as we read, perhaps on paper, in the margins, a text message to ourselves - wherever. The key is to capture ideas that speak to us.

Then, at some regular interval (ideally, the same day) we collect these fleeting notes and selectively transfer the notes that are worthy to be added to our second brain.

This is where I believe the vast majority of people go wrong. This is not a simple transcription process - it’s a game.

You need to do the work of testing your understanding. You need to try to think about tangentially related topics. I love to have pen and paper handy during this step. Sketch out connections, make sure things make sense. And the beautiful thing about this step, it gets MORE fun and EASIER with a more developed Roam Database (or whatever you’re using). The app will seemingly suggest connections for your consideration. Each one might send you off on an electric path of exciting connections and deeper understanding.

The work during this step, of filtering, transforming, and enriching fleeting notes into your zettelkasten, is what Ahrens calls making “permanent notes”. There’s definitely an art to it, but as Ahrens describes:

“A good workflow can easily turn into a virtuous circle, where the positive experience motivates us to take on the next task with ease, which helps us to get better at what we are doing,” (p. 46)

As great as this is, there’s one dangerous thing to be aware of during this process: bloat. You might create notes that are too half baked, or don’t really mean much on second inspection. Luhmann avoided this with intention:

“He usually wrote his notes with an eye towards already existing notes in the slip-box. And while the notes on the literature were brief, he wrote them with great care, not much different from his style in the final manuscript: in full sentences and with explicit references to the literature from which he drew his material” (p. 19)

Just as with code, eliminating and rewriting existing notes is probably just as valuable, if not more so, than adding new ones.

Let’s see it in action

Here’s a recent example of how I added a small tweet to my ever growing lattice of ideas. I’m no expert, but it’s useful to illustrate.

It started with a tweet I saw about picking a company to join: Shreyas Advice on Joining Company

I felt that it was useful, but I wasn’t sure how. So I made a fleeting note:

Fleeting note of tweet

I went about my day, doing other things, but at some later point, I decided to “process” that fleeting note some more. So I opened the [[prioritize growth]] page and went to work:

Working on permanent note

As you can see, I started by expanding upon the original note just a little, but as I started writing, I remembered an IndieHackers podcast that I had listened to recently. I plucked some quotes from that podcast and added it to the note.

I now had the opportunity to perform a comparative analysis of these two pieces of advice, one for startup founders, and another for employees. They felt eerily similar. So I started asking “Why is growth conducive to learning?”. And that question reminded me that a friend had sent me an article about Enabling Environments by Andy Matuschak just a few days before.

It felt related, and so I linked it as well.

This process of connecting snippets of information, going deeper on each idea, and then furthering my understanding was both joyful and effortless. Although Roam didn't supply all of the suggestions, using Roam has encouraged me to be on the lookout for connections.

Am I an expert on growth and enabling environments now? Absolutely not, but I’m certainly more thoughtful than if I had just hit the “like” button on Twitter.

Wrapping Up

“How to Take Smart Notes” can be summarized in 3 parts:

  1. Be curious and ask questions (if you don’t ask any questions, you don’t get any answers)
  2. Optimize for publishable insights (you must have a writing practice of some form, which gets evaluated under the rigor of public scrutiny)
  3. Take two-step notes (fleeting notes at first, high quality permanent notes second)

And if that is all you get from the book, that would be enough.

However, my favorite part of the book had little to do with this core argument. Ahrens has a terrific quote about salvaging interesting tidbits from the book:

“We constantly encounter interesting ideas along the way and only a fraction of them are useful for the particular paper we started reading it for. Why let them go to waste?”

With that in mind, here’s a bonus section - a list of interesting morsels I captured from the book, which you might wish to chew on as food for thought. Why let them go to waste?


Hermeneutic Circle

This might actually be my biggest takeaway from the book. As I understand it, the hermeneutic circle is a process by which something can be understood more deeply by first taking it out of its original context, then associating it with fresh ideas, and finally returning it to the original context with an augmented worldview. This process can be repeated indefinitely (hence, the circle).

While the academic definition might be more precise, this framing of the hermeneutic circle is most applicable to note taking and learning. The idea that a concept gains extra meaning in different contexts, and can be fed back into its original context to give new life to the whole, is a fascinating practice and I think should be applied everywhere.

The story of Solomon Shereshevsky

Solomon Shereshevsky was a Russian journalist who was best known for his seemingly perfect memory. And while many of us would view perfect memory as a great gift, it became a curse as he was unable to focus on important matters.

Interestingly, Solomon was diagnosed with synesthesia, which is a condition in which the senses become connected in unexpected ways. For example, you may hear a musical note and see a color. Or touch may trigger taste. The senses are overly connected - which was probably a key to Solomon’s mnemonic feats.


This is a book by John Ratey, a doctor who investigated how exercise gives rise to improved brain function. I’m now reading this book and will hopefully gain some insights that lead to behavior change. For now, I’ve added some extra movement into my day (if you’re curious, that’s pushups and juggling - particularly WFH friendly activities)

Zeigarnik Effect

This is a phenomenon where our recall abilities on unfinished tasks are superior to that for finished tasks. That is to say, our brains seem to reserve space for things that are unresolved, which makes it easier for us to recall the particulars of these unfinished tasks.

The Zeigarnik Effect seems to suffer from a lack of replication outside of its original study, but the concept resonates with me. Not only does my brain seem to allocate memory to unresolved tasks, it allocates compute as well - cycles spent on rumination, which is unactionable and keeps me up. Good to know there might be a neuroscientific root to our brains' need for closure.

Anthony Trollope

An author who started his morning every day at 5:30AM, and would write 250 words in 15 minute increments, until he had 10 pages each day. Love the consistency.

Mere-exposure Effect

Familiarity != Understanding. Ahrens does a great job describing this:

"mere-exposure effect: doing something many times makes us believe we have become good at it – completely independent of our actual performance (Bornstein 1989). We unfortunately tend to confuse familiarity with skill." (p. 53).

Our brains are extremely good at tricking us. As Feynman said: “you must not fool yourself - and you are the easiest person to fool”. Don’t fall for mere-exposure!

Malcolm McLean and Shipping Containers

Shipping containers standardized the logistics industry, which drastically brought down costs and unlocked second order innovation in ways that are hard to quantify. However, in order to achieve these cost savings, the entire system had to be on the standard, otherwise, there was no benefit. Shipping containers aren’t useful if only part of the supply chain uses them.

This sort of reminds me of Fedex, and how all mail gets routed to Memphis (or nowadays, at one of their hubs). It’s locally suboptimal, but globally optimal - and the global optimization only works when a critical mass has switched over. Another example of “slowly, then all at once”