xkcd, points out in a recent comic that on Wikipedia, if you take any article and click on the first link not in (parentheses) or italics, then repeat, you eventually end up at the page for "Philosophy". For example, the first link on the page for "Star Wars" is "Space operate", which leads to "Speculative fiction", and so on.
Two sites that follow the links for you are http://ryanelmquist.com/cgi-bin/xkcdwiki and http://www.xefer.com/2011/05/wikipedia.
All the terms I've chosen seem to work. I've created a graph of them below, showing how they all converge on "Philosophy":
My question is: what does the "philosophy" page link to? At this moment, it links to "reason", which links to "rationality", which leads back to "philosophy". This means that all pages eventually end in "reason" or "rationality" as well.
It seems like there must be some deep principle behind this, so I'm going to take a stab at what this is: the Enlightenment.
I don't think this graph defines a "natural law", that philosophy is the basis for all things. Instead, I think this is a cultural artifact, that we in modern, Western culture define everything in terms of philosophy and reason.
For example, the American right wing has created their own "Conservapedia" to combat what they see as left-wing bias in Wikipedia. Those articles don't converge. A tested many terms, and each ended in a loop rather than a "philosophy" or "reason".
Did we do that before the Renaissance/Enlightenment? If we gathered up all pre-Renaissance writings in Europe, filtered just the pages that attempted to "define" or "explain" things, and conducted a similar experience, what would happen? Would they lead to loops? Would they converge on something? I suspect that in pre-Enlightenment Europe or modern Islam, they would converge to religion, not reason.
Or what about ancient Chinese thought? Confucianism is a system of though that's dominated China and the far east for 2500 years. If we applied the same sort of trick, what would everything lead to? Would it be some Confucian principle like "governance" or "duty"?