Almost all fields today are concerned in one way or another with hierarchical structure, and a theory, or perhaps more usefully a metaphor, common to all may emerge if the features of many are compared.
Though the units in different fields are different, in all of them meaning comes through communication: patterns of communication are common to all, with aggregation leading to diversity or unity, and the clumps of unity themselves serving in turn as units in larger structrures based on more complex but still direct communication.
I'd been talking about this idea of a conditional art for a very long time, and what I did was actually accomplish it, the idea that there was not a normal structure to it, that every decision had to be intuitive or instinctual or tactile. You decide to go this way or that way, but there was no beginning, no middle, and no end and so there's no hierarchical structure to it at all. And at the end of it, I mean, after you wander for a while, you just ended it yourself because there was no solution to it.
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.
The roji, the garden path which leads from the machiai to the tea room, signified the first stage of meditation—the passage into self-illumination. The roji was intended to break connection with the outside world, and to produce a fresh sensation conducive to the full enjoyment of aestheticism in the tea room itself. One who has trodden this garden path cannot fail to remember how his spirit, as he walked in the twilight of evergreens over the regular irregularities of the stepping stones, beneath which lay dried pine needles, and passed beside the moss-covered granite lanterns, became uplifted above ordinary thoughts. One may be in the midst of a city, and yet feel as if he were in the forest far away from the dust and din of civilization.
...Thus prepared the guest will silently approach the sanctuary, and, if a samurai, will leave his sword on the rack beneath the eaves, the tea room being preeminently the house of peace. Then he will bend low and creep into the room through a small door not more than three feet in height. This proceeding was incumbent on all guests—high and low alike—and was intended to inculcate humility.