Zettelkasten: one idea per note, and the links do the thinking

A box of cards that talked back

Niklas Luhmann, a German sociologist, kept his notes on slips of paper in wooden drawers: about 90,000 of them by the end of his life, in two collections now held by Bielefeld University. Each slip held one thought, had a fixed number, and pointed to other slips by their numbers. He called the box a partner he could talk to, because following its links turned up connections he had not planned.

“Zettelkasten” is simply German for “slip box”. What made Luhmann's work was not the box itself but three habits: one idea per note, written in his own words, linked to the notes it relates to.

“A Zettelkasten makes connecting and not collecting a priority.”

zettelkasten.de, Introduction to the Zettelkasten Method

The principles

• One idea per note. A note small enough to hold a single thought can be linked precisely and reused in many arguments. Treat it as a compass rather than a law.
• In your own words. Copying a passage records what someone else said. Restating it forces you to understand it, and the note still makes sense years later.
• Linked, with a reason. A new note is connected to the notes it builds on, contradicts or illustrates. The links, not the folders, are the structure.
• A fixed address. Every note keeps an identity that never changes, so links to it never break, however the collection grows.

Four kinds of notes

Sönke Ahrens' book How to Take Smart Notes made the method widely known and split the work into stages. notespace follows that split:

Fleeting notesinbox/

Quick, rough captures of a thought. Turned into something lasting within a day or two, then thrown away.

Literature notesliterature/

One per source: what it says, briefly and in your own words, with a reference to where it says it.

Permanent noteszettel/

The point of the whole exercise: one idea each, written to stand on its own, linked to the notes around it.

Structure noteshubs/

Entry points into a topic: an ordered list of its key notes with a sentence on each, like a table of contents that you keep rewriting.

What an assistant changes

The hardest part of a Zettelkasten is the linking. With a few hundred notes, you can no longer remember which earlier note a new idea belongs next to, so links get skipped and the box turns back into a pile. An assistant can search every note by meaning before writing a new one, suggest the three it most relates to, and spot two notes that say the same thing.

The method's other half should stay yours. A note in “your own words” is valuable because you did the thinking. The best split is to explain an idea in conversation and let the assistant turn your explanation into a note, find its neighbours and file it, then read what it wrote.

Running it on notespace

The built-in zettelkasten methodology lays a space out like this:

inbox/<slug>       fleeting notes, processed within days
literature/<slug>  one per source, with its reference
zettel/<claim>     permanent notes; the name states the idea
hubs/<topic>       entry points into a topic

• Sources are cited. The server rejects a literature/ note without a source (a URL, or author, title and year).
• Names state the idea. A permanent note is called by its claim, such as zettel/spaced-repetition-beats-rereading, so a list of notes reads like a list of ideas.
• Search before writing. The assistant looks for the idea first, by meaning, and improves an existing note instead of adding a duplicate.
• Every link has a reason. A new permanent note links to at least one other, saying whether it builds on, contradicts or is an example of it, and back to the literature note it came from.
• Addresses never change. Every note has a permanent id, links are tracked in both directions, and renaming a note rewrites the links to it. The assistant can list broken links and notes nothing points to.

Start one

Connect notespace to your AI app, then ask in plain words. Your assistant proposes the change and nothing happens until you confirm it.

Changing a space's method never edits notes that are already there. If the rules do not fit how you work, ask your assistant to draft your own and approve them the same way.

Sources: Christian Tietze and Sascha Fast, Introduction to the Zettelkasten Method (zettelkasten.de), the source of the quotation; the Niklas Luhmann Archive at Bielefeld University; Sönke Ahrens, How to Take Smart Notes (2017).