Zettelkasten: Hypertext, Linearity, Sequentiality


  • Hypertext is a way to overcome linearity of text corpora.
  • Pure hypertext has the disadavantage of losing the sequentiality of argumentation it was written in.
  • A Zettelkasten is hypertext plus sequentiality, if it has a way to designate sequences of notes.

Table of Contents

  1. tl;dr
  2. Preliminary Remark: Tim Berners-Lee and Hypertext
  3. Zettelkasten
  4. Clarification of terms: Sequentiality vs. Linearity
    1. Definition Attempt:
  5. Disadvantages of pure hypertext corpora
  6. Zettelkasten: Hypertext plus Sequentiality
    1. Keywords as entry points

Preliminary Remark: Tim Berners-Lee and Hypertext

When Tim Berners-Lee (TBL) introduced the technology for the www and hypertext became an easy-to-implement concept for the first time, he criticised several problems with previous solutions for information management and classified these solutions as hierarchical tree systems and keyword catalogues.

He was right. Hierarchical tree systems and traditional index card catalogues have disadvantages and limitations, which can be views as incomplete approaches to overcoming linearity. His solution – Hypertext – overcomes linearity completely.


At first glance, a Zettelkasten as used by Niklas Luhmann is everything that TBL criticises: Sequences of notes, archived in a hierarchical tree structure. And these notes (mainly the beginning of sequences) have keywords.

However, because of the granularity of notes and the ability to link between them, a Zettelkasten is also hypertext. A Zettelkasten is hypertext plus a hierarchical tree structure and keywords.

One could argue that Luhmann's use of keywords and the hierarchy of his note's signatures (e.g. 1/9ca1b4) is just a byproduct of the fact that he implemented a hypertext system with handwritten paper notes.

And some people argue that all we need to implement a Zettelkasten is hypertext (preferably with backlinks). Others disagree and warn not to underestimate the power of the "Folgezettel".

While I do believe that there is not one single right way to do manage your knowledge storage, I believe that the sequentiality of Luhmann's system is more than just an obsolete byproduct, but has value on its own.

Clarification of terms: Sequentiality vs. Linearity

I just used the word sequentiality, which is not to be confused with linearity. So I'll attempt a definition of what I mean:

Definition Attempt:

  • Linearity means that the reader is forced to read the text in a certain order.
  • Sequentiality means that the reader can inspect the thought they're reading came to be in context of other thoughts: a sequence of thoughts.

So hypertext with sequentiality offers the reader the option to follow the author's thoughts in a linear way, but also the option to deviate from that path.

Beyond that, I see a surplus value in hypertext + sequentiality, which can described best by having a look at the disadvantages of pure hypertext corpora.

Disadvantages of pure hypertext corpora

When a hypertext corpus reaches a certain size, certain disadvantages become apparent:

  1. lack of orientation

    Usually, the entry node has various links that refer to other parts of the text. The reader has some idea what is hidden behind the link (if they're semantically labelled and not like this: "click here!"), but they can't know which further links will be found there. In order to get to a certain passage in the text, there can be different paths through the structure of hyperlinks. These paths can lead in circles or result in long detours. Fun Fact: TBL describes this as "feeling lost in hyperspace".

  2. lack of visible "chains" of thoughts

    If we assume that texts contain argumentations, i.e. sequences of statements reasons and conclusions, reading a pure hypertext corpus (depending on the path that has led one to the the current passage), can put the reader in the situation of reading a passage that relies on pieces of argumentation they haven't read yet. Inspecting backlinks might help, but it also might give the reader multiple link sources which have to be searched for the missing piece of argumentation or reasoning.

Pure hypertext corpora try to compensate for this with techniques like sitemaps, full-text search, tagging etc. Most of them don't fully establish sequentiality. And those that do don't emerge automatically by just writing your notes, but have to be maintained (sitemaps, indices etc.).

Zettelkasten: Hypertext plus Sequentiality

Luhmann's concept of a "Folgezettel" (a followup note) is a simple solution. If a given note can have multiple followup notes, but itself can be a followup of only one single other note, the result is full non-linearity (links to various followups and other links can be – well – followed) paired with an unambigous sequentiality:

  • If the reader wants to follow the author's chain of thoughts, they follow the sequence of followups "downwards".
  • If the reader arrived at a thought by other paths (e.g. a manual hyperlink) and needs context to understand what they're reading, they follow the sequence "upwards".

For the author however, it doesn't take much effort, all they do is continue writing in sequence.

Keywords as entry points

Keywords don't have the function of linking related notes in a system like this. They mark useful entry points, mostly the beginning of sequences.

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