Many systems are organized hierarchically. The CERNDOC documentation system is an example, as is the Unix file system, and the VMS/HELP system. A tree has the practical advantage of giving every node a unique name. However, it does not allow the system to model the real world. For example, in a hierarchical HELP system such as VMS/HELP, one often gets to a lead on a tree such as:
HELP COMPILER SOURCE_FORMAT PRAGMAS DEFAULTS
only to find a reference to another leaf: Please see
HELP COMPILER COMMAND OPTIONS DEFAULTS PRAGMAS
and it is necessary to leave the system and re-enter it. What was needed was a link from one node to another, because in this case the information was not naturally organized into a tree.
This, I think, is the brilliance of Notion, and what makes it one of the best examples of “fidelity to digital information” that I’ve come across. The structure of the app reflects the structure of the web itself: digital content is purposefully formatted, like semantic HTML elements, and exists in a hierarchical structure (directories on the web, nested pages in Notion), yet can be linked and referenced to create a complex network of information. And pages in Notion reveal the structure of the information: when nesting a page within a page, the child page always displays on the parent page. There’s no way to create a child page that doesn’t display on a parent page, no way to obscure the structure of the information. The semantic structure of Notion reflects the semantic structure of the web itself.
Truchet's approach was more topological than geometric, and the qualitative aspects of pattern take priority over the metric ones. His principles provide a kind of metaphor for the hierarchy of separation and connection in all things.
That’s the primary difference between an axiom like “Curiosity Killed The Cat” and an axiom like “You Are Not Your User. ” The former rings true in common experience. It’s test-able, like striking a tuning fork or dangling a bit of yarn in front of a kitten. The latter is just some stuff that somebody said.
Sometimes, axiomatic sayings like “You Are Not Your User” no longer have a who that’s saying them. They cease being an actual instruction, and instead serve as a kind of identity, to identify the person who’s repeating the axiom as One Of Us.
The technical term for when an axiom devolves into an ID card is shibboleth: a custom, principle, or belief distinguishing a particular class or group of people, especially a long-standing one regarded as outmoded or no longer important.