The problem with trees 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. Tim Berners-Lee, Seeing With Fresh Eyes A City Is Not a Tree hierarchywww
Cool URIs don't change An Essay by Tim Berners-Lee www.w3.org What makes a cool URI? A cool URI is one which does not change. What sorts of URI change? URIs don't change: people change them. The User Interface of URLs www
The group of blind mullahs In a natural landscape, each element is part of the greater whole, a sophisticated and intricate web of connections and energy flows. If we attempt to create landscapes using a strictly objective viewpoint, we will produce awkward and dysfunctional designs because all living systems are more than just a sum of their parts. Our culture has tried to define the landscape scientifically, by collecting extensive data about its parts. These methods are much like the group of blind mullahs in the Sufi tale, who try to describe an elephant. Bill Mollison, Introduction to Permaculture The blind men who felt the elephantThe blind men and the elephant holismnature