In this case Jeffrey Winter has turned to JQuery and the InfoViz toolkit and used them to create really nice graphics tree that builds up as the Wikipedia links are followed. You can specify a set of links and the app follows them drawing branches labeled with the subject on a Canvas element.
Of course it is a slightly self-fulfilling prophesy in that the app looks for links to Philosophy and stops when it finds one. Wikipedia isn't a single rooted tree but a more general complex graph for which extracting rooted subtrees should not be a difficult task.
Even so this app seems to have hit a chord and you can expect to see more Wikipedia graph analysis in the near future.
The code is open source and you can download it and modify it to prove that your particular choice of a general subject is the root of all knowledge.
The graphs are also intriguing in the way that they relate subjects together. Try a few subjects and then see if you can think of a subject that adds a substantial number of branches to the tree, i.e. a subject that is maximally distant from the tree you already have - it is harder than it seems.
Another way to spend a lot of time on the subject is to form hypotheses about what topics tends to funnel the references inevitably toward philosophy.
My next project is to find a way of proving the physics is the root of everything...
In the meantime just enjoy the user interface - it really is a nice one.
Try it out: All Roads Lead to Philosophy