A Zettelkasten is said to be a second brain. Through the linking of notes the system may surprise you in insightful ways.

What is a zettelkasten?

The word can be split into two ‘zettel’ and ‘kasten’. Zettel meaning a note and kasten simply box. So, a zettelkasten is a box of ideas. But what makes this box special/useful?

Ideas behind zettelkasten

Rather than writing notes down in categorized notebooks the notes should have a free-flowing category. This Medium article has some nice visualizations of this. Where the author starts with the ’normal’ system of notebooks, a set of dots (representing the notes) cast in concrete.

If the notes were kept on index cards it would more look like notes free-floating in air. Yet, impossible to track how notes relates to one another.

Putting these in rigid folders does organize them, but makes it too static. What if a note should be in two folders at the same time?

Tagging notes helps here. As notes can have multiple tags they can be part of multiple ‘categories’. See this why tagging should be used sparsely.

However, Luhmann went further, next to tagging notes he also linked notes together. Meaning that notes are not just grouped together, but also their connections are explicitly tracked. Creating a web of ideas. Additionally, it shows grouped topics. This means that categories naturally develop and are not forced upon notes beforehand.

Surprising factor

Claude Shannon realized that there is more information in a surprising message than a non-surprising message.

This relates to the Zettelkasten in the following way: Suppose the Zettelkasten is filled to the brim with forgotten ideas. Then with a question in mind you search the Zettelkasten stumbling upon all these ideas, surprising you.

The process

The process for writing a new note is explained here. The ID of a (new) note should follow these guidelines The principles of a Zettelkasten do need to be kept in mind.

What goes into the Zettelkasten?

The main thing that goes into a Zettelkasten are, ofcourse, notes. However, I think it is valuable to add quotes and thoughts too. It is important to detail the source though.